1
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Takeuchi T, Roy A, Ito H. Iterative Synthesis of Oligosilanes Using Methoxyphenyl- or Hydrogen-Substituted Silylboronates as Building Blocks: A General Synthetic Method for Complex Oligosilanes. J Am Chem Soc 2023. [PMID: 37436952 DOI: 10.1021/jacs.3c05385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Organosilanes have attracted the attention of researchers for more than 150 years due to their unique properties, and they have become indispensable industrial assets. However, many synthesized oligosilanes with multiple Si-Si bonds are relatively simple, i.e., they often only contain a single repeating unit. More laborious customized synthetic routes can lead to more complex oligosilanes, but compared to carbon-based molecules, their structural diversity remains limited. The development of effective and practical synthetic routes to complex oligosilanes that contain mixed substituents constitutes a long-standing challenge. Here, we describe an iterative synthesis of oligosilanes using methoxyphenyl- or hydrogen-substituted silylboronates, which were obtained via transition-metal-catalyzed Si-H borylation reactions. The first key reaction is a cross-Si-Si bond-forming reaction between chloro(oligo)silanes and silylboronates activated by MeLi. The second key reaction is the selective chlorination of the methoxyphenyl group or the hydrogen atom at the terminal of the oligosilanes. Iteration of these two key reactions enables the synthesis of various oligosilanes that are otherwise difficult to access. As a demonstration of the synthetic utility of this iterative synthetic approach, oligosilanes with different sequences were prepared by simply changing the order of the reaction of four different silicon units. Furthermore, a bespoke tree-shaped oligosilane is easily obtained via the present iterative synthesis. The solid-state structures of several of these oligosilanes were unequivocally determined using single-crystal X-ray diffraction analysis.
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Affiliation(s)
- Takumi Takeuchi
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Avijit Roy
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Hajime Ito
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
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2
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Kanno KI, Kyushin S. Transition Metal-Catalyzed Selective Functionalization of Oligosilanes without Si-Si Bond Cleavage. J SYN ORG CHEM JPN 2022. [DOI: 10.5059/yukigoseikyokaishi.80.574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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3
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Fang F, Jiang Q, Klausen RS. Poly(cyclosilane) Connectivity Tunes Optical Absorbance. J Am Chem Soc 2022; 144:7834-7843. [PMID: 35467855 DOI: 10.1021/jacs.2c01820] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report herein the influence of skeletal connectivity on the conformation-dependent optical properties of cyclosilane homo- and copolymers. 1,3-Linked cyclosilanes were bathochromically shifted by 20 nm in solution relative to 1,4-linked cyclosilanes, an effect reproduced by quantum chemical calculations on oligomeric model systems. Polysilane optical properties are conformation-dependent, and 1,3-linked cyclosilanes were hypothesized to adopt a favorable conformation unavailable to 1,4-linked cyclosilanes constrained to an endocyclic gauche conformation. Copolymerization of the isomeric cyclosilanes 1,3Si6 and 1,4Si6 afforded linear statistical copolymers, as characterized by 1H and 29Si NMR spectroscopies. The distinct connectivity of each comonomer was found to give rise to tunable absorption spectra, where the position of the absorption band systematically increased with the increased corporation of 1,3Si6. Computational studies pointed to conformation-dependent changes in orbital symmetry in shifting the most intense transition from the low-energy highest occupied molecular orbital (HOMO) → lowest unoccupied molecular orbital (LUMO) transition to a higher-energy HOMO → LUMO + n transition. The results of these studies demonstrate for the first time the role of silicon skeletal connectivity in controlling conformation and optoelectronic properties and provide new insight into the structure-based design of solution-processable silicon-based polymeric materials.
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Affiliation(s)
- Fan Fang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Qifeng Jiang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Rebekka S Klausen
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
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4
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Tsuji H. Carbon-bridged Oligo(phenylenevinylene)s that Reveal Cryogenic Phenomena at Room Temperature. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hayato Tsuji
- Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293
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5
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Koestler B, Bolte M, Lerner HW, Wagner M. Selective One-Pot Syntheses of Mixed Silicon-Germanium Heteroadamantane Clusters. Chemistry 2021; 27:14401-14404. [PMID: 34387917 PMCID: PMC8596519 DOI: 10.1002/chem.202102732] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Indexed: 11/09/2022]
Abstract
Si x Ge y alloys are emerging materials for modern semiconductor technology. Well-defined model systems of the bulk structures aid in understanding their intrinsic characteristics. Three such model clusters have now been realized in the form of the Si x Ge y heteroadamantanes [0] , [1] , and [2] via selective one-pot syntheses starting from Me 2 GeCl 2 , Si 2 Cl 6 , and [nBu 4 N]Cl. Compound [0] contains 6 GeMe 2 and 4 SiSiCl 3 vertices, while one and two of the GeMe 2 groups are replaced by SiCl 2 moieties in compounds [1] and [2] , respectively. Chloride ion-mediated rearrangement quantitatively converts [2] into [1] at room temperature and finally into [0] at 60 °C, which is not only remarkable in view of the rigidity of these cage structures but also sheds light on the assembly mechanism.
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Affiliation(s)
- Benedikt Koestler
- Goethe-Universitat Frankfurt am Main Fachbereich 14 Biochemie Chemie und Pharmazie, Inorganic Chemistry, GERMANY
| | - Michael Bolte
- Goethe-Universitat Frankfurt am Main Fachbereich 14 Biochemie Chemie und Pharmazie, Inorganic Chemistry, GERMANY
| | - Hans-Wolfram Lerner
- Goethe-Universitat Frankfurt am Main Fachbereich 14 Biochemie Chemie und Pharmazie, Inorganic Chemistry, GERMANY
| | - Matthias Wagner
- Goethe Universität, Institut für Anorganische Chemie, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, GERMANY
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6
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Iwamoto T, Yin D, Kobayashi A, Tamura M, Motomatsu D, Akasaka N, Yokouchi Y, Ishida S, Kira M. Lithiated 1,3-Disilabicyclo[1.1.0]butanes Synthesized via Selective Cleavage of Exocyclic Si–Si Bonds on Bridgehead Silicon Atoms. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Takeaki Iwamoto
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Dongzhu Yin
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Akifumi Kobayashi
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Makoto Tamura
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Daiki Motomatsu
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Naohiko Akasaka
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Yuki Yokouchi
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Shintaro Ishida
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Mitsuo Kira
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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7
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Abstract
This article reviews the scope of inorganic cluster compounds interrogated in single-molecule break-junction measurements. This body of work lies at the intersection between the fields of inorganic cluster chemistry and single-molecule electronics, where discrete inorganic cluster molecules are used as the active components in molecular electronic circuitry. We explore the breadth of transition metal and main group cluster compounds that have been studied in single-cluster junctions, largely within the context of scanning tunnelling microscopy break-junction (STM-BJ) measurements. Our discussion centers on how the structure and bonding of inorganic cluster compounds give rise to desirable quantum transport effects such as room-temperature current blockade, sequential tunneling, voltage-gated conductance switching, destructive quantum interference, and high thermoelectric currents.
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Affiliation(s)
- Timothy C Siu
- Department of Chemistry, University of California, Riverside, CA 92521, USA.
| | - Joshua Y Wong
- Department of Chemistry, University of California, Riverside, CA 92521, USA.
| | - Matthew O Hight
- Department of Chemistry, University of California, Riverside, CA 92521, USA.
| | - Timothy A Su
- Department of Chemistry, University of California, Riverside, CA 92521, USA. and Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
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8
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Affiliation(s)
- Vipin B. Kumar
- School of Chemical SciencesUniversity of Auckland 23 Symonds Street Auckland 1010 New Zealand
| | - Erin M. Leitao
- School of Chemical SciencesUniversity of Auckland 23 Symonds Street Auckland 1010 New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology Wellington New Zealand
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9
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Marro EA, Folster CP, Press EM, Im H, Ferguson JT, Siegler MA, Klausen RS. Stereocontrolled Syntheses of Functionalized cis- and trans-Siladecalins. J Am Chem Soc 2019; 141:17926-17936. [PMID: 31600060 DOI: 10.1021/jacs.9b09902] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis of both diastereomers of an all-silicon analog of decalin. Carbocyclic decalin is a ubiquitous bicyclic structural motif. The siladecalin synthesis provides materials functionalized with either Si-Ph or Si-H groups, versatile entry points for further chemical diversification. The synthesis of silicon-stereogenic silanes is significantly less precedented than the synthesis of asymmetric carbon centers, and strategies for control of relative stereochemistry in oligosilanes are hardly described. This study offers insights of potential generality, such as the epimerization of the cis-isomer to the thermodynamically downhill trans-isomer via a hypothesized pentavalent intermediate. Decalin is a classic example in the conformational analysis of organic ring systems, and the carbocyclic diastereomers have highly divergent conformational profiles. Like the carbocycle, we observe different conformational properties in cis- and trans-siladecalins with consequences for NMR spectroscopy, optical properties, and vibrational spectroscopy. This study showcases the utility of targeted synthesis for preparing complex and functionalized polycyclic silanes.
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Affiliation(s)
- Eric A Marro
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Carlton P Folster
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Eric M Press
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Hoyeon Im
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - John T Ferguson
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Maxime A Siegler
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Rebekka S Klausen
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
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10
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Rabanzo-Castillo KM, Hanif M, Söhnel T, Leitao EM. Synthesis, characterisation and electronic properties of naphthalene bridged disilanes. Dalton Trans 2019; 48:13971-13980. [PMID: 31483424 DOI: 10.1039/c9dt03058a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis of naphthalene bridged disilanes 2R (R = Me, Ph) was performed via catalytic dehydrocoupling. Using RhCl(PPh3)3 as a catalyst, an intramolecular Si-Si bond was readily formed from the corresponding disilyl precursors 1R (R = Me, Ph). For catalytic reactions using (C6F5)3B(OH2), bridged siloxanes (3Ph and 3Me) were observed. Attempts to install the 1,8-naphthalene bridge directly onto a disilane resulted in an unusual product (4), containing two silicon centres bridged through one naphthyl group, and another naphthyl group attached to a single Si centre. In order for this product to form, both a Si to Si hydrogen shift rearrangement as well as Si-Si bond cleavage occurred. The effects of phenyl and methyl substitutions on the structure and electronic properties of the synthesised compounds was investigated by single crystal X-ray diffraction, as well as IR and multinuclear NMR spectroscopic analysis. In addition, theoretical UV-Vis absorption maxima were evaluated using density functional theory (TD-SCF) on a B3LYP/6-31(++)G** level of theory and compared with experimental UV-Vis spectroscopic data.
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Affiliation(s)
- Kristel M Rabanzo-Castillo
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand. and The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Muhammad Hanif
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand.
| | - Tilo Söhnel
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand. and The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Erin M Leitao
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand. and The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
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11
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Garner MH, Li H, Neupane M, Zou Q, Liu T, Su TA, Shangguan Z, Paley DW, Ng F, Xiao S, Nuckolls C, Venkataraman L, Solomon GC. Permethylation Introduces Destructive Quantum Interference in Saturated Silanes. J Am Chem Soc 2019; 141:15471-15476. [PMID: 31500410 DOI: 10.1021/jacs.9b06965] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The single-molecule conductance of silanes is suppressed due to destructive quantum interference in conformations with cisoid dihedral angles along the molecular backbone. Yet, despite the structural similarity, σ-interference effects have not been observed in alkanes. Here we report that the methyl substituents used in silanes are a prerequisite for σ-interference in these systems. Through density functional theory calculations, we find that the destructive interference is not evident to the same extent in nonmethylated silanes. We find the same is true in alkanes as the transmission is significantly suppressed in permethylated cyclic and bicyclic alkanes. Using scanning tunneling microscope break-junction method we determine the single-molecule conductance of functionalized cyclohexane and bicyclo[2.2.2]octane that are found to be higher than that of equivalent permethylated silanes. Rather than the difference between carbon and silicon atoms in the molecular backbones, our calculations reveal that it is primarily the difference between hydrogen and methyl substituents that result in the different electron transport properties of nonmethylated alkanes and permethylated silanes. Chemical substituents play an important role in determining the single-molecule conductance of saturated molecules, and this must be considered when we improve and expand the chemical design of insulating organic molecules.
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Affiliation(s)
- Marc H Garner
- Nano-Science Center and Department of Chemistry , University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø , Denmark
| | - Haixing Li
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - Madhav Neupane
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Qi Zou
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Taifeng Liu
- Department of Chemistry , Columbia University , New York , New York 10027 , United States.,The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry , Shanghai Normal University , Shanghai 200234 , China
| | - Timothy A Su
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Zhichun Shangguan
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry , Shanghai Normal University , Shanghai 200234 , China
| | - Daniel W Paley
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Fay Ng
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Shengxiong Xiao
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry , Shanghai Normal University , Shanghai 200234 , China
| | - Colin Nuckolls
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States.,Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Gemma C Solomon
- Nano-Science Center and Department of Chemistry , University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø , Denmark
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12
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Jovanovic M, Michl J. Effect of Conformation on Electron Localization and Delocalization in Infinite Helical Chains [X(CH 3) 2] ∞ (X = Si, Ge, Sn, and Pb). J Am Chem Soc 2019; 141:13101-13113. [PMID: 31306578 DOI: 10.1021/jacs.9b04780] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An intuitive explanation of the effects of conformation (backbone dihedral angle) on electron delocalization in infinite saturated regular helices [(CH3)2]∞Si, [(CH3)2Ge]∞, [(CH3)2Sn]∞, and [(CH3)2Pb]∞ is offered in terms of the simple Ladder C model and confirmed by density functional theory calculations. The effective hole mass, which ranges from near zero to infinity as a function of conformation, is used as a measure of the degree of delocalization and relates to the effects of chain length extension in finite systems. The position of the Fermi level in reciprocal space has a simple counterpart in systems of finite length and is used to characterize the dominant mechanism, σ conjugation (geminal interactions) or σ hyperconjugation (vicinal interactions, through-bond coupling). Constructive or destructive interference of the two mechanisms produces three different delocalization regimes as a function of the backbone dihedral angle and analogy is drawn to polycyclic π-electron systems consisting of fused Hückel or Möbius four-membered rings.
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Affiliation(s)
- Milena Jovanovic
- Department of Chemistry , University of Colorado , Boulder , Colorado 80309-0215 , United States.,Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Flemingovo nám. 1 , 16610 Prague 6 , Czech Republic
| | - Josef Michl
- Department of Chemistry , University of Colorado , Boulder , Colorado 80309-0215 , United States.,Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Flemingovo nám. 1 , 16610 Prague 6 , Czech Republic
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13
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Purkait TK, Press EM, Marro EA, Siegler MA, Klausen RS. Low-Energy Electronic Transition in SiB Rings. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00804] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tapas K. Purkait
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Eric M. Press
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Eric A. Marro
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Maxime A. Siegler
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Rebekka S. Klausen
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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14
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Garner MH, Koerstz M, Jensen JH, Solomon GC. The Bicyclo[2.2.2]octane Motif: A Class of Saturated Group 14 Quantum Interference Based Single-Molecule Insulators. J Phys Chem Lett 2018; 9:6941-6947. [PMID: 30484655 DOI: 10.1021/acs.jpclett.8b03432] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The electronic transmission through σ-conjugated molecules can be fully suppressed by destructive quantum interference, which makes them potential candidates for single-molecule insulators. The first molecule with clear suppression of the single-molecule conductance due to σ-interference was recently found in the form of a functionalized bicyclo[2.2.2]octasilane. Here we continue the search for potential single-molecule insulators based on saturated group 14 molecules. Using a high-throughput screening approach, we assess the electron transport properties of the bicyclo[2.2.2]octane class by systematically varying the constituent atoms between carbon, silicon, and germanium, thus exploring the full chemical space of 771 different molecules. The majority of the molecules in the bicyclo[2.2.2]octane class are found to be highly insulating molecules. Though the all-silicon molecule is a clear-cut case of σ-interference, it is not unique within its class and there are many potential molecules that we predict to be more insulating. The finding of this class of quantum interference based single-molecule insulators indicates that a broad range of highly insulating saturated group 14 molecules are likely to exist.
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15
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Li H, Garner MH, Shangguan Z, Chen Y, Zheng Q, Su TA, Neupane M, Liu T, Steigerwald ML, Ng F, Nuckolls C, Xiao S, Solomon GC, Venkataraman L. Large Variations in the Single-Molecule Conductance of Cyclic and Bicyclic Silanes. J Am Chem Soc 2018; 140:15080-15088. [DOI: 10.1021/jacs.8b10296] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - Marc H. Garner
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Zhichun Shangguan
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Yan Chen
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Qianwen Zheng
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | | | | | - Taifeng Liu
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | | | | | | | - Shengxiong Xiao
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai 200234, China
| | - Gemma C. Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
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16
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Jovanovic M, Michl J. Understanding the Effect of Conformation on Hole Delocalization in Poly(dimethylsilane). J Am Chem Soc 2018; 140:11158-11160. [PMID: 30114903 DOI: 10.1021/jacs.8b05829] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory calculations confirm that the simple explanation of the origin of the striking conformational dependence of σ-electron localization/delocalization in polysilanes offered by the extremely simple Ladder C model is correct.
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Affiliation(s)
- Milena Jovanovic
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309-0215 , United States.,Institute of Organic Chemistry and Biochemistry , Academy of Sciences of the Czech Republic , Flemingovo nám. 2 , 16610 Prague 6, Czech Republic
| | - Josef Michl
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309-0215 , United States.,Institute of Organic Chemistry and Biochemistry , Academy of Sciences of the Czech Republic , Flemingovo nám. 2 , 16610 Prague 6, Czech Republic
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17
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Comprehensive suppression of single-molecule conductance using destructive σ-interference. Nature 2018; 558:415-419. [DOI: 10.1038/s41586-018-0197-9] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 03/15/2018] [Indexed: 11/08/2022]
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18
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Marro EA, Press EM, Siegler MA, Klausen RS. Directional Building Blocks Determine Linear and Cyclic Silicon Architectures. J Am Chem Soc 2018; 140:5976-5986. [DOI: 10.1021/jacs.8b02541] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Eric A. Marro
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Eric M. Press
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Maxime A. Siegler
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Rebekka S. Klausen
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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19
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Topp A, Köckerling M, Reinke H, Miethchen R, Mamat C. Facile Silylation of Cyclitols Using Silyl Bis(triflates). Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Anke Topp
- Institut für Chemie Universität Rostock Albert‐Einstein‐Straße 3a 18059 Rostock Germany
| | - Martin Köckerling
- Institut für Chemie Universität Rostock Albert‐Einstein‐Straße 3a 18059 Rostock Germany
| | - Helmut Reinke
- Institut für Chemie Universität Rostock Albert‐Einstein‐Straße 3a 18059 Rostock Germany
| | - Ralf Miethchen
- Institut für Chemie Universität Rostock Albert‐Einstein‐Straße 3a 18059 Rostock Germany
| | - Constantin Mamat
- Institut für Radiopharmazeutische Krebsforschung Helmholtz‐Zentrum Dresden‐Rossendorf Bautzner Landstraße 400 013228 Dresden Germany
- Fachrichtung Chemie und Lebensmittelchemie TU Dresden 01062 Dresden Germany
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20
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Teichmann J, Wagner M. Silicon chemistry in zero to three dimensions: from dichlorosilylene to silafullerane. Chem Commun (Camb) 2018; 54:1397-1412. [DOI: 10.1039/c7cc09063c] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As one of the simplest examples of functionalized Si(ii) species, the SiCl2/[SiCl3]− system is not only fundamentally interesting, but also an important starting point for the assembly of oligosilane chains, rings, and clusters.
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Affiliation(s)
- J. Teichmann
- Institut für Anorganische Chemie
- Goethe-Universität Frankfurt am Main
- 60438 Frankfurt am Main
- Germany
| | - M. Wagner
- Institut für Anorganische Chemie
- Goethe-Universität Frankfurt am Main
- 60438 Frankfurt am Main
- Germany
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21
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Stella F, Marschner C, Baumgartner J. Incorporating Methyl and Phenyl Substituted Stannylene Units into Oligosilanes. The Influence on Optical Absorption Properties. Molecules 2017; 22:molecules22122212. [PMID: 29231894 PMCID: PMC6149905 DOI: 10.3390/molecules22122212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/16/2022] Open
Abstract
Molecules containing catenated heavy group 14 atoms are known to exhibit the interesting property of σ-bond electron delocalization. While this is well studied for oligo- and polysilanes the current paper addresses the UV-absorption properties of small tin containing oligosilanes in order to evaluate the effects of Sn–Si and Sn–Sn bonds as well as the results of substituent exchange from methyl to phenyl groups. The new stannasilanes were compared to previously investigated oligosilanes of equal chain lengths and substituent pattern. Replacing the central SiMe2 group in a pentasilane by a SnMe2 unit caused a bathochromic shift of the low-energy band (λmax = 260 nm) of 14 nm in the UV spectrum. If, instead of a SnMe2, a SnPh2 unit is incorporated, the bathochromic shift of 33 nm is substantially larger. Keeping the SnMe2 unit and replacing the two central silicon with tin atoms causes shift of the respective band (λ = 286 nm) some 26 nm to the red. A similar approach for hexasilanes where the model oligosilane [(Me3Si)3Si]2(SiMe2)2 (λmax = 253 nm) was modified in a way that the central tetramethyldisilanylene unit was exchanged for a tetraphenyldistannanylene caused a 50 nm bathochromic shift to a low-energy band with λmax = 303 nm.
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Affiliation(s)
- Filippo Stella
- Institute for Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.
| | - Christoph Marschner
- Institute for Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.
| | - Judith Baumgartner
- Institute for Chemistry, Karl-Franzens-University Graz, Stremayrgasse 9, 8010 Graz, Austria.
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22
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Li H, Garner MH, Su TA, Jensen A, Inkpen MS, Steigerwald ML, Venkataraman L, Solomon GC, Nuckolls C. Extreme Conductance Suppression in Molecular Siloxanes. J Am Chem Soc 2017; 139:10212-10215. [DOI: 10.1021/jacs.7b05599] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Haixing Li
- Department
of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Marc H. Garner
- Nano-Science
Center and Department of Chemistry, University of Copenhagen, Universitetsparken
5, 2100 Copenhagen
Ø, Denmark
| | - Timothy A. Su
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Anders Jensen
- Nano-Science
Center and Department of Chemistry, University of Copenhagen, Universitetsparken
5, 2100 Copenhagen
Ø, Denmark
| | - Michael S. Inkpen
- Department
of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | | | - Latha Venkataraman
- Department
of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Gemma C. Solomon
- Nano-Science
Center and Department of Chemistry, University of Copenhagen, Universitetsparken
5, 2100 Copenhagen
Ø, Denmark
| | - Colin Nuckolls
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
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23
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Jovanovic M, Antic D, Rooklin D, Bande A, Michl J. Intuitive Understanding of σ Delocalization in Loose and σ Localization in Tight Helical Conformations of an Oligosilane Chain. Chem Asian J 2017; 12:1250-1263. [DOI: 10.1002/asia.201700226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Milena Jovanovic
- Department of Chemistry and Biochemistry University of Colorado Boulder CO 80309-0215 USA
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Flemingovo nám. 2 16610 Prague 6 Czech Republic
| | - Dean Antic
- Department of Chemistry and Biochemistry University of Colorado Boulder CO 80309-0215 USA
| | - David Rooklin
- Department of Chemistry and Biochemistry University of Colorado Boulder CO 80309-0215 USA
| | - Annika Bande
- Department of Chemistry and Biochemistry University of Colorado Boulder CO 80309-0215 USA
- Institute of Methods for Material Development Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 D-12489 Berlin Germany
| | - Josef Michl
- Department of Chemistry and Biochemistry University of Colorado Boulder CO 80309-0215 USA
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Flemingovo nám. 2 16610 Prague 6 Czech Republic
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24
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Su TA, Li H, Klausen RS, Kim NT, Neupane M, Leighton JL, Steigerwald ML, Venkataraman L, Nuckolls C. Silane and Germane Molecular Electronics. Acc Chem Res 2017; 50:1088-1095. [PMID: 28345881 DOI: 10.1021/acs.accounts.7b00059] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This Account provides an overview of our recent efforts to uncover the fundamental charge transport properties of Si-Si and Ge-Ge single bonds and introduce useful functions into group 14 molecular wires. We utilize the tools of chemical synthesis and a scanning tunneling microscopy-based break-junction technique to study the mechanism of charge transport in these molecular systems. We evaluated the fundamental ability of silicon, germanium, and carbon molecular wires to transport charge by comparing conductances within families of well-defined structures, the members of which differ only in the number of Si (or Ge or C) atoms in the wire. For each family, this procedure yielded a length-dependent conductance decay parameter, β. Comparison of the different β values demonstrates that Si-Si and Ge-Ge σ bonds are more conductive than the analogous C-C σ bonds. These molecular trends mirror what is seen in the bulk. The conductance decay of Si and Ge-based wires is similar in magnitude to those from π-based molecular wires such as paraphenylenes However, the chemistry of the linkers that attach the molecular wires to the electrodes has a large influence on the resulting β value. For example, Si- and Ge-based wires of many different lengths connected with a methyl-thiomethyl linker give β values of 0.36-0.39 Å-1, whereas Si- and Ge-based wires connected with aryl-thiomethyl groups give drastically different β values for short and long wires. This observation inspired us to study molecular wires that are composed of both π- and σ-orbitals. The sequence and composition of group 14 atoms in the σ chain modulates the electronic coupling between the π end-groups and dictates the molecular conductance. The conductance behavior originates from the coupling between the subunits, which can be understood by considering periodic trends such as bond length, polarizability, and bond polarity. We found that the same periodic trends determine the electric field-induced breakdown properties of individual Si-Si, Ge-Ge, Si-O, Si-C, and C-C bonds. Building from these studies, we have prepared a system that has two different, alternative conductance pathways. In this wire, we can intentionally break a labile, strained silicon-silicon bond and thereby shunt the current through the secondary conduction pathway. This type of in situ bond-rupture provides a new tool to study single molecule reactions that are induced by electric fields. Moreover, these studies provide guidance for designing dielectric materials as well as molecular devices that require stability under high voltage bias. The fundamental studies on the structure/function relationships of the molecular wires have guided the design of new functional systems based on the Si- and Ge-based wires. For example, we exploited the principle of strain-induced Lewis acidity from reaction chemistry to design a single molecule switch that can be controllably switched between two conductive states by varying the distance between the tip and substrate electrodes. We found that the strain intrinsic to the disilaacenaphthene scaffold also creates two state conductance switching. Finally, we demonstrate the first example of a stereoelectronic conductance switch, and we demonstrate that the switching relies crucially on the electronic delocalization in Si-Si and Ge-Ge wire backbones. These studies illustrate the untapped potential in using Si- and Ge-based wires to design and control charge transport at the nanoscale and to allow quantum mechanics to be used as a tool to design ultraminiaturized switches.
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Affiliation(s)
- Timothy A. Su
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | - Haixing Li
- Columbia University, Department of Applied Physics
and Applied Math, New York, New York 10027, United States
| | - Rebekka S. Klausen
- Johns Hopkins University, Department of Chemistry, Baltimore, Maryland 21228, United States
| | - Nathaniel T. Kim
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | - Madhav Neupane
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | - James L. Leighton
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | | | - Latha Venkataraman
- Columbia University, Department of Chemistry, New York, New York 10027, United States
- Columbia University, Department of Applied Physics
and Applied Math, New York, New York 10027, United States
| | - Colin Nuckolls
- Columbia University, Department of Chemistry, New York, New York 10027, United States
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25
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Kosai T, Ishida S, Iwamoto T. Pentasila-1,4-diene: Homoconjugation between Si═Si Double Bonds via a SiMe2 Unit. J Am Chem Soc 2016; 139:99-102. [DOI: 10.1021/jacs.6b11912] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomoyuki Kosai
- Department of Chemistry,
Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Shintaro Ishida
- Department of Chemistry,
Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Takeaki Iwamoto
- Department of Chemistry,
Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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26
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Hlina J, Stella F, Aghazadeh Meshgi M, Marschner C, Baumgartner J. σ-Bond Electron Delocalization in Oligosilanes as Function of Substitution Pattern, Chain Length, and Spatial Orientation. Molecules 2016; 21:molecules21081079. [PMID: 27548126 PMCID: PMC6273834 DOI: 10.3390/molecules21081079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 11/16/2022] Open
Abstract
Polysilanes are known to exhibit the interesting property of σ-bond electron delocalization. By employing optical spectroscopy (UV-vis), it is possible to judge the degree of delocalization and also differentiate parts of the molecules which are conjugated or not. The current study compares oligosilanes of similar chain length but different substitution pattern. The size of the substituents determines the spatial orientation of the main chain and also controls the conformational flexibility. The chemical nature of the substituents affects the orbital energies of the molecules and thus the positions of the absorption bands.
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Affiliation(s)
- Johann Hlina
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria.
| | - Filippo Stella
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria.
| | - Mohammad Aghazadeh Meshgi
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria.
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria.
| | - Judith Baumgartner
- Institut für Chemie, Karl Franzens Universität Graz, Stremayrgasse 9, 8010 Graz, Austria.
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27
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Kanazawa Y, Tsuji H, Ehara M, Fukuda R, Casher DL, Tamao K, Nakatsuji H, Michl J. Electronic Transitions in Conformationally Controlled Peralkylated Hexasilanes. Chemphyschem 2016; 17:3010-3022. [DOI: 10.1002/cphc.201600633] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Yuki Kanazawa
- SOKENDAI The Graduate University for Advanced Studies, Nishigonaka, Myodaiji Okazaki 444–8585 Japan
- Institute for Molecular Science and Research Center for Computational Science, Nishigonaka, Myodaiji Okazaki 444–8585 Japan
| | - Hayato Tsuji
- International Research Center for Elements Science (IRCELS) Institute for Chemical Research Kyoto University, Uji Kyoto 611-0011 Japan
- Department of Chemistry Faculty of Science Kanagawa University 2946 Tsuchiya Hiratsuka Kanagawa 259–1293 Japan
| | - Masahiro Ehara
- SOKENDAI The Graduate University for Advanced Studies, Nishigonaka, Myodaiji Okazaki 444–8585 Japan
- Institute for Molecular Science and Research Center for Computational Science, Nishigonaka, Myodaiji Okazaki 444–8585 Japan
- Elements Strategy Initiative for Catalysts and Batteries (ESICB) Kyoto University Kyoto 615–8520 Japan
| | - Ryoichi Fukuda
- Elements Strategy Initiative for Catalysts and Batteries (ESICB) Kyoto University Kyoto 615–8520 Japan
| | - Deborah L. Casher
- Department of Chemistry and Biochemistry University of Colorado at Boulder Boulder Colorado 80309-0215 USA
| | - Kohei Tamao
- International Research Center for Elements Science (IRCELS) Institute for Chemical Research Kyoto University, Uji Kyoto 611-0011 Japan
- RIKEN 2-1 Hirosawa Saitama 351-0198 Japan
| | - Hiroshi Nakatsuji
- Quantum Chemistry Research Institute Goryo Oohara 1–36, Nishikyo-ku Kyoto 615–8245 Japan
| | - Josef Michl
- Department of Chemistry and Biochemistry University of Colorado at Boulder Boulder Colorado 80309-0215 USA
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Flemingovo nám. 2 16610 Prague Czech Republic
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28
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Su TA, Li H, Zhang V, Neupane M, Batra A, Klausen RS, Kumar B, Steigerwald ML, Venkataraman L, Nuckolls C. Single-molecule conductance in atomically precise germanium wires. J Am Chem Soc 2015; 137:12400-5. [PMID: 26373928 DOI: 10.1021/jacs.5b08155] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While the electrical conductivity of bulk-scale group 14 materials such as diamond carbon, silicon, and germanium is well understood, there is a gap in knowledge regarding the conductivity of these materials at the nano and molecular scales. Filling this gap is important because integrated circuits have shrunk so far that their active regions, which rely so heavily on silicon and germanium, begin to resemble ornate molecules rather than extended solids. Here we unveil a new approach for synthesizing atomically discrete wires of germanium and present the first conductance measurements of molecular germanium using a scanning tunneling microscope-based break-junction (STM-BJ) technique. Our findings show that germanium and silicon wires are nearly identical in conductivity at the molecular scale, and that both are much more conductive than aliphatic carbon. We demonstrate that the strong donor ability of C-Ge σ-bonds can be used to raise the energy of the anchor lone pair and increase conductance. Furthermore, the oligogermane wires behave as conductance switches that function through stereoelectronic logic. These devices can be trained to operate with a higher switching factor by repeatedly compressing and elongating the molecular junction.
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Affiliation(s)
- Timothy A Su
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Haixing Li
- Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States
| | - Vivian Zhang
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Madhav Neupane
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Arunabh Batra
- Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States
| | - Rebekka S Klausen
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Bharat Kumar
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Michael L Steigerwald
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Latha Venkataraman
- Department of Chemistry, Columbia University , New York, New York 10027, United States.,Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States
| | - Colin Nuckolls
- Department of Chemistry, Columbia University , New York, New York 10027, United States
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29
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Hlina J, Zitz R, Wagner H, Stella F, Baumgartner J, Marschner C. σ-Bond electron delocalization of branched oligogermanes and germanium containing oligosilanes. Inorganica Chim Acta 2014; 422:120-133. [PMID: 25431502 PMCID: PMC4236089 DOI: 10.1016/j.ica.2014.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 11/13/2022]
Abstract
Oligogermanes and germaoligosilanes isostructural to oligosilanes were synthesized. UV absorption data and X-ray diffraction revealed only marginal differences. Conformational flexibility is directly reflected in the UV absorption spectrum.
In order to evaluate the influence of germanium atoms in oligo- and polysilanes, a number of oligosilane compounds were prepared where two or more silicon atoms were replaced by germanium. While it can be expected that the structural features of thus altered molecules do not change much, the more interesting question is, whether this modification would have a profound influence on the electronic structure, in particular on the property of σ-bond electron delocalization. The UV-spectroscopic comparison of the oligosilanes with germanium enriched oligosilanes and also with oligogermanes showed a remarkable uniform picture. The expected bathochromic shift for oligogermanes and Ge-enriched oligosilanes was observed but its extent was very small. For the low energy absorption band the bathochromic shift from a hexasilane chain (256 nm) to a hexagermane chain with identical substituent patterns (259 nm) amounts to a mere 3 nm.
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Affiliation(s)
- Johann Hlina
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Rainer Zitz
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Harald Wagner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Filippo Stella
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
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30
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Tsuji H, Fogarty HA, Ehara M, Fukuda R, Casher DL, Tamao K, Nakatsuji H, Michl J. Electronic transitions in conformationally controlled tetrasilanes with a wide range of SiSiSiSi dihedral angles. Chemistry 2014; 20:9431-41. [PMID: 25043859 DOI: 10.1002/chem.201403495] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Indexed: 11/08/2022]
Abstract
Unlike π-electron chromophores, the peralkylated n-tetrasilane σ-electron chromophore resembles a chameleon in that its electronic spectrum changes dramatically as its silicon backbone is twisted almost effortlessly from the syn to the anti conformation (changing the SiSiSiSi dihedral angle ω from 0 to 180°). A combination of UV absorption, magnetic circular dichroism (MCD), and linear dichroism (LD) spectroscopy on conformationally controlled tetrasilanes 1-9, which cover fairly evenly the full range of angles ω, permitted a construction of an experimental correlation diagram for three to four lowest valence electronic states. The free chain tetrasilane n-Si4 Me10 (10), normally present as a mixture of three enantiomeric conformer pairs of widely different angles ω, has also been included in our study. The spectral trends are interpreted in terms of avoided crossings of 1B with 2B and 2A with 3A states, in agreement with SAC-CI calculations on the excited states of 1-7 and conformers of 10.
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Affiliation(s)
- Hayato Tsuji
- International Research Center for Elements Science (IRCELS), Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Present address: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,Tokyo 113-0033 (Japan)
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31
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Kanno KI, Niwayama Y, Kyushin S. Selective catalytic monoreduction of dichlorooligosilanes with Grignard reagents. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.10.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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32
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Stueger H, Hasken B, Gross U, Fischer R, Torvisco Gomez A. Synthesis and Properties of Bridgehead-Functionalized Permethylbicyclo[2.2.2]octasilanes. Organometallics 2013; 32:4490-4500. [PMID: 23997386 PMCID: PMC3755819 DOI: 10.1021/om400184y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Indexed: 11/28/2022]
Abstract
A series of previously unknown bridgehead-functionalized bicyclo[2.2.2]octasilanes, Me3Si-Si8Me12-X, X-Si8Me12-X, and X-Si8Me12-Y [X, Y = -SiMe n Ph3-n (n = 1, 2) (2, 3, 10), -SiMe2Fc (Fc = ferrocenyl) (4, 11, 13, 14), -COR (R = Me, tBu) (6, 7, 12), COOMe (8), COOH (9)], have been prepared by the reaction of the silanides Me3Si-Si8Me12-K+ or K+-Si8Me12-K+ with proper electrophiles and fully characterized. The molecular structures of 2, 3, 4, 6, 8, 9, 10, and 13 as determined by single-crystal X-ray diffraction analysis exhibit a slightly twisted structure of the bicyclooctasilane cage. Endocyclic bond lengths, bond angles, and dihedral angles are not influenced considerably by the substituents attached to the bridgehead silicon atoms. Due to σ(SiSi)/π(aryl) conjugation, a 20-30 nm bathochromic shift of the longest wavelength UV absorption band relative to Me3Si-Si8Me12-SiMe3 (1) is evident in the UV absorption spectra of the phenyl and ferrocenyl derivatives. Otherwise, UV absorption data do not support the assumption of aryl/aryl or aryl/C=O interaction via the σ(SiSi) bicyclooctasilane framework.
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Affiliation(s)
- Harald Stueger
- Institute of Inorganic Chemistry, Graz University of
Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Bernd Hasken
- Institute of Inorganic Chemistry, Graz University of
Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Uwe Gross
- Institute of Inorganic Chemistry, Graz University of
Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Roland Fischer
- Institute of Inorganic Chemistry, Graz University of
Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Ana Torvisco Gomez
- Institute of Inorganic Chemistry, Graz University of
Technology, Stremayrgasse 9, A-8010 Graz, Austria
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33
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Suzuki N, Fujiki M, Kimpinde-Kalunga R, Koe JR. Chiroptical Inversion in Helical Si–Si Bond Polymer Aggregates. J Am Chem Soc 2013; 135:13073-9. [DOI: 10.1021/ja405570q] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nozomu Suzuki
- Graduate School of Materials
Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Michiya Fujiki
- Graduate School of Materials
Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Ruth Kimpinde-Kalunga
- Department of Material Science, International Christian University, 3-10-2 Osawa, Mitaka,
Tokyo, 181-8585, Japan
| | - Julian R. Koe
- Department of Material Science, International Christian University, 3-10-2 Osawa, Mitaka,
Tokyo, 181-8585, Japan
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34
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Wallner A, Emanuelsson R, Baumgartner J, Marschner C, Ottosson H. Coupling of Disilane and Trisilane Segments Through Zero, One, Two, and Three Disilanyl Bridges in Cyclic and Bicyclic Saturated Carbosilanes. Organometallics 2013. [DOI: 10.1021/om3006678] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas Wallner
- Department
of Chemistry-BMC, Uppsala University, Box 576, SE-75123 Uppsala, Sweden
| | - Rikard Emanuelsson
- Department
of Chemistry-BMC, Uppsala University, Box 576, SE-75123 Uppsala, Sweden
| | - Judith Baumgartner
- Institut für Anorganische
Chemie, Technische Universität Graz, A-8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische
Chemie, Technische Universität Graz, A-8010 Graz, Austria
| | - Henrik Ottosson
- Department
of Chemistry-BMC, Uppsala University, Box 576, SE-75123 Uppsala, Sweden
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Wagner H, Baumgartner J, Marschner C. Rearrangement/Fragmentation Reactions of Oligosilanes with Aluminum Chloride. Organometallics 2011; 30:3939-3954. [PMID: 21818171 PMCID: PMC3148123 DOI: 10.1021/om1011165] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Indexed: 11/28/2022]
Abstract
Reinvestigation of the Lewis acid catalyzed rearrangement of some open-chain permethyloligosilanes with the Al(Fe)Cl(3) catalyst system exhibited several cases of additional reactivity: namely, a fragmentation/cyclization reaction. Introduction of (trimethylsilyl)methyl substituents into the oligosilane substrates strongly facilitated this reaction, yielding cyclic or bicyclic carbacyclosilanes. Investigations concerning the composition of the catalyst system indicated that the incorporation of about 0.1% FeCl(3) into the AlCl(3) lattice provided an effective catalyst.
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Affiliation(s)
- Harald Wagner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
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Wallner A, Hlina J, Wagner H, Baumgartner J, Marschner C. Conformational Control of Polysilanes: Use of CH(2) Spacers in the Silicon Backbone. Organometallics 2011; 30:3930-3938. [PMID: 21818170 PMCID: PMC3148124 DOI: 10.1021/om1011159] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Indexed: 11/29/2022]
Abstract
By the reaction of a number of oligosilyl potassium compounds with (trimethylsilyl)chloromethane, derivatives containing the (trimethylsilyl)methyl substituent were prepared. Using X-ray single-crystal structure analysis and UV spectroscopy the conformational properties of some of the compounds were studied. It was found that the (trimethylsilyl)methylated examples exhibit UV absorption properties which correspond to lower energy transitions in comparison to those of analogous trimethylsilylated molecules. The influence of this effect decreases, however, with increasing chain lengths.
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Affiliation(s)
- Andreas Wallner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Johann Hlina
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Harald Wagner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, A-8010 Graz, Austria
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Zhao L, Duan XM, Xue XG, Li MH, Li ZS. Self-assembled monolayers of oligosilane on the silicon (001) surface: molecular dynamics simulations. J Mol Model 2010; 17:721-6. [DOI: 10.1007/s00894-010-0774-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Accepted: 05/28/2010] [Indexed: 10/19/2022]
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Wallner A, Hlina J, Konopa T, Wagner H, Baumgartner J, Marschner C, Flörke U. Cyclic and Bicyclic Methylpolysilanes and Some Oligosilanylene-Bridged Derivatives. Organometallics 2010. [DOI: 10.1021/om901104h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas Wallner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Johann Hlina
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Tina Konopa
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Harald Wagner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Ulrich Flörke
- Anorganische und Analytische Chemie, Universität Paderborn, Warburger Strasse 100 D-33098 Paderborn, Germany
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Bande A, Michl J. Conformational dependence of sigma-electron delocalization in linear chains: permethylated oligosilanes. Chemistry 2009; 15:8504-8517. [PMID: 19658142 DOI: 10.1002/chem.200901521] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effects of sigma-electron delocalization on optical properties of saturated linear chains of permethylated oligosilanes are strongly conformation dependent. We analyze the origin of the conformational dependence of the energies of molecular orbitals and of electronic excitations in simple intuitively understandable terms by using a first-order approximation to the Hückel version of the "Ladder C" model. The analysis is supported by comparison with results of numerical calculations from time-dependent density functional theory, which agree well with experiment. To facilitate the comparison, a simple procedure has been developed that defines the overall and local fractional sigma and pi characters of a backbone molecular orbital and a fractional overall and local sigma sigma* and sigma pi* characters of an excited state for any conformation of a linear chain.
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Affiliation(s)
- Annika Bande
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
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George CB, Ratner MA, Lambert JB. Strong Conductance Variation in Conformationally Constrained Oligosilane Tunnel Junctions. J Phys Chem A 2009; 113:3876-80. [DOI: 10.1021/jp809963r] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Mark A. Ratner
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Joseph B. Lambert
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
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Zirngast M, Baumgartner J, Marschner C. Synthesis of Cyclic and Bicyclic Polysilanes of Variable Ring Sizes. Organometallics 2008. [DOI: 10.1021/om800842p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michaela Zirngast
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
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Wallner A, Wagner H, Baumgartner J, Marschner C, Rohm HW, Köckerling M, Krempner C. Structure, Conformation, and UV Absorption Behavior of Partially Trimethylsilylated Oligosilane Chains. Organometallics 2008. [DOI: 10.1021/om8004383] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas Wallner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Harald Wagner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Henning W. Rohm
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Martin Köckerling
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Clemens Krempner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria, and Department of Chemistry, University of Rostock, A.-Einstein-Str. 3a, D-18059 Rostock, Germany
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Strohmann C, Däschlein C, Kellert M, Auer D. Ein hoch enantiomerenangereichertes Lithiosilan durch selektive Spaltung einer Silicium-Phenyl-Bindung mit Lithium. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604636] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Strohmann C, Däschlein C, Kellert M, Auer D. A Highly Enantiomerically Enriched Lithiosilane by Selective Cleavage of a Silicon–Phenyl Bond with Lithium. Angew Chem Int Ed Engl 2007; 46:4780-2. [PMID: 17516593 DOI: 10.1002/anie.200604636] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carsten Strohmann
- Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Sandström N, Piqueras MC, Ottosson H, Crespo R. Electronic excitations of 1,4-disilyl-substituted 1,4-disilabicycloalkanes: a MS-CASPT2 study of the influence of cage size. J Phys Chem A 2007; 111:2804-10. [PMID: 17388376 DOI: 10.1021/jp070010n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a multistate complete active space second-order perturbation theory computational study aimed to predict the low-lying electronic excitations of four compounds that can be viewed as two disilane units connected through alkane bridges in a bicyclic cage. The analysis has focused on 1,4-disilyl-1,4-disilabicyclo[2.2.1]heptane (1a), 1,4-bis(trimethylsilyl)-1,4-disilabicyclo[2.2.1]heptane (1b), 1,4-disilyl-1,4-disilabicyclo[2.1.1]hexane (2a), and 1,4-bis(trimethylsilyl)-1,4-disilabicyclo[2.1.1]hexane (2b). The aim has been to find out the nature of the lowest excitations with significant oscillator strengths and to investigate how the cage size affects the excitation energies and the strengths of the transitions. Two different substituents on the terminal silicon atoms (H and CH3) were used in order to investigate the end group effects. The calculations show that the lowest allowed excitations are of the same character as that found in disilanes but now red-shifted. As the cage size is reduced from a 1,4-disilabicyclo[2.2.1]heptane to a 1,4-disilabicyclo[2.1.1]hexane, the Si...Si through-space distance decreases from approximately 2.70 to 2.50 A and the lowest allowed transitions are red-shifted by up to 0.9 eV, indicating increased interaction between the two Si-Si bonds. The first ionization potential, which corresponds to ionization from the Si-Si sigma orbitals, is lower in 1b and 2b than in Si2Me6 by approximately 0.9 and 1.2 eV, respectively. Moreover, 1b and 2b, which have methyl substituents at the terminal Si atoms, have slightly lower excitation energies than the analogous species 1a and 2a.
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Affiliation(s)
- Niclas Sandström
- Department of Biochemistry and Organic Chemistry, Box 576, Uppsala University, 751 23 Uppsala, Sweden
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Krempner C, Reinke H. An Approach to Dendritic Oligosilanes: Controlling the Conformation through Ring Formation. Organometallics 2007. [DOI: 10.1021/om060964k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Krempner
- Institut für Chemie der Universität Rostock, A.-Einstein-Strasse 3a, D-18059 Rostock, Germany
| | - H. Reinke
- Institut für Chemie der Universität Rostock, A.-Einstein-Strasse 3a, D-18059 Rostock, Germany
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Affiliation(s)
- Thomas Baumgartner
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
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Shibano Y, Sasaki M, Tsuji H, Araki Y, Ito O, Tamao K. Conformation effect of oligosilane linker on photoinduced electron transfer of tetrasilane-linked zinc porphyrin–[60]fullerene dyads. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2006.05.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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