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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Siu TC, Imex Aguirre Cardenas M, Seo J, Boctor K, Shimono MG, Tran IT, Carta V, Su TA. Site‐Selective Functionalization of Sila‐Adamantane and Its Ensuing Optical Effects. Angew Chem Int Ed Engl 2022; 61:e202206877. [DOI: 10.1002/anie.202206877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Timothy C. Siu
- Department of Chemistry University of California Riverside CA 92521 USA
| | | | - Jacob Seo
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Kirllos Boctor
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Miku G. Shimono
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Isabelle T. Tran
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Veronica Carta
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Timothy A. Su
- Department of Chemistry University of California Riverside CA 92521 USA
- Materials Science and Engineering Program University of California Riverside CA 92521 USA
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3
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Highly insulating alkane rings with destructive σ-interference. Sci China Chem 2022. [DOI: 10.1007/s11426-022-1341-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Siu TC, Imex Aguirre Cardenas M, Seo J, Boctor K, Shimono MG, Tran IT, Carta V, Su TA. Site‐Selective Functionalization of Sila‐Adamantane and Its Ensuing Optical Effects. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Timothy C. Siu
- Department of Chemistry University of California Riverside CA 92521 USA
| | | | - Jacob Seo
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Kirllos Boctor
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Miku G. Shimono
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Isabelle T. Tran
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Veronica Carta
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Timothy A. Su
- Department of Chemistry University of California Riverside CA 92521 USA
- Materials Science and Engineering Program University of California Riverside CA 92521 USA
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5
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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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6
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Zitz R, Baumgartner J, Marschner C. Chemistry of a 1,5-Oligosilanylene Dianion Containing a Disiloxane Unit. Organometallics 2019; 38:1159-1167. [PMID: 30880866 PMCID: PMC6415795 DOI: 10.1021/acs.organomet.9b00013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Indexed: 11/30/2022]
Abstract
Synthesis of a number of disiloxane containing cyclo- and bicyclooligosilanes is described starting from the dipotassium 1,5-oligosiloxanylene diide derived from 1,3-bis[tris(trimethylsilyl)silyl]tetramethyldisiloxane. In addition, the use of this particular fragment as ligand for zinc and group 4 metallocene complexes was studied. Both types of compounds exhibit marked structural differences compared to related compounds containing Si-Si-Si units instead of the Si-O-Si fragment.
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Affiliation(s)
- Rainer Zitz
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, 8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, 8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, 8010 Graz, Austria
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7
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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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8
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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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9
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Tsurusaki A, Koyama Y, Kyushin S. Decasilahexahydrotriquinacene and Decasilaisotwistane: σ Conjugation on a Bowl Surface. J Am Chem Soc 2017; 139:3982-3985. [PMID: 28192667 DOI: 10.1021/jacs.7b00250] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The first bowl-shaped oligosilane, hexadecamethyldecasilahexahydrotriquinacene (1), and a related oligosilane, hexadecamethyldecasilaisotwistane (2), were synthesized, and their structures and properties were studied. The results revealed importance of σ conjugation on a bowl surface: the HOMOs of 1 are σ orbitals delocalized on the bowl surface, whereas the LUMO is a pseudo π* orbital on the convex and concave sides of the bowl surface.
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Affiliation(s)
- Akihiro Tsurusaki
- Department of Chemistry, Osaka Prefecture University , Sakai, Osaka 599-8531, Japan
| | - Yu Koyama
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University , Kiryu, Gunma 376-8515, Japan
| | - Soichiro Kyushin
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University , Kiryu, Gunma 376-8515, Japan
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10
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Aghazadeh Meshgi M, Baumgartner J, Jouikov VV, Marschner C. Electron Transfer and Modification of Oligosilanylsilatranes and Related Derivatives. Organometallics 2017; 36:342-351. [PMID: 28133409 PMCID: PMC5264216 DOI: 10.1021/acs.organomet.6b00786] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Indexed: 11/29/2022]
Abstract
Several silatranyl -substituted oligosilanes were prepared starting from bis(trimethylsilyl)silatranylsilanide. Electrochemical and theoretical investigations of some oligosilanes revealed that electrooxidation occurs by formation of a short-lived cation radical. This species undergoes structural relaxation to form a pair of conformers, with endo and exo relationships with respect to the Si-N interaction. Reaction of a 1,4-disilatranyl-1,4-disilanide with 1,2-dichlorotetramethyldisilane gave a mixture of cis and trans diastereomers of a cyclohexasilane with the trans isomer showing a diminished Si-N distance.
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Affiliation(s)
| | - Judith Baumgartner
- Institut
für Chemie, Universität Graz, Stremayrgasse 9, 8010 Graz, Austria
| | - Viatcheslav V. Jouikov
- UMR
6226, Chimie et Photonique Moléculaires, Université de Rennes 1, 35042 Rennes, France
| | - Christoph Marschner
- Institut
für Anorganische Chemie, Technische
Universität Graz, Stremayrgasse 9, 8010 Graz, Austria
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11
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Zaitsev KV, Lam K, Zhanabil Z, Suleimen Y, Kharcheva AV, Tafeenko VA, Oprunenko YF, Poleshchuk OK, Lermontova EK, Churakov AV. Oligogermanes Containing Only Electron-Withdrawing Substituents: Synthesis and Properties. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00767] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kirill V. Zaitsev
- Department
of Chemistry, Moscow State University, Leninskye Gory 1, Moscow 119991, Russia
| | - Kevin Lam
- Department
of Chemistry, School of Science and Technology, Nazarbayev University, Astana, Kazakhstan, 010000
| | - Zhaisan Zhanabil
- Department
of Chemistry, School of Science and Technology, Nazarbayev University, Astana, Kazakhstan, 010000
| | - Yerlan Suleimen
- Department
of Chemistry, School of Science and Technology, Nazarbayev University, Astana, Kazakhstan, 010000
| | - Anastasia V. Kharcheva
- Department
of Chemistry, Moscow State University, Leninskye Gory 1, Moscow 119991, Russia
| | - Viktor A. Tafeenko
- Department
of Chemistry, Moscow State University, Leninskye Gory 1, Moscow 119991, Russia
| | - Yuri F. Oprunenko
- Department
of Chemistry, Moscow State University, Leninskye Gory 1, Moscow 119991, Russia
| | - Oleg Kh. Poleshchuk
- National Research Tomsk Polytechnic University, Lenin Avenue, 30, Tomsk 634050, Russia
- Tomsk State Pedagogical University, Kievskaya Street, 60, Tomsk 634061, Russia
| | - Elmira Kh. Lermontova
- Russian Academy of Science, N.S. Kurnakov General and Inorganic Chemistry Institute, Leninskii
pr., 31, Moscow 119991, Russia
| | - Andrei V. Churakov
- Russian Academy of Science, N.S. Kurnakov General and Inorganic Chemistry Institute, Leninskii
pr., 31, Moscow 119991, Russia
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12
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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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13
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Kishimoto Y, Ishida S, Iwamoto T. Ferrocenyl-substituted Bicyclo[1.1.1]pentasilanes: Evaluation of Significant Interactions between Ferrocenyl Units and Rigid Silicon Cages. CHEM LETT 2016. [DOI: 10.1246/cl.151089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Yusuke Kishimoto
- Department of Chemistry, Graduate School of Science, Tohoku University
| | - Shintaro Ishida
- Department of Chemistry, Graduate School of Science, Tohoku University
| | - Takeaki Iwamoto
- Department of Chemistry, Graduate School of Science, Tohoku University
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14
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Abstract
Oligosilanes with attached silatranyl units were obtained by reactions of potassium oligosilanides with a silatranyl triflate. Interaction between Si and N atoms was observed in the 29Si NMR spectra (upfield-shifted SiO3 resonances) and in the solid-state structures (Si-N distances between 2.29 and 2.16 Å). The Si-N interaction can be "switched off" either by protonation of the nitrogen lone pair or by potassium silanide formation caused by trimethylsilyl group cleavage in the presence of potassium tert-butoxide.
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Affiliation(s)
- Mohammad Aghazadeh Meshgi
- Institut für Anorganische Chemie der Technischen Universität Graz and Institut für Chemie, der Karl Franzens Universität Graz , Stremayrgasse 9, 8010 Graz, Austria
| | - Judith Baumgartner
- Institut für Anorganische Chemie der Technischen Universität Graz and Institut für Chemie, der Karl Franzens Universität Graz , Stremayrgasse 9, 8010 Graz, Austria
| | - Christoph Marschner
- Institut für Anorganische Chemie der Technischen Universität Graz and Institut für Chemie, der Karl Franzens Universität Graz , Stremayrgasse 9, 8010 Graz, Austria
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15
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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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16
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Emanuelsson R, Löfås H, Wallner A, Nauroozi D, Baumgartner J, Marschner C, Ahuja R, Ott S, Grigoriev A, Ottosson H. Configuration- and Conformation-Dependent Electronic-Structure Variations in 1,4-Disubstituted Cyclohexanes Enabled by a Carbon-to-Silicon Exchange. Chemistry 2014; 20:9304-11. [DOI: 10.1002/chem.201402610] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Indexed: 11/09/2022]
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17
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Tibbelin J, Wallner A, Emanuelsson R, Heijkenskjöld F, Rosenberg M, Yamazaki K, Nauroozi D, Karlsson L, Feifel R, Pettersson R, Baumgartner J, Ott S, Ottosson H. 1,4-Disilacyclohexa-2,5-diene: a molecular building block that allows for remarkably strong neutral cyclic cross-hyperconjugation. Chem Sci 2014. [DOI: 10.1039/c3sc52389f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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18
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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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19
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