1
|
Dhara D, Endres L, Krummenacher I, Arrowsmith M, Dewhurst RD, Engels B, Bertermann R, Finze M, Demeshko S, Meyer F, Fantuzzi F, Braunschweig H. Synthesis and Reactivity of a Dialane-Bridged Diradical. Angew Chem Int Ed Engl 2024; 63:e202401052. [PMID: 38415886 DOI: 10.1002/anie.202401052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/29/2024]
Abstract
Radicals of the lightest group 13 element, boron, are well established and observed in numerous forms. In contrast to boron, radical chemistry involving the heavier group 13 elements (aluminum, gallium, indium, and thallium) remains largely underexplored, primarily attributed to the formidable synthetic challenges associated with these elements. Herein, we report the synthesis and isolation of planar and twisted conformers of a doubly CAAC (cyclic alkyl(amino)carbene)-radical-substituted dialane. Extensive characterization through spectroscopic analyses and X-ray crystallography confirms their identity, while quantum chemical calculations support their open-shell nature and provide further insights into their electronic structures. The dialane-connected diradicals exhibit high susceptibility to oxidation, as evidenced by electrochemical measurements and reactions with o-chloranil and a variety of organic azides. This study opens a previously uncharted class of dialuminum systems to study, broadening the scope of diradical chemistry and its potential applications.
Collapse
Affiliation(s)
- Debabrata Dhara
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Lukas Endres
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Physical and Theoretical Chemistry Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Merle Arrowsmith
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maik Finze
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Felipe Fantuzzi
- School of Chemistry and Forensic Science, University of Kent, Canterbury, Park Wood Rd, CT2 7NH, United Kingdom
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| |
Collapse
|
2
|
Ebeler F, Neumann B, Stammler HG, Ghadwal RS. Divergent Reactivity of a Cyclic Bis-Hydridostannylene: A Masked Sn(I) Diradicaloid. Chemistry 2024; 30:e202400382. [PMID: 38294490 DOI: 10.1002/chem.202400382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/01/2024]
Abstract
Herein, reactivity studies of a cyclic bis-hydridostannylene [(ADC)SnH]2 (1-H2) (ADC=PhC{(NDipp)C}2; Dipp=2,6-iPr2C6H3) with various unsaturated organic substrates are reported. Reactions of terminal alkynes (RC≡CH) with 1-H2 afford mixed acetylide-vinyl-functionalized bis-stannylenes via dehydrogenation and hydrostannylation. Treatment of 1-H2 with PhC≡CCH3 gives a unique distannabarrelene via dehydrogenative C(sp3)-H stannylation and hydrostannylation of the C≡CCH3 moiety. 1-H2 undergoes dehydrogenative [2+2]-cycloaddition reactions with diphenylacetylene, azobenzene, acetone, benzophenone, and benzaldehyde to form the 1,4-distannabarrelene derivatives. The elimination of H2 in these reactions suggests the masked-diradical property of 1-H2. In fact, these [2+2]-cycloaddition products are also accessible on treatments of the Sn(I) diradicaloid [(ADC)Sn]2 (1) with appropriate reagents. All compounds have been characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. Moreover, the catalytic activity of 1-H2 has been shown for the hydroboration of unsaturated substrates.
Collapse
Affiliation(s)
- Falk Ebeler
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany
| | - Beate Neumann
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany
| | - Hans-Georg Stammler
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany
| | - Rajendra S Ghadwal
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany
| |
Collapse
|
3
|
Li S, Chen J. Synthesis and Properties of Novel Alkyl-Substituted Hexaazacyclophanes and Their Diradical Dications. Molecules 2024; 29:789. [PMID: 38398541 PMCID: PMC10893516 DOI: 10.3390/molecules29040789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Radicals based on arylamine cyclophanes can be used as functional materials and show application potential in fields such as synthetic chemistry, molecular electronic components, organic light-emitting diodes, and catalytic chemistry. Using a Buchwald-Hartwig palladium-catalyzed aryl halide amination method, we synthesized a series of neutral hexaazacyclophane compounds 1-3 with different substituents in the meta-meta-meta positions of the phenyl rings. Three characteristic high-spin hexaazacyclophane diradical dications were obtained by two-electron oxidation using AgSbF6: 12·+•2[SbF6]-, 22·+•2[SbF6]-, and 32·+•2[SbF6]-. The electronic structures and physical properties of these compounds were then investigated by 1H and 13C nuclear magnetic resonance spectroscopy, cyclic voltammetry, electron paramagnetic resonance spectroscopy, superconducting quantum interferometry, ultraviolet-visible spectroscopy, and density functional theory calculations. The findings provide new ideas for designing radical species with novel physical properties and electronic structures. Importantly, the obtained radical species are not sensitive to air, making them valuable functional materials for practical applications.
Collapse
Affiliation(s)
- Shunjie Li
- College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China
| | - Jian Chen
- College of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China
| |
Collapse
|
4
|
Choi Y, Min K, Han N, Tae G, Kim DY. Novel Application of NIR-I-Absorbing Quinoidal Conjugated Polymer as a Photothermal Therapeutic Agent. ACS Appl Mater Interfaces 2023; 15:39117-39126. [PMID: 37551880 DOI: 10.1021/acsami.3c06807] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Conjugated polymer nanoparticles (CP NPs) that could absorb the first near-infrared (NIR-I) window have emerged as highly desirable therapeutic nanomaterials. Here, a quinoidal-conjugated polymer (QCP), termed PQ, was developed as a novel class of therapeutic agents for photothermal therapy (PTT). Owing to its intrinsic quinoid structure, PQ exhibits molecular planarity and π-electron overlap along the conjugated backbone, endowing it with a narrow band gap, NIR-I absorption, and diradical features. The obtained PQ was coated with a poly(ethylene glycol) (PEG) moiety, affording nanosized and water-dispersed PQ nanoparticles (PQ NPs), which consequently show a high photothermal conversion efficiency (PCE) of 63.2%, good photostability, and apparent therapeutic efficacy for both in vitro and in vivo PTTs under an 808 nm laser irradiation. This study demonstrates that QCPs are promising active agents for noninvasive anticancer therapy using NIR-I light.
Collapse
Affiliation(s)
- Yeonsu Choi
- School of Materials Science and Engineering, Heeger Center for Advanced Materials (HCAM), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Kiyoon Min
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Nara Han
- School of Materials Science and Engineering, Heeger Center for Advanced Materials (HCAM), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Giyoong Tae
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Dong-Yu Kim
- School of Materials Science and Engineering, Heeger Center for Advanced Materials (HCAM), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| |
Collapse
|
5
|
Fischer I, Hemberger P. Photoelectron Photoion Coincidence Spectroscopy of Biradicals. Chemphyschem 2023; 24:e202300334. [PMID: 37325876 DOI: 10.1002/cphc.202300334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
The electronic structure of biradicals is characterized by the presence of two unpaired electrons in degenerate or near-degenerate molecular orbitals. In particular, some of the most relevant species are highly reactive, difficult to generate cleanly and can only be studied in the gas phase or in matrices. Unveiling their electronic structure is, however, of paramount interest to understand their chemistry. Photoelectron photoion coincidence (PEPICO) spectroscopy is an excellent approach to explore the electronic states of biradicals, because it enables a direct correlation between the detected ions and electrons. This permits to extract unique vibrationally resolved photoion mass-selected threshold photoelectron spectra (ms-TPES) to obtain insight in the electronic structure of both the neutral and the cation. In this review we highlight most recent advances on the spectroscopy of biradicals and biradicaloids, utilizing PEPICO spectroscopy and vacuum ultraviolet (VUV) synchrotron radiation.
Collapse
Affiliation(s)
- Ingo Fischer
- Julius-Maximilians-Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Am Hubland, D-97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland
| |
Collapse
|
6
|
Dai JW, Li YQ, Li ZY, Zhang HT, Herrmann C, Kumagai S, Damjanović M, Enders M, Nojiri H, Morimoto M, Hoshino N, Akutagawa T, Yamashita M. Dual-radical-based molecular anisotropy and synergy effect of semi-conductivity and valence tautomerization in a photoswitchable coordination polymer. Natl Sci Rev 2023; 10:nwad047. [PMID: 37476568 PMCID: PMC10354699 DOI: 10.1093/nsr/nwad047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/05/2022] [Accepted: 12/27/2022] [Indexed: 07/22/2023] Open
Abstract
Organic radicals are widely used as linkers or ligands to synthesize molecular magnetic materials. However, studies regarding the molecular anisotropies of radical-based magnetic materials and their multifunctionalities are rare. Herein, a photoisomerizable diarylethene ligand was used to form {[CoIII(3,5-DTSQ·-)(3,5-DTCat2-)]2(6F-DAE-py2)}·3CH3CN·H2O (o-1·3CH3CN·H2O, 6F-DAE-py2 = 1,2-bis(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene), a valence-tautomeric (VT) coordination polymer. We directly observed dual radicals for a single crystal using high-field/-frequency (∼13.3 T and ∼360 GHz) electron paramagnetic resonance (EPR) spectroscopy along the c-axis, which was further confirmed by angle-dependent Q-band EPR spectroscopy. Moreover, a conductive anomaly close to the VT transition temperature was observed only when probes were attached at the ab plane of the single crystal, indicative of synergy between valence tautomerism and conductivity. Structural anisotropy studies and density functional theory (DFT) calculations revealed that this synergy is due to electron transfer associated with valence tautomerism. This study presents the first example of dual-radical-based molecular anisotropy and charge-transfer-induced conductive anisotropy in a photoswitchable coordination polymer.
Collapse
Affiliation(s)
| | | | | | - Hai-Tao Zhang
- Institute of Inorganic and Applied Chemistry, University of Hamburg, Hamburg22761, Germany
| | - Carmen Herrmann
- Institute of Inorganic and Applied Chemistry, University of Hamburg, Hamburg22761, Germany
| | - Shohei Kumagai
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai980-8578, Japan
| | - Marko Damjanović
- Institute of Inorganic Chemistry, University of Heidelberg, HeidelbergD-69120, Germany
| | - Markus Enders
- Institute of Inorganic Chemistry, University of Heidelberg, HeidelbergD-69120, Germany
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Sendai980-8577, Japan
| | | | - Norihisa Hoshino
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai980-8577, Japan
| | - Tomoyuki Akutagawa
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai980-8577, Japan
| | | |
Collapse
|
7
|
Miyazawa Y, Wang Z, Hatano S, Takagi R, Matsuoka H, Amamizu N, Kitagawa Y, Kayahara E, Yamago S, Abe M. Generation and Characterization of a Tetraradical Embedded in a Curved Cyclic Paraphenylene Unit. Chemistry 2023:e202301009. [PMID: 37132401 DOI: 10.1002/chem.202301009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/01/2023] [Accepted: 05/02/2023] [Indexed: 05/04/2023]
Abstract
Unique spin-spin (magnetic) interactions, ring-size effects on ground-state spin multiplicity, and in-plane aromaticity has been found in localized 1,3-diradicals embedded in curved benzene structures such as cycloparaphenylene (CPP). In this study, we characterized the magnetic interactions in a tetraradical consisting of two localized 1,3-diradical units connected by p-quaterphenyl within a curved CPP skeleton by electron paramagnetic resonance (EPR) spectroscopy and quantum chemical calculations. Persistent triplet species with zero-field splitting parameters similar to those of a triplet 1,3-diphenylcyclopentane-1,3-diyl diradical were observed by continuous wave (CW) or pulsed X-band EPR measurements. The quintet state derived from the ferromagnetic interaction between the two triplet diradical moieties was not detected at 20 K under glassy matrix conditions. At the B3LYP/6-31G(d) level of theory, the singlet state was lower in energy than the triplet and quintet states. These findings will aid in the development of open-shell species for material science application.
Collapse
Affiliation(s)
- Yuki Miyazawa
- Hiroshima University: Hiroshima Daigaku, Department of Chemistry, JAPAN
| | - Zhe Wang
- Hiroshima University: Hiroshima Daigaku, Department of Chemistry, JAPAN
| | - Sayaka Hatano
- Hiroshima University: Hiroshima Daigaku, Department of Chemistry, JAPAN
| | - Ryukichi Takagi
- Hiroshima University: Hiroshima Daigaku, Department of Chemistry, JAPAN
| | - Hideto Matsuoka
- Osaka Metropolitan University: Osaka Koritsu Daigaku, Department of Chemistry, JAPAN
| | - Naoka Amamizu
- Osaka University: Osaka Daigaku, Department of Chemistry, JAPAN
| | | | - Eiichi Kayahara
- Kyoto University: Kyoto Daigaku, Institute for Chemical Research, JAPAN
| | - Shigeru Yamago
- Kyoto University: Kyoto Daigaku, Institute for Chemical Research, JAPAN
| | - Manabu Abe
- Hiroshima University, Department of Chemistry, Kagamiyama 1-3-1, 739-8526, Higashi-Hiroshima City, JAPAN
| |
Collapse
|
8
|
Li X, Zhang D, Yin C, Lu G, Wan Y, Huang Z, Tan J, Li S, Luo J, Lee CS. A Diradicaloid Small Molecular Nanotheranostic with Strong Near-Infrared Absorbance for Effective Cancer Photoacoustic Imaging and Photothermal Therapy. ACS Appl Mater Interfaces 2021; 13:15983-15991. [PMID: 33788531 DOI: 10.1021/acsami.0c21889] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Organic small molecule-based phototheranostics hold great promise for clinical translation by virtue of their distinct chemical structure, easy reproducibility, and high purity. However, reported molecular agents typically have relatively low optical absorbances, particularly over the near-infrared (NIR) region, and this limits their phototheranostic performance. Herein, we first exploit a diradicaloid molecular structure for enhancing NIR absorption to facilitate efficient photoacoustic imaging (PAI)-guided photothermal therapy (PTT). The donor-acceptor interaction in the diradicaloid molecule (DRM) leads to strong charge transfer resulting on obvious diradical characteristics, which is beneficial for NIR absorption. The DRM possesses excellent light-harvesting ability, with a mass extinction coefficient of ∼220 L g-1 cm-1, which is much higher than those (∼5-100 L g-1 cm-1) of typical organic molecules. After assembling into nanoparticles, they show good water dispersibility, good photostability, and impressive performance for PAI-guided PTT in vitro and in vivo. The impressive in vitro and in vivo performances show that developing small molecules with diradicaloid structures can be an effective approach for enhancing NIR harvesting capability for biomedical applications.
Collapse
Affiliation(s)
- Xiaozhen Li
- Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
| | - Di Zhang
- Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, P.R. China
| | - Chao Yin
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, P.R. China
| | - Guihong Lu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, 1 North 2nd Street, Zhong Guan Cun, Beijing 100190, P.R. China
| | - Yingpeng Wan
- Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
| | - Zhongming Huang
- Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
| | - Jihua Tan
- Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
| | - Shengliang Li
- Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
- College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, P.R. China
| | - Jingdong Luo
- Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, P.R. China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF), Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, P.R. China
| |
Collapse
|
9
|
Sharma MK, Rottschäfer D, Glodde T, Neumann B, Stammler HG, Ghadwal RS. An Open-Shell Singlet Sn I Diradical and H 2 Splitting. Angew Chem Int Ed Engl 2021; 60:6414-6418. [PMID: 33460280 PMCID: PMC7986611 DOI: 10.1002/anie.202017078] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Indexed: 11/17/2022]
Abstract
The first SnI diradical [(ADCPh)Sn]2 (4) based on an anionic dicarbene (ADCPh={CN(Dipp)}2CPh; Dipp=2,6‐iPr2C6H3) scaffold has been isolated as a green crystalline solid by KC8 reduction of the corresponding bis‐chlorostannylene [(ADCPh)SnCl]2 (3). The six‐membered C4Sn2‐ring of 4 containing six π‐electrons shows a diatropic ring current, thus 4 may also be regarded as the first 1,4‐distannabenzene derivative. DFT calculations suggest an open‐shell singlet (OS) ground state of 4 with a remarkably small singlet–triplet energy gap (ΔEOS–T=4.4 kcal mol−1), which is consistent with CASSCF (ΔES–T=6.6 kcal mol−1 and diradical character y=37 %) calculations. The diradical 4 splits H2 at room temperature to yield the bis‐hydridostannylene [(ADCPh)SnH]2 (5). Further reactivity of 4 has been studied with PhSeSePh and MeOTf.
Collapse
Affiliation(s)
- Mahendra K Sharma
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Dennis Rottschäfer
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Timo Glodde
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Beate Neumann
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Hans-Georg Stammler
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| | - Rajendra S Ghadwal
- Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany
| |
Collapse
|
10
|
da Silva Filho AJ, da Cruz Dantas L, de Santana OL. Diradicalar Character and Ring Stability of Mesoionic Heterocyclic Oxazoles and Thiazoles by Ab Initio Mono and Multi-Reference Methods. Molecules 2020; 25:molecules25194524. [PMID: 33023193 PMCID: PMC7582729 DOI: 10.3390/molecules25194524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 11/16/2022] Open
Abstract
Mesoionics are neutral compounds that cannot be represented by a fully covalent or purely ionic structure. Among the possible mesomeric structures of these compounds are the diradical electronic configurations. Theoretical and experimental studies indicate that some mesoionic rings are unstable, which may be related to a significant diradical character, that until then is not quantified. In this work, we investigated the diradical character of four heterocycles: 1,3-oxazol-5-one, 1,3-oxazol-5-thione, 1,3-thiazole-5-one, and 1,3-thiazole-5-thione. The oxazoles are known to be significatively less stable than thiazoles. DFT and ab initio single (B3LYP, MP2, CCSD, and QCISD) and ab initio multi-reference (MR-CISD) methods with three basis sets (6-311+G(d), aug-cc-pVDZ, and aug-cc-pVTZ) were employed to assess the diradical character of the investigated systems, in gas phase and DMSO solvent, from three criteria: (i) HOMO-LUMO energy gap, (ii) determination of energy difference between singlet and triplet wave functions, and (iii) quantification of the most significant diradical character (y0, determined in the unrestricted formalism). All of the results showed that the diradical character of the investigated systems is very small. However, the calculated electronic structures made it possible to identify the possible origin of the oxazoles instability, which can help the design of mesoionic systems with the desired properties.
Collapse
|
11
|
Abstract
By virtue of multitunable spin structures upon designing the π-electron topologies, phenalenyl-based nanographenes are of substantial interest in fundamental science and for potential applications in spintronics. Heptauthrene, as one of the well-known phenalenyl diradicals, is composed of one benzene-fused bisphenalenyls in mirror symmetry and expected to have a triplet ground state. However, the synthesis of unsubstituted heptauthrene remains very challenging due to the high reactivity of triplet diradicals. Here, we report a combined in-solution and on-surface synthesis of unsubstituted heptauthrene, whose chemical structure is characterized through bond-resolved atomic force microscopy. Combined with mean-field Hubbard model calculations, its triplet ground state is unambiguously confirmed by the underscreened Kondo resonance in response to the magnetic field, as well as the engineered spin-state switching upon extra hydrogen atom addition and dissociation on the radical site. Our results provide access to phenalenyl-based nanographenes with high-spin ground state, potentially useful in constructing high-spin networks.
Collapse
Affiliation(s)
- Xuelei Su
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Can Li
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qingyang Du
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Kun Tao
- Key Lab for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, 730000 LanZhou, China
| | - Shiyong Wang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ping Yu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| |
Collapse
|
12
|
Gil-Guerrero S, Peña-Gallego Á, Ramos-Berdullas N, Martín Pendás Á, Mandado M. Assessing the Reversed Exponential Decay of the Electrical Conductance in Molecular Wires: The Undeniable Effect of Static Electron Correlation. Nano Lett 2019; 19:7394-7399. [PMID: 31525054 DOI: 10.1021/acs.nanolett.9b03063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An extraordinary new family of molecular junctions, inaccurately referred to as "anti-Ohmic" wires in the recent literature, has been proposed based on theoretical predictions. The unusual electron transport observed for these systems, characterized by a reversed exponential decay of their electrical conductance, might revolutionize the design of molecular electronic devices. This behavior, which has been associated with intrinsic diradical nature, is reexamined in this work. Since the diradical character arises from a near-degeneracy of the frontier orbitals, the employment of a multireference approach is mandatory. CASSCF calculations on a set of nanowires based on polycyclic aromatic hydrocarbons (PAHs) demonstrate that, in the frame of an appropriate multireference treatment, the ground state of these systems shows the expected exponential decay of the conductance. Interestingly, these calculations do evidence a reversed exponential decay of the conductance, although now in several excited states. Similar results have been obtained for other recently proposed candidates to "anti-Ohmic" wires. These findings open new horizons for possible applications in molecular electronics of these promising systems.
Collapse
Affiliation(s)
- Sara Gil-Guerrero
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
| | - Ángeles Peña-Gallego
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
| | - Nicolás Ramos-Berdullas
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
- Institute of Theoretical Chemistry , University of Vienna , Währinger Str. 17 , 1090 Vienna , Austria
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry , University of Oviedo , Calle Julián Clavería 8 , 33006 Oviedo , Spain
| | - Marcos Mandado
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
| |
Collapse
|
13
|
Ortiz R, Boto RA, García-Martínez N, Sancho-García JC, Melle-Franco M, Fernández-Rossier JN. Exchange Rules for Diradical π-Conjugated Hydrocarbons. Nano Lett 2019; 19:5991-5997. [PMID: 31365266 DOI: 10.1021/acs.nanolett.9b01773] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A variety of planar π-conjugated hydrocarbons such as heptauthrene, Clar's goblet and, recently synthesized, triangulene have two electrons occupying two degenerate molecular orbitals. The resulting spin of the interacting ground state is often correctly anticipated as S = 1, extending the application of Hund's rules to these systems, but this is not correct in some instances. Here we provide a set of rules to correctly predict the existence of zero mode states as well as the spin multiplicity of both the ground state and the low-lying excited states, together with their open- or closed-shell nature. This is accomplished using a combination of analytical arguments and configuration interaction calculations with a Hubbard model, both backed by quantum chemistry methods with a larger Gaussian basis set. Our results go beyond the well established Lieb's theorem and Ovchinnikov's rule, as we address the multiplicity and the open-/closed-shell nature of both ground and excited states.
Collapse
Affiliation(s)
- Ricardo Ortiz
- QuantaLab , International Iberian Nanotechnology Laboratory (INL) , Av. Mestre José Veiga , 4715-330 Braga , Portugal
- Departamento de Física Aplicada , Universidad de Alicante , 03690 Sant Vicent del Raspeig , Spain
- Departamento de Química Física , Universidad de Alicante , 03690 Sant Vicent del Raspeig , Spain
| | - Roberto A Boto
- CICECO, Departamento de Química , Universidade de Aveiro , 3810-193 Aveiro , Portugal
| | - Noel García-Martínez
- QuantaLab , International Iberian Nanotechnology Laboratory (INL) , Av. Mestre José Veiga , 4715-330 Braga , Portugal
- Departamento de Física Aplicada , Universidad de Alicante , 03690 Sant Vicent del Raspeig , Spain
| | - Juan C Sancho-García
- Departamento de Química Física , Universidad de Alicante , 03690 Sant Vicent del Raspeig , Spain
| | - Manuel Melle-Franco
- CICECO, Departamento de Química , Universidade de Aveiro , 3810-193 Aveiro , Portugal
| | - Joaquı N Fernández-Rossier
- QuantaLab , International Iberian Nanotechnology Laboratory (INL) , Av. Mestre José Veiga , 4715-330 Braga , Portugal
| |
Collapse
|
14
|
Dornevil K, Davis I, Fielding AJ, Terrell JR, Ma L, Liu A. Cross-linking of dicyclotyrosine by the cytochrome P450 enzyme CYP121 from Mycobacterium tuberculosis proceeds through a catalytic shunt pathway. J Biol Chem 2017; 292:13645-13657. [PMID: 28667013 DOI: 10.1074/jbc.m117.794099] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 06/29/2017] [Indexed: 12/12/2022] Open
Abstract
CYP121, the cytochrome P450 enzyme in Mycobacterium tuberculosis that catalyzes a single intramolecular C-C cross-linking reaction in the biosynthesis of mycocyclosin, is crucial for the viability of this pathogen. This C-C coupling reaction represents an expansion of the activities carried out by P450 enzymes distinct from oxygen insertion. Although the traditional mechanism for P450 enzymes has been well studied, it is unclear whether CYP121 follows the general P450 mechanism or uses a different catalytic strategy for generating an iron-bound oxidant. To gain mechanistic insight into the CYP121-catalyzed reaction, we tested the peroxide shunt pathway by using rapid kinetic techniques to monitor the enzyme activity with its substrate dicyclotyrosine (cYY) and observed the formation of the cross-linked product mycocyclosin by LC-MS. In stopped-flow experiments, we observed that cYY binding to CYP121 proceeds in a two-step process, and EPR spectroscopy indicates that the binding induces active site reorganization and uniformity. Using rapid freeze-quenching EPR, we observed the formation of a high-spin intermediate upon the addition of peracetic acid to the enzyme-substrate complex. This intermediate exhibits a high-spin (S = 5/2) signal with g values of 2.00, 5.77, and 6.87. Likewise, iodosylbenzene could also produce mycocyclosin, implicating compound I as the initial oxidizing species. Moreover, we also demonstrated that CYP121 performs a standard peroxidase type of reaction by observing substrate-based radicals. On the basis of these results, we propose plausible free radical-based mechanisms for the C-C bond coupling reaction.
Collapse
Affiliation(s)
- Kednerlin Dornevil
- From the Department of Chemistry, University of Texas, San Antonio, Texas 78249 and.,the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Ian Davis
- From the Department of Chemistry, University of Texas, San Antonio, Texas 78249 and.,the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Andrew J Fielding
- From the Department of Chemistry, University of Texas, San Antonio, Texas 78249 and
| | - James R Terrell
- the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Li Ma
- From the Department of Chemistry, University of Texas, San Antonio, Texas 78249 and
| | - Aimin Liu
- From the Department of Chemistry, University of Texas, San Antonio, Texas 78249 and
| |
Collapse
|
15
|
Matsui H, Nagami T, Takamuku S, Ito S, Kitagawa Y, Nakano M. Theoretical Study on the Second Hyperpolarizailities of Oligomeric Systems Composed of Carbon and Silicon π-Structures. Molecules 2016; 21:molecules21111540. [PMID: 27854296 PMCID: PMC6274231 DOI: 10.3390/molecules21111540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 10/18/2016] [Accepted: 11/09/2016] [Indexed: 11/30/2022]
Abstract
To explore the prospect of molecules involving silicon-silicon multiple bonds as nonlinear optical molecular systems, the relationship between the structure and the second hyperpolarizabilities γ of the oligomeric systems composed of carbon and silicon π-structures is investigated using the density functional theory method. It is found that these compounds indicate intramolecular charge transfer (ICT) from the silicon units to the carbon units together with nonzero diradical characters. The γ values of these compounds are shown to be 2–13 times as large as those of the carbon analogs. Although asymmetric carbon and silicon π-systems exhibit comparable enhancement to the corresponding symmetric systems, donor-π-donor structures exhibit remarkable enhancement of γ despite of their both-end short silicon π-chain moieties (donor units). Further analysis using the odd electron and γ densities clarifies that the intermediate diradical character also contributes to the enhancement of γ. These results predict that even short π-conjugated silicone moieties can cause remarkable enhancement of γ by introducing them into π-conjugated hydrocarbon structures.
Collapse
Affiliation(s)
- Hiroshi Matsui
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Takanori Nagami
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Shota Takamuku
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Soichi Ito
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Yasutaka Kitagawa
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Masayoshi Nakano
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| |
Collapse
|
16
|
Abstract
Higher acenes have drawn much attention as promising organic semiconductors with versatile electronic properties. However, the nature of their ground state and electronic excited states is still not fully clear. Their unusual chemical reactivity and instability are the main obstacles for experimental studies, and the potentially prominent diradical character, which might require a multireference description in such large systems, hinders theoretical investigations. Here, we provide a detailed answer with the particle-particle random-phase approximation calculation. The (1)Ag ground states of acenes up to decacene are on the closed-shell side of the diradical continuum, whereas the ground state of undecacene and dodecacene tilts more to the open-shell side with a growing polyradical character. The ground state of all acenes has covalent nature with respect to both short and long axes. The lowest triplet state (3)B2u is always above the singlet ground state even though the energy gap could be vanishingly small in the polyacene limit. The bright singlet excited state (1)B2u is a zwitterionic state to the short axis. The excited (1)Ag state gradually switches from a double-excitation state to another zwitterionic state to the short axis, but always keeps its covalent nature to the long axis. An energy crossing between the (1)B2u and excited (1)Ag states happens between hexacene and heptacene. Further energetic consideration suggests that higher acenes are likely to undergo singlet fission with a low photovoltaic efficiency; however, the efficiency might be improved if a singlet fission into multiple triplets could be achieved.
Collapse
|
17
|
Rana A, Cinar ME, Samanta D, Schmittel M. Solving the puzzling competition of the thermal C(2)-C(6) vs Myers-Saito cyclization of enyne-carbodiimides. Beilstein J Org Chem 2016; 12:43-9. [PMID: 26877807 PMCID: PMC4734315 DOI: 10.3762/bjoc.12.6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/24/2015] [Indexed: 11/23/2022] Open
Abstract
The mechanism of the thermal cyclization of enyne-carbodiimides 7a–c has been studied computationally by applying the DFT method. The results indicate that enyne-carbodiimides preferentially follow the C2–C6 (Schmittel) cyclization pathway in a concerted fashion although the Myers–Saito diradical formation is kinetically preferred. The experimentally verified preference of the C2–C6 over the Myers–Saito pathway is guided by the inability of the Myers–Saito diradical to kinetically compete in the rate-determining trapping reactions, either inter- or intramolecular, with the concerted C2–C6 cyclization. As demonstrated with enyne-carbodiimide 11, the Myers–Saito channel can be made the preferred pathway if the trapping reaction by hydrogen transfer is no more rate determining.
Collapse
Affiliation(s)
- Anup Rana
- Department of Chemistry and Biology, Universität Siegen, Adolf-Reichwein-Str. 2, D-57068 Siegen, Germany
| | - Mehmet Emin Cinar
- Department of Chemistry and Biology, Universität Siegen, Adolf-Reichwein-Str. 2, D-57068 Siegen, Germany
| | - Debabrata Samanta
- Department of Chemistry and Biology, Universität Siegen, Adolf-Reichwein-Str. 2, D-57068 Siegen, Germany
| | - Michael Schmittel
- Department of Chemistry and Biology, Universität Siegen, Adolf-Reichwein-Str. 2, D-57068 Siegen, Germany
| |
Collapse
|
18
|
Dong G, Wang H, Cong J, Wang C, Guo J, Zhang T, Yang J, Yang G, Wu K. Calibration ruler for CW-EPR distance measurement using diradical molecule of rigid structure. Acta Biochim Biophys Sin (Shanghai) 2015; 47:342-8. [PMID: 25841441 DOI: 10.1093/abbs/gmv021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/04/2015] [Indexed: 11/13/2022] Open
Abstract
Many experimental factors and uncontrollable factors may introduce errors in the distance measurement by continuous wave electron paramagnetic resonance. To deal with this problem, several C60 nitroxide diradical adducts with rigid structure and definite molecular dimension were used as distance calibration rulers. Based on the improvement of distance calculation program via adding simulation programs of experimental spectra and dipolar broadening function, respectively, the distance calibration method was developed under different conditions such as different solvent, solution concentration, measuring temperature, and microwave power. As a result, stable distance calibration rulers were established within the range of 8-13 Å. The distance calibration effect was evaluated resulting in a corresponding distance measurement precision of 0.84 Å. The results suggested that the influence of non-dipolar spectral broadening factors could be overcome, and the established experimental and calculation methods were suitable to a wide range of situations. The developed method will ensure more accurate and objective distance measurement in biomacromolecular analysis.
Collapse
Affiliation(s)
- Guofu Dong
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hongyao Wang
- College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianbo Cong
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Changzhen Wang
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Junwang Guo
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Tong Zhang
- College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingkui Yang
- College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guoshan Yang
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Ke Wu
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| |
Collapse
|
19
|
Qiu YQ, Wang WY, Ma NN, Wang CH, Zhang MY, Zou HY, Liu PJ. Computational investigation on redox-switchable nonlinear optical properties of a series of polycyclic p-quinodimethane molecules. J Mol Model 2013; 19:5479-87. [PMID: 24241127 PMCID: PMC3851701 DOI: 10.1007/s00894-013-2035-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 10/09/2013] [Indexed: 10/28/2022]
Abstract
The polycyclic p-quinodimethanes are proposed to be the novel candidates of the high-performance nonlinear optical (NLO) materials because of their large third order polarizabilities (γ). We investigate the switchable NLO responses of a series of polycyclic p-quinodimethanes with redox properties by employing the density functional theory (DFT). The polycyclic p-quinodimethanes are forecasted to exhibit obvious pure diradical characters because of their large y 0 index (the y 0 index is a value between 0 [closed-shell state] and 1 [pure biradical state]). The γ values of these polycyclic p-quinodimethanes and their corresponding one-electron and two-electron reduced/oxidized species are calculated by the (U)BHandHLYP method. The γ values of polycyclic p-quinodimethanes and their corresponding one-electron reduced species are all positive and significantly different. The large differences of the γ values are due to a change in the transition energy and are related to the different delocalization of the spin density, which demonstrates that the NLO switching is more effective on one-electron reduction reactions. Therefore, the study on these polycyclic p-quinodimethanes provides a guideline for a molecular design of highly efficient NLO switching.
Collapse
Affiliation(s)
- Yong-Qing Qiu
- College Chemistry & Chemical Engineering, Hainan Normal University, Haikou, Hainan 571158 People’s Republic of China
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024 People’s Republic of China
| | - Wen-Yong Wang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024 People’s Republic of China
| | - Na-Na Ma
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024 People’s Republic of China
| | - Cun-Huan Wang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024 People’s Republic of China
| | - Meng-Ying Zhang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024 People’s Republic of China
| | - Hai-Yan Zou
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024 People’s Republic of China
| | - Peng-Jun Liu
- College Chemistry & Chemical Engineering, Hainan Normal University, Haikou, Hainan 571158 People’s Republic of China
| |
Collapse
|