1
|
Cruz TFC, Loupy V, Veiros LF. Zinc-Catalyzed Hydroboration of Carbon Dioxide Amplified by Borane-Tethered Heteroscorpionate Bis(Pyrazolyl)methane Ligands. Inorg Chem 2024; 63:8244-8256. [PMID: 38656156 PMCID: PMC11080050 DOI: 10.1021/acs.inorgchem.4c00500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/26/2024]
Abstract
The borane-functionalized (BR2) bis(3,5-dimethylpyrazolyl)methane (LH) ligands 1a (BR2: 9-borabicyclo[3.3.1]nonane or 9-BBN), 1b (BR2: BCy2), and 1c (BR2: B(C6F5)2) were synthesized by the allylation-hydroboration of LH. Metalation of 1a,b with ZnCl2 yielded the heteroscorpionate dichloride complexes [(1a,b)ZnCl2] 3a,b. The reaction of 1a with ZnEt2 led to the formation of the zwitterionic complex [Et(1a)ZnEt(THF)] 5. The reaction of complex 3a with two equivalents of KHBEt3 under a carbon dioxide (CO2) atmosphere gave rise to the formation of the dimeric bis(formate) complex [(1a)Zn(OCHO)2]2 8, in which its borane moieties intermolecularly stabilize the formate ligands of opposite metal centers. The allylated precursor Lallyl and its zinc dichloride, diethyl and bis(formate) complexes [(Lallyl)ZnCl2] 2, [(Lallyl)ZnEt2] 4, and [(Lallyl)Zn(OCHO)2] 7 were also isolated. The catalyst systems composed of 1 mol % of 3a or 3b and two equivalents of KHBEt3 hydroborated CO2 at 1 bar with pinacolborane (HBPin) to the methanol-level product H3COBPin (and PinBOBPin) in yields of 42 or 86%, respectively. The catalyst systems using the unfunctionalized complex [(LH)ZnCl2] 6 and KHBEt3 or KHBEt3/nOctBR2 (BR2: 9-BBN or BCy2) hydroborated CO2 to H3COBPin but in 2.5- to 6-fold lower activities than those exhibited by 3a,b/KHBEt3. The hydroboration of CO2 using 8 as a catalyst led to yields of 39-43%, comparable to those obtained with 3a/KHBEt3. The results confirmed that the catalytic intermediates benefit from the incorporated boranes' intra- or intermolecular stabilizations.
Collapse
Affiliation(s)
- Tiago F. C. Cruz
- Centro de Química
Estrutural, Institute of Molecular Sciences, Departamento de Engenharia
Química, Instituto Superior Técnico,
Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisboa, Portugal
| | - Valentin Loupy
- Centro de Química
Estrutural, Institute of Molecular Sciences, Departamento de Engenharia
Química, Instituto Superior Técnico,
Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisboa, Portugal
| | - Luís F. Veiros
- Centro de Química
Estrutural, Institute of Molecular Sciences, Departamento de Engenharia
Química, Instituto Superior Técnico,
Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisboa, Portugal
| |
Collapse
|
2
|
Kumar R, Meher RK, Karmakar H, Panda TK. Hydrosilylation of nitriles and tertiary amides using a zinc precursor. Org Biomol Chem 2024; 22:3053-3058. [PMID: 38545870 DOI: 10.1039/d4ob00161c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
We report a competent and selective hydrosilylation of nitriles and tertiary amides catalyzed by the readily available zinc bis(hexamethyldisilazide) under solvent-free and mild conditions, making it a sustainable and desirable alternative to existing methods. Both protocols afforded high conversion, superior selectivity, and a broad substrate scope, from electron-withdrawing to electron-donating and heterocyclic substitutions.
Collapse
Affiliation(s)
- Ravi Kumar
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| | - Rohan Kumar Meher
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| | - Himadri Karmakar
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| | - Tarun K Panda
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| |
Collapse
|
3
|
Mandal C, Joshi S, Das S, Mishra S, Mukherjee D. 2-Anilidomethylpyridine-Derived Three-Coordinate Zinc Hydride: The Journey Unveils Anilide Backbone's Reactive Nature. Inorg Chem 2024; 63:739-751. [PMID: 38127496 DOI: 10.1021/acs.inorgchem.3c03673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Low-coordinate heteroleptic zinc hydrides are catalytically important but rare and synthetically challenging. We herein report three-coordinate monomeric zinc hydride on a 2-anilidomethylpyridine framework (NNL). The synthetic success comes through systematically screening a few different routes from different precursors. During the process, the ligand's anilide backbone interestingly appears to be more reactive than Zn's terminal site to electrophilic Lewis and Brønsted acids. The proligand NNLH reacts with [Zn{N(SiMe3)2}2] and ZnEt2 to give [(NNL)ZnA] (A = N(SiMe3)2 (1), Et(2)). Both are inert to PhSiH3 and H2 but react with HBpin only through the internal Zn-Nanilide bond to give the borylated ligand NNLBpin (3). The reactions of 1 and 2 with Ph3EOH (E = C, Si) afford a series of divergent compounds like [(NNLH)Zn(OSiPh3)2] (4), [Zn3(OSiPh3)4Et2] (5), and [EtZn(OCPh3)] (6). But in all cases, it is invariably the Zn-Nanilide bond protonated by the -OH with equal or higher preference than the terminal Zn-N or Zn-C bonds. A DFT analysis rationalizes the origin of such a reactivity pattern. Realizing that an acid-free route might be the key, reacting [(NNL)Li] with ZnBr2 gives [(NNL)Zn(μ-Br)]2 (7), which on successively treating with KOSiPh3 and PhSiH3 gives the desired [(NNL)ZnH] (8) as a three-coordinate monomer with a terminal Zn-H bond. Estimating the ligand steric in 8 shows the openness in Zn's coordination sphere, a desired criterion for efficient catalysis. This and a positive influence of the pyridyl sidearm is reflected in 8's superior activity in hydroborating PhC(O)Me by HBpin in comparison to Jones' two-coordinate anilido zinc hydride.
Collapse
Affiliation(s)
- Chhotan Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Shalini Joshi
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Sanjay Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Debabrata Mukherjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| |
Collapse
|
4
|
Bisht SK, Sharma D, Kannan R, Rajeshkumar T, Maron L, Venugopal A. Quest for Active Species in Al/B-Catalyzed CO 2 Hydrosilylation. Inorg Chem 2023; 62:18543-18552. [PMID: 37906233 DOI: 10.1021/acs.inorgchem.3c02771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
We demonstrate the catalytic role of aluminum and boron centers in aluminum borohydride [(2-Me2CH2C6H4)(C6H5)Al(μ-H)2B(C6H5)2] (6) during carbon dioxide (CO2) hydrosilylation. Preliminary investigations into CO2 reduction using [(2-Me2NCH2C6H4)(H)Al(μ-H)]2 (1) and [Ph3C][B(3,5-C6H3Cl2)4] (2) in the presence of Et3SiH and PhSiH3 resulted in CH2(OSiR3)2 and CH3OSiR3, which serve as formaldehyde and methanol surrogates, respectively. In pursuit of identifying the active catalytic species, three compounds, B(3,5-C6H3Cl2)3 (3), [(2-Me2NCH2C6H4)(3,5-C6H3Cl2)Al(μ-H)2B(3,5-C6H3Cl2)2] (4), and [(2-Me2NCH2C6H4)2Al(THF)][B(3,5-C6H3Cl2)4] (5), were isolated. Among compounds 2-5, the highest catalytic conversion was achieved by 4. Further, 4 and 6 were prepared in a straightforward method by treating 1 with 3 and BPh3, respectively. 6 was found to be in equilibrium with 1 and BPh3, thus making the catalytic process of 6 more efficient than that of 4. Computational investigations inferred that CO2 reduction occurs across the Al-H bond, while Si-H activation occurs through a concerted mechanism involving an in situ generated aluminum formate species and BPh3.
Collapse
Affiliation(s)
- Sheetal Kathayat Bisht
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| | - Deepti Sharma
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| | - Ramkumar Kannan
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, Toulouse, Cedex 4 31077, France
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, Toulouse, Cedex 4 31077, France
| | - Ajay Venugopal
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| |
Collapse
|
5
|
Ankur, Sharma D, Andrews AP, Venugopal A. Reactivity of a quasi-four-coordinate butylmagnesium cation. Dalton Trans 2023; 52:1533-1537. [PMID: 36692073 DOI: 10.1039/d3dt00018d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We present the reactivity of the Mg-C and the β-CH bonds in the trigonal pyramidal [(pmdta)Mg(nBu)]+ exhibiting a weak Mg⋯F interaction with counter anion, [B(C6F5)4]-. Instantaneous β-hydride reactivity with benzophenone, reductive alkylation of phenyl benzoate, and straightforward synthesis of [(pmdta)MgH]+via metathesis with pinacolborane/phenylsilane are discussed.
Collapse
Affiliation(s)
- Ankur
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| | - Deepti Sharma
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| | - Alex P Andrews
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| | - Ajay Venugopal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India.
| |
Collapse
|
6
|
Listyarini RV, Kriesche BM, Hofer TS. The solvation structure of CO2 in dichloromethane – A comparative correlated, semi-empirical and classical MD simulation study. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
7
|
Ratanasak M, Murata T, Adachi T, Hasegawa J, Ema T. Mechanism of BPh
3
‐Catalyzed N‐Methylation of Amines with CO
2
and Phenylsilane: Cooperative Activation of Hydrosilane. Chemistry 2022; 28:e202202210. [DOI: 10.1002/chem.202202210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Manussada Ratanasak
- Institute for Catalysis Hokkaido University Kita 21, Nishi 10, Kita-ku, Sapporo Hokkaido 001-0021 Japan
| | - Takumi Murata
- Division of Applied Chemistry Graduate School of Natural Science and Technology Okayama University Tsushima-naka 3-1-1 Okayama 700-8530 Japan
| | - Taishin Adachi
- Division of Applied Chemistry Graduate School of Natural Science and Technology Okayama University Tsushima-naka 3-1-1 Okayama 700-8530 Japan
| | - Jun‐ya Hasegawa
- Institute for Catalysis Hokkaido University Kita 21, Nishi 10, Kita-ku, Sapporo Hokkaido 001-0021 Japan
| | - Tadashi Ema
- Division of Applied Chemistry Graduate School of Natural Science and Technology Okayama University Tsushima-naka 3-1-1 Okayama 700-8530 Japan
| |
Collapse
|
8
|
Baalbaki HA, Shu J, Nyamayaro K, Jung HJ, Mehrkhodavandi P. Thermally stable zinc hydride catalyst for hydrosilylation of CO 2 to silyl formate at atmospheric pressure. Chem Commun (Camb) 2022; 58:6192-6195. [PMID: 35506769 DOI: 10.1039/d2cc01498j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neutral zinc complexes supported by H[PNNO], a diaminophenolate ligand bearing a pendant phosphine group, were synthesized and characterized. The phosphine arm adopts two different configurations in solution and prevents aggregation. The monomeric zinc hydride complex is stable at elevated temperatures up to 125 °C and reacts readily with CO2 to afford a zinc formate complex. The zinc hydride is active for CO2 hydrosilylation at atmospheric CO2 pressure and is selective for CO2 reduction to the silyl-formate product.
Collapse
Affiliation(s)
- Hassan A Baalbaki
- University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC, Canada.
| | - Julia Shu
- University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC, Canada.
| | - Kudzanai Nyamayaro
- University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC, Canada.
| | - Hyuk-Joon Jung
- University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC, Canada.
| | - Parisa Mehrkhodavandi
- University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC, Canada.
| |
Collapse
|
9
|
Ruccolo S, Sambade D, Shlian DG, Amemiya E, Parkin G. Catalytic reduction of carbon dioxide by a zinc hydride compound, [Tptm]ZnH, and conversion to the methanol level. Dalton Trans 2022; 51:5868-5877. [PMID: 35343979 DOI: 10.1039/d1dt04156h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The zinc hydride compound, [Tptm]ZnH, may achieve the reduction of CO2 by (RO)3SiH (R = Me, Et) to the methanol oxidation level, (MeO)xSi(OR)4-x, via the formate species, HCO2Si(OR)3. However, because insertion of CO2 into the Zn-H bond is more facile than insertion of HCO2Si(OR)3, conversion of HCO2Si(OR)3 to the methanol level only occurs to a significant extent in the absence of CO2.
Collapse
Affiliation(s)
- Serge Ruccolo
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - David Sambade
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Daniel G Shlian
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Erika Amemiya
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Gerard Parkin
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| |
Collapse
|
10
|
Shlian DG, Amemiya E, Parkin G. Synthesis of bis(2-pyridylthio)methyl zinc hydride and catalytic hydrosilylation and hydroboration of CO 2. Chem Commun (Camb) 2022; 58:4188-4191. [PMID: 35266933 DOI: 10.1039/d1cc06963b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of bis(2-pyridylthio)methane with Me2Zn and Zn[N(SiMe3)2]2 afford [Bptm]ZnMe and [Bptm]ZnN(SiMe3)2, thereby providing access to a variety of other [Bptm]ZnX derivatives, including the zinc hydride complex [Bptm]ZnH, which serves as a catalyst for the reduction of CO2 and other carbonyl compounds via hydrosilylation and hydroboration.
Collapse
Affiliation(s)
- Daniel G Shlian
- Department of Chemistry, Columbia University, New York, NY 10027, USA.
| | - Erika Amemiya
- Department of Chemistry, Columbia University, New York, NY 10027, USA.
| | - Gerard Parkin
- Department of Chemistry, Columbia University, New York, NY 10027, USA.
| |
Collapse
|
11
|
He W, Liu X, Cui D. Hydroboration of CO 2 catalyzed by heteroscorpionate zwitterionic zinc and magnesium hydride complexes. Dalton Trans 2022; 51:4786-4789. [PMID: 35253824 DOI: 10.1039/d2dt00279e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The heteroscorpionate zinc hydride complex LZnH 2, (L = (MePz)2CP(Ph)2NPh, MePz = 3,5-dimethylpyrazolyl), its formate complex 3, and magnesium hydride complex LMgH 5 with the same ligand were synthesized and detected for the catalytic hydroboration reaction of CO2. With BH3·SMe2 as the reductant, zinc-based hydride complex 2 and formate complex 3 show a similar capability of hydroboration of CO2, featuring excellent reactivity and selectivity. The conversion of BH3·SMe2 reached 84%, the highest TON of 252 compared to other zinc catalysts was achieved at room temperature and borate ester products at reduction levels of CH3OH were obtained. Magnesium-based hydride complex 5 showed inferior activity for the hydroboration reduction of CO2.
Collapse
Affiliation(s)
- Wenhao He
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. .,School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Xinli Liu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
| | - Dongmei Cui
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. .,School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
| |
Collapse
|
12
|
Ritter F, Morris LJ, McCabe KN, Spaniol TP, Maron L, Okuda J. Deaggregation of Zinc Dihydride by Lewis Acids Including Carbon Dioxide in the Presence of Nitrogen Donors. Inorg Chem 2021; 60:15583-15592. [PMID: 34591456 DOI: 10.1021/acs.inorgchem.1c02207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Thermally sensitive polymeric zinc dihydride [ZnH2]n can conveniently be prepared by the reaction of ZnEt2 with [AlH3(NEt3)]. When reacted with CO2 (1 bar) in the presence of chelating N-donor ligands Ln = N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethyl-1,3-propanediamine (TMPDA), N,N,N',N″,N''-pentamethyldiethylenetriamine (PMDTA), and 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (Me4TACD), insertion into the Zn-H bond readily occurred. Depending on the denticity n, formates [(Ln)Zn(OCHO)2] were isolated and structurally characterized, either as a molecule (Ln = TMEDA, TMPDA, PMDTA) or a charge-separated ion pair [(Ln)Zn(OCHO)][OCHO] (Ln = Me4TACD). The reaction of [ZnH2]n with the mild Lewis acid BPh3 in the presence of chelating N-donor ligands Ln gave a series of hydridotriphenylborates, either as a contact ion pair [(L2)Zn(H)(HBPh3)] (L2 = TMEDA, TMPDA) or a separated ion pair [(Ln)Zn(H)][HBPh3] (Ln = PMDTA, Me4TACD). In the crystal, the contact ion pair [(TMEDA)Zn(H)(HBPh3)] showed a bent Zn-H-B bridge indicative of a delocalized Zn-H-B interaction. In contrast, a linear Zn-H-B bridge for [(TMPDA)Zn(H)(HBPh3)] was observed, suggesting a contact ion pair. In THF solution, both complexes show an exchange with free BPh3 as well as [HBPh3]-. DFT calculations suggest the presence of [HBPh3]- anion with a highly polarized B-H bond that interacts with the Lewis acidic zinc hydride cation [(L2)Zn(H)]+. The hydridotriphenylborates [(Ln)Zn(H)(HBPh3)] underwent CO2 insertion to give (formato)zinc (formoxy)triphenylborate complexes [(Ln)Zn(OCHO)][(OCHO)BPh3] (Ln = TMPDA, PMDTA, Me4TACD). For Ln = TMEDA, a dinuclear complex [(Ln)2Zn2(μ-OCHO)3][(OCHO)BPh3] was isolated. Hydridotriphenylborates [(Ln)Zn(H)(HBPh3)] catalyzed the hydrosilylation of CO2 (1 bar) by nBuMe2SiH in THF at 70 °C to give formoxysilane and (methoxy)silane.
Collapse
Affiliation(s)
- Florian Ritter
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Louis J Morris
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Karl N McCabe
- CNRS, INSA, UPS, UMR 5215, LPCNO, Université de Toulouse, 135 avenue de Rangueil, 31077 Toulouse, France
| | - Thomas P Spaniol
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Laurent Maron
- CNRS, INSA, UPS, UMR 5215, LPCNO, Université de Toulouse, 135 avenue de Rangueil, 31077 Toulouse, France
| | - Jun Okuda
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| |
Collapse
|