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Saha S, Krause JA, Guan H. C(sp)-H, S-H, and Sn-H Bond Activation with a Cobalt(I) Pincer Complex. Inorg Chem 2024; 63:13689-13699. [PMID: 38976491 DOI: 10.1021/acs.inorgchem.4c01993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
This study focuses on the stoichiometric reactions of {2,6-(iPr2PO)2C6H3}Co(PMe3)2 with terminal alkynes, thiols, and tin hydrides as part of an effort to develop catalytic, two-electron processes with cobalt. This specific Co(I) pincer complex proves to be effective for cleaving the C(sp)-H, S-H, and Sn-H bonds to give oxidative addition products with the general formula {2,6-(iPr2PO)2C6H3}CoHX(PMe3) (X = alkynyl, thiolate, and stannyl groups) along with the free PMe3. These reactions typically reach completion when the substituents on acetylene, sulfur, and tin are electron-withdrawing groups (e.g., phenyl, pyridyl, and alkenyl groups). In contrast, alkyl-substituted acetylenes, 1-pentanethiol, and tributyltin hydride are partially converted due to the equilibria with the corresponding oxidative addition products. The Co(I) pincer complex is not a hydrothiolation catalyst but capable of catalyzing the hydrostannation of terminal alkynes with Ph3SnH to produce β-(Z)-alkenylstannanes selectively.
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Affiliation(s)
- Sayantani Saha
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221-0172, United States
| | - Jeanette A Krause
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221-0172, United States
| | - Hairong Guan
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221-0172, United States
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Prakash R, Joseph J, Andrews AP, Varghese B, Venugopal A. From Sn(II) to Sn(IV): Enhancing Lewis Acidity Via Oxidation. Inorg Chem 2023; 62:14828-14832. [PMID: 37676732 DOI: 10.1021/acs.inorgchem.3c01911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
We demonstrate the increased Lewis acidity on going from Sn(II) to Sn(IV) by oxidizing TpMe2SnOTf (OTf = SO3CF3) to TpMe2SnF(OTf)2. Replacement of the fluoride ion in TpMe2SnF(OTf)2 by a triflate, resulting in TpMe2Sn(OTf)3 further enhances the Lewis acidity at tin. 119Sn NMR spectroscopy, modified Gutmann-Beckett test, computational analysis, and catalytic phosphine oxide deoxygenation support the claims.
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Affiliation(s)
- Rini Prakash
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura Thiruvananthapuram 695551, Kerala, India
| | - Jerin Joseph
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura Thiruvananthapuram 695551, Kerala, India
| | - Alex P Andrews
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura Thiruvananthapuram 695551, Kerala, India
| | - Babu Varghese
- Sophisticated Analytical Instruments Facility, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
| | - Ajay Venugopal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura Thiruvananthapuram 695551, Kerala, India
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3
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Cairns KR, King RP, Bannister RD, Levason W, Reid G. Synthesis, spectroscopic and structural properties of Sn(II) and Pb(II) triflate complexes with soft phosphine and arsine coordination. Dalton Trans 2023; 52:2293-2308. [PMID: 36723113 DOI: 10.1039/d2dt03687h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Reaction of the divalent M(OTf)2 (M = Sn, Pb; OTf = CF3SO3) with soft phosphine and arsine ligands, L, where L = o-C6H4(ER2)2 (E = P, R = Me or Ph; E = As, R = Me), MeC(CH2ER2)3 (E = P, R = Ph; E = As, R = Me), PhP(CH2CH2PPh2)2 or P(CH2CH2PPh2)3, affords complexes of stoichiometry M(L)(OTf)2 as white powders, which have been characterised via elemental analysis, 1H, 19F{1H}, 31P{1H} and 119Sn NMR spectroscopy, with the expected 31P-119Sn and 31P-207Pb couplings clearly evident. The crystal structures of nine of these pnictine complexes are reported, in each case revealing retention of one or both OTf anions, which gives rise to a diverse range of coordination environments including monomers, as well as varying degrees of oligomerisation to form weakly associated (OTf-bridged) dimers, trimers and polymers. 19F{1H} NMR spectra indicate that the OTf is essentially anionic (dissociated) in solution. Anion metathesis of [M(OTf)2{MeC(CH2PPh2)3}] with Na[BArF] (BArF = B{3,5-(CF3)2C6H3}4) yields the corresponding [M{MeC(CH2PPh2)3}][BArF]2 salts, the crystal structures of all three (M = Ge, Sn, Pb) reveal pyramidal dications with discrete [BArF]- anions providing charge balance. Density functional theory (DFT) calculations on these [M{MeC(CH2PPh2)3}]2+ (M = Ge, Sn, Pb) dications using the B3LYP-D3 functional show the presence of a directional lone pair, which is a mixture of valence s and pz character, with the valence p-orbital character decreasing down group 14. Natural bond orbital (NBO) analysis also shows that the natural charge at the metal centre increases and the charge on the P centre decreases upon going down group 14.
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Affiliation(s)
- Kelsey R Cairns
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - Rhys P King
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - Robert D Bannister
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - William Levason
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - Gillian Reid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
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King RP, Dyke JM, Levason W, Reid G. Neutral and Cationic Complexes of Silicon(IV) Halides with Phosphine Ligands. Inorg Chem 2022; 61:16905-16913. [PMID: 36222839 PMCID: PMC9597660 DOI: 10.1021/acs.inorgchem.2c02949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Indexed: 11/21/2022]
Abstract
The reaction of SiI4 and PMe3 in n-hexane produced the yellow salt, [SiI3(PMe3)2]I, confirmed from its X-ray structure, containing a trigonal bipyramidal cation with trans-phosphines. This contrasts with the six-coordination found in (the known) trans-[SiX4(PMe3)2] (X = Cl, Br) complexes. The diphosphines o-C6H4(PMe2)2 and Et2P(CH2)2PEt2 form six-coordinate cis-[SiI4(diphosphine)], which were also characterized by X-ray crystallography, multinuclear NMR, and IR spectroscopy. Reaction of trans-[SiX4(PMe3)2] (X = Cl, Br) with Na[BArF] (BArF = [B{3,5-(CF3)2C6H3}4]) produced five-coordinate [SiX3(PMe3)2][BArF], but while Me3SiO3SCF3 also abstracted chloride from trans-[SiCl4(PMe3)2], the reaction products were six-coordinate complexes [SiCl3(PMe3)2(OTf)] and [SiCl2(PMe3)2(OTf)2] with the triflate coordinated. X-ray crystal structures were obtained for [SiCl3(PMe3)2][BArF] and [SiCl2(PMe3)2(OTf)2]. The charge distribution across the silicon species was also examined by natural bond orbital (NBO) analyses of the computed density functional theory (DFT) wavefunctions. For the [SiX4(PMe3)2] and [SiX3(PMe3)2]+ complexes, the positive charge on Si decreases and the negative charge on X decreases going from X = F to X = I. Upon going from [SiX4(PMe3)2] to [SiX3(PMe3)2]+, i.e., removal of X-, there is an increase in positive charge on Si and a decrease in negative charge on the X centers (except for the case X = F). The positive charge on P shows a slight decrease.
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Affiliation(s)
- Rhys P. King
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - John M. Dyke
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - William Levason
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Gillian Reid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
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Fluoro-Germanium (IV) Cations with Neutral Co-Ligands—Synthesis, Properties and Comparison with Neutral GeF4 Adducts. INORGANICS 2022. [DOI: 10.3390/inorganics10080107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The reaction of [GeF4L2], L = dmso (Me2SO), dmf (Me2NCHO), py (pyridine), pyNO (pyridine-N-oxide), OPPh3, OPMe3, with Me3SiO3SCF3 (TMSOTf) and monodentate ligands, L, in a 1:1:1 molar ratio in anhydrous CH2Cl2 formed the monocations [GeF3L3][OTf]. These rare trifluoro-germanium (IV) cations were characterised by microanalysis, IR, 1H, 19F{1H} and, where appropriate, 31P{1H} NMR spectroscopy. The 19F{1H} NMR data show that in CH3NO2 solution the complexes exist as a mixture of mer and fac isomers, with the mer isomer invariably having the higher abundance. The X-ray structure of mer-[GeF3(OPPh3)3][OTf] is also reported. The attempts to remove a second fluoride using a further equivalent of TMSOTf and L were mostly unsuccessful, although a mixture of [GeF2(OAsPh3)4][OTf]2 and [GeF3(OAsPh3)3][OTf] was obtained using excess TMSOTf and OAsPh3. The reaction of [GeF4(MeCN)2] with TMSOTf in CH2Cl2 solution, followed by the addition of 2,2′:6′,2”-terpyridine (terpy) formed mer-[GeF3(terpy)][OTf], whilst a similar reaction with 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3-tacn) in MeCN solution produced fac-[GeF3(Me3-tacn)][OTf]. Dicationic complexes bearing the GeF22+ fragment were isolated using the tetra-aza macrocycles, 1,4,7,10-tetramethyl-1,4,7,10-tetra-azacyclododecane (Me4-cyclen) and 1,4,8,11-tetramethyl-1,4,8,11-tetra-azacyclotetradecane (Me4-cyclam), which reacted with [GeF4(MeCN)2] and two equivalents of TMSOTf to cleanly form the dicationic difluoride salts, cis-[GeF2(Me4-cyclen)][OTf]2 and trans-[GeF2(Me4-cyclam)][OTf]2. The 19F{1H} NMR spectroscopy shows that in CH3NO2 solution there are four stereoisomers present for trans-[GeF2(Me4-cyclam)][OTf]2, whereas the smaller ring-size of Me4-cyclen accounts for the formation of only cis-[GeF2(Me4-cyclen)][OTf], and is confirmed crystallographically. New spectroscopic data are also reported for [GeF4(L)2] (L = dmso, dmf and pyNO). Density functional theory calculations were used to probe the effect on the bonding as fluoride ligands were sequentially removed from the germanium centre in the OPMe3 complexes.
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Ngo K, Averkiev B, Reeves GT, Wu A, Ki DW. Tin(IV) halide complexes with 5,7-dimethyl-8-quinolinol: structures, optical and thermal properties. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2081918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Kathleen Ngo
- School of Natural Sciences and Mathematics, Stockton University, Galloway, NJ, USA
| | - Boris Averkiev
- Department of Chemistry, Kansas State University, Manhattan, KS, USA
| | - Gordan Tyson Reeves
- School of Natural Sciences and Mathematics, Stockton University, Galloway, NJ, USA
| | - Andrew Wu
- School of Natural Sciences and Mathematics, Stockton University, Galloway, NJ, USA
| | - Daniel Wooseok Ki
- School of Natural Sciences and Mathematics, Stockton University, Galloway, NJ, USA
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Cairns KR, King RP, Levason W, Reid G. Self-assembly of [Sn(OPMe 3) 3(CF 3SO 3) 2] 6 metallocyclic Sn( ii) hexamer stacks with CF 3-lined channel interiors. CrystEngComm 2022. [DOI: 10.1039/d2ce01029a] [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 preparation, spectroscopic and structural characterisation of a [Sn(OPMe3)3(CF3SO3)2]6, a Sn(ii)-based metallocyclic hexamer, containing hydrophobic CF3-lined 8.0 Å diameter channels is reported.
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Affiliation(s)
- Kelsey R. Cairns
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Rhys P. King
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - William Levason
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Gillian Reid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
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King RP, Levason W, Reid G. Neutral and cationic germanium(IV) fluoride complexes with phosphine coordination - synthesis, spectroscopy and structures. Dalton Trans 2021; 50:17751-17765. [PMID: 34812814 DOI: 10.1039/d1dt03339e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The neutral complexes trans-[GeF4(PiPr3)2] and [GeF4(κ2-L)] (L = CH3C(CH2PPh2)3 or P(CH2CH2PPh2)3) are obtained from [GeF4(MeCN)2] and the ligand in CH2Cl2. Treatment of [GeF4(PMe3)2] with n equivalents of TMSOTf (Me3SiO3SCF3) leads to formation of the series [GeF4-n(PMe3)2(OTf)n] (n = 1, 2, 3), each of which contains six-coordinate Ge(IV) with trans PMe3 ligands and X-ray structural data confirm that the OTf groups interact with Ge(IV) to varying degrees. Unexpectedly, [GeF3(PMe3)2(OTf)] undergoes reductive defluorination in solution, forming the Ge(II) complex, [Ge(PMe3)3][OTf]2 (and [FPMe3]+). The bulkier PiPr3 leads to formation of the ionic [GeF3(iPr3P)2][OTf], containing a [GeF3(iPr3P)2]+ cation. [GeF4{o-C6H4(PMe2)2}], containing the cis-chelating diphosphine, also reacts with n equivalents of TMSOTf to generate [GeF4-n{o-C6H4(PMe2)2}(OTf)n] (n = 1, 2, 3). As for the PMe3 system, the trifluoride, [GeF3{o-C6H4(PMe2)2}(OTf)], is unstable to reductive defluorination in solution, producing the pyramidal Ge(II) complex [Ge{(o-C6H4(PMe2)2}(OTf)][OTf], whose crystal structure has been determined. The [GeF3{Ph2P(CH2)2PPh2}(OTf)] and [GeF2{Ph2P(CH2)2PPh2}(OTf)2], obtained similarly from the parent tetrafluoride complex, are poorly soluble, however their structures were confirmed crystallographically. The complexes in this work have been characterised via variable temperature 1H, 19F{1H} and 31P{1H} NMR studies in solution, IR spectroscopy and microanalysis and through single crystal X-ray analysis of representative examples across each series. Trends in the NMR and structural parameters are also discussed.
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Affiliation(s)
- Rhys P King
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - William Levason
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - Gillian Reid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
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