Niobium tetrachloride complexes with thio-, seleno- and telluro-ether coordination – synthesis and structures
Niobium tetrachloride complexes with thio-, seleno- and telluro-ether coordination – synthesis and structures
NbCl4 reacts with the dithioethers MeS(CH2)nSMe (n = 2 or 3), iPrS(CH2)2SiPr or o-C6H4(CH2SEt)2 in a 1:1 molar ratio in CH2Cl2 or toluene over several days, to give red or orange, paramagnetic complexes, [NbCl4(dithioether)]. Their X-ray crystal structures confirm distorted octahedral geometries with chelating dithioether. MeS(CH2)2SMe, alone, also forms an [NbCl4{MeS(CH2)2SMe}2] complex based upon eight-coordinate Nb(IV) in a square antiprismatic geometry. Similar six-coordinate cis-[NbCl4(diselenoether)] are formed by MeSe(CH2)nSeMe (n = 2 or 3) and nBuSe(CH2)3SenBu. The monodentate ligands Me2S, Me2Se and nBu2Se form [NbCl4(R2E)2] (E = S, Se) which are unstable in solution, losing R2E to form complexes with a 1:1 stoichiometry, which are shown to be diamagnetic dimers, [(Me2E)Cl3Nb(?-Cl)2NbCl3(Me2E)], with single Nb–Nb ?-bonds. Tellurium ligands tend to decompose in these reactions, but reaction at room temperature of Me2Te and NbCl4 formed [NbCl4(Me2Te)2], the X-ray structure of which revealed an eight-coordinate dimer, [Nb2Cl4(?-Cl)4(Me2Te)4]. The new complexes have been characterised by microanalysis, IR, UV-visible spectroscopy and magnetic measurements. X-ray crystal structures are reported for [NbCl4(L–L)] (L–L = MeS(CH2)nSMe, n = 2 or 3, iPrS(CH2)2SiPr, o-C6H4(CH2SEt)2, MeSe(CH2)3SeMe), [Nb2Cl8(Me2Te)4], [Nb2Cl8(Me2S)2] and [Nb2Cl8(Me2Se)2]. The complexes are very sensitive to moisture and dioxygen, and some also readily undergo C–E bond cleavage. Two ligand fragmentation products were identified –[Nb2Cl4(?-S)2{MeS(CH2)3SMe}2] and [Nb2Cl4(?-Se)2{o-C6H4(CH2)2Se}4]. X-ray crystal structures are also reported for the oxidation/hydrolysis products [NbOCl3(Me2S)] and [NbOCl3{MeS(CH2)2SMe}].
16262-16274
Chang, Yao-Pang
9516eba3-1424-411c-8f13-c564cae63407
Levason, William
e7f6d7c7-643c-49f5-8b57-0ebbe1bb52cd
Light, Mark
cf57314e-6856-491b-a8d2-2dffc452e161
Reid, Gillian
37d35b11-40ce-48c5-a68e-f6ce04cd4037
7 November 2016
Chang, Yao-Pang
9516eba3-1424-411c-8f13-c564cae63407
Levason, William
e7f6d7c7-643c-49f5-8b57-0ebbe1bb52cd
Light, Mark
cf57314e-6856-491b-a8d2-2dffc452e161
Reid, Gillian
37d35b11-40ce-48c5-a68e-f6ce04cd4037
Chang, Yao-Pang, Levason, William, Light, Mark and Reid, Gillian
(2016)
Niobium tetrachloride complexes with thio-, seleno- and telluro-ether coordination – synthesis and structures.
Dalton Transactions, 45 (41), .
(doi:10.1039/C6DT02979E).
Abstract
NbCl4 reacts with the dithioethers MeS(CH2)nSMe (n = 2 or 3), iPrS(CH2)2SiPr or o-C6H4(CH2SEt)2 in a 1:1 molar ratio in CH2Cl2 or toluene over several days, to give red or orange, paramagnetic complexes, [NbCl4(dithioether)]. Their X-ray crystal structures confirm distorted octahedral geometries with chelating dithioether. MeS(CH2)2SMe, alone, also forms an [NbCl4{MeS(CH2)2SMe}2] complex based upon eight-coordinate Nb(IV) in a square antiprismatic geometry. Similar six-coordinate cis-[NbCl4(diselenoether)] are formed by MeSe(CH2)nSeMe (n = 2 or 3) and nBuSe(CH2)3SenBu. The monodentate ligands Me2S, Me2Se and nBu2Se form [NbCl4(R2E)2] (E = S, Se) which are unstable in solution, losing R2E to form complexes with a 1:1 stoichiometry, which are shown to be diamagnetic dimers, [(Me2E)Cl3Nb(?-Cl)2NbCl3(Me2E)], with single Nb–Nb ?-bonds. Tellurium ligands tend to decompose in these reactions, but reaction at room temperature of Me2Te and NbCl4 formed [NbCl4(Me2Te)2], the X-ray structure of which revealed an eight-coordinate dimer, [Nb2Cl4(?-Cl)4(Me2Te)4]. The new complexes have been characterised by microanalysis, IR, UV-visible spectroscopy and magnetic measurements. X-ray crystal structures are reported for [NbCl4(L–L)] (L–L = MeS(CH2)nSMe, n = 2 or 3, iPrS(CH2)2SiPr, o-C6H4(CH2SEt)2, MeSe(CH2)3SeMe), [Nb2Cl8(Me2Te)4], [Nb2Cl8(Me2S)2] and [Nb2Cl8(Me2Se)2]. The complexes are very sensitive to moisture and dioxygen, and some also readily undergo C–E bond cleavage. Two ligand fragmentation products were identified –[Nb2Cl4(?-S)2{MeS(CH2)3SMe}2] and [Nb2Cl4(?-Se)2{o-C6H4(CH2)2Se}4]. X-ray crystal structures are also reported for the oxidation/hydrolysis products [NbOCl3(Me2S)] and [NbOCl3{MeS(CH2)2SMe}].
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NbCl4-chalcogenoether finalaccepted.pdf
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Accepted/In Press date: 13 September 2016
e-pub ahead of print date: 13 September 2016
Published date: 7 November 2016
Organisations:
Faculty of Natural and Environmental Sciences
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Local EPrints ID: 404387
URI: http://eprints.soton.ac.uk/id/eprint/404387
ISSN: 0300-9246
PURE UUID: 22e5ba14-0997-48c2-8be8-2e2b0c4730f6
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Date deposited: 09 Jan 2017 09:48
Last modified: 16 Mar 2024 03:04
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Author:
Yao-Pang Chang
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