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Dinuclear Vanadium Sulfide Clusters: Synthesis, Redox Behavior, and Magnetic Properties
Author(s) -
Fomenko Iakov S.,
Gushchin Artem L.,
Nadolinny Vladimir A.,
Efimov Nikolay N.,
Laricheva Yuliya A.,
Sokolov Maxim N.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800449
Subject(s) - chemistry , unpaired electron , dithiocarbamate , electron paramagnetic resonance , dichloromethane , redox , magnetochemistry , crystallography , vanadium , sulfide , inorganic chemistry , medicinal chemistry , molecule , nuclear magnetic resonance , organic chemistry , crystal structure , physics , solvent
The complex [V 2 S 4 ( n Bu 2 dtc) 4 ] ( 1 ) (dtc = dithiocarbamate) was prepared by a self‐assembly reaction from [VO( n Bu 2 dtc) 3 ] and H 2 S. 1 H, 13 C, and 51 V NMR spectra indicate the presence in solution of two isomers (centrosymmetric and non‐centrosymmetric) with different relative orientations of the dithiocarbamate chelate rings. Thermogravimetric studies of 1 show that the thermolysis products are VS 2 (in He) or VS (in H 2 ). The cyclic voltammogram (CV) in dichloromethane reveals a chemically reversible one‐electron oxidation at +0.61 V followed by an irreversible oxidation at +1.51 V (vs. Ag/AgCl). The redox processes can be attributed to V‐centered oxidation. This interpretation is supported by DFT calculations, indicating the predominantly V–V bonding character of the HOMO in both cases. The removal of one electron from the HOMO causes weakening of the V–V bond in 1 + . The mixed‐valence V(IV/V) product of the one‐electron oxidation, [V 2 S 4 ( n Bu 2 dtc) 4 ](BF 4 ) {[ 1 ](BF 4 )}, was isolated from the reaction with NOBF 4 and characterized by elemental analysis, IR spectroscopy, mass spectrometry (ESI‐MS), CV, EPR spectroscopy, and magnetochemistry. The EPR spectrum of [ 1 ](BF 4 ) in dichloromethane exhibits a single 15‐line signal arising from the hyperfine interaction between the unpaired electron and two equivalent 51 V nuclei with I = 7/2, indicating complete delocalization of the unpaired electron over both metal centers. The magnetic behavior of [ 1 ](BF 4 ) confirms the presence of one unpaired electron and the mixed‐valence V(IV/V) oxidation state without any significant magnetic exchange interactions between the paramagnetic complexes.