TY - JOUR

T1 - A novel Nb2S4 complex with a dithiophosphinate ligand

T2 - Synthesis, structure and redox properties

AU - Gushchin, Artem L.

AU - Rogachev, Alexander V.

AU - Fomenko, Iakov S.

AU - Romashev, Nikolay F.

AU - Nadolinny, Vladimir A.

AU - Abramov, Pavel A.

AU - Laricheva, Yuliya A.

AU - Sokolov, Maxim N.

N1 - Publisher Copyright: © 2018 Elsevier Ltd

PY - 2019/1/15

Y1 - 2019/1/15

N2 - A new diisobutyldithiophosphinate complex, [Nb2S4(S2PiBu2)4] (1), was obtained by a ligand substitution reaction using (Bu4N)4[Nb2S4(NCS)8] and NaS2PiBu2·3H2O. Its crystal structure has been determined. The Nb–Nb distance is 2.9034(7) Å. The cyclic voltammogram (CV) of 1 in dichloromethane exhibits two successive chemically reversible one-electron oxidation waves at +0.55 and +1.10 V (versus Ag/AgCl) attributed to the NbIV/NbV couple. This is the first {Nb2S4} cluster that shows two reversible oxidations. The paramagnetic mixed-valence Nb(IV/V) product of the one-electron oxidation, [Nb2S4(S2PiBu2)4]+ (1+), was generated in situ. The EPR spectrum of 1+ in acetonitrile reveals a 19-line signal arising from the hyperfine interaction between the unpaired electron and two equivalent 93Nb nuclei with I = 9/2, indicating complete delocalization of the unpaired electron over both metal centers. DFT calculations have been performed for the complexes [Nb2S4(S2PMe2)4], [Nb2S4(S2P(OMe)2)4], [Nb2S4(S2CNMe2)4] and [Nb2S4(S2COMe)4] and their single and double oxidized species in order to explain the peculiarities of their redox behavior. The results show that the HOMOs responsible for oxidation have a predominantly metallic character in all cases, but they are significantly more high-lying for the dithiophosphinate and dithiocarbamate complexes, which explains their ability to be oxidized.

AB - A new diisobutyldithiophosphinate complex, [Nb2S4(S2PiBu2)4] (1), was obtained by a ligand substitution reaction using (Bu4N)4[Nb2S4(NCS)8] and NaS2PiBu2·3H2O. Its crystal structure has been determined. The Nb–Nb distance is 2.9034(7) Å. The cyclic voltammogram (CV) of 1 in dichloromethane exhibits two successive chemically reversible one-electron oxidation waves at +0.55 and +1.10 V (versus Ag/AgCl) attributed to the NbIV/NbV couple. This is the first {Nb2S4} cluster that shows two reversible oxidations. The paramagnetic mixed-valence Nb(IV/V) product of the one-electron oxidation, [Nb2S4(S2PiBu2)4]+ (1+), was generated in situ. The EPR spectrum of 1+ in acetonitrile reveals a 19-line signal arising from the hyperfine interaction between the unpaired electron and two equivalent 93Nb nuclei with I = 9/2, indicating complete delocalization of the unpaired electron over both metal centers. DFT calculations have been performed for the complexes [Nb2S4(S2PMe2)4], [Nb2S4(S2P(OMe)2)4], [Nb2S4(S2CNMe2)4] and [Nb2S4(S2COMe)4] and their single and double oxidized species in order to explain the peculiarities of their redox behavior. The results show that the HOMOs responsible for oxidation have a predominantly metallic character in all cases, but they are significantly more high-lying for the dithiophosphinate and dithiocarbamate complexes, which explains their ability to be oxidized.

KW - Cyclic voltammetry

KW - Dinuclear clusters

KW - EPR

KW - Mixed-valence complexes

KW - Niobium

KW - ENERGY

KW - NIOBIUM

KW - VANADIUM

KW - SERIES

KW - APPROXIMATION

KW - CLUSTERS

KW - ELECTRONIC-STRUCTURE

UR - http://www.scopus.com/inward/record.url?scp=85057568892&partnerID=8YFLogxK

U2 - 10.1016/j.poly.2018.11.035

DO - 10.1016/j.poly.2018.11.035

M3 - Article

AN - SCOPUS:85057568892

VL - 158

SP - 458

EP - 463

JO - Polyhedron

JF - Polyhedron

SN - 0277-5387

ER -