TY - JOUR

T1 - Rhenium Complex with Noninnocent Dioxolene Ligand

T2 - Combined Experimental and ab Initio Study of [(3,5-di-tert-Bu2C6H2O2)ReCl3(OPPh3)]

AU - Abramov, Pavel A.

AU - Gritsan, Nina P.

AU - Suturina, Elizaveta A.

AU - Bogomyakov, Artem S.

AU - Sokolov, Maxim N.

PY - 2015/7/20

Y1 - 2015/7/20

N2 - Reaction of [ReOCl3(PPh3)2] with 3,5-di-tert-butyl-1,2-benzoquinone (3,5-DTBQ) in hot toluene produces a new complex [(3,5-di-tert-Bu2C6H2O2)Re(OPPh3)Cl3] (1), which was isolated and characterized by elemental analysis, IR, UV-vis spectroscopy, and cyclic voltammetry. In order to clarify the charge state of rhenium and the coordinated dioxolene ligand, X-ray experiments at 150 and 290 K were carried out. The C-O, C-C, and Re-O bond distances at both 150 and 290 K fall between those for semiquinolate (3,5-DTBSQ) and catecholate (3,5-DTBCat) forms; an empirical "metrical oxidation state" of the dioxolene ligand was estimated to be -1.5. High-level ab initio calculations (SOC-CASSCF/NEVPT2) revealed a mixed valence nature of the triplet ground state of complex 1 corresponding to a superposition of the ReIV-SQ and ReV-cat forms. In agreement with the high-level ab initio and DFT calculations, the temperature dependence of the magnetic susceptibility (5-300 K) is well described in the assumption of the triplet ground state, with the anomalously large zero-field splitting (ZFS) arising from the spin-orbit coupling. According to the ab initio calculations, all absorption bands in the visible region of the electronic absorptions spectrum are assigned to the LMCT bands, with significant contribution of the intraligand transition in the most intense band at 555 nm. (Graph Presented).

AB - Reaction of [ReOCl3(PPh3)2] with 3,5-di-tert-butyl-1,2-benzoquinone (3,5-DTBQ) in hot toluene produces a new complex [(3,5-di-tert-Bu2C6H2O2)Re(OPPh3)Cl3] (1), which was isolated and characterized by elemental analysis, IR, UV-vis spectroscopy, and cyclic voltammetry. In order to clarify the charge state of rhenium and the coordinated dioxolene ligand, X-ray experiments at 150 and 290 K were carried out. The C-O, C-C, and Re-O bond distances at both 150 and 290 K fall between those for semiquinolate (3,5-DTBSQ) and catecholate (3,5-DTBCat) forms; an empirical "metrical oxidation state" of the dioxolene ligand was estimated to be -1.5. High-level ab initio calculations (SOC-CASSCF/NEVPT2) revealed a mixed valence nature of the triplet ground state of complex 1 corresponding to a superposition of the ReIV-SQ and ReV-cat forms. In agreement with the high-level ab initio and DFT calculations, the temperature dependence of the magnetic susceptibility (5-300 K) is well described in the assumption of the triplet ground state, with the anomalously large zero-field splitting (ZFS) arising from the spin-orbit coupling. According to the ab initio calculations, all absorption bands in the visible region of the electronic absorptions spectrum are assigned to the LMCT bands, with significant contribution of the intraligand transition in the most intense band at 555 nm. (Graph Presented).

UR - http://www.scopus.com/inward/record.url?scp=84937705871&partnerID=8YFLogxK

U2 - 10.1021/acs.inorgchem.5b00407

DO - 10.1021/acs.inorgchem.5b00407

M3 - Article

C2 - 26135029

AN - SCOPUS:84937705871

VL - 54

SP - 6727

EP - 6735

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 14

ER -