Interligand communication in a metal mediated LL′CT system - a case study
A series of oxo-Mo( iv ) complexes, [MoO(Dt 2− )(Dt 0 )] (where Dt 2− = benzene-1,2-dithiol (bdt), toluene-3,4-dithiol (tdt), quinoxaline-2,3-dithiol (qdt), or 3,6-dichloro-benzene-1,2-dithiol (bdtCl 2 ); Dt 0 = N , N ′-dimethylpiperazine-2,3-dithione (Me 2 Dt 0 ) or N , N ′-diisopropylpiperazine-2,...
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Published in | RSC advances Vol. 11; no. 39; pp. 24381 - 24386 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
12.07.2021
The Royal Society of Chemistry |
Subjects | |
Online Access | Get full text |
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Summary: | A series of oxo-Mo(
iv
) complexes, [MoO(Dt
2−
)(Dt
0
)] (where Dt
2−
= benzene-1,2-dithiol (bdt), toluene-3,4-dithiol (tdt), quinoxaline-2,3-dithiol (qdt), or 3,6-dichloro-benzene-1,2-dithiol (bdtCl
2
); Dt
0
=
N
,
N
′-dimethylpiperazine-2,3-dithione (Me
2
Dt
0
) or
N
,
N
′-diisopropylpiperazine-2,3-dithione (
i
Pr
2
Dt
0
)), possessing a fully oxidized and a fully reduced dithiolene ligand have been synthesized and characterized. The assigned oxidation states of coordinated dithiolene ligands are supported with spectral and crystallographic data. The molecular structure of [MoO(tdt)(
i
Pr
2
Dt
0
)] (
6
) demonstrates a large ligand fold angle of 62.6° along the S S vector of the Dt
0
ligand. The electronic structure of this system is probed by density functional theory (DFT) calculations. The HOMO is largely localized on the Dt
2−
ligand while virtual orbitals are mostly Mo and Dt
0
in character. Modeling the electronic spectrum of
6
with time dependent (TD) DFT calculations attributes the intense low energy transition at ∼18 000 cm
−1
to a ligand-to-ligand charge transfer (LL′CT). The electron density difference map (EDDM) for the low energy transition depicts the electron rich Dt
2−
ligand donating charge density to the redox-active orbitals of the electron deficient Dt
0
ligand. Electronic communication between dithiolene ligands is facilitated by a Mo-monooxo center and distortion about its primary coordination sphere.
The interligand communication between non-innocent dithiolene ligands of different oxidation states has been described in a Mo system. The fully reduced ene-dithiolate (Dt
2−
) acts as a donor moiety to the oxidized dithione (Dt
0
) in an LL′CT process. |
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Bibliography: | For ESI and crystallographic data in CIF or other electronic format see DOI 2021145 Electronic supplementary information (ESI) available: CCDC 10.1039/d1ra04716g |
ISSN: | 2046-2069 2046-2069 |
DOI: | 10.1039/d1ra04716g |