Experimental and computational tuning of metalla-N-heterocyclic carbenes at palladium() and platinum() centers
Palladium( ii ) and platinum( ii ) complexes featuring metalla-N-heterocyclic carbenes ( 7-12 ) were synthesised via metal-mediated coupling between equimolar cis -[MCl 2 (CNR) 2 ] (R = 2,6-Me 2 C 6 H 3 (Xyl), 2,4,6-Me 3 C 6 H 3 (Mes)) and 2-aminopyridine or 2-aminopyrazine. Thiocyanate complexes 13...
Saved in:
Published in | Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 17; pp. 6718 - 6734 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
03.05.2022
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Palladium(
ii
) and platinum(
ii
) complexes featuring metalla-N-heterocyclic carbenes (
7-12
) were synthesised
via
metal-mediated coupling between equimolar
cis
-[MCl
2
(CNR)
2
] (R = 2,6-Me
2
C
6
H
3
(Xyl), 2,4,6-Me
3
C
6
H
3
(Mes)) and 2-aminopyridine or 2-aminopyrazine. Thiocyanate complexes
13-18
with two thiocyanate ligands were obtained through the ligand exchange in the parent compounds
7-12
with NH
4
CNS in acetone/CH
2
Cl
2
. Complexes
7-18
were isolated and characterised by HRESI
+
-MS, IR,
1
H and
13
C{
1
H} NMR spectroscopy and single-crystal X-ray diffraction (in the case of
11
,
16
, and
18
). The UV-vis properties of
7-18
and the electrochemical properties of
7-12
were also evaluated. To study the electronic structure and bonding nature in the new compounds, the quantum theory of atoms in molecules (QTAIM) and Mayer bond order analysis together with the extended transition state with the natural orbitals for chemical valence (ETS-NOCV) method, were used. X-ray diffraction studies and theoretical considerations indicate that the thiocyanate derivatives
16
and
18
form supramolecular dimers by two symmetrical pairs M
1
C
5
and S
1
C
2
with short intermolecular contacts between an electron-rich M
II
-center and thiocyanate ligand on the one side and the electron-poor π-system of an azaheterocyclic ring on the other side. Representative carbenes
8
,
11
and
12
were evaluated as photocatalysts for the hydrosilylation of diphenylacetylene with triethylsilane giving 1,2-(diphenylvinyl)triethylsilane in 98% yield under visible light irradiation (blue light, 445 nm).
Chemical and computational optimisation of the structures of the new binuclear pallada(
ii
)-N-heterocyclic and platina(
ii
)-N-heterocyclic carbene complexes leads to dramatic changes in their photophysical and electrochemical properties. |
---|---|
Bibliography: | Electronic supplementary information (ESI) available. CCDC For ESI and crystallographic data in CIF or other electronic format see DOI and , 2133435 2133433 2133432 http://doi.org/10.1039/d2dt00252c ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1477-9226 1477-9234 |
DOI: | 10.1039/d2dt00252c |