Abstract
Reaction of 2-(arylazo)pyrimidines (R-C6H4-N=N-C4H3N2, abbreviated aapm; R=H (papm), o-Me (o-tapm), m-Me (m-tapm), p-Me (p-tapm), p-Cl (p-Clpapm)) with (NH4)(2)[OsCl6] in 2-methoxyethanol gives two isomers of composition OsCl2(aapm)(2). They are structurally characterised by H-1 NMR spectra and established as the cis-trans-cis (ctc) and cis-cis-cis (ccc) isomer. With reference to the coordination pairs of Cl; N(pyrimidine) (N) and N(azo) (N'), the structure of ctc-OsCl2(p-tapm)(2) is confirmed by an X-ray diffraction study. The complexes exhibit multiple MLCT transitions in the visible to near-IR region. Redox studies show an Os(III)/Os(II) couple at 1.2-1.3 V and Os(IV)/Os(III) couple at similar to2 V versus SCE. EHMO calculations and comparison with analogous ruthenium(II) complexes explain the spectral and redox properties of the complexes. (C) 2002 Published by Elsevier Science Ltd.
| Original language | English |
|---|---|
| Pages (from-to) | 753-762 |
| Number of pages | 10 |
| Journal | Polyhedron |
| Volume | 21 |
| Publication status | Published - 1 Apr 2002 |
Keywords
- arylazopyrimidines
- osmium(II) complexes
- geometrical isomers
- X-ray structures
- MLCT transitions
- redox property
- RAY CRYSTAL-STRUCTURES
- SPECTRAL CHARACTERIZATION
- REDOX PROPERTIES
- BIS<2-(ARYLAZO)PYRIMIDINE> COMPLEXES
- RUTHENIUM(II) COMPLEXES
- AROMATIC HYDROXYLATION
- HOMOGENEOUS CATALYSIS
- AZO
- LIGANDS
- SILVER(I)