ISSN:
1434-1948
Keywords:
Rhodium
;
Iridium
;
N ligands
;
Coordination modes
;
Polymerizations
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Complexation of [RhI(cod)]+ and [IrI(cod)]+ by the new pyridine-amine-pyrrole ligands Py-CH2-N(R)-CH2-Pyr-H (HLR; R = H, Bzl, Bu) and the corresponding pyridine-amine-pyrrolate ligands [Py-CH2-N(R)-CH2-Pyr]- (LR-; R = H, Bzl, Bu, CH2Py) has been investigated. The neutral ligands HLR (R = H, Bu, Bzl) give [(HLR)MI(cod)]+ (M = Rh, Ir) in which HLR acts as a didentate ligand via the pyridine nitrogen (NPy) and the amine nitrogen (NRamine). The crystal structures of [(HLH)MI(cod)]PF6 (M = Rh: [1]PF6 and M = Ir: [2]PF6) have been determined. Deprotonation of [(HLR)MI(cod)]+ (M = Rh, Ir; R = H, Bzl, Bu) results in the neutral complexes [(LR)MI(cod)] (M = Rh, Ir) of the mono-anionic ligands LR- (R = H, Bzl, Bu). In square-planar [(LH)MI(cod)] (M = Rh: 3, M = Ir: 4), LH- is didentate via NHamine and the pyrrolate nitrogen (NPyr). The X-ray structures of 3 and 4 reveal that in both cases the uncoordinated NPy accepts a hydrogen bond from NHamine. The X-ray structures of [(LBzl)MI(cod)] (M = Rh: 5, M = Ir: 6), show that LBzl- is didentate via Namine and NPyr for M = Rh and tridentate for M = Ir. In solution LBzl- is tridentate for both M = Rh and M = Ir. The neutral complexes [{Py-CH2-N(R)-CH2-Pyr}MI(cod)] (M = Rh, Ir) cannot be oxidised selectively with H2O2. This is in marked contrast to the previously observed selective oxidation of the corresponding cationic complexes [{Py-CH2-N(R)-CH2-Py}RhI(cod)]+. Rhodium complex 5 is an active catalyst for the stereoregular polymerisation of phenylacetylene, whereas iridium complex 6 is inactive.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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