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Title: Chemistry of iridium(I) and rhodium(I) compounds containing pyridylmethyl ligation

Journal Article · · Organometallics; (United States)
DOI:https://doi.org/10.1021/om00161a026· OSTI ID:5943464
; ;  [1]
  1. Purdue Univ., West Lafayette, IN (United States)

Treatment of the chloro-bridged dimers ((COD)M({mu}-Cl)){sub 2} (M = Rh, Ir; COD = 1,5-cyclooctadiene) with ((6-methyl-2-pyridyl)methyl)lithium (Li-CH{sub 2}-py-6Me)leads to the formation of the dinuclear compounds ((COD)M({mu}-CH{sub 2}-py-6Me-C,N)){sub 2} (M = Rh, 1; Ir, 2) in high yields. The solid-state structures of orange 1 and red 2 show the compounds to possess an open book type structure consisting of two square planes held together by the pyridylmethyl bridges similar to the known hydroxypyridinato analogues. A long metal-metal distance of 3.6806 (3) {angstrom} for 1 and 3.5889 (3) {angstrom} for 2 indicates little interaction between adjacent square planes. Treatment of iridium compound 2 with EtPPh{sub 2} did not lead to displacement of the COD ligand. Instead formation of the mononuclear compound (COD)Ir(EtPPh{sub 2}){sub 2}(CH{sub 2}-py-6Me) (3) takes place. A solid-state structural analysis of 3 confirmed the stoichiometry and showed the pyridylmethyl group to be only carbon bound with a five-coordinate (18-electron) iridium metal center. Attempts to form new binuclear species by reaction of 1 and 2 with dppm (Ph{sub 2}PCH{sub 2}PPh{sub 2}) led instead to new compounds of formula ((dppm)M(dppm-H)) (M = Rh, 4; Ir, 5). In this reaction, the pyridylmethyl group has acted as an intramolecular base, leading to deprotonation of the methylene group of one of the dppm ligands and formation of 2,6-dimethylpyridine. A single-crystal X-ray diffraction study of rhodium complex 4 showed a square-planar rhodium(I) center chelated through the phosphorus atoms of both dppm and its deprotonated, methanide form.

OSTI ID:
5943464
Journal Information:
Organometallics; (United States), Vol. 9:11; ISSN 0276-7333
Country of Publication:
United States
Language:
English