Jump to main content
Jump to site search

Issue 39, 2010
Previous Article Next Article

Synthesis and reactivity of rhodium and iridium alkene, alkyl and silyl complexes supported by a phenyl-substituted PNP pincer ligand

Author affiliations

Abstract

New rhodium and iridium complexes supported by the phenyl-substituted PNP pincer ligand PNPPhH (HN(2-PPh2-4-Me-C6H3)2) (1) were synthesized. The reaction of 2 equiv. of 1 with [(COD)IrCl]2 afforded the coordination complex [(PNPPhH)Ir(COD)]Cl (2) featuring hydrogen bonding between the N–H group and the chloride anion, as characterized by NMR spectroscopy and X-ray crystallography. Reaction of 1 with [(COE)2IrCl]2 or [(COE)2RhCl]2 in benzene provided a mixture of complexes including (PNPPhH)MHCl2 (M = Ir (4), M = Rh (7)) and (PNP)M(COE) (M = Ir (5), M = Rh (8)). Alkene complexes of the type (PNPPh)M(L) (M = Ir, L = COD (3) and COE (5); M = Rh, L = COE (8) and L = ethylene (9)) were synthesized by reaction of (PNPPh)Li with the appropriate alkene chloride complexes. Reactions of silanes with 5, 8 or 9 produced silyl hydride complexes (PNPPh)MH(SiR3) (M = Ir, R = Ph (16) and R = Et (17); M = Rh, R = Ph (18), Et (19) and Ph2Cl (20)) via Si–H oxidative addition. The JSiH coupling constants for rhodium complexes 18, 19 and 20 were determined to be ca. 35 Hz, while iridium complexes 16 and 17 exhibited coupling constants less than 10 Hz. X-Ray crystal structures of 16 and 18 reveal isostructural complexes featuring a trigonal bipyramidal geometry about iridium with a mer binding of the PNPPh ligand. A hydride ligand, located from the Fourier map for 18, has a short contact of 1.83(3) Å with the silicon atom. Oxidative addition of iodomethane to 5 and 8 afforded (PNPPh)M(Me)(I)(THF) (M = Rh (14), M = Ir (12)), respectively. Arene C–H activation upon thermolysis of 12 in benzene produced (PNPPh)M(Ph)(I)(THF). Iridium silyl iodide complexes (PNPPh)IrI(SiR3) (SiR3 = SiPh3 (21), SiH2Mes (22) and SiH2Xyl (23)) resulted from addition of organosilanes to 12, via elimination of CH4.

Graphical abstract: Synthesis and reactivity of rhodium and iridium alkene, alkyl and silyl complexes supported by a phenyl-substituted PNP pincer ligand

Back to tab navigation

Supplementary files

Article information


Submitted
08 Dec 2009
Accepted
02 Mar 2010
First published
16 Apr 2010

Dalton Trans., 2010,39, 9250-9263
Article type
Paper

Synthesis and reactivity of rhodium and iridium alkene, alkyl and silyl complexes supported by a phenyl-substituted PNP pincer ligand

E. Calimano and T. D. Tilley, Dalton Trans., 2010, 39, 9250
DOI: 10.1039/B925856F

Social activity

Search articles by author

Spotlight

Advertisements