D. Griffiths, M. J. Al-Jeboori, P. Arnold
Apr 5, 2010
Citations
0
Influential Citations
5
Citations
Journal
Inorganica Chimica Acta
Abstract
The reaction of N -benzoyl and N -acetyl tris(pyridin-2-yl)methylamine 1b and 1c (LH = tpmbaH and tpmaaH) with [Re(CO) 5 Br] has been investigated and shown to proceed via the initial formation of a cationic rheniumtricarbonyl complex [(LH)Re(CO) 3 ]Br in which coordination of the ligand occurs via the three pyridine rings. For tpmbaH 1b , but not tpmaaH 1c , this initial complex 2b readily undergoes the loss of HBr to give a neutral octahedral complex 4b [(L)Re(CO) 3 ] where coordination occurs via two of the pyridine rings and the deprotonated amide nitrogen. The 1 H NMR spectrum of the latter complex 4b is very unusual in that at room temperature the signals for the 3-H protons on the coordinated pyridine rings are not visible due to extreme broadening of these resonances. Comparison with the analogous complex 7 from N -benzoyl bis(pyridin-2-yl)methylamine 6b (bpmbaH) confirms that this is due to rotation of the uncoordinated pyridine ring. The structure of the cationic complex 3d [(LH)Re(CO) 3 ]Br formed from N -benzyl tris(pyridin-2-yl)methylamine 1d (bz-tpmaH) is also discussed. The crystal structures of complexes [(tpmba)Re(CO) 3 ] 4b , [(bz-tpmaH)Re(CO) 3 ]Br 3d and [(bpmba)Re(CO) 3 ] 7 have been determined. In all complexes the coordination geometry around Re is distorted octahedral with a fac -{Re(CO) 3 } + core.