Studies of rheniumtricarbonyl complexes of tripodal pyridyl-based ligands
摘要:
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 H-1 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. (C) 2009 Elsevier B.V. All rights reserved.
Studies of rheniumtricarbonyl complexes of tripodal pyridyl-based ligands
摘要:
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 H-1 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. (C) 2009 Elsevier B.V. All rights reserved.
Studies of rheniumtricarbonyl complexes of tripodal pyridyl-based ligands
作者:D. Vaughan Griffiths、Mohamad J. Al-Jeboori、Phillip J. Arnold、Yuen-Ki Cheong、Philip Duncanson、Majid Motevalli
DOI:10.1016/j.ica.2009.11.039
日期:2010.4
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 H-1 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 facRe(CO)(3)}(+) core. (C) 2009 Elsevier B.V. All rights reserved.