Rhenium and Technetium Complexes with Diphenyl(2-pyridyl)phosphine

Rhenium and Technetium Complexes with Diphenyl(2-pyridyl)phosphine

Abram, U.; Alberto, R.; Dilworth, J. R.; Zheng, Y.; Ortner, K.

The potentially bidentate ligand diphenyl(2-pyridyl)phosphine (PPh2py) reacted with (NEt4)2[MI(CO)3X3] complexes (M = Re, Tc) to give (NEt4)[MI(CO)3X2(PPh2py-P)] or [MI(CO)3X(PPh2py-P)2] depending on the amount of the ligand used. The reaction with (NBu4)[TcVINCl4] yielded [TcVNCl2(PPh2py-P)2] whereas from the reaction with (NBu4)[ReOCl4] the complexes [ReVOCl3(PPh2py-P,N)], [ReVOCl3(OPPh2py-O,N)], [ReIVCl4(OPPh2py-O,N) and [ReIVCl3(OH)(OPPh2py-O,N)] have been isolated. Reduction of the metal center occurs using an excess of PPh2py and heating of the reaction mixtures under reflux.
The products have been characterised spectroscopically and by X-ray structure analysis. Monodentate co-ordination via phosphorus has been found for the rhenium(I) carbonyl complexes and [TcVNCl2(PPh2py-P)2]. In the latter compound a trigonal-bipyramidal coordination sphere is formed with the phosphines as axial ligands (bond angle P-Re-P: 161.69(3)°). The chelated complexes show small N-Re-P and N-Re-O bite angles of 63.6° and 77.7 - 82.2° due to the 4-membered or 5-membered chelate rings. The pyridine nitrogen occupies the axial position (trans to "O2-") in [ReOCl3(PPh2py-P,N)] whereas equatorial co-ordination is found in [ReOCl3(OPPh2py-O,N)].

Keywords: Rhenium; Technetium; Diphenylpyridylphosphine; Diphenylpyridylphosphine oxide; X-ray structures

  • Polyhedron 18 (1999) 2995-3005

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Publ.-Id: 1937