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Synthesis and characterization of organoimido- and organoamido-rhenium(V) complexes. Crystal structures of [ReCl2(NC6H4PPh2-2)(HNC6H4PPh2-2)], [Re(8-HNC9H6N)2O(PPh3)][BPh4] and [Re(NPh)(NC5H3S-2-SiMe3-3)2(PPh3)][BPh4]

1995; Royal Society of Chemistry; Issue: 18 Linguagem: Inglês

10.1039/dt9950003041

2050-5671

Mustafa T. Ahmet, Brian Coutinho, Jonathan R. Dilworth, John R. Miller, Suzanne J. Parrott, Yifan Zheng, Mary E. Harman, Michael B. Hursthouse, Abdul Malik,

Coordination Chemistry and Organometallics

The reaction of [ReCl3O(PPh3)2] in toluene with 2-diphenylphosphinoaniline yielded the brown rhenium(V) amido/imido-complex [ReCl2(NC6H4PPh2-2)(HNC6H4PPh2-2)]1. This represents the first example of a metal complex where a 2-aminophenylphosphine is fully deprotonated to give an N,P chelated imido-complex. The crystal structure of 1 shows a distorted-octahedral geometry with the imido-nitrogen trans to chloride whereas the amido-nitrogen is disposed trans to a phosphorus. The Re–N length of 1.988(4)Å for the amido nitrogen is consistent with protonation of the nitrogen in the chelated ligand. A Re–N bond length of 1.757(4)Å and a Re–N–C angle of 137.8(3)° for the deprotonated imide nitrogen imply substantial multiple bonding. The oxo-complex [Re(8-HNC9H6N)2O(PPh3)][BPh4]2 was the unexpected product in the reaction of [ReCl3O(PPh3)2] with 8-aminoquinoline in ethanol. It has a distorted-octahedral structure with two chelated amide ligands. The two quinoline-ring nitrogens as well as the two amido-nitrogens are arranged in a mutually cis configuration. The oxo and triphenylphosphine ligands occupy the remaining co-ordination sites. Reaction of [ReCl3(NPh)(PPh3)2] in ethanol with the sterically hindered 3-trimethylsilylpyridine-2-thiol (Htspyt) yielded the green rhenium(V) phenylimido-complex [Re(NPh)(PPh3)(tspyt)2][BPh4]3. Reaction of the unsubstituted pyridine-2-thiol (Hpyt) with the parent imido-complex yielded the analogous complex [Re(NPh)(PPh3)(pyt)2][BPh4]4. The crystal structure of 3 reveals a distortedoctahedral configuration of the ligands about the central rhenium atom. The imide and phosphine ligands are cis with the remaining sites being occupied by the S,N chelated pyridinethiolate ligands. A ReN bond length of 1.725(8)Å and a Re–N–C bond angle of 166.0(6)° are indicative of the imide ligand functioning as a four-electron donor.