Synthesis and NMR solution properties of Rhenium(I) and Platinum(IV) complexes of oligopyridines
摘要:
Syntheses and characterisation data are reported for the following Re-I and Pt-IV bidentate chelate complexes of oligopyridines, [{ReBr(CO)(3)}(2)L] (L=2,2':6',2:6 ",2'''-quaterpyridine (QP), or 4',4 "-bis(4-tert-butylphenyl)-2,2':6',2 ":6 ",2'''-quaterpyridine (BPQP)), [(PtIMe3)(2) (QP)], [ReBr(CO)(3)(QP)] and [ReBr(CO)(3)(BPQNP)] (BPQNP=4',4"'-bis(4-tert-butylphenyl)-2,2':6',2 ":6 ",2''':6''',2''''-quinquepyridine). The mononuclear complexes do not exhibit metallotropic shifts in solution as occur in the three-ring 2,2':6',2 "-terpyridine complex analogues. This is attributed to the steric effects of the uncoordinated portions of these ligands, which also lead to severe restrictions to rotation of these pendant arms. Such movements were investigated by low temperature NMR spectra. (C) 1999 Elsevier Science Ltd. All rights reserved.
Soluble 4-tert-butylphenyl substituted derivatives of 2,2':6',2''-terpyridine, 2,2':6',2'':6'',2'''-quaterpyridine, 2,2':6',2'':6'',2''':6''',2''''-quinquepyridine and 2,2':6',2'':6'',2''':6''',2'''':6'''',2'''''-sexipyridine have been prepared. The ligands and their metal complexes are more soluble than unsubstituted analogues, but the introduction of the bulky substituent does not perturb any metal centred processes.