摘要:
The blue colored imido complexes [Re(NC6H4Cl)X-3(L)] have been synthesized by three methods: (i) reaction of [(ReOX3)-O-V(L)] with p-ClC6H4NH2, (ii) reaction of [Re-III(OPPh3)X-3(L)] with p-ClC6H4NH2 and (iii) reaction of [(ReOX3)-O-V(PPh3)(2)] with L followed by the addition of p-ClC6H4NH2 in boiling toluene. Here, X = Cl, Br, I and L are 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine (L-2) and its dimethyl (L-1) and pyrazinyl (L-3) analogues. The [Re(NC6H4Cl) Cl-3(L-1)] (1a), [Re(NC6H4Cl)Cl-3(L-2)] (1b), [Re(NC6H4Cl) Br-3(L-2)] (1c), [Re(NC6H4Cl)I-3(L-2)] (1d), [Re(NC6H4Cl)Cl-3(L-3)] (1e), [Re(NC6H4Cl)Br-3(L-3)] (1f), [Re(NC6H4Cl)I-3(L-3)] (1g), complexes have been characterized electrochemically and spectroscopically. The X-ray structures of [Re(NC6H4Cl)Cl-3(L-2)] and [Re(NC6H4Cl)I-3(L-3)] reveal that the ReCl3 fragment is meridionally disposed and that the L ligand is N,N-coordinated such that the pyridine/pyrazine nitrogen lies trans to the imide nitrogen. The feasibility of generating the rhenium(VI) congener of the imidorhenium(V) complex is also examined with the help of six-line EPR spectra at room temperature. (c) 2008 Elsevier B.V. All rights reserved.