Synthesis and characterization of new imidorhenium(V) and imidorhenium(VI) complexes of pyridyltriazines and pyrazinyltriazine with halide coligands including rare iodide

The blue colored imido complexes [Re(NC6H4Cl)X3(L)] have been synthesized by three methods: (i) reaction of [ReVOX3(L)] with p-ClC6H4NH2, (ii) reaction of [ReIII(OPPh3)X3(L)] with p-ClC6H4NH2 and (iii) reaction of [ReVOX3(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 (L2) and its dimethyl (L1) and pyrazinyl (L3) analogues. The [Re(NC6H4Cl)Cl3(L1)] (1a), [Re(NC6H4Cl)Cl3(L2)] (1b), [Re(NC6H4Cl)Br3(L2)] (1c), [Re(NC6H4Cl)I3(L2)] (1d), [Re(NC6H4Cl)Cl3(L3)] (1e), [Re(NC6H4Cl)Br3(L3)] (1f), [Re(NC6H4Cl)I3(L3)] (1g), complexes have been characterized electrochemically and spectroscopically. The X-ray structures of [Re(NC6H4Cl)Cl3(L2)] and [Re(NC6H4Cl)I3(L3)] 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.

The blue colored imidorhenium(V) complexes of pyridyltriazines and pyrazinyltriazine with various halide coligands including rare iodide have been synthesized by three methods. The complexes have been characterized structurally, spectroscopically and electrochemically. The feasibility of generating the rhenium(VI) congener of the imidorhenium(V) complex is examined with help of six-line EPR spectra at room temperature.Figure optionsDownload as PowerPoint slide