ISOMERIC DITHIOCYANATE COMPLEXES OF RUTHENIUM(II), SYNTHESIS, CHARACTERIZATION OF ALL POSSIBLE BOND ISOMERS OF TRANS,CIS-RU(CNS)2L2 [L = 2-(ARYLAZO)PYRIDINE] AND STUDIES OF ISOMERIZATION

A series of isomeric new dithiocyanate ruthenium(II) complexes of the type trans,cis-Ru(CNS)2L2 [L = 2-(arylazo)pyridine] have been synthesi zed by a stereoretentive substitution reaction from the known diaquo c ationic complex trans,cis-[Ru(OH2)2L2]2+. All possible linkage isomers have been separated on a silica gel column and investigated for linka ge isomerism. These isomers have been thoroughly characterized from ph ysical properties, H-1 NMR, IR and UV-vis spectroscopy. It has been sh own that the most stable linkage isomer in this case is S,S bonded. Tw o (S,N and N,N) out of three isomers of trans,cis-Ru(CNS)2L2 are conve rted into the third (S,S) isomer on boiling in xylene. Similar transfo rmations have also been observed in the solid state. Factors influenci ng the population of the various isomers are noted.