synthesis, characterization, electrochemical and spectroelectrochemical properties of ruthenium(ii) complexes containing phenylcyanamide ligands and effect of the inner- sphere on the ru-ncn chromophore

[ru(terpy)(bpy)(l)]pf6 complexes, where terpy is 2,2΄:6′,2″– terpyridine, bpy is 2,2΄ - bipyridine and l is monoanions of  4 - bromophenylcyanamide (4 - brpcyd), 4-methoxyphenylcyanamide (4 - meopcyd), 2, 4 - dibromophenylcyanamide (2,4 - br2pcyd), 2,4-dimethylphenylcyanamide (2,4 - me2pcyd), 2 - methylphenylcyanamide  (2 - mepcyd), phenylcyanamide  (pcyd) and naphtylcyanamide  (ncyd)  have been prepared  and  characterized  by elemental   analysis,  ir,  1h-nmr and uv-vis spectroscopies and cyclic voltammetry. spectroelectrochemistry was used  to  generate  the electronic  absorption  spectra  of  the ru(iii)  complexes, [ru(terpy)(bpy)(l)]2+  in acetonitrile  solution. the  spectral  data  associated  with the  ru(iii)-cyanamido lmct chromophore were  compared to those  derived from  ru(iii) analogues in  order to gain a greater understanding  the effect of spectator ligands on the nature of the ru(iii)-cyanamide bond.the data supports greater covalency in the ru(iii)-cyanamide bond of [ru(terpy)(bpy)(l)]2+ complexes compared to their ru(iii) analogues.