Can geometry control the coordination behaviour of 2-hydroxy-1-naphthaldehyde-N(4)-phenylthiosemicarbazone? A study towards its origin

2-Hydroxy-1-naphthaldehyde-N(4)-phenylthiosemicarbazone [H2-Nap-ptsc] (H2L) was reacted with square planar complexes of the type [MCl2(EPh3)2] (where M = Ni or Pd; E = P or As) and octahedral [RuHCl(CO)(PPh3)3]. Square planar complexes ([Ni(Nap-ptsc)PPh3)]; [Pd(Nap-ptsc)PPh3)]; [Pd(Nap-ptsc)AsPh3)]) gave products with only ONS tri coordinated thiosemicarbazone whereas octahedral ruthenium complex gave two products, one with NS and the other with ONS coordination. It is interesting to note that NS bi coordination leads to the formation of more strained four member ring. All the new complexes have been characterised by analytical, spectral, crystallographic and electrochemical methods.