Synthesis, structure and bonding of cadmium(II) thiocyanate systems featuring nitrogen based ligands of different denticity

, and di-μ-S,N-thiocyanatobis{(N,N-diethyl-N′-(1-pyridine-2-yl-ethylidene)-ethane-1,2-diamine)(N-thiocyanato)cadmium(II)}, [Cd(NCS)(μ-SCN)(L3)]2 (3) have been synthesized by reacting cadmium acetate/NH4SCN with 4-amino-pyridine (L1), C5H4N–C(CH3)double bond; length as m-dashNNH2 (L2), and C5H4N–C(CH3)double bond; length as m-dashN–CH2–CH2–N(C2H5)2 (L3), respectively, in methanol. Characterization by single-crystal X-ray crystallography shows that in compounds 1 and 2 the cadmium atoms have a 4N2S-hexa-coordination sphere, exhibiting pseudo-octahedral geometry. The cadmium atoms are bridged by two thiocyanate ions generating 1-D polymeric chains. Compound 3 is a centrosymmetric dimeric complex, with the cadmium atom pseudo octahedrally surrounded by a 5N1S coordination sphere. In compound 1 the crystal packing is controlled mainly by interchain N–H⋯N and C–H⋯π interactions between the aminopyridine moieties, whereas in complexes 2 and 3 π-stacking interactions between the pyridyl planes stabilize the interchain or intermolecular packing, respectively. Thiocyanate and pyridylimine chelation to metal center is also scrutinized with EHMO analysis.