Syntheses, Characterization, Thermal, and Antimicrobial Studies of Lanthanum(III) Tolyl/Benzyldithiocarbonates

Lanthanum(III) tris( O -tolyl/benzyldithiocarbonates), [La(ROCS 2 )] (R = o -, m -, p -CH 3 C 6 H 4 and C 6 H 5 CH 2 ), were isolated as yellow solid by the reaction of LaCl 3 · 7H 2 O with sodium salt of tolyl/benzyldithiocarbonates, ROCS 2 Na (R = o -, m -, p -CH 3 C 6 H 4 and C 6 H 5 CH 2 ), in methanol under anhydrous conditions in 1 : 3 molar ratio. These complexes have formed adducts with nitrogen and phosphorus donor molecules by straightforward reaction of these complexes with donor ligands, which have the composition of the type [La(ROCS 2 ) 3 · nL] (where n = 2, L = NC 5 H 5 or P(C 6 H 5 ) 3 and n = 1, L = N 2 C 12 H 8 or N 2 C 10 H 8 ). Elemental analyses, mass, IR, TGA, and heteronuclear NMR ( 1 H, 13 C and 31 P) spectroscopic studies indicated bidentate mode of bonding by dithiocarbonate ligands leading to hexacoordinated and octacoordinated geometry around the lanthanum atom. Antimicrobial (antifungal and antibacterial) activity of the free ligands and some of the complexes have also been investigated which exhibited significantly more activity for the complexes than the free ligands.