“…The pyridyl based bis-thiosemicarbazones form a series of seven-coordinate complexes of general formula, [R 2 SnL] 547-553 [133,160,334,368,[374][375][376]378] (Chart 75). In complex, [Ph 2 Sn(HL)]Cl, 549 [133], the ligand is mononegative with one chlorine outside the coordination sphere, while it is neutral in [Bu n 2 Sn(H 2 L)]Cl 2 , 552 [376] and dinegative in [R 2 SnL] (547, 548, 550, 551 and 553) (Fig.…”