Study of Dehydrocoupling Reactions of Diorganotin Dihydrides R 1 R 2 SnH 2 with Biuret

The reaction of unsymmetrical phenylmethyltin dihydride (PhMeSnH 2 ), phenylethyltin dihydride (PhEtSnH 2 ), phenylbutyltin dihydride (PhBuSnH 2 ) and butylmethyltin dihydride (BuMeSnH 2 ) with biuret (H 2 L) proceeds via SnH/NH dehydrocoupling to afford the corresponding tetra‐coordinate cyclic products. The reactions in the molar ratios of 1:1, 2:1 and 1:2 have been studied. The yellow derivatives so isolated were soluble in polar solvents and insoluble in nonpolar solvents. It was found that 1:1 reaction went to completion while 2:1 and 1:2 did not go to completion. The derivatives had been characterized by elemental analysis and spectroscopic techniques viz. IR, 1 H NMR, 13 C NMR, 119 Sn NMR. DSC and TGA of the reaction products have also been studied. All the derivatives were thermally stable upto (190±10) °C and degradation occurred after that.