Study of Dehydrocoupling Reactions of Diorganotin Dihydrides R1R2SnH2 with Biuret

phenylmethyltin dihydride (PhMeSnH₂), phenylethyltin dihydride (PhEtSnH₂), phenylbutyltin dihydride (PhBuSnH₂) and butylmethyltin dihydride (BuMeSnH₂) with biuret (H₂L) 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, ¹H NMR, ¹³C NMR, ¹¹⁹Sn NMR. DSC and TGA of the reaction products have also been studied. All the derivatives were thermally stable upto (190±10) ℃ and degradation occurred after that.