N-[hydroxy(dimethyl)silylmethyl]-N,N′-propylene urea hydrochloride: Synthesis and structure

The new N-chlorodimethylsilylmethyl-N′-trimethylsilyl-N,N′-propylene urea 5 was synthesized by trans-silylation reaction of N,N′-bis(trimethylsilyl)-N,N′-propylene urea 4 with ClCH2SiMe2Cl. Mild hydrolysis of compound 5 results in the formation of N-[hydroxy(dimethyl)silylmethyl]-N,N′-propylene urea hydrochloride 6. The structure of the studied compounds in solution was determined by 1H, 13C and 29Si NMR spectroscopy and by X-ray analysis in the solid state. The results of these studies are indicative of pentacoordination of the silicon atoms in ureas 5 and 6. Compound 6 is a new example of poorly known protonated silanols with hypervalent silicon atom.

► The new silanol LCH2SiMe2OH·HCl (L-propylene urea) was obtained.
► The structure of silanol was determined by 1H, 13C and 29Si NMR spectroscopy.
► X-ray structural investigation confirmed a pentacoordination of the silicon atom.