From chlorogermylenes to stable hydroxy- and siloxy-germylene-tungsten complexes

Reaction of the chlorogermylene ArGeCl [Ar = 2,6-bis((diethylamino)methyl)phenyl] with lithium amides afforded the aminogermylenes ArGeNR2 1 (1a, R = SiMe3; 1b, R = Pr-i); la was structurally analyzed by X-ray diffraction. A protic reagent such as 2,4,6-trimethylphenol (Ar'OH) reacts with 1b, leading to the mesityloxygermylene ArGeOAr' 2. Subsequent hydrolysis of tungsten complexes 1.W(CO)(5) gave ArGeOH-W(CO)(5),3. From la, ArGeOSiMe3.W(CO)(5) (4) also was obtained. Compounds 3 and 4 are the first stable hydroxy- and siloxygermylene complexes. X-ray analysis of 3 shows an increased coordination of the side-chain nitrogen atoms to the germanium resulting from the complexation Ge-->W. This complexation can also explain the significant acidity of the hydroxy group in 3, in the same range as triphenylgermanol Ph3GeOH.