Synthese und Metallierungen der tripodalen Siloxazan-Liganden tBuSi(OSiMe2NHR)3 [R = H,Me, tBu,Ph, SiMe3]

Synthesis and Metalation of Tripodal Siloxazane Ligands ^tBuSi(OSiMe₂NHR)₃ R = H, Me, ^tBu, Ph, SiMe₃] ^tBuSi(OSiMe₂Cl)₃ ( 1 ) was generated by the condensation of tert-butylsilanetriol with dichlorodimethylsilane under elimination of HCl. A series of tripodal amines ^tBuSi(OSiMe₂NHR)₃ R = H ( 2 ), R = Me ( 3 ), R = ^tBu ( 4 ), R = Ph ( 5 )] was synthesized by ammonolysis, aminolysis or salt elimination of 1 with primary lithium amides. 5  has been subjected to single crystal X-ray diffraction, which confirmed the triarmed amine. The siloxamine ^tBuSi(OSiMe₂NHSiMe₃)₃ ( 6 ) was generated by the reaction of 2 with three moles of chlorotrimethylsilane. The lithium amides ^tBuSi(OSiMe₂NLi]^tBu)₃ ( 7 ), ^tBuSi(OSiMe₂NLi]Ph)₃ ( 8 ) and ^tBuSi(OSiMe₂NLi]SiMe₃)₃ ( 11 ) and the sodium amide ^tBuSi(OSiMe₂NNa]^tBu)₃ ( 9 ) were obtained by the complete hydrogen–metal exchange of the amines 4 – 6 with n-butyl lithium and n-butyl sodium in hexane, respectively. The transmetalation of 7 with copper(I) chloride gave the copper amide ^tBuSi(OSiMe₂NCu]^tBu)₃ ( 10 ). The single crystal X-ray diffraction of the metal amides 7 , 9 and 11 shows a trifold coordination by additional interactions between each of the two metal atoms with oxygens in the siloxane groups in contrast to the copper amide 10 , which lacks such contacts. The almost isostructural metal amides 7 , 9 – 11 are monomeric and possess, similary to 5 , a pseudo three fold symmetry in the solid state. 5 and 7 crystallize in the monoclinic space group P2₁/c whereas the compounds 9 – 11 crystallize in the centrosymmetric triclinic space group P 1.