Synthesis and Characterization of Organoboryl Germanium(Ⅱ)Oxides Containing Ge-O-B and Ge-O-B-O-Ge Cores

Organoboryl germanium(Ⅱ)oxides were synthesized from the 1,4-addition reaction of L′Ge(L′=HC[C(CH2)N(Ar)]C(Me)N(Ar),Ar=2,6-iPr2C6H3)with selected monosubstituted arylboronic acids RB(OH)2(R=2,6-Me2C6H3,2,4,6-Me3C6H2,1-Naph)at the molar ratios of 1:1 and 2:1.The mononuclear products RB(OH)OGeL(L=CH[C(Me)N(Ar)]2,Ar=2,6-iPr2C6H3;R=2,6-Me2C6H3(1),2,4,6-Me3C6H2(2),1-Naph(3))containing the Ge–O–B core were obtained smoothly through the 1:1 reaction.However,the reaction of L′Ge with 2,6-Me2C6H3B(OH)2 in a 2:1 ratio gave only the mononuclear product(1)instead of the expected binuclear one.What’s more,a new borate compound[(2,6-Me2C6H3)4B5O6]-[H:C]+(4)(:C=C[N(iPr)C(Me)]2)was concomitantly formed when the in situ prepared L′Ge was used as the precursor.In contrast,the use of 2,4,6-Me3C6H2B(OH)2 or 1-NaphB(OH)2 as the organoboryl source in the similar reaction led to the formation and isolation of the binuclear products RB(OGeL)2(R=2,4,6-Me3C6H2(5),1-Naph(6))containing the Ge–O–B–O–Ge core in a straight way.Compounds 1~6 were determined by single-crystal X-ray diffraction analysis.