Synthesis and Structure of Zwitterionic Silylborates and Silylzincates with Pendant Polydonor Arms

The synthesis and structure of well-defined zinc- and
potassium-containing
heterobimetallic zwitterions that have pendant polydonor arms is reported.
The zwitterionic complexes [Me2ZnSi­(SiMe2OCH2CH2OMe)3Li] (Li-2), [Cl2ZnSi­(SiMe2OCH2CH2OMe)3K] (K-3), and [I2ZnSi­(SiMe2OCH2CH2OMe)3K] (K-4) were prepared from reactions of [Si­(SiMe2OCH2CH2OMe)3M] (M = Li, K) (M-1) with
ZnCl2, ZnI2, and ZnMe2, respectively.
Reaction of K-1 with B­(C6F5)3 gave the potassium silyl borate [(C6F5)3BSi­(SiMe2OCH2CH2OMe)3K] (K-5) in 90% yield. Treatment of 2 equiv of
K-1 with ZnCl2 afforded the nonzwitterionic
zinc silanide Zn­(Si­(SiMe2OCH2CH2OMe)3)2 (6), as a liquid, which upon treatment
with 1 equiv of ZnMe2 and 4 equiv of B­(C6F5)3 could be converted into the zwitterionic zinc
silyl borate [(C6F5)3BSi­(SiMe2OCH2CH2OMe)3Zn]­[MeB­(C6F5)3] (7). The structures
of the zwitterionic complexes K-4, K-5,
and 7 were determined by X-ray crystallography.

本文报道了一类带有悬挂式多供体配臂(pendant polydonor arms)、结构明确的含锌与钾的异双金属两性离子(heterobimetallic zwitterions)的合成与结构表征。三类两性离子配合物[二甲基锌基三(二甲基硅基乙氧基甲氧基)硅锂](Li-2)、[二氯化锌基三(二甲基硅基乙氧基甲氧基)硅钾](K-3)以及[二碘化锌基三(二甲基硅基乙氧基甲氧基)硅钾](K-4)，分别通过[三(二甲基硅基乙氧基甲氧基)硅金属](M = Li, K)(M-1)与氯化锌、碘化锌及二甲基锌的反应制得。K-1与三(五氟苯基)硼(B(C₆F₅)₃)反应，以90%的收率得到硅基硼酸钾配合物[(C₆F₅)₃BSi(SiMe₂OCH₂CH₂OMe)₃K](K-5)。将2当量K-1与氯化锌反应，可得到非两性离子型硅锌化物二(三(二甲基硅基乙氧基甲氧基)硅基)锌(6)，该化合物为液体；将其与1当量二甲基锌及4当量三(五氟苯基)硼反应，可转化为两性离子型硅基硼酸锌配合物[(C₆F₅)₃BSi(SiMe₂OCH₂CH₂OMe)₃Zn][MeB(C₆F₅)₃](7)。通过X射线晶体衍射法(X-ray crystallography)确定了两性离子配合物K-4、K-5及7的晶体结构。