Chiral Spirocyclic Germanium Thiolates – An Evaluation of Their Suitability for Twin Polymerization based on A Combined Experimental and Theoretical Study
Chiral Spirocyclic Germanium Thiolates – An Evaluation of Their Suitability for Twin Polymerization based on A Combined Experimental and Theoretical Study
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DOI：
10.1002/slct.201600314
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发表时间：
2016-05
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通讯作者：
Philipp Kitschke;T. Rüffer;H. Lang;A. Auer;M. Mehring
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作者：
Philipp Kitschke;T. Rüffer;H. Lang;A. Auer;M. Mehring
合成了螺环硫代锗盐4H，4’H-2，2’-spirobi[benzo[d][1，3，2]dithiagermine](1)、4H，4’H-2，2’-spirobi[benzo[d][1，3，2]oxathiagermine](2)和4H，4’H-2，2’-spirobi[benzo[e][1，3，2]oxathiagermine](3)，并对其结构进行了表征。化合物3结晶为外消旋团聚体，而化合物1和2在固体状态下形成外消旋体。测试了它们对孪晶聚合(TP)的反应活性。关于质子辅助TP的研究表明，与最近报道的硅衍生物4H，4’H-2，2’-spirobi[benzo[d][1，3，2]dioxasiline](A)相比，反应性显著降低。对1-3和模型化合物4H，4’H-2，2’-spirobi[benzo[d][1，3，2]dioxagermine](4)进行了DFT−D计算，以评估引发质子辅助TP过程的第一步反应。具有四个氧原子的锗的化合物4被证明是最活跃的前体，但它的合成失败了。密度泛函−D计算表明，化合物1和2不适合TP。从化合物3出发，通过热退火得到了含锗和硫的有机-无机杂化材料。
The spirocyclic germanium thiolates, 4H,4’H-2,2’-spirobi[benzo[d][1,3,2]dithiagermine] (1), 4H,4’H-2,2’-spirobi[benzo[d][1,3,2]oxathiagermine] (2) and 4H,4’H-2,2’-spirobi[benzo[e][1,3,2]oxathiagermine] (3) were synthesized and fully characterized. Compound 3 crystallizes as racemic conglomerate, whereas 1 and 2 give racemates in the solid state. Their reactivity towards twin polymerization (TP) was tested. The studies with regard to proton-assisted TP revealed a significantly reduced reactivity as compared to the recently reported silicon derivative, 4H,4’H-2,2’-spirobi[benzo[d][1,3,2]dioxasiline] (A). DFT−D calculations were performed for 1–3 and the model compound 4H,4’H-2,2’-spirobi[benzo[d][1,3,2]dioxagermine] (4) to evaluate the first reaction step initiating the processes of proton-assisted TP. Compound 4 with germanium bound to four oxygen atoms proved to be the most reactive precursor, but its synthesis failed. As indicated by the DFT−D calculations, compounds 1 and 2 are not suitable for TP. Starting from compound 3 a germanium and sulfur containing organic-inorganic hybrid material was obtained by thermal annealing.