Supramolecular Chemistry And Self-assembly Special Feature: Configurationally homogeneous diastereomers of a linearhexa(tertiary phosphine): Enantioselective self-assembly of adouble-stranded parallel helicate of the type(P)-Cu3(hexaphos)2(PF6)3
Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph2PCH2CH2P(Ph)CH2CH2P(Ph)CH2CH2P(Ph)CH2CH2P(Ph)CH2CH2PPh2 (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R)-(−) form of the ligand combines with copper(I) ions to generate by stereoselective self-assembly the P enantiomer of a parallel helicate of the type [Cu3(hexaphos)2](PF6)3, which has been characterized by x-ray crystallography. Theoretical modeling of the cation indicates that it is the relationship between the helicities of the two 10-membered rings containing thethree copper ions, each of which has the twist-boat–chair–boatconformation, and the configurations of the three chiral, tetrahedralcopper stereocenters of P configuration that determinesthe stereochemistry of the parallel and double α-helix conformers ofthe double-stranded trinuclear metal helicate.
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机译：线性六（叔膦）Ph2PCH2CH2P（Ph）CH2CH2P（Ph）CH2CH2P（Ph）CH2CH2P（Ph）CH2CH2PPh2（hexaphos）的三种构型均质非对映异构体已被分离为对映体纯形式，即（R，S，S，R） -，（R，S，S，S）-和（S，S，S，S）-hexaphos。配体的强螺旋（R，S，S，R）-（-）形式与铜（I）离子结合，通过立体选择性自组装产生平行螺旋结构的 P 对映体类型[Cu3（hexaphos）2]（PF6）3，已通过X射线晶体学表征。阳离子的理论模型表明，它是包含10个环的两个10元环的螺旋之间的关系。三个铜离子，每个铜离子都有扭力船-椅子-船构象以及三个手性四面体的构型 P 配置的铜质立体中心确定的平行和双α-螺旋构象异构体的立体化学双链三核金属螺旋。
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