Self-assembling molecular wires of halogen-bridged platinum complexes in organic media. Mesoscopic supramolecular assemblies consisting of a mixed valent Pt(II)/Pt(IV) complex and anionic amphiphiles.
Self-assembling molecular wires of halogen-bridged platinum complexes in organic media. Mesoscopic supramolecular assemblies consisting of a mixed valent Pt(II)/Pt(IV) complex and anionic amphiphiles.
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有机介质中卤素桥铂配合物的自组装分子线。
作者：
N. Kimizuka;N. Oda;T. Kunitake
在有机介质中发展了一类新型的超分子组装，它由卤素桥联铂配合物[Pt(En)2][PtCl2(En)2]4+(en=1，2-二氨基乙烷)和阴离子两亲分子组成。当使用双链磷酸盐或磺酸盐时，生成的[Pt(En)2][PtCl2(En)2](4+)-脂类络合物在结晶态显示出价间电荷转移(CT)吸收带。它们可以溶于有机溶剂，因为它们具有两亲性的超结构，其中疏溶剂的一维铂配合物被亲溶剂的烷基链包围。卤素桥联的线性络合物的CT吸收带在有机介质中保持不变，其颜色取决于组成的两亲分子的化学结构。单烷基磷酸盐未能形成有色的卤素桥联三元络合物，可能是因为它们与PtII(En)2的轴位配位。电子显微镜证实了在有机介质中形成了介观超分子组装。有趣的是，由丁二酸二十六烷基磺酸酯和[Pt(En)2][PtCl2(En)2]4+组成的超分子络合物显示出透明的深蓝色溶液，这与[Pt(En)2][PtCl2(En)2]/二烷基磷酸盐络合物的黄色不同。当将溶液加热到60摄氏度时，前一种络合物的深蓝色消失，而通过将溶液冷却到室温时，它可逆地重新出现。在电子显微镜下，冷却后观察到最小宽度为18 nm、长度为700-1700 nm的棒状纳米结构，但在高温下没有观察到。显然，脂质-[Pt(En)2][PtCl2(En)2]4+络合物在氯仿中经历了可逆解离和重组过程，重组过程后其分散性更好。这一发现开辟了一条通向低维无机络合物溶液化学的一般途径，并使自组装无机分子线的合理设计和控制成为可能。
A novel class of supramolecular assemblies in organic media consisting of a molecular wire of a halogen-bridged platinum complex [Pt(en)2][PtCl2(en)2]4+ (en = 1,2-diaminoethane) and anionic amphiphiles is developed. When double-chained phosphates or sulfonates are employed, the resultant [Pt(en)2][PtCl2(en)2](4+)-lipid complexes displayed intervalence charge transfer (CT) absorption bands in the crystalline state. They are soluble in organic solvents because of the amphiphilic superstructure, in which the solvophobic one-dimensional platinum complex is surrounded by solvophilic alkyl chains. CT absorption bands of halogen-bridged linear complexes are maintained in organic media, with varied colors that depend on the chemical structure of constituent amphiphiles. Monoalkylated phosphates failed to form colored, halogen-bridged ternary complexes probably because of their coordination to the axial position of PtII(en)2. Formation of mesoscopic supramolecular assemblies in organic media was confirmed for the [Pt(en)2][PtCl2(en)2] complexes by electron microscopy. Interestingly, a supramolecular complex consisting of dihexadecyl sulfosuccinate and [Pt(en)2][PtCl2(en)2]4+ displayed clear, indigo solutions that are distinct from the yellow color observed for those of [Pt(en)2][PtCl2(en)2]/dialkyl phosphate complexes. The indigo color of the former complex disappeared upon heating the solution to 60 degrees C, whereas it reappeared reversibly by cooling the solution to room temperature. In electron microscopy, rodlike nanostructures with a minimum width of 18 nm and lengths of 700-1700 nm were observed after cooling, though not at elevated temperatures. Apparently, the lipid-[Pt(en)2][PtCl2(en)2]4+ complex undergoes reversible dissociation and reassembly processes in chloroform, and it becomes better dispersed after the reassembling process. The present finding opens a general route to solution chemistry of low-dimensional inorganic complexes and enables rational design and control of self-assembling inorganic molecular wires.