The reactivity of the novel cationic ligand precursor [(dppm)₂CH](PF₆) (1) with a weakly coordinating anion and [ReBr(CO)₅] is reported. The initial coordination results in the formation of the facially coordinated dicationic complex fac-[({dppm}₂CH)Re(CO)₃]X₂ (fac-2, X=Br, PF₆). The facial coordination mode is retained in fac-[({dppm}₂C)Re(CO)₃](PF₆) (fac-3) upon deprotonation of the central cationic donor group. Quantum chemical investigations indicate that for both complexes, 2 and 3, the meridional coordination mode is thermodynamically favored. In line with these findings, the isomerization of the facially coordinated complex fac-3 to the meridionally coordinated complex mer-[({dppm}₂C)Re(CO)₃](PF₆) (mer-3) is observed under irradiation with UV-light.

中文翻译：

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具有基于碳二正膦的三齿配体的 ReI 三羰基复合物中的面部与经向协调模式

报道了新型阳离子配体前体 [(dppm) ₂ CH](PF ₆ ) ( 1 ) 与弱配位阴离子和 [ReBr(CO) ₅ ] 的反应性。初始协调导致形成面部协调的双阳离子复合物fac- [({dppm} ₂ CH)Re(CO) ₃ ]X ₂ ( fac- 2 , X=Br, PF ₆ )。面部协调模式保留在fac- [({dppm} ₂ C)Re(CO) ₃ ](PF ₆ ) ( fac- 3) 在中央阳离子供体基团去质子化时。量子化学研究表明，对于复合物2和3，经向配位模式在热力学上是有利的。与这些发现一致，在辐照下观察到面部配位复合物fac- 3异构化为经向配位复合物mer- [({dppm} ₂ C)Re(CO) ₃ ](PF ₆ ) ( mer- 3 )用紫外线。