Synthesis and Structure of Silver and Rhodium 1,2,3-Triazol-5-ylidene Mesoionic Carbene Complexes

New mono- and bidentate 1,2,3-triazol-5-ylidene mesoionic
carbene
(MIC) ligands have been synthesized and reacted with silver oxide,
forming cationic 1:2 and 2:2 Ag:MIC ([AgL2]Br and [Ag2L2]­[Ag2Br4]) complexes, respectively.
These complexes have been isolated and characterized. They were further
found to be potent transmetalation agents toward rhodium, resulting
in the preparation of mono- and bimetallic rhodium complexes. The
reaction of the 2:2 Ag:L complex with [Rh­(COD)2]­BF4 results in the first reported example of a cationic bimetallic
rhodium MIC complex. This complex was fully characterized, and
its X-ray structure is reported. Interestingly, this complex exhibits
various secondary noncovalent interactions in the solid state of the
general type C–H···X, where X = F, Cl.

本研究成功合成了新型单齿与双齿1,2,3-三唑-5-亚基介离子卡宾（1,2,3-triazol-5-ylidene mesoionic carbene, MIC）配体，并将其与氧化银反应，分别得到阳离子型1:2与2:2型银-MIC配合物([AgL₂]Br与[Ag₂L₂][Ag₂Br₄])。上述配合物均已完成分离与表征。进一步研究表明，这类配合物可作为高效金属转移试剂与铑发生反应，成功制备出单金属与双金属铑配合物。其中，2:2型银-配体配合物与[二(1,5-环辛二烯)铑(I)]四氟硼酸盐([Rh(COD)₂]BF₄)的反应，得到了首例阳离子型双金属铑MIC配合物。该配合物已被全面表征，其X射线晶体结构也已被报道。值得注意的是，该配合物在固态下存在多种通式为C–H···X（X=F、Cl）的次级非共价相互作用。