Zhu Lin, Tang Xiao, Yu Qi, Lv Wen, Yan Hong, Zhao Qiang, Huang Wei
State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093 (P.R. China).
Chemistry. 2015 Mar 16;21(12):4721-30. doi: 10.1002/chem.201405897. Epub 2015 Feb 6.
2-Thienylpyridyl iridium(III) complexes containing an o-, m-, or p-carboranylvinyl-2,2'-bipyridine ligand and various counteranions (denoted o-PF6, m-BF4, m-PF6, m-SbF6, m-ClO4, m-OTf, m-NO3, m-BPh4, m-F, m-Cl, and p-PF6) were synthesized by using C-formyl carboranes as starting materials. The solid-state structures of o-PF6, m-PF6, m-ClO4, and m-BF4 showed that the cations form twisted cavities in which the anions are fixed by multiple hydrogen bonds. Anion-hydrogen interactions were investigated for nine m-carborane-based complexes with different counteranions. All carborane-based iridium(III) complexes show similar phosphorescence yields in solution but significantly different emission in the solid state. Anion-exchange titration and theoretical calculations revealed the relationships between structures and optical properties. The size of the anion and C-H⋅⋅⋅X anion-hydrogen bonds strongly influence the phosphorescence quantum yield in the solid state. In particular, the Ccar-H⋅⋅⋅X hydrogen bonds between the carboranyl unit and the anion play an important role in solid-state phosphorescence. Complex p-PF6 was successfully applied in phosphorescence-lifetime bioimaging owing to its low toxicity and near-infrared emission.
以碳甲酰基碳硼烷为起始原料合成了含有邻位、间位或对位碳硼烷基乙烯基-2,2'-联吡啶配体及各种抗衡阴离子（分别表示为o-PF6、m-BF4、m-PF6、m-SbF6、m-ClO4、m-OTf、m-NO3、m-BPh4、m-F、m-Cl和p-PF6）的2-噻吩基吡啶铱(III)配合物。o-PF6、m-PF6、m-ClO4和m-BF4的固态结构表明，阳离子形成扭曲的空腔，其中阴离子通过多个氢键固定。研究了九种具有不同抗衡阴离子的间位碳硼烷基金属配合物的阴离子-氢相互作用。所有碳硼烷基金属铱(III)配合物在溶液中表现出相似的磷光产率，但在固态时发射有显著差异。阴离子交换滴定和理论计算揭示了结构与光学性质之间的关系。阴离子的大小和C-H⋅⋅⋅X阴离子-氢氢键强烈影响固态下的磷光量子产率。特别是，碳硼烷基单元与阴离子之间的Ccar-H⋅⋅⋅X氢键在固态磷光中起重要作用。配合物p-PF6因其低毒性和近红外发射而成功应用于磷光寿命生物成像。
