Vittal Jagadese J, Quah Hong Sheng
Department of Chemistry, National University of Singapore, Singapore 117543.
Dalton Trans. 2017 Jun 6;46(22):7120-7140. doi: 10.1039/c7dt00873b.
This perspective focusses on the solid-state reactivity and structural transformation driven by photochemical methods in discrete metal complexes, organometallic compounds, metallo-macrocycles and cages. Changes in the metal-metal bond distances, racemization of chiral centres, fusion of cages, formation of coordination polymers, expected [2 + 2] and [4 + 4] cycloaddition products, unusual phenyl-olefin dimerization, and linkage isomerization of -SO, -NO & -NO ligands cause the structural transformations. Of these, [2 + 2] photo-cycloaddition reactions have been widely studied and the photoreactions are made possible by various supramolecular interactions including hydrogen bonds, metallophilic, ππ and C-Hπ interactions, ligand design and metallic clips to bring the reactive functional groups closely into correct orientation close to the transition state. These photoreactions are often accompanied by crystal bending, mechanical motion, and changes in the magnetic and photoluminescence properties. In several cases, the single crystals have been preserved at the end of the reactions, which are known as single-crystal-to-single-crystal (SCSC) reactions.
这一观点聚焦于由光化学方法驱动的离散金属配合物、有机金属化合物、金属大环化合物和笼状化合物中的固态反应性和结构转变。金属-金属键距的变化、手性中心的外消旋化、笼状化合物的融合、配位聚合物的形成、预期的[2 + 2]和[4 + 4]环加成产物、异常的苯基-烯烃二聚化以及-SO、-NO和-NO配体的键合异构化导致了结构转变。其中，[2 + 2]光环加成反应已得到广泛研究，并且通过各种超分子相互作用（包括氢键、亲金属作用、ππ和C-Hπ相互作用、配体设计以及金属夹）使反应官能团紧密排列成接近过渡态的正确取向，从而实现光反应。这些光反应通常伴随着晶体弯曲、机械运动以及磁性和光致发光性质的变化。在几种情况下，反应结束时单晶得以保留，这被称为单晶到单晶（SCSC）反应。
