Ru(II)- and Os(II)-Induced Cycloisomerization of Phenol-Tethered Alkyne for Functional Chromene and Chromone Complexes

Diphosphine-containing Ru­(II)/Os­(II)–chromene and −chromone complexes were synthesized from reactions between phenol ynone HCC­(CO)­(o-C6H4OH) and cis-[Ru/Os­(dppm)2Cl2] (dppm = 1,1-bis­(diphenylphosphino)­methane). The structures of these complexes in the solid state along with their pH-dependent chromene/chromone equilibrium behavior in aqueous medium were investigated. The cis–trans equilibration in solution demonstrated by chloride-ligated Ru–chromene and −chromone series represents a rare example for Ru complexes bearing dppm auxiliary ligands. More importantly, these metalated chromene and chromone complexes exhibit moderate to strong cytotoxicity against several human cancer cell lines and stronger antioxidative activities in comparison with their organic counterpart. Overall, these findings highlight the potential applications of metalated chromenes and chromones as anticancer agents and antioxidants.以酚基炔酮HC≡C(C=O)(o-C6H4OH)与顺式-[Ru/Os(dppm)₂Cl₂]（dppm=1,1-双(二苯基膦)甲烷，1,1-bis(diphenylphosphino)methane）为反应底物，合成了含双膦配体的钌(II)/锇(II)-色烯及色酮配合物。本研究考察了该类配合物的固态结构，以及其在水介质中依赖pH的色烯/色酮平衡行为。由氯配位的钌-色烯及色酮系列配合物所展现的溶液相顺反异构平衡，是搭载dppm辅助配体的钌配合物中极为罕见的实例。尤为重要的是，此类金属化色烯与色酮配合物对多种人类癌细胞系表现出中等至较强的细胞毒性，且相较于其有机母体化合物，抗氧化活性更为突出。综上，上述研究结果凸显了金属化色烯及色酮作为抗癌剂与抗氧化剂的潜在应用价值。