Synthesis and Reactivity Studies of Irida-carbolong Complexes 铱杂碳龙配合物的合成及反应性

The term "carbolong complexes" represents a series of novel π-conjugating aromatic frameworks, which are formed by the chelation of a carbon chain (carbolong ligand) containing not less than 7 carbon atoms with a transition metal fragment. Carbolong complexes show unique photophysical properties, thus exhibiting promising potential applications. Inspired by the efficient strategies for the construction of Os-, Ru-, and Rh-carbolong complexes by the reactions of multiynes with simple metal sources, we describe here the reasonable design of two multiyne compounds 1 and 2, which could react with the iridium precursor [Ir(CHCN)(CO)(PPh)]BF ( 3) to produce the irida-carbolong complexes 4and 5 with a large π conjugation system via a "one-pot" method, respectively. This is the first time to expand the carbolong complex to iridium. In addition, the ligand substitution reactions of 4 and 5have been investigated. Treatment of corresponding ligands with 4 and 5resulted in the generation of several new irida-carbolong complexes 6~ 9. All the prepared irida-carbolong complexes were fully characterized by NMR and HRMS. The molecular structures of the irida-carbolong complexes 4~ 8 were further confirmed by single crystal X-ray diffractions. A possible mechanism was proposed for the formation of the irida-carbolong complexes on the basis of the X-ray characterization of the key intermediate Int 2. Due to the unique large π conjugation system, all the synthesized irida-carbolong complexes exhibit remarkable absorption properties in the ultraviolet visible region, and some of them even show considerable absorption characteristics in the near infrared region (NIR). The consequently photothermal property investigation indicates that complex 5 has a good NIR photothermal effect: by measuring the temperature of its solution under the NIR laser irradiation (808 nm, 1.0 W•cm ), the temperature of ethanol/water solution containing 5 (0.1 mg•mL ) can be increased by nearly 40 ℃ in 10 min, providing numerous possibilities for the follow-up application research based on carbolong complexes.