An Efficient and Recyclable Catalytic System Comprising Nano-Iridium(0) and a Pyridinium Salt of nido-Carboranyldiphosphine for the Synthesis of One-Dimensional Boronate Esters via Hydroboration Reaction

作者：Zhu Yinghuai^*; Jang Shi Hui Agnes; Tham Yue Hao; Algin Oh Biying; Maguire John A; Hosmane Narayan S

来源：Organometallics, 2012, 31(7): 2589-2596.

DOI：10.1021/om200379c

The reaction of N-pentyl-4-methylpyridinium bromide with Na[7,8-bis(dicyclohexylphosphino)-7,8-dicarba-nido-C2B9H10] led to the formation of a pyridinium salt of the carboranyldiphosphine ligand, [N-pentyl-4-methylpyridinium](+) [7,8-bis(dicyclohexylphosphino)-7,8-dicarba-nido-C2B9H10](-) (1), in 86% yield. [7,8-bis(dicydohexylphosphino)-7,8-dicarba-nido-C2B9H10](-) was produced in situ from the decapitation of 1,2bis(dicydohexylphosphino)-1,2-dicarba-closo-dodecaborane with sodium hydroxide. Ligand 1 is highly soluble in ionic liquids such as trihexyltetradecylphosphonium dodecylbenzene sulfonate ([THTdp][DBS]) and 1-hexyl-3-methylimidazolium trifluoromethansulfonate ([HMIM][CF3SO3]) and was used as a bulky catalyst composite with the ionic liquids [THTdP][DBS] and [HMIM][CF3SO3], with stabilized iridium(0) nanoparticles produced by thermolysis of Ir-4(CO)(12), or with the iridium complex [Ir(coe)(2)Cl](2) (coe = cyclooctene) and in the ionic liquid [THTdP] [DBS] and [HMIM][CF3SO3] for the hydroboration of methyl oleate (MO), methyl 10-undecenoate, and 1-hexene. The new Ir(0) catalytic system was found to be efficient, robust, and recyclable so that a number of repetitious hydroborations of MO with high product selectivity could be accomplished.