Ortho phosphorylation of PPh3 to give a diphosphine and formation of a "butterfly" structure on a tetrairidium framework

Bo Keun Park, Md Arzu Miah, Hongkyu Kang, Kwangyeol Lee, Youn Jaung Cho, David G. Churchill, Sangwoo Park, Moon Gun Choi, Joon T. Park

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Abstract

A brief thermolysis of the bis-phosphine-substituted tetrairidium cluster Ir4(CO)10(PPh3)2 (1) in chlorobenzene (CB) converts it rapidly to the diphosphine cluster Ir 4(CO)7(μ-CO)32-Ph 2P(o-C6H4)PPh2} (2) in 53% yield, providing evidence for ortho phosphorylation at the tetrairidium cluster framework. Treatment of 2 with excess C60 affords the "butterfly" Ir4-C60 complex Ir 4(CO)6)(μ-CO){μ32- Ph2P(o-C6H4)P(η1-o-C 6H4)}(μ32: η2η2-c60 (3) in 71% yield. Interestingly, compound 3 can be prepared directly from the thermolysis of 1 with excess C60 in moderate yield (52%). Compounds 2 and 3 have been characterized by micro-analysis, spectroscopy, and single-crystal X-ray diffraction studies. A molecular structure determination reveals that complex 2 adopts a regular tetrahedral geometry with three edge-bridging CO groups around the basal triangle and a diphosphine κ2-Ph2P(o- C6H4)PPh2 ligand chelating one of the basal iridium atoms. In contrast, complex 3 possesses a "butterfly" geometry in which the C60 ligand is coordinated to the lower wing of the "butterfly" by an arene type μ32: η22-C60 bonding mode. One unique feature of 3 is the presence of both ortho phosphorylated and ortho-metalated phenyl rings forming five-membered [Ir-P-C-C-P] and [Ir-Ir-P-C-C] metallocycles joined in a spiro union at the iridium-indium-bridged phosphorus atom. A crossover experiment confirms that the conversion of 1 to 2 is intramolecular. Plausible reaction pathways for the formation of 2 and 3 are proposed.

Original languageEnglish
Pages (from-to)675-679
Number of pages5
JournalOrganometallics
Volume24
Issue number4
DOIs
Publication statusPublished - 2005 Feb 14

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Cite this

Park, B. K., Miah, M. A., Kang, H., Lee, K., Cho, Y. J., Churchill, D. G., Park, S., Choi, M. G., & Park, J. T. (2005). Ortho phosphorylation of PPh3 to give a diphosphine and formation of a "butterfly" structure on a tetrairidium framework. Organometallics, 24(4), 675-679. https://doi.org/10.1021/om049303i