Rh(II) and Rh(I) two-legged piano-stool complexes: Structure, reactivity, and electronic properties

Felicia M. Dixon, Martin S. Masar, Peter E. Doan, Joshua R. Farrell, Frederick P. Arnold, Chad A. Mirkin*, Christopher D. Incarvito, Lev N. Zakharov, Arnold L. Rheingold

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Scopus citations


The ligand 1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene, 3, was used to synthesize a mononuclear Rh(II) complex [(η161-1,4-bis[4- (diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh] [PF6]2, 6+, in a two-legged piano-stool geometry. The structural and electronic properties of this novel complex including a single-crystal EPR analysis are reported. The complex can be cleanly interconverted with its Rh(I) form, allowing for a comparison of the structural properties and reactivity of both oxidation states. The Rh(I) form 6 reacts with CO, tert-butyl isocyanide, and acetonitrile to form a series of 15-membered mononuclear cyclophanes [(η11-1,4-bis[4- (diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CO)3][PF6] (8), [(η11-1,4-bis[4-(diphenylphosphino)butyl]-2, 3,5,6-tetramethylbenzene)Rh(CNC(CH3)3)2] [PF6] (10), and [η11-1,4-bis[4-(diphenylphosphino)butyl]-2, 3,5,6tetramethylbenzene)Rh(CO)(CH3CN)][PF6] (11). The Rh(II) complex 6+ reacts with the same small molecules, but over shorter periods of time, to form the same Rh(I) products. In addition, a model two-legged piano-stool complex [(η161-1,4-bis[3- (diphenylphosphino)propoxy] -2,3,5,6-tetramethyl benzene) Rh][B(C6F5)4], 5, has been synthesized and characterized for comparison purposes. The solid-state structures of complexes 5, 6, 6+, and 11 are reported. Structure data for 5: triclinic; P1-; a = 10.1587(7) Å; b = 11.5228(8) Å; c = 17.2381(12) Å; α = 96.4379(13)°; β = 91.1870(12)°; γ = 106.1470(13)°; Z= 2. 6: triclinic; P1- a = 11.1934(5) Å; b = 12.4807(6) Å; c = 16.1771(7) Å; α = 81.935(7)°; β = 89.943(1)°; γ = 78.292(1)°; γ = 78.292(1)°; Z = 2. 6+: monoclinic; P2(1)/n; a = 11.9371(18) Å; b = 32.401(5) Å; c = 12.782(2) Å; β = 102.890(3)°; Z = 4. 11: triclinic; P1-; a = 13.5476(7) Å; b = 13.8306(7) Å; c = 14.9948(8) Å; α = 74.551(1)°; β = 73.895(1)°; γ = 66.046(1)°; Z = 2.

Original languageEnglish (US)
Pages (from-to)3245-3255
Number of pages11
JournalInorganic chemistry
Issue number10
StatePublished - May 19 2003

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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    Dixon, F. M., Masar, M. S., Doan, P. E., Farrell, J. R., Arnold, F. P., Mirkin, C. A., Incarvito, C. D., Zakharov, L. N., & Rheingold, A. L. (2003). Rh(II) and Rh(I) two-legged piano-stool complexes: Structure, reactivity, and electronic properties. Inorganic chemistry, 42(10), 3245-3255. https://doi.org/10.1021/ic0204981