## Abstract

Two unusual carbonyl bridged dirhodium complexes [(CH_{3})_{2}PC_{6}H_{5}](CO)Rh(μ-CO)(μ-SC_{6}H_{11})_{2}-RhCl_{2}[(CH_{3})_{2}PC_{6}H_{5}](7) and [(CH_{3})_{2}PC_{6}H_{5}]_{2}ClRh-(μ-CO)(μ-Cl)(μ-SC_{6}H_{11})RhCl[(CH_{3})_{2}PC_{6}H_{5}] (8) were obtained from the reaction of [Rh(CO)_{2}]_{2}(μ-Cl)_{2} (1) with (CH_{3})_{2}PC_{6}H_{5} (4) and (CH_{3})_{3}SiSC_{6}H_{11} (5). Their geometric structures as well as the structure of trans-RhCl(CO)[(CH_{3})_{2}PC_{6}H_{5}]_{2} (6) were determined by X-ray diffraction analysis, and qualitative molecular orbital pictures were obtained from extended Hückel molecular orbital (EHMO) calculations. Both dirhodium complexes can be described in terms of the combination of one square pyramid and one octahedron. Complex 6 is square planar and belongs to space group P1 with a = 10.277(2), b = 15.881(3), c = 6.025(1) Å; α = 96.60(4), β = 93.65(5), γ = 83.81(5)°; Z = 2; R = 0.043 and R_{w} = 0.069 for 2702 reflections with I≥ 3σ_{I}. Compound 7 belongs to space group P2_{1}/n with a = 11.976(3), b = 22.721(4), c = 14.153(3) Å; β = 97.03(5)°; Z = 4; R = 0.066 and R_{w} = 0.087 for 3204 reflections with I≥3σ_{I}. The two rhodium atoms are connected by two cyclohexylthiolato bridges and by one carbonyl bridge. The Rh(1)-Rh(2) distance is 2.848 Å, yet EHMO calculations indicate no direct interactions between the two metal atoms. Complex 8 belongs to space group P2_{1}/c with a = 15.832(4), b = 11.080, c = 21.407(5) Å; β = 108.66(5)°; Z = 4; R = 0.047 and R_{w} = 0.067 for 3699 reflections with I≥ 2σ_{I}. Chlorine, carbonyl and cyclohexylthiolato groups serve as bridging ligands. The Rh(1)-Rh(2) distance is of the same order of magnitude as in 7 (2.873 Å), yet the calculations reveal some metal-metal interactions that involve the d(xy) and d(z^{2}) orbitals of both rhodium atoms. The existence of Rh(1)-Rh(2) interactions is also confirmed by the temperature dependent ESR spectrum.

Original language | English |
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Pages (from-to) | 191-201 |

Number of pages | 11 |

Journal | Inorganica Chimica Acta |

Volume | 172 |

Issue number | 2 |

DOIs | |

State | Published - 15 Jun 1990 |

Externally published | Yes |