Unligated dirhodium tetra(trifluoroacetate): preparation, crystal structure and electronic structure

Abstract

The title compound, Rh 2(O 2CCF 3) 4, without any exogenous axial ligands, has been obtained in crystalline form by sublimation. Its crystal structure has been determined: space group P 1 with α = 5.2499(5), b = 8.491(2), c = 9.172(2) A ̊ , α = 88.80(2), β = 88.53(1), γ = 76.43(1)°, V = 397.3(1) A ̊ 3, Z = 1 . The molecules are linked by axially ligating each other to form infinite chains. The Rh-Rh distance is 2.3813 (8) Å. The volatility of Rh 2(O 2CCF 3) 4 should allow spectrospcopic study of the isolated molecules and therefore the electronic structure has been treated by the SCF-Xα-SW method. The level ordering and composition show significant differences from those of Rh 2(O 2CH) 2, although in both molecules there is a strong Rh-Rh σ bond. Ionizatio potential have been estimated by the transition state method.