Synthesis and crystal and molecular structures of mixed-valence tetranuclear, [Re4I8(CO)6], and trinuclear, [ Re3I6(CO)6], compounds of rhenium obtained by di-iodine oxidation of rhenium(I) carbonyl complexes

Fausto Calderazzo (1) , Fabio Marchetti (1) , Rinaldo Poli (1) , Dario Vitali (1) , Pier Francesco Zanazzi (2)

1 University of Pisa - Università di Pisa
2 UNIPG - Università degli Studi di Perugia = University of Perugia

Di-iodine oxidation of [Re2I2(CO)6(thf)2](thf = tetrahydrofuran) at room temperature in heptane as solvent gave [ReI3(CO)3](1) and the tetranuclear [Re4I8(CO)6](2). A mononuclear molecular structure of C3v symmetry is suggested for (1), on the basis of spectroscopic and magnetic susceptibilty measurements. The reaction of [Re2I2(CO)8] with di-iodine at the reflux temperature of heptane gave the trinuclear complex [Re3I6(CO)6](3). The crystal and molecular structures of both (2) and (3) have been solved by X-ray diffraction methods. Compound (2) is monoclinic, space group C2/c, z= 4, with unit-cell dimensions a= 22.316(4), b= 8.679(3), c= 12.705(3)Å, β= 96.02(2)°; R= 0.059 for 1 700 observed reflections. It belongs to the family of [Re2X8]2– complexes, with bridging iodine to two terminal Re(CO)3 groupings. Compound (3) is trigonal, space group R[3 with combining macron], Z= 3, with dimensions a= 6.915(2) and c= 36.939(3)Å; R= 0.068 for 490 observed reflections. It comprises a ReI6 central core iodide-bridged to two terminal Re(CO)3 groupings in a molecular geometry of idealized D3d symmetry.

Domaines: Chimie de coordination; Cristallographie

Fausto Calderazzo, Fabio Marchetti, Rinaldo Poli, Dario Vitali, Pier Francesco Zanazzi. Synthesis and crystal and molecular structures of mixed-valence tetranuclear, [Re4I8(CO)6], and trinuclear, [ Re3I6(CO)6], compounds of rhenium obtained by di-iodine oxidation of rhenium(I) carbonyl complexes. Journal of the Chemical Society Dalton Transactions, 1982, 9, pp.1665-1670. ⟨10.1039/DT9820001665⟩. ⟨hal-03545532⟩