A dimer of bis­(N-heterocyclic carbene)rhodium(I) centres spanned by a dibenzo-18-crown-6 bridge from synchrotron radiation

摘要

The compound (μ-3,3′,3′′,3′′′-{[2,5,8,15,18,21-hexa­oxatricyclo­[20.4.0.0^9,14]hexa­cosa-1(22),9,11,13,23,25-hexa­ene-11,12,24,25-tetra­yl]tetra­kis­(methyl­ene)}tetra­kis­(1-methyl-1H-imidazol-2-yl))bis­[(η⁴-cyclo­octa-1,4-diene)rhodium(I)] bis­(hexa­fluoridophosphate) acetonitrile sesquisolvate dihydrate, [Rh2(C8H12)2(C40H42N8O6)](PF6)2·1.5CH3CN·2H2O, crystallized from acetonitrile under an atmosphere of diethyl ether. In the crystal structure, the complex cation exhibits two square-planar Rh^I centres, each bound by a cyclo­octa­diene (COD) ligand and by two adjacent imidazolyl­idene N-heterocyclic carbene (NHC) donors from the same phen­oxy ring of the {[dibenzo-18-crown-6-11,12,24,25-tetra­yl]tetra­kis­(methyl­ene)}tetra­kis­(1-methyl-1H-imidazol-2-yl) (L) ligand. The dibenzo-crown ether bridge of L spans the Rh centres and forms hydrogen bonds with water mol­ecules. One water mol­ecule with half occupancy bridges adjacent macrocycles in the lattice. Another water with full occupancy forms weak hydrogen bonds to the crown ether O atoms and is, in turn, part hydrogen bonded by a lattice water with half occupancy. The latter water is within hydrogen-bonding distance of a fourth water also with partial occupancy. The result of these inter­actions is the formation of a layer in the ab plane. Two PF6 ⁻ ions, one of which is twofold disordered, and one ordered and one twofold disordered (with 0.5 occupancy) lattice acetonitrile mol­ecules complete the crystal structure.