Neutral one-dimensional metal chains consisting of alternating anionic and cationic rhodium complexes

Abstract

The metallophilic interactions were investigated within chains of oppositely charged rhodium carbonyl complexes. The cationic [Rh(CO)(2)(L)](+) (L = 2,2'-bipyridine and 1,10-phenanthroline) and anionic [RhCl(2)(CO)(2)](-) units were self-assembled into one dimensional rhodium chains supported by electrostatic interactions. The array of Rh centers in {[Rh(CO)(2)(2,2'-bpy)][RhCl(2)(CO)(2)]}(n) was found to be nearly linear with a Rh···Rh···Rh angle of 170.927(11)° and Rh···Rh distances of 3.3174(5) Å and 3.4116(5) Å. The crystal structure of {[Rh(CO)(2)(1,10-phen)][RhCl(2)(CO)(2)]} consisted of two sets of crystallographically independent chains with slightly different Rh···Rh···Rh angles (170.275(9)° and 159.573(9)°). The higher linearity allowed closer packing of the rhodium complexes. The Rh···Rh distances were 3.2734(3) Å and 3.3155(3) Å for the more linear and 3.3498(3) Å and 3.3211(3) Å for the less linear system. The existence of metallophilic interactions was confirmed computationally by TD-DFT and QTAIM analysis. The computational results also indicated that the intermolecular charge transfer from the cation to the anion had a significant contribution to the absorption properties of the chain compounds.