Intermolecular Carbonyl···Carbonyl Interactions in Transition-Metal Complexes

Abstract

We performed a comprehensive analysis of intermolecular carbonyl-carbonyl interactions in transition-metal complexes. Those interactions can be classified in two main types depending on the organometallic or organic nature of the donor carbonyl: M-CO···CO and R-CO···CO, respectively. By means of a combined structural and computational study we unraveled their geometrical features and strength. Moreover, electronic structure, natural bond orbitals, energy decomposition analysis, and quantum theory of atoms in molecules calculations were performed to try to understand their nature. Remarkably, we discovered that these carbonyl-carbonyl contacts have several features of the n → π* interaction. The charge transfer from an oxygen lone pair to an empty antibonding π orbital of the acceptor carbonyl is also accompanied by an electrostatic O···C interaction. To the best of our knowledge this is the first report of an intermolecular n → π* interaction in metal complexes. These results might be significant, for instance, for the catalytic activation of carbonyl-containing small molecules with metal compounds or in the design of hybrid organic-inorganic materials, metal-organic frameworks, and other extended structures.

Incorporation of a p‐Phenylene Unit into the Azuliporphyrinogens Frame—Oxidation and Ruthenium Cluster Coordination

“…Non‐coordinated azulene sides are separated from each other, thus no π⋅⋅⋅π stacking is present. Instead, a new source of interactions introduced by coordination to Ru 4 (CO) 9 , that is, dipole⋅⋅⋅dipole interactions of CO groups create a supramolecular chains along the a axis (Figure b).…”

“…Thus, the dihedrala ngle between five-memberedr ings belonging to two opposite azulene subunits decreases markedly from 58.13(14)8 to 13.0(4)8.T he coordination induces also the thiophene ringi nversion in respectt ot he same plane. The crystal structure of 6a-Ru (Figure 5b)iss ignificantly alteredb ycoordi- nation of clusters in comparison to 6a.N on-coordinated azulene sides are separatedf rom each other,t hus no p···p stacking is present.I nstead, an ew source of interactions introduced by coordination to Ru 4 (CO) 9 ,t hat is, dipole···dipole interactions of CO groups [10] create as upramolecular chains along the a axis (Figure 5b).…”

Not Only Hydrogen Bonds: Other Noncovalent Interactions

“…Upon formation of the complex, the trivalent triel atom usually suffers a large deformation, changing its planar structure to a pseudo-tetrahedral one thus changing to an sp 3 -hybridization. Recently, 'like-like' In(III)• • • In(III) interactions was studied by Echeverría [101,102] in the crystal of trimethyltriphenyl-phosphine-indium. These unprecedented metallophilic interactions have not been described for the lighter elements of group 13.…”

Structural, Non-Covalent Interaction, and Natural Bond Orbital Studies on Bromido-Tricarbonyl Rhenium(I) Complexes Bearing Alkyl-Substituted 1,4-Diazabutadiene (DAB) Ligands

“…Therefore, the structural and computational studies of such interactions are of great interest and a new topic in the structural and computational chemistry of metal carbonyl complexes [36][37][38]. In continuation of our work on synthesis, characterization, structural chemistry, and computational studies of transition metal-carbonyl complexes [39,40], we here report the synthesis, spectroscopic, structural and computational studies of new Re(I)-tricarbonyl bromo complexes bearing 1,4-diazabutadiene as non-heterocyclic diimine ligands, namely: N,N-bis(2,4-dimethylbenzene)-1,4-diazabutadiene, (3); and N,N-bis(2,6-diisopropylbenzene)-1,4-diazabutadiene, 2,6-ipr 2 DAB (4).…”