Supramolecular Interactions of Group VI Metal Carbonyl Complexes: The Facilitating Role of 1,3-Bis( p-isocyanophenyl)urea

Inorg Chem. 2019 Jun 17;58(12):8130-8139. doi: 10.1021/acs.inorgchem.9b00917. Epub 2019 May 24.

Abstract

An investigation of supramolecular phenomena involving zerovalent transition metal complexes was facilitated by the production of the ditopic isocyanide ligand 1,3-bis( p-isocyanophenyl)urea, which was synthesized via substoichiometric phosgenation of 4-isocyanophenylamine and used to coordinate group VI metal carbonyl fragments. The resulting binuclear organometallic complexes were observed to pack into ladder-like anisotropic arrays in the solid state. Crystallographic and computational evidence suggests that this packing motif can be attributed to a combination of intermolecular π-π and urea-π interactions. Similar to other N, N'-diarylureas bearing electron-withdrawing groups, 1,3-bis( p-isocyanophenyl)urea and the organometallic complexes prepared therefrom also exhibit an affinity toward anion binding in nonaqueous solution. Equilibrium constants ( K) for the formation of host-guest complexes between the organometallic derivatives of 1,3-bis( p-isocyanophenyl)urea and chloride, nitrate, and acetate anions exceed 103, 104, and 105 M-1, respectively.