Activation of the Cyano Group at Imidazole via Copper Stimulated Alcoholysis

Reactions of 4,5-dicyano-1-methylimidazole with CuX2 (X = Cl, Br) in alcohol solvents (ethanol and methanol) resulted in the formation of Cu(II) carboximidate complexes [CuCl2(5- cyano-4-C(OEt)N-1-methylimidazole)(EtOH)] (1), [Cu2(µ-Cl)2Cl2(5-cyano-4-C(OMe)N-1-methylimidazole)2] (2), [Cu2(µ-Br)2Br2(5-cyano-4-C(OMe)N-1-methylimidazole)2] (3), and [Cu2(µ-Br)2Br2(5-cyano-4-C(OEt)N-1-methylimidazole)2] (4). The structures were determined by the X-ray crystallographic method, and further spectroscopic and computational methods were employed to explain the structural features. The solvent contributed to the alcoholysis reaction of the cyano group, as the result of which the ligand coordinated to the metal center in bidentate mode forming a five-membered chelating ring. In 1, the solvent also acts as an additional ligand, which coordinates to the metal center of a monomeric complex. In compounds 2–4, two halogen ligands link the metal atoms forming dihalo-bridged copper dimers. The infrared absorption characteristics were verified by simulation of the infrared spectra at the density functional theory level. In addition, the electronic absorption characteristics were explained by simulation of the UV–Vis spectra using the TD-DFT method. Molecular modelling at the DFT level was performed to study the effects of halogen type and steric hindrance of the alkoxy groups in forming the copper(II) complexes

Activation of the Cyano Group at Imidazole via Copper Stimulated Alcoholysis

Reactions of 4,5-dicyano-1-methylimidazole with CuX2 (X = Cl, Br) in alcohol solvents (ethanol and methanol) resulted in the formation of Cu(II) carboximidate complexes [CuCl2(5- cyano-4-C(OEt)N-1-methylimidazole)(EtOH)] (1), [Cu2(µ-Cl)2Cl2(5-cyano-4-C(OMe)N-1-methylimidazole)2] (2), [Cu2(µ-Br)2Br2(5-cyano-4-C(OMe)N-1-methylimidazole)2] (3), and [Cu2(µ-Br)2Br2(5-cyano-4-C(OEt)N-1-methylimidazole)2] (4). The structures were determined by the X-ray crystallographic method, and further spectroscopic and computational methods were employed to explain the structural features. The solvent contributed to the alcoholysis reaction of the cyano group, as the result of which the ligand coordinated to the metal center in bidentate mode forming a five-membered chelating ring. In 1, the solvent also acts as an additional ligand, which coordinates to the metal center of a monomeric complex. In compounds 2–4, two halogen ligands link the metal atoms forming dihalo-bridged copper dimers. The infrared absorption characteristics were verified by simulation of the infrared spectra at the density functional theory level. In addition, the electronic absorption characteristics were explained by simulation of the UV–Vis spectra using the TD-DFT method. Molecular modelling at the DFT level was performed to study the effects of halogen type and steric hindrance of the alkoxy groups in forming the copper(II) complexes.peerReviewe

Solvent directs the dimensionality of Cu-dicyanoimidazoles

In this paper, we report one-pot reactions of the same reactants 4,5-dicyanoimidazole and CuI in different solvents. In pure MeCN, the reaction resulted in previously reported MOF structure [Cu(4,5-dicyanoimidazole)]n.(MeCN)0.5n (1). On the other hand, when MeCN/MeOH solvent mixture was used, a new coordination polymer [Cu(4,5-dicyanoimidazole)(MeCN)(CuI)]n (2) was formed. The crystallization yielded very different structures as determined by X-ray crystallography. In 1, the solvent molecule acetonitrile occupies the MOF pores via weak interactions, but in 2 it is coordinated to the metal center. Computational DFT calculations and topological charge density analysis were utilized to explore the different crystal structures with the focus on the role of the methanol solvent.peerReviewe