title: Hirshfeld and DFT analysis of the N-heterocyclic carbene proligand methylenebis(N-butylimidazolium) as the acetonitrile-solvated diiodide salt.
abstract: N-Heterocyclic carbene (NHC) based systems are usually exploited in the exploration of catalytic mechanisms and processes in organocatalysis, and homo- and heterogeneous catalysis. However, their molecular structures have not received adequate attention. The NHC proligand methylenebis(N-butylimidazolium) has been synthesized as the acetonitrile solvate of the diiodide salt, C15H26N4(2+)·2I(-)·CH3CN [1,1'-methylenebis(3-butylimidazolium) diiodide acetonitrile monosolvate], and fully characterized. An interesting cation-anion connection pattern has been identified in the crystal lattice, in which three iodide anions interact simultaneously with the cisoid-oriented cation. A Hirshfeld surface analysis reveals the predominance of hydrogen bonding over anion-π interactions. This particular arrangement is observed in different methylene-bridged bis(imidazolium) cations bearing chloride or bromide counter-anions. Density functional theory (DFT) calculations with acetonitrile as solvent reproduce the geometry of the title cation.
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza, Zaragoza 50009, Spain.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cebollada
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza, Zaragoza 50009, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Vellé
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza, Zaragoza 50009, Spain.
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: Sanz Miguel
keywords: C—H...I hydrogen bonds; DFT analysis; Hirshfeld surface analysis; N-heterocyclic carbene; NHC; catalysis; computational chemistry; crystal structure; imidazolium salts; interaction pattern