Crystal Structure of Bis[acetone‐1‐naphthoylhydrazinato(−1)]copper(II) and Investigations of Intermolecular Interactions

Abstract

In the crystal structure of the bis(acetone‐1‐naphthoylhydrazinato)copper(II) complex there are interactions of neighbouring molecules via naphthyl groups; the naphthyl group of one molecule interacts with the copper centre and CH3 group of another molecule. The geometry of the crystal structure and dispositions of charges in the naphthyl and chelate rings indicate that there are stacking interactions between the aromatic ring and, not only the copper atom, but also the whole chelate ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Intermolecular Interactions between Chelate Rings and Phenyl Rings in Square‐Planar Copper(II) Complexes

“…The EPR studies on the single-crystal samples of (-tryptophanyl-glycinato)copper() [29] suggest that magnetic interactions are transmitted through cationϪπ contacts. The observed mutual slipped-parallel (offset face to face) orientation of the chelate ring, with delocalized π-bonds, and the phenyl ring, [24] resemble the stacking orientation of two benzene molecules. [30] We assumed that chelate rings with delocalized π-bonds can be involved in noncovalent interactions in ways similar to aromatic organic molecules.…”

“…[23Ϫ25] We have reported [24] the structure of the square-planar bis(acetone-1-naphthoylhydrazinato)copper() complex. In this structure the closest intermolecular distance between the copper() and aromatic carbon atom is 3.185(3) Å , which is below the sum of van der Waals radii (4.05 Å ).…”

Very Strong Parallel Interactions Between Two Saturated Acyclic Groups Closed with Intramolecular Hydrogen Bonds Forming Hydrogen-Bridged Rings

“…The data in Figure 3 show that most of the parallel contacts have the normal distances between 3.0 and 3.5 Å. These are distances typical for stacking of organic aromatic rings (3-4 Å) [17][18][19][20][21][22] and other planar rings that form stacking interactions [24][25][26][27][43][44][45][46]. The data in Figure 3 show that most of the parallel contacts have the normal distances between 3.0 and 3.5 Å.…”

“…Interestingly, several studies showed that stacking interactions of other planar molecules can be even stronger than stacking between aromatic molecules , indicating the importance of these interactions. Analysis of the crystal structures from Cambridge Structural Database (CSD) have shown that planar chelate rings with delocalized π-bonds can form stackinginteractions with C 6 -aromatic rings, and with other chelate rings [24][25][26][27]. The interaction energies of nickel and copper six-membered chelate rings with benzene, calculated at very acurate CCSD(T)/CBS level, are´4.77 and´6.39 kcal/mol respectively [43,44], remarkably stronger than stacking interaction between two benzene molecules,´2.73 kcal/mol [10].…”

Intramolecular C−H···π Interactions in Metal-Porphyrin Complexes

“…Noncovalent interactions in metal complexes between π-systems and ligands with X − H (X = N, O, C) have been noticed and investigated by searching data bases of crystal structures, by quantum chemical calculations and by spectroscopic methods [2]. Noncovalent interactions of chelate rings with delocalized π-bonds were observed and investigated in a few studies [3][4][5]. In our previous work we observed that chelate ring, as π-system, can be involved in C−H···π interactions.…”