Using cocrystals as a tool to study non-crystallizing molecules: crystal structure, Hirshfeld surface analysis and computational study of the 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine and acetic acid.

Using a 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π-π interactions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and computational studies, we reveal the molecular arrangement within this cocrystal, demonstrating the presence of hydrogen bonding between the acetic acid molecule and the pyridyl group, along with π-π interactions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π-π interactions without necessitating full halogenation of the aromatic ring.

Exploring and predicting intermolecular binding preferences in crystalline Cu(ii) coordination complexes.

A simple model focusing on electrostatic contributions to interaction energies was found to be very effective for rationalizing the appearance of specific supramolecular interactions in a series of Cu(ii) coordination compounds. The experimental space was provided by a combination of Cu(ii) cations with acac-based anions (hexafluoracetylacetonato and trifluoracetylacetonato) and a series of pyridine-oxime ligands (3-pyridinealdoxime, methyl 3-pyridyl ketoxime, 4-pyridinealdoxime, methyl 4-pyridyl ketoxime, phenyl 4-pyridyl ketoxime). The calculated molecular electrostatic potential (MEP) values at competing hydrogen-bond acceptor sites, for ten structurally characterized complexes, provided guidelines for predicting supramolecular connectivity in cases when the MEP difference exceeded certain cut-off values, while two different and well-defined outcomes are possible within the so called 'grey zone', delineated by a range of MEP differences. It was also shown that the structural outcome within this region is determined by the influence of relatively weak, but distinct, auxillary interactions.

Crystal structure of di-µ-hydroxido-bis-[aqua-(1,10-phenanthroline-κ(2) N,N')copper(II)] naphthalene-2,6-di-carboxyl-ate hexa-hydrate.

In the title compound, [Cu2(OH)2(C12H8N2)2(H2O)2](C12H6O4)·6H2O, the two hydroxide groups bridge the two Cu(II) cations, forming a centrosymmetric binuclear complex cation, in which the Cu(II) cation is coordinated by a 1,10-phenanthroline (phen) mol-ecule, one water mol-ecule and two bridging hydroxide O atoms in a distorted N2O3 square-pyramidal coordination geometry. The naphthalene-2,6-di-carboxyl-ate anion is also located on an inversion centre. In the crystal, O-H⋯O hydrogen bonds link the cations, anions and lattice water mol-ecules into a three-dimensional supra-molecular architecture. Extensive π-π stacking is observed between the parallel or nearly parallel aromatic rings of adjacent phen ligands and naphthalenedi-carboxyl-ate anions, the centroid-to-centroid distances ranging from 3.4990 (16) to 3.8895 (16) Å.

(µ-3,4-Diacetyl-hexa-2,4-diene-2,5-diol-ato-κO,O:O,O)bis-[aqua(1,10-phen-an-thro-line-κN,N')copper(II)] bis-(tetra-fluorid-oborate) monohydrate.

In the title compound, [Cu(2)(C(10)H(12)O(4))(C(12)H(8)N(2))(2)(H(2)O)(2)](BF(4))(2)·H(2)O, the two Cu atoms are each chelated by the acetyl-acetonate unit of the 3,4-diacetyl-hexa-2,4-diene-2,5-diolate (tae) ligand. The Cu atoms are square-pyramidally penta-coordinated, with one bidentate 1,10-phenanthroline (phen) and the tae ligand basal and one water mol-ecule apical. The pyridyl rings of the phen ligands participate in π-π [centroid-centroid distance = 3.894 (3) Å] and C-H ⋯ π inter-actions, generating layers which are inter-connected through O-H⋯O and O-H⋯F hydrogen bonds between the water mol-ecules and the tetra-fluorido-borate anions. The F atoms of both tetra-fluorido-borate anions are each disordered over two positions of equal occupancy.