Is there any point in making co-crystals?

Citation: Aakeroy, C. (2015). Is there any point in making co-crystals? Acta Crystallographica Section B-Structural Science Crystal Engineering and Materials, 71, 387-391. doi:10.1107/s2052520615010872Many aspects of co-crystals, including their synthesis, characterization and possible applications, are receiving considerable attention from academia and industry alike. The question is, can this interdisciplinary activity be translated into new fundamental insight and new solid forms of high-value materials with improved performances

Bis(4-methyl­imidazolium) succinate succinic acid solvate

In the title compound, 2C4H7N2 +·C4H4O4 2−·C4H6O4, the asymmetric unit consists of two 4-methyl­imidazolium cations, one succinate dianion and one netrual succinic acid mol­ecule and within the latter components, the C—O, C=O and C O bonds are clearly evidenced from their relative distances. In the crystal structure, the individual components are linked by inter­molecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds into a two-dimensional network parallel to the (101) plane in which R 3 3(9), R 3 3(12) and R 4 4(18) hydrogen-bond motifs are present

[4-Bromo-N-(pyridin-2-yl­methyl­idene)aniline-κ2 N,N′]bis­(1,1,1,5,5,5-hexa­fluoro­pentane-2,4-dionato-κ2 O,O′)nickel(II)

The title compound, [Ni(C5HF6O2)2(C12H9BrN2)], the NiII atom exhibits a pseudo-octa­hedral coordination geometry. The structure packs through C—H⋯Br inter­actions, forming a hydrogen-bonded ladder. There are also strong hydrogen-bonding inter­actions between two of the O atoms of the β-diketonate ligands and two H atoms on the pyridine ring of the Schiff base ligand

3-Allyl-1-(3-cyano­phenyl­methyl­ene)-2-methyl-1H-benzoimidazol-3-ium bromide monohydrate

In the title compound, C19H18N3 +·Br−·H2O, the dihedral angle between the allyl group and the imidazole ring is 89.59 (14)°, while the dihedral angle between the cyanophenyl ring and the imidazole ring is 78.72 (7)°. O—H⋯Br hydrogen bonds form an infinite chain in the c-axis direction and C—H⋯Br and C—H⋯O inter­actions expand this chain into an infinite three-dimensional network

Supramolecular Hierarchy among Halogen-Bond Donors

Through a combination of structural chemistry, vibrational spectroscopy, and theory, we have systematically examined the relative structure-directing importance of a series of ditopic halogen-bond (XB) donors. The molecular electrostatic potential surfaces of six XB donors were evaluated, which allowed for a charge-based ranking. Each molecule was then co-crystallized with 21 XB acceptors and the results have made it possible to map out the supramolecular landscape describing the competition between I/Br-ethynyl donors, perfluorinated I/Br donors, and I/Br-phenyl based donors. The results offer practical guidelines for synthetic crystal engineering driven by robust and directional halogen bonds. Copyright 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Supramolecular assemblies involving metal organic ring interactions: Heterometallic Cu(II)-Ln(III) two dimensional coordination polymers

Three isostructural two-dimensional coordination polymers of the general formula [Ln2(CuL)3(H2O)9]$5.5H2O, where Ln is La (1), Nd (2), and Gd (3), have been synthesized and isolated from aqueous solutions and their single-crystal structures determined by X-ray diffraction. The supramolecular interaction between the non-aromatic metallorings plays an important role in stabilizing the structure of these compounds. The thermal stability, reversible solvent uptake, electronic properties and magnetic studies of these compounds are also reported

3-Carb­oxy-2-methoxy­phenyl­boronic acid

The mol­ecular structure of the title compound, 3-COOH-2-CH3O—C6H3B(OH)2 or C8H9BO5, is stabilized in part due to the presence of an intra­molecular O—H⋯O hydrogen bond. In the crystal structure, mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds, generating a two-dimensional sheet structure aligned parallel to the (11) plane

2-Amino­pyrimidinium hydrogen chloranilate monohydrate

In the title compound, C4H6N3 +·C6HCl2O4 −·H2O, anions, cations and water mol­ecules are linked by inter­molecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds into one-dimensional tapes along [111]. These tapes are further linked by weak Cl⋯Cl inter­actions [Cl⋯Cl = 3.394 (2) Å], forming sheets parallel to the (10) plane

The role of acid in the formation of hydrogen-bonded networks featuring 4,4'-dicarboxy-2,2'-bipyridine (H2dcbp): Synthesis, structural and magnetic characterisation of {[Cu(H2dcbp)Cl2].H2O}2 and [Cu(H2dcbp)(NO3)2(H2O)]

Reported herein are the synthesis, structural and magnetic characterisation of two hydrogen-bonded networks featuring the 4,4?-dicarboxy-2,2?-bipyridine (H2dcbp) ligand: {[Cu(H2dcbp)(Cl)2]·H2O}2 1 and [Cu(H2dcbp)(NO3)2(H2O)] 2. Compounds 1 and 2 result from the reaction of CuCl2 and Cu(NO3)2, respectively, with H2dcbp under hydrothermal conditions in the presence of either HCl or HNO3. The acid ensures that H2dcbp remains protonated and provides the anions required for charge balance irrespective of Cu(II) precursor. Within 1 and 2 the H2dcbp ligand performs a dual role of Cu(II) coordination, via the 2,2?-bipyridine moiety, and propagates the formation of chains through hydrogen-bonding involving the peripheral 4,4?-dicarboxylic acid functionalities. Additional hydrogen bonding between the 4,4?-dicarboxylic acid groups, metal bound chloride and nitrate anions, in 1 and 2 respectively, and water molecules generate 3D networks. Variable temperature magnetic susceptibility measurements reveal very weak antiferromagnetic coupling between the Cu(II) centres across the chloride bridges in 1 (J = ?3.02 cm?1)

2-Amino-5-methyl­pyridinium 4-hydroxy­benzoate

In the title salt, C6H9N2 +·C7H5O3 −, the carboxyl­ate mean plane of the 4-hydroxy­benzoate anion is twisted by 13.07 (4)° from the attached ring. In the crystal structure, the ions are linked into a two-dimensional network by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds. Within this network, the N—H⋯O hydrogen bonds generate R 2 2(8) ring motifs. In addition, π–π inter­actions involving the pyridinium rings, with a centroid–centroid distance of 3.7599 (4) Å, are observed