Adducts of Trimeric Perfluro-o-Phenylene Mercury with TTF or DTT

Since the discovery of metallic conductivity in the TTF-TCNQ complex, the charge transfer (CT) complex materials have been studied for such properties as semiconductivity or superconductivity. The synthesis of new CT materials using trimeric perfluoro-ortho-phenylene mercury (Hg3) as electron acceptor compound was done first by Haneline and Gabaï [1]. A series of studies of CT materials containing Hg3 and tetrathiafulvalene (TTF) or dithieno thiophene (DTT) as an electron donor compounds was carried out by different methods. Co-crystalzation with TTF gave a larger variety of co-crystals than with DTT, producing three polymorphs and one pseudo-polymorph. One pot crystal growth of TTF and Hg3 in a 1:1 mixture of solvents dichloromethane (DCM) and dichloroethane (DCA) has led to the formation of TTF polymorphs 1 and 2 with same 1:1 donor acceptor ratio [Hg3·TTF] as well a pseudopolymorph [Hg3·TTF·DCA] 3 that contains the solvent DCA in the asymmetric unit. Slow evaporation in a 1:1 mixture of dichloromethane and carbon disulfide was used to obtain the previously reported CT [(Hg3)2·TTF] (4)1. By slow evaporation as well in pure dichloromethane was obtained the CT material [Hg3·DTT·DCM] 5. All these five CT co-crystals contain mixed donor acceptor stacks, however only in 3, 4 and 5 these stacks are parallel to each other. In the packing of 1 and 2 these stacks are in herringbone arrangement. Polymorphs 1 and 2 differ in crystal shape and color. Contacts Hg···S shorter than the sum of the Van Der Walls radii were observed in the five CTs materials reported, however only 1, 2, 3, and 5 have extended short donor acceptor molecular associates. Moreover only 3, and 5 has these extended donor acceptor associates along one direction.

Cocrystallization of acetaminophen and glutaric acid with different coformers

Recently cocrystallization became a popular tool for crystal engineering that allows, for instance, improving properties of pharmaceutical materials, creating new materials for nonlinear optical applications and solar cell technologies. To attract students to crystallographic studies we carried out project that included crystal growth of two series of cocrystals with acetaminophen and with dicarbonic glutaric acid. We attempted cocrystallization of acetaminophen with more than ten different coformers which gave no cocrystals or salts. However, as a result of cocrystallization we obtained new polymorph modification of hydroxyquinoline. On the contrary, cocrystallization of glutaric acid with basic organic compounds gave several new salts. Interesting examples among them are systems of glutaric acid with 2-pyridinamine and with 6-methyl-2-pyridinamine. In spite of the presence of the same substituents that are prone to H-bond formation, cocrystals have different H-bonding systems and even different molecular conformation of glutaric acid. Details of physical properties, such as spectral characteristics and melting points, of obtained multicomponent materials are discussed.