STRUCTURAL CHARACTERIZATION OF DICYANIDOBIS(N,N?-DIMETHYLTHIOUREA-kS)CADMIUM(II)

crystal chemistry single crystal X-ray diffraction proton transfer hydrogen bonding caffeine dipicolinic acid

КРИСТАЛЛИЧЕСКАЯ СТРУКТУРА СОЛЕЙ АНИОНА транс-[Rh(NH3)2(NO2)4]– С КАТИОНАМИ K+, Cs+, Ag+ И (CH3)4N+, ОБЛАСТИ ГОМОГЕННОСТИ ДВОЙНЫХ МОЛИБДАТОВ В СИСТЕМЕ Na2MoO4—MgMoO4 И СТРОЕНИЕ ТРИКЛИННЫХ Na1,51Mg2,245(MoO4)3 И Na1,66Mn2,17(MoO4)3, ...

2013. 54, 5 UDC 548.737 A COCRYSTAL OF CAFFEINE AND DIPICOLINIC ACID: SYNTHESIS, CHARACTERIZATION, X-RAY CRYSTALLOGRAPHY, AND SOLUTION STUDIES A. Moghimi 1 , H.R. Khavasi 2 , F. Dashtestani 1, D. Kordestani 3 , E. Behbo odi 1 , B. Maddah 4 1Department of Chemistry, Islamic Azad University, Tehran North Branch, Tehran, Iran 2 E-mail: f.dashtestani@gmail.com 3Department of Chemistry, Shahid Beheshti University, G. C., Tehran, Iran 4Department of Chemistry, Razi University, Kermanshah, Iran Department of Chemistry, Imam Hossein University, Tehran, Iran Received June, 21, 2012 A reaction between caffeine (caff) and dipicolinic acid = 2,6-pyridine dicarboxylic acid (pydc.H2) in water results in the formation of a cocrystal compound (pydc.H2.H2O)(caff) 1. <...> The characterization of the resulting crystallohydrate is performed using 1H, 13C NMR and IR spectroscopy and X-ray crystallography. <...> X-ray crystal structure analysis reveals the presence of both starting materials and water in the lattice. <...> It also indicates intensive intermolecular H-bonding interactions between carboxylic acid, caffeine, and water as well as — stacking between the pydc.H2 and caff rings as constituents of the cocrystal. <...> The hydrogen bonding and non-covalent interactions play roles in the formation of the cocrystal. <...> The crystal system is triclinic with the space group P-1 and two formula units per unit cell. <...> Keywords: crystal chemistry, single crystal X-ray diffraction, proton transfer, hydrogen bonding, caffeine, dipicolinic acid. <...> Smith and co-workers have prepared a series of cocrystal compounds from the reaction of 2-aminopyrimidine, 3-amino-1,2,4-triazole, and 5-nitroquinoline with heterocyclic carboxylic acids, such as 2,6-dihydroxybenzoic acid, 4-aminobenzoic acid, phenoxyacetic acid, salicylic acid [ 3 ], indole-3-acetic acid, thiophen-2-carboxylic acid [ 4 ], and indole-2-acetic acid [ 5 ]. <...> The design of cocrystal compounds from pharmaceutical agents has already been of interest in the field of solid-state science [ 6 ]. <...> The protonation equilibrium of caff has been studied by 1H, 13C NMR and UV spectroscopy in aqueous sulfuric and perchloride acids [ 15 ]. <...> It also participates in the construction of extinctive H-bonding networks within the lattice [ 17 ]. <...> Here we report the synthesis, characterization, X-ray crystal structure and solution studies of a cocrystal compound obtained from caff and pydc.H2. <...> X-ray <...>

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