An organic channel structure formed by the supramolecular assembly of trithiocyanuric acid and 4,4'-bipyridyl

Trithiocyanuric acid (TCA) and 4,4'-bipyridyl (BP) form hydrogen-bonded co-crystals with aromatic compounds such as benzene, toluene, p-xylene and anthracene. The TCA-BP co-crystal is composed of cavities formed by the N-H···N hydrogen bonds between the two molecules, and the three-dimensional structure contains channels of approximately 10 Å where aromatic molecules are accommodated. The molar ratios of TCA, BP and the aromatic compound in the co-crystals are 2:1:1 or 2:1:0.5. Benzene, toluene and p-xylene are removed from the channels around 190, 183 and 170°C respectively, and these aromatic guests can be reintroduced into the empty channels of the apo-hosts. The apo-hosts with empty channels have reasonable thermal stability and exhibit shape selectivity in that the empty channels accommodate p-xylene but not m- or o-xylene or mesitylene

A novel hybrid layer compound containing silver sheetsand an organic spacer

A novel compound of the formula Ag2·CA (CA=cyanuric acid) possessing Ag sheets and hydrogen-bonded CA chains, exhibits anisotropic conductivity and acts as an infinite parallel plate capacitor with a high dielectric constant

Proton Transfer, Hydrogen Bonding, and Disorder: Nitrogen Near-Edge X-ray Absorption Fine Structure and X-ray Photoelectron Spectroscopy of Bipyridine-Acid Salts and Co-crystals

The sensitivity of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to Brønsted donation and the protonation state of nitrogen in the solid state is investigated through a series of multicomponent bipyridine–acid systems alongside X-ray photoelectron spectroscopy (XPS) data. A large shift to high energy occurs for the 1s → 1π* resonance in the nitrogen K-edge NEXAFS with proton transfer from the acid to the bipyridine base molecule and allows assignment as a salt (C═NH+), with the peak ratio providing the stoichiometry of the types of nitrogen species present. A corresponding binding energy shift for C═NH+ is observed in the nitrogen XPS, clearly identifying protonation and formation of a salt. The similar magnitude shifts observed with both techniques relative to the unprotonated nitrogen of co-crystals (C═N) suggest that the chemical state (initial-state) effects dominate. Results from both techniques reveal the sensitivity to identify proton transfer, hydrogen bond disorder, and even the potential to distinguish variations in hydrogen bond length to nitrogen

Solid state dimerisation of β-nitrostyrene: a disordered photoreactive

The unusual solid state dimerisation of β-nitrostyrene to yield two isomeric cyclobutanes is accounted for by its disordered, photoreactive crystal structure which permits a trans→cis isomerisation

Synthesis and structure analysis of three new lanthanide complexes, [Ce(NO 3 ) 6 ].[(H- phen ) 6 .(NO 3 ) 3 ], [Pr(NO 3 ) 6 ].[(H- phen ) 6 .(NO 3 ) 3 ] and [Sm(NO 3 ) 3 ].( phen ).(H 2 O) 2 ].[(H- phen ).(NO 3 ).H 2 O]

Three coordination assemblies, 1 – 3, [Ce(NO3)6].[(H-phen)6.(NO3)3], [Pr(NO3)6].[(H-phen)6.(NO3)3,] and [Sm(NO3)3(phen)(H2O)2].[(H-phen).(NO3).H2O], respectively, wherein (H-phen = 1,10-phenanthroline), have been reported. In the complexes of 1 and 2, secondary coordination spheres yield a host-network, into which primary coordination sphere is encapsulated. In the complex, 3, however, both primary and secondary coordination spheres direct the formation of crossed ribbon structure, with voids being filled by water molecules. Nevertheless, acid molecules did not present in any of the complexes 1 – 3. Three-dimensional structures are determined by single crystal X-ray diffraction method and the analysis of packing of the molecules within the crystal lattices has been discussed in detail

A crystallographic scale of carbon acidity

For several carbon acids C-H, mean C-H···O distances in 551 crystal structures correlate well with conventional pKa(Me2SO) values, thus furnishing a new scale of carbon acidity

Unexpected isomerization of maleic acid to fumaric acid on co-crystallization with 4,4'-bipyridine

Co-crystallization of maleic acid, 1, with 4,4'-bipyridine, 2, in acetone, chloroform, ethylacetate and methanol gives a hydrogen bonded 2:1 adduct of 1 with 2 (monoclinic space group, C2/c, a=24.056(8), b=6.891(2), c=11.474(6)Å, β=116.10(4)°). Co-crystallization in dimethylformamide and dimethylsulfoxide, however, yields a 1:1 adduct of fumaric acid with 2 (triclinic space group P1̅ , a=3.875(1), b=8.906(1), c=10.016(1)Å, α=109.60(1)°, β=98.64(1)°, γ=96.64(1)°). Maleic acid isomerizes to fumaric acid while forming a 1:1 complex with 4,4'-bipyridine in DMSO solution

Rational Analysis of Melting Point Behavior of Co-Crystals of 4‑Nitrophenol with Some Aza-Compounds

Various co-crystals of 4-nitrophenol with aza-compounds have been synthesized and characterized by single-crystal X-ray diffraction method. Thermal analysis of all the co-crystals infers higher melting point compared to their respective co-formers and the increase in melting point perhaps because of the cross-chain close-packed arrangement of the constituent molecules. The trend of increase in melting point among the co-crystals reported here is difficult to correlate because of the diverse nature of the aza-compounds. Therefore, we have grouped the co-crystals based on the position of the nitrogen atom of aza-compounds. Apart from structural features the melting point trend among the co-crystals has also been correlated by considering the parameters such as crystal density, packing efficiency, and number of strong hydrogen bonds. It has been noticed that within the group the co-crystal with higher value of above said parameters shows higher melting point compared to the co-crystals with lower values, inferring a linear correlation between any of these parameters and the corresponding melting point of the co-crystal

Some Hydrated Molecular Complexes of 4-Cyanophenylboronic acid: Significanceof Water in the Structure Stabilization by Theoretical Investigations

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