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Your search keyword '"Michael G. Siskos"' showing total 4 results
Start Over Author "Michael G. Siskos" Publisher american chemical society
4 results on '"Michael G. Siskos"'

1. Self-organization of four symmetric tri-phenyl-benzene derivatives

Author

George Pistolis, Stavroula Skoulika, Nikos Boukos, Michael G. Siskos, Adonis Michaelides, George Varvounis, and Vassiliki Vergadou

Subjects
complexes, Chemistry, Hydrogen bond, Intermolecular force, Stacking, Substituent, hydrogen-bonded networks, General Chemistry, Crystal structure, trimesic acid, Condensed Matter Physics, Excimer, excimer formation, Fluorescence spectroscopy, cellulose, chemistry.chemical_compound, Crystallography, emission, Molecule, General Materials Science, hosts, fluorescence, phases, crystal-structures
Abstract

The self-assembly of four symmetrically substituted tri-aryl-benzene derivatives of formula C24H15X3, where X = H (1), Cl (2), COOMe (3), and COOH (4), was studied as a function of the substituent X. Crystal packing analysis of compounds 1-3 showed that in 1, there are no strong face-to-face stacking interactions, whereas in both compounds 2 and 3, molecular columns were formed, held by numerous "lateral" C-H center dot center dot center dot Cl and C-H center dot center dot center dot O hydrogen bonds, respectively. However, strong intermolecular face-to-face aromatic interactions, appropriate for excimer formation, were observed only in 3, in line with results obtained by fluorescence spectroscopy. The pi-pi aromatic interactions are significantly stronger in the case of the triacid 4, but a lack of adequate single crystals of this compound prevented any detailed study for correlating crystal architecture with fluorescence emission observed. However, FT-IR and TEM experiments showed the existence of dimeric H-bonds and short (0.35 nm) distances between the phenyl rings. Crystal Growth & Design

Published
2006

2. Crystal structure and solid-state reactivity of a Cd(II) polymeric complex with acetylenedicarboxylic acid

Author

Panagiotis Dallas, and Yiannis Deligiannakis, Michael G. Siskos, Stavroula Skoulika, and Adonis Michaelides

Subjects
spectroscopy, Acetylenedicarboxylic acid, Chemistry, Stereochemistry, Coordination polymer, General Chemical Engineering, Acetylenedicarboxylate, transition, General Chemistry, Crystal structure, hydrothermal reactions, Triple bond, chemistry, chemistry.chemical_compound, Crystallography, coordination polymer, Polymerization, frameworks, Materials Chemistry, derivatives, Reactivity (chemistry), molecules, decarboxylation, copper(ii), Monoclinic crystal system
Abstract

The novel one-dimensional coordination polymer [Cd(ADC)(H2O)(3)] H2O, where ADC(2-) = acetylenedicarboxylate dianion, was synthesized and characterized by single-crystal X-ray diffraction. The titled compound crystallizes in the monoclinic system, P2(1)/n, a = 6.908(1) Angstrom, b = 7.946(1) Angstrom, c = 16.390(1) Angstrom, beta = 100.21(1)degrees, V = 885.4(2) Angstrom(3), and Z = 4. The structure is made up of metal-organic chains linked by hydrogen bonds to form channels along the b axis. The carbon-carbon triple bonds are in close proximity (3.27 Angstrom) along the a axis. This induces, upon heating, polymerization with formation of conjugated polycarboxylic chains. Detailed EPR studies have been performed in order to understand the polymerization process. Chemistry of Materials

Published
2003

3. Structural Diversity in a Family of Quasi-Tetrahedral Organic Molecules: From Van Der Waals Solids to Helices and Molecular Complexes.

Author

Michael G. Siskos, Stavroula Skoulika, Adonis Michaelides, Antonios K. Zarkadis, and Nikolaos I. Tzerpos

Subjects
*MOLECULES, *ORGANIC compounds, *X-ray crystallography, *SPECTRUM analysis
Abstract

The crystal structure and packing of a series of six nearly tetrahedral organic compounds 1– 6, of general formula PhNH-CAr 1Ar 2Ar 3[ 1(Ph, Ph, Ph), 2(Ph, Ph, 2-Py), 3(Ph, Ph, 3-Py), 4(Ph, Ph, 4-Py), 5(Ph, 2-Py, 2-Py), and 6(2-Py, 2-Py, 2-Py)], were investigated by X-ray crystallography and supported, in some cases, by ab initio calculations, IR spectroscopy, and 1H NMR. All molecules have in common an aniline group, but they differ in the number of phenyl groups that are replaced by pyridyl ones ( 1, 2, 5, 6) or the position of the nitrogen heteroatom at the pyridyl ring ( 2– 4). Purely van der Waals solids are obtained when the molecule can form an intramolecular N−H···N hydrogen bond ( 2, 5, 6), and, in this case, a correlation between melting point and structure was attempted. However, when intermolecular N−H···N bonds were established, helices ( 4) or tetrameric (two organic molecules + two solvent molecules) molecular complexes ( 3) were obtained. [ABSTRACT FROM AUTHOR]

Published
2008
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