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Dimer Units (dimer + unit)
Selected AbstractsStructural motifs in ,-pyridyl- and ,-furylcinnamic acid assemblies, A molecular modeling studyINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 2 2001I. Pálinkó Abstract The aggregation properties of stereoisomeric 2-(3,-furyl)-3-phenylpropenoic acids (FU3E, FU3Z, ,-furylcinnamic acids) and 2-(4,-pyridyl)-3-phenylpropenoic acids (PY4E, PY4Z, ,-pyridylcinnamic acids) were studied by the PM3 semiempirical quantum chemical method. Calculations revealed that (aromatic)CH,N(O) hydrogen bonds made possible the attachment of dimer units; thus, virtually infinite chains can be built out of FU3Z, PY4E, and PY4Z. The energy-minimized structure had zig-zag configuration. PY4Z dimers allowed the formation of ribbonlike network; however, the number of structural units could not be increased infinitely. One of the furyl derivatives (FU3E) could not be stabilized either in the ribbon or the chain form; however, (aromatic)CH,, or (aromatic),,(aromatic), interactions contribute to the packing pattern of the two dimers. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 269,275, 2001 [source] Interactions between dimers of {1,1,-[o -phenylenebis(nitrilomethylidyne)]di-2-naphtholato-,4O,N,N,,O,}nickel(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Anita Blagus In the title compound, [Ni(C28H18N2O2)], the NiII centre has a square-planar coordination geometry in which the Schiff base ligand acts as a cis - O,N,N,,O,-tetradentate ligand. The crystal structure is built up of centrosymmetric dimer units stacked into chains along the [010] direction. Adjacent chains associate via C,H...O hydrogen bonding only, leading to a two-dimensional sheet-like structure consisting of layers parallel to (10). The cofacial dimeric complex contains an Ni...Ni contact of 3.291,(4),Ĺ. [source] Crystal Structure of , -Cyclodextrin-Felbinac Inclusion ComplexCHINESE JOURNAL OF CHEMISTRY, Issue 10 2009Enju Wang Abstract The crystal structure of the inclusion complex of , -cyclodextrin (, -CD) synthesized with felbinac (4-biphenylacetic acid) was determined by single crystal X-ray diffraction at 150 K. The complex contains two , -CDs, two felbinac molecules, twenty-two water molecules in the asymmetric unit, and could be formulated as (C42H70O35)2·(C14H12O2)2·22(H2O). In the crystal lattice, the two , -CD moieties form a head-to-head dimer jointed through hydrogen bonds, and the felbinacs that interact by face-to-face ,-, stacking are included in the , -CD dimer cavity with their carboxyl groups protruding out from cavity opening. In crystals the dimer units of , -CD are stacked in an intermediate type (IM) that consists of closely packed , -CD dimer layers. [source] Self-assembly of Two Novel Supramolecular Frameworks Based on Flexible Oligo- , -Pyridylamino Ligands and Copper(II) MaleateCHINESE JOURNAL OF CHEMISTRY, Issue 10 2005Cai-Hua Zhou Abstract Two novel supramolecular complexes, [Cu(bpapa)(mal)]·H2O·CH3OH (1) and {[Cu(bpapap)](Hmal)2}·2H2O (2) [bpapa=bis-[6-(2-pyridylamino)pyrid-2-yl]amine, bpapap=2,6-bis-[6-(pyrid-2-ylamino)pyrid-2-ylamino]-pyridine, mal=maleate dianion] were rationally designed and synthesized based on flexible multidentate ligands and copper(II) maleate. Complexes 1 and 2 were all characterized by elemental analysis, spectroscopic techniques, thermal analysis and single crystal X-ray diffraction analysis. Complex 1 is of an infinite 3-D supramolecular framework constructed by 2-D sheets to contain 1-D helical chains formed by intermolecular hydrogen bond interactions between the non-coordinated oxygen atoms from maleate and nitrogen atoms from amino groups of bpapa. Complex 2 also takes a 3-D supramolecular structure, which is built from 2-D rhombic sheets produced by sequential dimer units. Interestingly, three pairs of symmetrical hydrogen bonds generate these dimer units. [source] | ||||||||||