03213nas a2200181   4500008004100000022001400041245022200055210006900277260011000346300001400456490000700470520232700477100002702804700002402831700002702855700002502882856012402907       2010                        eng d  a1466-803300aHelical self-assembly of molecules in pseudopolymorphs of racemic 2,6-di-O-(4-halobenzoyl)-myo-inositol 1,3,5-orthoformates: clues for the construction of molecular assemblies for intermolecular acyl transfer reaction0 aHelical selfassembly of molecules in pseudopolymorphs of racemic  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAug  a4184-41970 v123 a<p>The crystal structure of racemic 2,6-di-O-benzoyl-myo-inositol 1,3,5-orthoformate (1) which underwent a facile intermolecular benzoyl transfer reaction in the solid state, revealed a helical assembly of molecules along the two-fold screw axis via O-H center dot center dot center dot O hydrogen bond bringing the electrophile (C=O) and the nucleophile (-OH) in close proximity along the helical axis. However, structurally related racemic 2,6-di-O-(p-halobenzoyl)-myo-inositol 1,3,5-orthoformates (bromo (2) and chloro (3)) produced triclinic dimorphs (both P (1) over bar) when crystallized from methanol and ethyl acetate. Molecules in either form did not assemble spirally (like 1), and instead exhibited a one-dimensional isostructurality, bridging O-H center dot center dot center dot O linked identical molecular strings via C-H center dot center dot center dot O interactions across the inversion center. However, the molecules of 2 and 3 assembled in a helical manner similar to 1 with inclusion of solvent molecules in the crystal lattice when crystallized from other common organic solvents. Remarkably, in all the solvates the host molecules formed strikingly similar helices around the crystallographic 2(1)-screw axis through O-H center dot center dot center dot O bond involving the -OH group and carbonyl oxygen of the equatorial C2-O-benzoyl group. Comparison of the crystal structure of dimorphs and the solvatomorphs revealed that the solvent molecules, which interact with the orthoformate-bridge, trigger the helix formation of the host. The difference in the crystal structures of solvatomorphs arises in the interlinking of the neighbouring helices, which creates voids of different sizes to accommodate the solvent molecules. All the solvates crystallized in the monoclinic system distributed over three different space groups P2(1)/n, P2(1)/c and C2/c. In the P2(1)/n system, the adjacent helices are linked via C-X center dot center dot center dot O contacts, in P2(1)/c via C-H center dot center dot center dot X (X Cl, Br) contacts and in C2/c via short X center dot center dot center dot X contacts (X = Cl). The helical organization achieved through solvent mediation and inclusion is of significance in creating molecular packing for intermolecular acyl transfer reactions in crystals.</p>1 aKrishnaswamy, Shobhana1 aGonnade, Rajesh, G.1 aShashidhar, Mysore, S.1 aBhadbhade, Mohan, M.  uhttps://library.ncl.res.in/content/helical-self-assembly-molecules-pseudopolymorphs-racemic-26-di-o-4-halobenzoyl-myo-001627nas a2200193   4500008004100000022001400041245012100055210006900176260007100245300001400316490000700330520084000337100002801177700002401205700002501229700002501254700002401279856013001303       2011                        eng d  a1528-748300aHalogen bonding in 2,5-dichloro-1,4-benzoquinone: insights from experimental and theoretical charge density analysis0 aHalogen bonding in 25dichloro14benzoquinone insights from experi  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY  a1855-18620 v113 a<p>Experimental charge density distribution in 2, 5-dichloro-1, 4-benzoquinone has been carried out using high resolution X-ray diffraction data at 90 K to quantitatively evaluate the nature of C-Cl center dot center dot center dot O=C halogen bond in molecular crystals. Additionally, the halogen bond is studied from geometrical point of view and the same has been visualized using Hirshfeld surface analysis. The obtained results from experimental charge density analysis are compared with periodic quantum calculations using B3LYP 6-31G(d,p) level of theory. The topological values at bond critical point, three-dimensional static deformation density features and electrostatic potential isosurfaces unequivocally establish the attractive nature of C-Cl center dot center dot center dot O=C halogen bond in crystalline lattice.</p>1 aHathwar, Venkatesha, R.1 aGonnade, Rajesh, G.1 aMunshi, Parthapratim1 aBhadbhade, Mohan, M.1 aRow, Tayur, N. Guru  uhttps://library.ncl.res.in/content/halogen-bonding-25-dichloro-14-benzoquinone-insights-experimental-and-theoretical-charge-001789nas a2200157   4500008004100000245022900041210006900270260000800339300001200347490000700359520105400366100002701420700002701447700002501474856013201499       2017                        eng d00aHelical preorganization of molecules drives solid-state intermolecular acyl-transfer reactivity in crystals: structures and reactivity studies of solvates of racemic 2,6-Di-O-(4-fluorobenzoyl)-myo-inositol 1,3,5-orthoformate0 aHelical preorganization of molecules drives solidstate intermole  cJAN  a117-1260 v173 aRacemic 2,6-di-O-(4-fluorobenzoyl)-myo-inositol 1,3,5-orthoformate yielded structurally dissimilar solvent-free and solvated crystals depending upon the solvent of crystallization. The solvated crystals exhibited helical assembly of host molecules, due to the interaction of the guest molecules with the orthoformate moiety of the host. Some of the solvates showed specific but incomplete benzoyl group transfer reactivity below the phase transition temperature, whereas the reaction in solvent-free crystals led to a mixture of several products. These results reveal the necessity of helical molecular packing of the reacting molecules in their crystals to facilitate specific intermolecular acyl transfer reactivity. The crystal, structures of the fluorobenzoate solvates were similar to those of the solvates of the analogous chloro and bromobenzoates. The latter could be thermally :transformed into their solvent-free form via melt crystallization, resulting in the conversion of a helical molecular packing into a nonhelical molecular packing.1 aKrishnaswamy, Shobhana1 aShashidhar, Mysore, S.1 aBhadbhade, Mohan, M.  uhttps://library.ncl.res.in/content/helical-preorganization-molecules-drives-solid-state-intermolecular-acyl-transfer-reactivity