<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sahoo, Subash Chandra</style></author><author><style face="normal" font="default" size="100%">Kundu, Tanay</style></author><author><style face="normal" font="default" size="100%">Banerjee, Rahul</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Helical water chain mediated proton conductivity in homochiral metal-organic frameworks with unprecedented zeolitic unh-topology</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of the American Chemical Society</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">NOV</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">44</style></number><publisher><style face="normal" font="default" size="100%">AMER CHEMICAL SOC</style></publisher><pub-location><style face="normal" font="default" size="100%">1155 16TH ST, NW, WASHINGTON, DC 20036 USA</style></pub-location><volume><style face="normal" font="default" size="100%">133</style></volume><pages><style face="normal" font="default" size="100%">17950-17958</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Four new homochiral metal-organic framework (MOF) isomers, [Zn(l-L-Cl)(Cl)](H2O)(2) (1), [Zn(l-L-Br)(Br)]-(H2O)(2) (2), [Zn(d-L-Cl)(Cl)(H2O)(2) (3), and [Zn(d-L-Br)-(Br)] (H2O)(2) (4) [L = 3-methyl-2-(pyridin-4-ylmethylamino)-butanoic acid], have been synthesized by using a derivative of L-/D-valine and Zn(CH3COO)(2)center dot 2H(2)O. A three-periodic lattice with a parallel ID helical channel was formed along the crystallographic c-axis. Molecular rearrangement results in an unprecedented zeolitic unh-toparigy in 1-4. In each case, two lattice water molecules (one H-bonded. to halogen atoms) form a secondary helical continuous water chain inside the molecular helix. MOFs 1 and 2 shows different water adsorption properties and hence different water affinity. The arrangement of water molecules inside the channel Was monitored by variable temperature single crystal X-ray diffraction, which indicated that MOF 1 has a higher water holding capacity than MOF 2. In MOF 1, water escapes. at 80 degrees C, while in T the same happens at a much lower temperature (similar to 40 degrees C). All the MOFs reported here shows reversible crystallization by readily reabsorbing moisture. In MOFs 1 and 2, the frameworks are stable after solvent removal, which is confirmed by a single-crystal to single crystal transformation. MOFs 1 and 3 show high proton conductivity of 4.45 x 10(-5) and 4.42 x 10(-5) S cm(-1), respectively, while 2 and 4 shows zero proton conductivity. The above result is attributed to the fact that MOF 1 has a higher water holding capacity than MOF 2.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">44</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">10.47
</style></custom4></record></records></xml>