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A three-dimensional (3D) bimetallic (4f−3d) supramolecular framework, {[Nd(pyno)2(H2O)4][Fe(CN)6]·H2O}n(1) (pyno = pyridine-N-oxide), has been synthesized and structurally characterized. Structure determination reveals that one-dimensional (1D) cyano-bridged chains of NdIIIand FeIIIform an alternative basket-like arrangement and are connected by (O−H···N) H-bonding interactions through coordinated water molecules and pendent CN groups forming a two-dimensional (2D) sheet-like structure. 2D sheets are further connected by another set of similar (O−H···N) interactions resulting in a 3D supramolecular framework with 1D water-filled channels. Controlled heating of the as-synthesized crystal at 85 °C causes a color change from yellow to a light brown compound {[Nd(pyno)2(H2O)4][Fe(CN)6]}n(1′) and structure determination shows significant contraction of the overall framework with selective removal of the guest water molecules. 1′exhibits a similar framework topology as 1. The dehydrated crystal (1′) regenerates the virgin as-synthesized framework (1a) with structural expansion upon exposure to the water vapor. Adsorption studies reveal that 1′can selectively uptake H2O but not MeOH, EtOH, and CO2consistent with the channel size. Removal of the guest as well as coordinated water molecules gives another phase {[Nd(pyno)2][Fe(CN)6]}n(2), which shows sorption of H2O and MeOH vapors but not CO2. Temperature-dependent magnetic measurement (300−2 K) suggests the as-synthesized framework is antiferromagnetically coupled at low temperature. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) robust porous coordination polymer, {[Cu(azpy)(glut)](H2O)2}n(1) (azpy= N,N′-bis-pyridin-4-ylmethylene-hydrazine, glut= glutarate), has been synthesized and structurally characterized. Single crystal X-ray diffraction analysis reveals that each of paddle-wheel Cu2(CO2)4units is connected with glutarates in the crystallographic bcplane to form a two-dimensional (2D) sheet which is pillared by an azpylinker to afford a 3D porous framework. Controlled heating of the as-synthesized crystal 1at ∼150 °C under reduced pressure causes a color change of {[Cu(azpy)(glut)]}n(1a) from deep green to light green. The structure determination of the dehydrated compound shows the same framework structure as that of {[Cu(azpy)(glut)](H2O)2}n(1) with the only difference of the nonexistence of lattice water molecules resulting in a large void in the framework. The dehydrated light green crystal 1aregenerates the virgin as-synthesized crystal 1with the formula of {[Cu(azpy)(glut)](H2O)2}nupon exposure to water vapor (1a), suggesting complete reversibility upon dehydration and rehydration. Dehydrated compound 1ashows remarkable CO2selectivity over N2, a typical type I profile with MeOH and EtOH, and gated adsorption behavior with H2O. The selectivity in gas uptake and interesting vapor adsorption profiles was correlated with the polarity of the pore surface in 1ato the corresponding adsorbates molecules. [ABSTRACT FROM AUTHOR]