Temperature-Dependent Emission and Turn-Off Fluorescence Sensing of Hazardous "Quat" Herbicides in Water by a Zn-MOF Based on a Semi-Rigid Dibenzochrysene Tetraacetic Acid Linker.

A zinc metal-organic framework, i.e., Zn-MOF (Zn-DBC), with ca.

Fluorescent 2D metal-organic framework nanosheets (MONs): design, synthesis and sensing of explosive nitroaromatic compounds (NACs).

2D metal-organic framework nanosheets (MONs) lie at the heart of contemporary research on metal-organic materials. We have rationally designed and synthesized a fluorescent 6-connecting hexaacid linker HTPA based on the 1,3,5-triphenylbenzene core to access layered MOFs by metal-assisted self-assembly. Treatment of HTPA with In salt does indeed lead to a layered porous MOF, i.

Robust MOFs of "tsg" Topology Based on Trigonal Prismatic Organic and Metal Cluster SBUs: Single Crystal to Single Crystal Postsynthetic Metal Exchange and Selective CO Capture.

The self-assembly of a rigid and trigonal prismatic triptycene-hexaacid H THA with Co(NO ) or Mn(NO ) leads to isostructural metal-organic frameworks (MOFs) that are sustained by 6-connecting metal cluster [M (μ -O)(COO) ] secondary building units (SBUs). The Co- and Mn-MOFs, constructed from organic and metal-cluster building blocks that are both trigonal prismatic, correspond to the heretofore unknown "tsg" topology. Due to the rigidity and concave attributes of H THA, the networks in the Co- and Mn-MOFs are highly porous and undergo 3-fold interpenetration.

Remarkably selective and enantiodifferentiating sensing of histidine by a fluorescent homochiral Zn-MOF based on pyrene-tetralactic acid.

A highly luminescent and water-stable homochiral Zn-MOF, , , has been developed based on a pyrene-tetralactic acid, which inherently features concave shapes for guest inclusion, to explore sensing of amino acids by fluorescence quenching; the solid-state fluorescence quantum yield of the MOF was found to be 46%. The fluorescence of an aqueous suspension of was shown to be quenched specifically by histidine amongst all the other amino acids. Selective sensing of histidine is of prime importance due to its relevance in a variety of biological functions.

A fluorescent paramagnetic Mn metal-organic framework based on semi-rigid pyrene tetra-carboxylic acid: sensing of solvent polarity and explosive nitroaromatics.

An Mn metal-organic framework (Mn-MOF), Mn-L, based on a pyrene-tetraacid linker (H4 L), displays a respectable fluorescence quantum yield of 8.3% in spite of the presence of the paramagnetic metal ions, due presumably to fixation of the metal ions in geometries that do not allow complete energy/charge-transfer quenching. Remarkably, the porous Mn-L MOF with ∼25% solvent-accessible volume exhibits a heretofore unprecedented solvent-dependent fluorescence emission maximum, permitting its use as a probe of solvent polarity; the emission maxima in different solvents correlate excellently with Reichardt's solvent polarity parameter (E T (N)).

Carbon Dioxide Capture by a Metal-Organic Framework with Nitrogen-Rich Channels Based on Rationally Designed Triazole-Functionalized Tetraacid Organic Linker.

A semirigid tetraacid linker H4L functionalized with 1,2,3-triazole was rationally designed and synthesized to access nitrogen-rich MOFs for selective adsorption of CO2. The cadmium MOF, that is, Cd-L, obtained by the reaction of H4L with Cd(NO3)2, is found to be a 3D porous framework structure that is robust to desolvation. Crystal structure analysis reveals channels that are decorated by the triazole moieties of L.

Single crystal-to-single crystal site-selective postsynthetic metal exchange in a Zn-MOF based on semi-rigid tricarboxylic acid and access to bimetallic MOFs.

The metal ions in a neutral Zn-MOF constructed from tritopic triacid H3 L with inherent concave features, rigid core, and peripheral flexibility are found to exist in two distinct SBUs, that is, 0D and 1D. This has allowed site-selective postsynthetic metal exchange (PSME) to be investigated and reactivities of the metal ions in two different environments in coordination polymers to be contrasted for the first time. Site-selective transmetalation of Zn ions in the discrete environment is shown to occur in a single crystal-to-single crystal (SCSC) fashion, with metal ions such as Fe(3+) , Ru(3+) , Cu(2+) , Co(2+) , etc.

Mobility in the structure of E.coli recQ helicase upon substrate binding as seen from molecular dynamics simulations.

RecQ helicases feature multiple domains in their structure, of which the helicase domain, the RecQ-Ct domain and the HRDC domains are well conserved among the SF2 helicases. The helicase domain and the RecQ-Ct domain constitute the catalytic core of the enzyme. The domain interfaces are the DNA binding sites which display significant conformational changes in our molecular dynamics simulation studies.

Cis-->trans and trans-->cis isomerizations of styrylcoumarins in the solid state. Importance of the location of free volume in crystal lattices.

We have examined the photobehavior of a set of isomers of 2-pyranone-annulated stilbenes (6-styrylcoumarin 1, 7-styrylcoumarin 2, 4-methyl-6-styrylcoumarin 3, and 4-methyl-7-styrylcoumarin, 4) in their crystalline phases. While the cis isomers of 1-3 undergo cis-->trans photoisomerizations in the solid state, cis-4 and the trans isomers of 1-3 do not; the trans isomer of 4 undergoes photo-induced intermolecular reactions. Solution-state irradiations of the trans isomers of 1-4 lead to the cis isomers quite readily, as does cis-4 lead to trans-4, which suggests that the absence of geometric isomerization of the trans isomers and the lack of reactivity of cis-4 in the solid state are due to molecular packing effects.