Coordination Polymers Built with a Linear Bis-Imidazole and Different Dicarboxylates: Unusual Entanglement and Emission Properties

The linear linker bis­(4-imidazol-1-ylphenyl)­diazene (L) has been used to construct eight new coordination polymers with Zn­(II), Cd­(II) and Co­(II) metal ions and different carboxylate donor ligands, viz., 1,1′-ferrocenedicarboxylic acid (H₂Fc), 2′,5′-dimethylterphenyl-4,4″-dicarboxylic acid (H₂MDA), diphenic acid (H₂DPA), biphenyl-4,4′-dicarboxylic acid (H₂BIPH), 4,4′-oxybis (benzoic acid) (H₂BIOXY), l-(−)-malic acid (H₃LMA) and 2,2′-dibromo-6,6′-dinitrobiphenyl-4,4′-dicarboxylic acid (H₂DBDPA). Compounds formed solvothermally are {[Cd­(L)­(Fc)­(H₂O)]·(H₂O)₂}_<i>n</i> (<b>1</b>), {[Cd­(L)­(MDA)]·DMF·CH₃OH}_<i>n</i> (<b>2</b>), {[Zn­(L)­(MDA)]·3H₂O}_<i>n</i> (<b>3</b>), {[Cd­(L)­(DPA)]}_<i>n</i> (<b>4</b>), {[Cd₂(L)₂(BIPH)₂(H₂O)₂]·H₂O}_<i>n</i> (<b>5</b>), {[Cd₂(L)₂(BIOXY)₂]·H₂O·CH₃OH}_<i>n</i> (<b>6</b>), {[Zn₃(L)₅(LMA)₂]·2.5H₂O}_<i>n</i> (<b>7</b>) and {[Co­(L)­(DBDPA)]·H₂O}_<i>n</i> (<b>8</b>). All the complexes have been characterized by single crystal X-ray diffraction, IR spectroscopy, thermogravimetry, elemental analysis and powder X-ray diffraction (PXRD). Interestingly, all complexes topologically exhibit 4-connected net except complex <b>7</b>, which is (4,6). Moreover, the degree of interpenetration varies in <b>1</b>–<b>8</b>. Complexes <b>1</b>, <b>4</b> and <b>6</b> exhibit commonly occurring <i>sql</i> topology, while complexes <b>2</b> and <b>3</b> are 8-fold interpenetrated <i>dia</i> net. Contrary to this, complexes <b>5</b> and <b>8</b> show rare <i>cdl</i> and <i>dmp</i> nets with three and five mutual interpenetrative nets, respectively. However, <b>7</b> forms a novel <i>pkb</i>6 topological net with 2-fold interpenetration. Upon excitation at 322 nm, complexes <b>1</b>–<b>8</b> exhibit solid-state luminescence at room temperature

Coordination Polymers Built with a Linear Bis-Imidazole and Different Dicarboxylates: Unusual Entanglement and Emission Properties

The linear linker bis­(4-imidazol-1-ylphenyl)­diazene (L) has been used to construct eight new coordination polymers with Zn­(II), Cd­(II) and Co­(II) metal ions and different carboxylate donor ligands, viz., 1,1′-ferrocenedicarboxylic acid (H₂Fc), 2′,5′-dimethylterphenyl-4,4″-dicarboxylic acid (H₂MDA), diphenic acid (H₂DPA), biphenyl-4,4′-dicarboxylic acid (H₂BIPH), 4,4′-oxybis (benzoic acid) (H₂BIOXY), l-(−)-malic acid (H₃LMA) and 2,2′-dibromo-6,6′-dinitrobiphenyl-4,4′-dicarboxylic acid (H₂DBDPA). Compounds formed solvothermally are {[Cd­(L)­(Fc)­(H₂O)]·(H₂O)₂}_<i>n</i> (<b>1</b>), {[Cd­(L)­(MDA)]·DMF·CH₃OH}_<i>n</i> (<b>2</b>), {[Zn­(L)­(MDA)]·3H₂O}_<i>n</i> (<b>3</b>), {[Cd­(L)­(DPA)]}_<i>n</i> (<b>4</b>), {[Cd₂(L)₂(BIPH)₂(H₂O)₂]·H₂O}_<i>n</i> (<b>5</b>), {[Cd₂(L)₂(BIOXY)₂]·H₂O·CH₃OH}_<i>n</i> (<b>6</b>), {[Zn₃(L)₅(LMA)₂]·2.5H₂O}_<i>n</i> (<b>7</b>) and {[Co­(L)­(DBDPA)]·H₂O}_<i>n</i> (<b>8</b>). All the complexes have been characterized by single crystal X-ray diffraction, IR spectroscopy, thermogravimetry, elemental analysis and powder X-ray diffraction (PXRD). Interestingly, all complexes topologically exhibit 4-connected net except complex <b>7</b>, which is (4,6). Moreover, the degree of interpenetration varies in <b>1</b>–<b>8</b>. Complexes <b>1</b>, <b>4</b> and <b>6</b> exhibit commonly occurring <i>sql</i> topology, while complexes <b>2</b> and <b>3</b> are 8-fold interpenetrated <i>dia</i> net. Contrary to this, complexes <b>5</b> and <b>8</b> show rare <i>cdl</i> and <i>dmp</i> nets with three and five mutual interpenetrative nets, respectively. However, <b>7</b> forms a novel <i>pkb</i>6 topological net with 2-fold interpenetration. Upon excitation at 322 nm, complexes <b>1</b>–<b>8</b> exhibit solid-state luminescence at room temperature

Solvent-Induced Carboxylate Shift and Movement of an Anthryl Side-Group in Single-Crystal to Single-Crystal Structural Dynamics in a Gadolinium Coordination Polymer

Single crystal to single crystal (SC–SC) transformation involving cooperative movement of atoms represents one of the most fascinating phenomena in coordination polymers. Here, we describe a novel two-dimensional coordination polymer {[Gd₂(L)₃(DMF)₂­(H₂O)₂]­·(DMF)₂­·(H₂O)_5.5}_<i>n</i> (<b>1</b>) synthesized from carboxylate-based flexible ligand 5-[(anthracen-9-ylmethyl)-amino]-isophthalic acid and Gd­(III) ion by the solvothermal technique. The complex undergoes solvent-induced rearrangement reactions with the cleavage and formation of coordination bonds and substantial movement of the anthracene side groups without losing crystallinity to form the daughter products as {[Gd₂(L)₃(H₂O)₄]­·(DMF)₄­·(H₂O)_1.5}_<i>n</i> (<b>1a</b>), {[Gd₂(L)₃(DMF)₂­(H₂O)]­·(DMF)₂­·(DCM)₂­·(H₂O)₅}_<i>n</i> (<b>1b</b>), and [Gd­(L)₂(DEF)]_<i>n</i> (<b>1c</b>). These transformations exhibit a crystallographic snapshot of “carboxylate-shift” process which is further supported by IR spectroscopy, elemental analysis, and powder X-ray diffraction patterns. To the best of our knowledge, it is the first example of carboxylate shift in a Gd­(III) coordination polymer. The mother crystal <b>1</b> and the daughters <b>1a </b>and<b> 1c</b> exhibit 4-connected <i><b>sql</b></i> topology, while <b>1b</b> shows a 3-connected <i><b>hcb</b></i> topology. Magnetic susceptibility measurements at variable temperature indicate the existence of antiferromagnetic interactions in all the complexes. The photoluminescent properties of the complexes in the solid state are also investigated at room temperature

Coordination Polymers of Copper and Zinc Ions with a Linear Linker Having Imidazole at Each End and an Azo Moiety in the Middle: Pedal Motion, Gas Adsorption, and Emission Studies

The imidazole donor ligand bis­(4-imidazol-1-yl-phenyl)-diazene (azim) reacts readily with M­(ClO₄)₂·6H₂O [M­(II) = Zn­(II) and Cu­(II)] salts at room temperature to afford {[Zn­(azim)₂]·(ClO₄)₂·3DMF}_<i>n</i> (<b>1</b>) and {[Cu­(azim)₂(DMF)₂]·(ClO₄)₂·2DMF}_<i>n</i> (<b>2</b>) (DMF = <i>N</i>,<i>N</i>′-dimethylformamide). With MCl₂·6H₂O [M­(II) = Zn­(II) and Cu­(II)] salts under solvothermal conditions, compounds {[Zn­(azim)­(HCOO)₂]}_<i>n</i> (<b>3</b>) and {[Cu­(azim)­(Cl)]}_<i>n</i> (<b>4</b>) are obtained in moderate yields. Complexes <b>1</b> and <b>2</b> crystallize as 2D four-connected 4⁴ sql networks with rectangular and rhombus grids, respectively. The frameworks are stabilized by an intricate array of hydrogen bonding interactions with guest molecules that also results in overall 3D frameworks. On the other hand, complexes <b>3</b> and <b>4</b> form 1D zigzag infinite chain structures. All compounds have been characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD) measurements. The TGA and PXRD measurements reveal that the integrity of the frameworks <b>1</b> and <b>2</b> is maintained upon guest removal. N₂ and CO₂ adsorption measurements were carried out for evacuated frameworks <b>1</b> and <b>2</b>, and the adsorption studies show CO₂ selectivity over N₂ at low pressure in the case of <b>2</b>. Interestingly, heat and guest induced bicycle pedal motion of the azo moiety can be observed in <b>1</b> and <b>4</b> without loss of crystallinity. Upon excitation at 304 nm, compounds <b>1</b>–<b>4</b> and <b>4′</b> exhibit solid-state luminescence at room temperature

Coordination Polymers of Copper and Zinc Ions with a Linear Linker Having Imidazole at Each End and an Azo Moiety in the Middle: Pedal Motion, Gas Adsorption, and Emission Studies

The imidazole donor ligand bis­(4-imidazol-1-yl-phenyl)-diazene (azim) reacts readily with M­(ClO₄)₂·6H₂O [M­(II) = Zn­(II) and Cu­(II)] salts at room temperature to afford {[Zn­(azim)₂]·(ClO₄)₂·3DMF}_<i>n</i> (<b>1</b>) and {[Cu­(azim)₂(DMF)₂]·(ClO₄)₂·2DMF}_<i>n</i> (<b>2</b>) (DMF = <i>N</i>,<i>N</i>′-dimethylformamide). With MCl₂·6H₂O [M­(II) = Zn­(II) and Cu­(II)] salts under solvothermal conditions, compounds {[Zn­(azim)­(HCOO)₂]}_<i>n</i> (<b>3</b>) and {[Cu­(azim)­(Cl)]}_<i>n</i> (<b>4</b>) are obtained in moderate yields. Complexes <b>1</b> and <b>2</b> crystallize as 2D four-connected 4⁴ sql networks with rectangular and rhombus grids, respectively. The frameworks are stabilized by an intricate array of hydrogen bonding interactions with guest molecules that also results in overall 3D frameworks. On the other hand, complexes <b>3</b> and <b>4</b> form 1D zigzag infinite chain structures. All compounds have been characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD) measurements. The TGA and PXRD measurements reveal that the integrity of the frameworks <b>1</b> and <b>2</b> is maintained upon guest removal. N₂ and CO₂ adsorption measurements were carried out for evacuated frameworks <b>1</b> and <b>2</b>, and the adsorption studies show CO₂ selectivity over N₂ at low pressure in the case of <b>2</b>. Interestingly, heat and guest induced bicycle pedal motion of the azo moiety can be observed in <b>1</b> and <b>4</b> without loss of crystallinity. Upon excitation at 304 nm, compounds <b>1</b>–<b>4</b> and <b>4′</b> exhibit solid-state luminescence at room temperature

Characterization of <i>Arabidopsis</i> sterol glycosyltransferase <i>TTG15/UGT80B1</i> role during freeze and heat stress

<p>Sterol glycosyltransferases regulate the properties of sterols by catalyzing the transfer of carbohydrate molecules to the sterol moiety for the synthesis of steryl glycosides and acyl steryl glycosides. We have analyzed the functional role of <i>TTG15/UGT80B1</i> gene of <i>Arabidopsis thaliana</i> in freeze/thaw and heat shock stress using T-DNA insertional <i>sgt</i> knockout mutants. Quantitative study of spatial as well as temporal gene expression showed tissue-specific and dynamic expression patterns throughout the growth stages. Comparative responses of Col-0, <i>TTG15/UGT80B1</i> knockout mutant and <i>p</i>35<i>S</i>:<i>TTG15/UGT80B1</i> restored lines were analyzed under heat and freeze stress conditions. Heat tolerance was determined by survival of plants at 42°C for 3 h, MDA analysis and chlorophyll fluorescence image (CFI) analysis. Freezing tolerance was determined by survival of the plants at -1°C temperature in non-acclimatized (NA) and cold acclimatized (CA) conditions and also by CFI analysis, which revealed that, <i>p</i>35S:<i>TTG15/UGT80B1</i> restored plants were more adapted to freeze stress than <i>TTG15/UGT80B1</i> knockout mutant under CA condition. HPLC analysis of the plants showed reduced sterol glycoside in mutant seedlings as compared to other genotypes. Following CA condition, both β-sitosterol and sitosterol glycoside quantity was more in Col-0 and <i>p</i>35<i>S</i>:<i>TTG15/UGT80B1</i> restored lines, whereas it was significantly less in <i>TTG15/UGT80B1</i> knockout mutants. From these results, it may be concluded that due to low content of free sterols and sterol glycosides, the physiology of mutant plants was more affected during both, the chilling and heat stress.</p

Gender difference in adherence to medical treatment.

<p>n = number of study participants; *P≤0.05.</p

Selective questionnaire response results among 10–21 years old patients.

<p>n = number of study participants; *P≤0.05.</p

Pathway studio analysis used for prediction of molecular network modulated by expression of CYP like gene <i>Os08g01480</i> in <i>Arabidopsis</i>.

<p>Pathway studio is utilized for finding common molecular connections between the proteins/transcription factors encoded by the expressed probe sets. This software analyses through the ResNet database for all known interactions between genes/proteins such as regulation and their expression. Each arrow indicates interactions between genes and a cell process pathway.</p

Expression of Rice CYP450-Like Gene (<i>Os08g01480</i>) in <i>Arabidopsis</i> Modulates Regulatory Network Leading to Heavy Metal and Other Abiotic Stress Tolerance

<div><p>Heavy metal (HM) toxicity has become a grave problem in the world since it leads to hazardous effects on living organisms. Transcriptomic/proteomic studies in plants have identified a large number of metal-responsive gene families. Of these, cytochrome-P450 (CYPs) family members are composed of enzymes carrying out detoxification of exogenous molecules. Here, we report a CYP-like protein encoded by <i>Os08g01480</i> locus in rice that helps the plant to combat HM and other abiotic stresses. To functionally characterize CYP-like gene, cDNA and promoter were isolated from rice to develop <i>Arabidopsis</i> transgenic lines. Heterologous expression of <i>Os08g01480</i> in <i>Arabidopsis</i> provided significant tolerance towards abiotic stresses. <i>In silico</i> analysis reveals that <i>Os08g01480</i> might help plants to combat environmental stress via modulating auxin metabolism. Transgenic lines expressing reporter gene under control of <i>Os08g01480</i> promoter demonstrated differential promoter activity in different tissues during environmental stresses. These studies indicated that differential expression of <i>Os08g01480</i> might be modulating response of plants towards environmental stresses as well as in different developmental stages.</p></div