Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Dec 1, 2005
New organotin(IV) complexes of the general formula R3Sn(L) (where R=Me, n-Bu and HL=L-proline; R=... more New organotin(IV) complexes of the general formula R3Sn(L) (where R=Me, n-Bu and HL=L-proline; R=Me, Ph and HL=trans-hydroxy-L-proline and L-glutamine) and R2Sn(L)2 (where R=n-Bu, Ph and HL=L-proline; R=Ph, HL=trans-hydroxy-L-proline) have been synthesized by the reaction of RnSnCl(4-n) (where n=2 or 3) with sodium salt of the amino acid (HL). n-Bu2Sn(Pro)2 was synthesized by the reaction of n-Bu2SnO with L-proline under azeotropic removal of water. The bonding and coordination behavior in these complexes have been discussed on the basis of IR and 119Sn Mössbauer spectroscopic studies in the solid-state. Their coordination behavior in solution has been discussed with the help of multinuclear (1H, 13C and 119Sn) NMR spectral studies. The 119Sn Mössbauer and IR studies indicate that L-proline and trans-hydroxy-L-proline show similar coordination behavior towards organotin(IV) compounds. Pentacoordinate trigonal-bipyramidal and hexacoordinate octahedral structures, respectively, have been proposed for the tri- and diorganotin(IV) complexes of L-proline and trans-hydroxy-L-proline, in which the carboxylate group acts as bidentate group. L-glutamine shows different coordination behavior towards organotin(IV) compounds, it acts as monoanionic bidentate ligand coordinating through carboxylate and amino group. The triorganotin(IV) complexes of L-glutamine have been proposed to have trigonal-bipyramidal environment around tin. The newly synthesized complexes have been tested for their antiinflammatory and cardiovascular activities. Their LD50 values are >1000 mg kg-1.
Synthesis and reactivity in inorganic and metal-organic chemistry, Oct 1, 1993
A variety of N-(2-hydroxyphenyl)ethylidene-amino acid Schiff bases (abbreviated as OHACPh:AA) coo... more A variety of N-(2-hydroxyphenyl)ethylidene-amino acid Schiff bases (abbreviated as OHACPh:AA) coordinated to cobalt(II), nickel(II) and copper(II) have teen synthesized and characterized by elemental analyses, conductivity measurements and magnetic, electronic and infrared spectral studies. The results suggest that the complexes are four-coordinate with 1:2 (metal:ligand) stoichiometry. The ligands coordinate through the imino nitrogen and carboxylate oxygen.
Synthesis and reactivity in inorganic and metal-organic chemistry, Jul 1, 1998
Abstract Some transition metal complexes of the type ML2. nH2O [where M = Co(II), Ni(II) and Cu(I... more Abstract Some transition metal complexes of the type ML2. nH2O [where M = Co(II), Ni(II) and Cu(II); n = 2 and when M = Zn, n = 0; L = anion of the Schiff bases derived from the condensation of 2-amino-5-phenyl-1,3,4-thiadiamle with 2-hydroxy-1-naphthaldehyde (HL1) or 2-hydroxy-acetophenone (HL2) and derived from 2-amino-5-(2-methoxyphenyl)-1,3,4-thiadiazole and 2-hydroxybenzaldehyde (HL3) or 2-hydroxyacetophenone (HL4)] have been synthesized and characterized by elemental analyses, molar conductance, magnetic measurements, infrared and electronic spectral studies. The analytical data show 1:2 metal to ligand stoichiometry of the complexes. Magnetic moments, along with electronic spectral data, suggest a distorted octahedral geometry for the Co. Ni and Cu complexes, whereas, a tetrahedral structure has been proposed for the Zn complexes. The presence of water molecules in the Co(II), Ni(II) and Cu(II) complexes is also indicated by the thermal studies.
The development of an efficient sustainable catalyst for effective removal of hazardous chemicals... more The development of an efficient sustainable catalyst for effective removal of hazardous chemicals, viz. nitrophenols and organic dyes, from wastewater is a challenging task. Herein, facile synthesis of Ag/NiO composites by anchoring Ag nanoparticles (NPs) on NiO octahedrons with different amounts of Ag NPs (AN-5% (5% Ag), AN-10% (10% Ag) and AN-15% (15% Ag)) has been demonstrated. SEM (scanning electron microscopic) and TEM (transmission electron spectroscopic) images ensured the proper anchoring of spherical Ag NPs (particle size = 16.54 ± 1.88 nm) on octahedron particles of NiO, which was also ensured by XPS (X-ray photoelectron spectroscopy) analysis. Moreover, the resulting composites have an average surface area (49-52 m2g‒1) and pore size (2.39-2.26 nm). All three synthesized Ag/NiO composites (100 μL) catalyzed the complete reduction of para-np (4-nitrophenol: 0.1587 mM) within 2-3 min in the presence of 0.04 M NaBH4. Among them, AN-5% has been chosen because of the lowest anchored Ag (5%) to obtain the optimized catalyst's amount (50 μL) and concentration of para-np (0.1587 mM). AN-5% also exhibited excellent catalytic activity towards different nitro substituted phenols, viz. ortho-np (2-nitrophenol), meta-np (3-nitrophenol), para-np (4-nitrophenol) and tri-np (2,4,6-trinitrophenol). AN-5% displayed ∼100% catalytic efficiency for reducing meta-np in 2 min with the apparent first order rate constant (kapp) and normalized rate constant (Knor) as 1.99 s-1 and 398.14 s-1 g-1, respectively. Additionally, AN-5% (29.41 μg mL-1) reduced >95% of the colouring dyes (10 ppm) such as CONG-R (congo red: 95% in 6 min), METH-O (methyl orange: 97.5% in 7 min), METH-B (methylene blue: 98.3% in 10 min) and RHOD-B (rhodamine B: 99.2% in 5 min). AN-5% not only demonstrated catalytic reduction towards individual pollutants, but also showed excellent activity for reduction of the mixtures of nitrophenols/dyes and for treatment of simulated industrial effluent samples (EFF1, EFF2) and a real industrial sample (textile dye-bath effluent). AN-5% can also be reused up to several cycles with almost same efficiency and followed the Langmuir-Hinshelwood apparent first order kinetics model.
Phosphorus Sulfur and Silicon and The Related Elements, Feb 1, 2002
... Mala Nath and Sunita Goyal Department of Chemistry, University of Roorkee, Roorkee 247 667, I... more ... Mala Nath and Sunita Goyal Department of Chemistry, University of Roorkee, Roorkee 247 667, India ... acid systems.25−31 Pyridoxyl (Vitamin B6 aldehyde)-amino acid Schiff bases are believed to be intermediates in biologically important amination processes.32 Furthermore ...
Multi-Core–shell TiO2NPs@ZIF-8 composites were synthesized by in situ encapsulation of different ... more Multi-Core–shell TiO2NPs@ZIF-8 composites were synthesized by in situ encapsulation of different amounts of TiO2NPs (150, 300 and 500 μL suspension of TiO2NPs in methanol) in ZIF-8 at room temperature. Encapsulation of TiO2NPs in ZIF-8 was confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy. ZIF-8 and its core–shell composites have similar crystal structure and morphology as confirmed by powder X-ray diffraction analysis and scanning electron microscopy. The detailed photocatalytic degradation and adsorption studies of methylene blue and rhodamine-B were investigated by considering various factors, viz. amount of loading of TiO2NPs in ZIF-8, amount of photocatalyst, pH and initial concentration of the dye. At higher pH (11.5−12.6), TiO2NPs@ZIF-8 composite exhibited higher (≈ 8 times) photocatalytic activity as compared to TiO2NPs and the optimum amount of TiO2NPs@ZIF-8 composite was 10 mg for the maximum photodegradation of 3.19 mg L−1 (93 %) and 2.4 mg L−1 (57 %) of methylene blue and rhodamine-B, respectively.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Dec 1, 2005
New organotin(IV) complexes of the general formula R3Sn(L) (where R=Me, n-Bu and HL=L-proline; R=... more New organotin(IV) complexes of the general formula R3Sn(L) (where R=Me, n-Bu and HL=L-proline; R=Me, Ph and HL=trans-hydroxy-L-proline and L-glutamine) and R2Sn(L)2 (where R=n-Bu, Ph and HL=L-proline; R=Ph, HL=trans-hydroxy-L-proline) have been synthesized by the reaction of RnSnCl(4-n) (where n=2 or 3) with sodium salt of the amino acid (HL). n-Bu2Sn(Pro)2 was synthesized by the reaction of n-Bu2SnO with L-proline under azeotropic removal of water. The bonding and coordination behavior in these complexes have been discussed on the basis of IR and 119Sn Mössbauer spectroscopic studies in the solid-state. Their coordination behavior in solution has been discussed with the help of multinuclear (1H, 13C and 119Sn) NMR spectral studies. The 119Sn Mössbauer and IR studies indicate that L-proline and trans-hydroxy-L-proline show similar coordination behavior towards organotin(IV) compounds. Pentacoordinate trigonal-bipyramidal and hexacoordinate octahedral structures, respectively, have been proposed for the tri- and diorganotin(IV) complexes of L-proline and trans-hydroxy-L-proline, in which the carboxylate group acts as bidentate group. L-glutamine shows different coordination behavior towards organotin(IV) compounds, it acts as monoanionic bidentate ligand coordinating through carboxylate and amino group. The triorganotin(IV) complexes of L-glutamine have been proposed to have trigonal-bipyramidal environment around tin. The newly synthesized complexes have been tested for their antiinflammatory and cardiovascular activities. Their LD50 values are >1000 mg kg-1.
Synthesis and reactivity in inorganic and metal-organic chemistry, Oct 1, 1993
A variety of N-(2-hydroxyphenyl)ethylidene-amino acid Schiff bases (abbreviated as OHACPh:AA) coo... more A variety of N-(2-hydroxyphenyl)ethylidene-amino acid Schiff bases (abbreviated as OHACPh:AA) coordinated to cobalt(II), nickel(II) and copper(II) have teen synthesized and characterized by elemental analyses, conductivity measurements and magnetic, electronic and infrared spectral studies. The results suggest that the complexes are four-coordinate with 1:2 (metal:ligand) stoichiometry. The ligands coordinate through the imino nitrogen and carboxylate oxygen.
Synthesis and reactivity in inorganic and metal-organic chemistry, Jul 1, 1998
Abstract Some transition metal complexes of the type ML2. nH2O [where M = Co(II), Ni(II) and Cu(I... more Abstract Some transition metal complexes of the type ML2. nH2O [where M = Co(II), Ni(II) and Cu(II); n = 2 and when M = Zn, n = 0; L = anion of the Schiff bases derived from the condensation of 2-amino-5-phenyl-1,3,4-thiadiamle with 2-hydroxy-1-naphthaldehyde (HL1) or 2-hydroxy-acetophenone (HL2) and derived from 2-amino-5-(2-methoxyphenyl)-1,3,4-thiadiazole and 2-hydroxybenzaldehyde (HL3) or 2-hydroxyacetophenone (HL4)] have been synthesized and characterized by elemental analyses, molar conductance, magnetic measurements, infrared and electronic spectral studies. The analytical data show 1:2 metal to ligand stoichiometry of the complexes. Magnetic moments, along with electronic spectral data, suggest a distorted octahedral geometry for the Co. Ni and Cu complexes, whereas, a tetrahedral structure has been proposed for the Zn complexes. The presence of water molecules in the Co(II), Ni(II) and Cu(II) complexes is also indicated by the thermal studies.
The development of an efficient sustainable catalyst for effective removal of hazardous chemicals... more The development of an efficient sustainable catalyst for effective removal of hazardous chemicals, viz. nitrophenols and organic dyes, from wastewater is a challenging task. Herein, facile synthesis of Ag/NiO composites by anchoring Ag nanoparticles (NPs) on NiO octahedrons with different amounts of Ag NPs (AN-5% (5% Ag), AN-10% (10% Ag) and AN-15% (15% Ag)) has been demonstrated. SEM (scanning electron microscopic) and TEM (transmission electron spectroscopic) images ensured the proper anchoring of spherical Ag NPs (particle size = 16.54 ± 1.88 nm) on octahedron particles of NiO, which was also ensured by XPS (X-ray photoelectron spectroscopy) analysis. Moreover, the resulting composites have an average surface area (49-52 m2g‒1) and pore size (2.39-2.26 nm). All three synthesized Ag/NiO composites (100 μL) catalyzed the complete reduction of para-np (4-nitrophenol: 0.1587 mM) within 2-3 min in the presence of 0.04 M NaBH4. Among them, AN-5% has been chosen because of the lowest anchored Ag (5%) to obtain the optimized catalyst's amount (50 μL) and concentration of para-np (0.1587 mM). AN-5% also exhibited excellent catalytic activity towards different nitro substituted phenols, viz. ortho-np (2-nitrophenol), meta-np (3-nitrophenol), para-np (4-nitrophenol) and tri-np (2,4,6-trinitrophenol). AN-5% displayed ∼100% catalytic efficiency for reducing meta-np in 2 min with the apparent first order rate constant (kapp) and normalized rate constant (Knor) as 1.99 s-1 and 398.14 s-1 g-1, respectively. Additionally, AN-5% (29.41 μg mL-1) reduced >95% of the colouring dyes (10 ppm) such as CONG-R (congo red: 95% in 6 min), METH-O (methyl orange: 97.5% in 7 min), METH-B (methylene blue: 98.3% in 10 min) and RHOD-B (rhodamine B: 99.2% in 5 min). AN-5% not only demonstrated catalytic reduction towards individual pollutants, but also showed excellent activity for reduction of the mixtures of nitrophenols/dyes and for treatment of simulated industrial effluent samples (EFF1, EFF2) and a real industrial sample (textile dye-bath effluent). AN-5% can also be reused up to several cycles with almost same efficiency and followed the Langmuir-Hinshelwood apparent first order kinetics model.
Phosphorus Sulfur and Silicon and The Related Elements, Feb 1, 2002
... Mala Nath and Sunita Goyal Department of Chemistry, University of Roorkee, Roorkee 247 667, I... more ... Mala Nath and Sunita Goyal Department of Chemistry, University of Roorkee, Roorkee 247 667, India ... acid systems.25−31 Pyridoxyl (Vitamin B6 aldehyde)-amino acid Schiff bases are believed to be intermediates in biologically important amination processes.32 Furthermore ...
Multi-Core–shell TiO2NPs@ZIF-8 composites were synthesized by in situ encapsulation of different ... more Multi-Core–shell TiO2NPs@ZIF-8 composites were synthesized by in situ encapsulation of different amounts of TiO2NPs (150, 300 and 500 μL suspension of TiO2NPs in methanol) in ZIF-8 at room temperature. Encapsulation of TiO2NPs in ZIF-8 was confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy. ZIF-8 and its core–shell composites have similar crystal structure and morphology as confirmed by powder X-ray diffraction analysis and scanning electron microscopy. The detailed photocatalytic degradation and adsorption studies of methylene blue and rhodamine-B were investigated by considering various factors, viz. amount of loading of TiO2NPs in ZIF-8, amount of photocatalyst, pH and initial concentration of the dye. At higher pH (11.5−12.6), TiO2NPs@ZIF-8 composite exhibited higher (≈ 8 times) photocatalytic activity as compared to TiO2NPs and the optimum amount of TiO2NPs@ZIF-8 composite was 10 mg for the maximum photodegradation of 3.19 mg L−1 (93 %) and 2.4 mg L−1 (57 %) of methylene blue and rhodamine-B, respectively.
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