Arunachalam Ramanan | Indian Institute of Technology Delhi (original) (raw)
Papers by Arunachalam Ramanan
Crystal Growth & Design, Mar 25, 2022
Inorganic Chemistry, Jun 16, 1998
Three new, mixed-valent layered vanadyl phosphates, Ago^VOPO^I^O (AgVPO), Cuo.1eVOPO4-2.5H2O (CuV... more Three new, mixed-valent layered vanadyl phosphates, Ago^VOPO^I^O (AgVPO), Cuo.1eVOPO4-2.5H2O (CuVPO), and Zno.11VOPO4-2.5H2O (ZnVPO), have been synthesized hydrothermally and their structures determined by single-crystal X-ray diffraction: AgVPO is triclinic, space group PI, a) 6.287(1), b) 6.283(1), and c) 13.240(1) A, R) 80.98(1), /3) 86.58(1) and γ) 90.00(1)°, Z) 4; CuVPO is triclinic, space group PI, a) 6.260(2), b) 6.249(3), and c) 7.257(1) A, R) 83.62(3), fi) 73.99(2), and γ) 90.13(4)°, Z) 2; ZnVPO is triclinic, space group PI, a) 6.252(1), b) 6.248(2), and c) 7.339(3) A, R) 83.24(4), /?) 73.93(2), and y) 90.00(2)°, Z) 2. The structures are related to that of VOPO 4-2H 2 O. Metal powders have been found to be effective both as reductants and as countercations. Supporting Information Available: Listings of full X-ray powder diffraction data, complete crystallographic parameters, anisotropic thermal parameters, interatomic distances, and bond angles (18 pages). Ordering information is given on any current masthead page.
ChemInform, Aug 18, 2010
ChemInform Abstract Inelastic and quasi-elastic neutron scattering studies of Na,Cs-Rho have been... more ChemInform Abstract Inelastic and quasi-elastic neutron scattering studies of Na,Cs-Rho have been carried out in order to investigate the bonding sites and geometries of framework hydrogen atoms as well as temp.-induced changes in structure. The information obtained is consistent with the commonly accepted idea of bridging hydroxyl groups. The slight change in structure on heating is accompanied by a transfer of Hatoms to some new bonding sites of unknown structure.
Acta Crystallographica Section E-structure Reports Online, Apr 11, 2006
Use of mixed-ligand (bromide and thiocyanate ions) coordination with nickel has led to the crysta... more Use of mixed-ligand (bromide and thiocyanate ions) coordination with nickel has led to the crystallization of the title compound, (C24H20As)2[Ni(NCS)2Br2]. X-ray crystal structure analysis reveals that the asymmetric unit contains one (C6H5)4As+ cation and one half [Ni(NCS)2Br2]2− anion, the latter lying on a crystallographic twofold axis.
![Research paper thumbnail of Novel self-assembled decavanadate clusters forming 1D molecular chains and 2D molecular arrays: [HMTA-H···H2O][HMTA-CH2OH][H3V10O28{Na(H2O)4}]·4H2O and [Na2(H2O)10] [H3V10O28 {Na(H2O)2}]·3H2O](https://attachments.academia-assets.com/119169060/thumbnails/1.jpg)
](Crystal Engineering, Dec 1, 2000
WORLD SCIENTIFIC eBooks, Feb 1, 1995
![Research paper thumbnail of New inorganic-organic hybrid materials based on polyoxovanadates: [Morp]6[VO4cV14O32(OH)6]‚2H2O, [HMTA-H][HMTA-CH2OH]2[H5V10O28]‚6H2O](https://attachments.academia-assets.com/119169302/thumbnails/1.jpg)
](In this paper we report on the first mesoporous catalyst based on SBA-15 incorporating simultaneo... more In this paper we report on the first mesoporous catalyst based on SBA-15 incorporating simultaneously basic and acid functions able to promote the Friedländer reaction between 2-aminoaryl ketones and ethyl acetoacetate leading to quinolines 1 with high yields. From 2-aminobenzophenone (3a) it is possible to prepare quinoline 1a with the highest selectivity (86%) as compared with other mesoporous acidic catalysts. In contrast, the reaction catalyzed by amine-grafted SBA-15 yielded selectively (98%) the corresponding quinolone 2a in accordance with our previous results. Experimental results have been justified by theoretical calculations as function of the stability of reaction intermediate species, which could be involved in the process.
Journal of Molecular Structure
Acta Crystallographica Section A Foundations and Advances
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Acta Crystallographica Section A Foundations and Advances, 2017
There is considerable interest in seeking new dielectric materials due to their potential applica... more There is considerable interest in seeking new dielectric materials due to their potential applications in modern electronic devices such as memory elements, high performance insulators and resonators.1 Search for new dielectric materials still poses formidable challenge owing to stringent permittivity requirements imposed by operative frequency, power levels, types of application and stability.2 Recently, CPs/MOFs are being sought as low dielectric constant (low-κ) materials for interlayer dielectrics with high thermal stability, electrically insulating property.3 Alkaline-earth metal coordination polymers are promising candidates for exploring dielectric and ferroelectric properties. Since the framework lacks positional freedom, dielectric constants of these solids are expected to be very low and mostly arise from mobile solvent molecules and polarizability of the organic linkers. In this work, we attempted to explore the structural landscape of calcium or strontium based dicarboxylates under solvothermal condition with an objective was to study the influence of selected aromatic dicarboxylic acid based ligands and polar aprotic solvents in dictating the crystal structures of the final solids. In this poster, we report crystal structure, photoluminescence and dielectric properties of several new alkaline-earth CPs.
Acta Crystallographica Section A Foundations and Advances, Dec 1, 2017
Nonsteroidal anti-inflammatory drugs (nsaids) are among the most commonly used pharmaceutical sol... more Nonsteroidal anti-inflammatory drugs (nsaids) are among the most commonly used pharmaceutical solids and primarily used as anti-inflammatory, analgesic, and antipyretic agents.1 In this study we focused on two nsaids molecules Niflumic acid (Nif) and Mefenamic acid (Mef) which are BCS (Biopharmaceutical classification system) class II drug with poor solubility and high permeability.2 Both these molecules have important pharmacological activity. The first drug Nif used in rheumatoid arthritis and arthrosis the second drug Mef prescribed in conditions of dental pain, premenstrual syndrome, headache and postoperative surgeries. Recently Mef is also found to have therapeutic effect in Alzheimer's diseases and anti-cancer activity (colon and liver cancer).3 We extended our approach to exploit acid•••pyridine synthon to obtain new multicomponent solids based on Nif and Mef. In this poster, we discuss the design strategy, comparative structural features of twelve new solids based on Nif and Mef.
Inorganica Chimica Acta, 2019
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Chemischer Informationsdienst, 1984
ChemInform Abstract Die Titelwolframate (Darstellung durch Fällung aus wässrigen Lösungen) mit x ... more ChemInform Abstract Die Titelwolframate (Darstellung durch Fällung aus wässrigen Lösungen) mit x bis zu 0.5 kristallisieren in der orthorhombischen BiZWOÖ-Struktur. Bi,"5Fe"5WO" wandelt sich bei hohen Temp. irreversibel in eine monokline Scheelit-artige Struktur um. Die Proben mit x = l kristallisieren in einer defekten Pyrochlorstruktur und wandeln sich bei ca. 1270 K in eine Struktur vom tetragonalen W-Bronze-Typ um (Elektronen-und Röntgen-Beugung, elektronenmikroskopische Untersuchungen, IR-und diffuse Reflexionsspektren, magnetische Suszeptibilitäten.
Crystal Growth & Design, Mar 25, 2022
Inorganic Chemistry, Jun 16, 1998
Three new, mixed-valent layered vanadyl phosphates, Ago^VOPO^I^O (AgVPO), Cuo.1eVOPO4-2.5H2O (CuV... more Three new, mixed-valent layered vanadyl phosphates, Ago^VOPO^I^O (AgVPO), Cuo.1eVOPO4-2.5H2O (CuVPO), and Zno.11VOPO4-2.5H2O (ZnVPO), have been synthesized hydrothermally and their structures determined by single-crystal X-ray diffraction: AgVPO is triclinic, space group PI, a) 6.287(1), b) 6.283(1), and c) 13.240(1) A, R) 80.98(1), /3) 86.58(1) and γ) 90.00(1)°, Z) 4; CuVPO is triclinic, space group PI, a) 6.260(2), b) 6.249(3), and c) 7.257(1) A, R) 83.62(3), fi) 73.99(2), and γ) 90.13(4)°, Z) 2; ZnVPO is triclinic, space group PI, a) 6.252(1), b) 6.248(2), and c) 7.339(3) A, R) 83.24(4), /?) 73.93(2), and y) 90.00(2)°, Z) 2. The structures are related to that of VOPO 4-2H 2 O. Metal powders have been found to be effective both as reductants and as countercations. Supporting Information Available: Listings of full X-ray powder diffraction data, complete crystallographic parameters, anisotropic thermal parameters, interatomic distances, and bond angles (18 pages). Ordering information is given on any current masthead page.
ChemInform, Aug 18, 2010
ChemInform Abstract Inelastic and quasi-elastic neutron scattering studies of Na,Cs-Rho have been... more ChemInform Abstract Inelastic and quasi-elastic neutron scattering studies of Na,Cs-Rho have been carried out in order to investigate the bonding sites and geometries of framework hydrogen atoms as well as temp.-induced changes in structure. The information obtained is consistent with the commonly accepted idea of bridging hydroxyl groups. The slight change in structure on heating is accompanied by a transfer of Hatoms to some new bonding sites of unknown structure.
Acta Crystallographica Section E-structure Reports Online, Apr 11, 2006
Use of mixed-ligand (bromide and thiocyanate ions) coordination with nickel has led to the crysta... more Use of mixed-ligand (bromide and thiocyanate ions) coordination with nickel has led to the crystallization of the title compound, (C24H20As)2[Ni(NCS)2Br2]. X-ray crystal structure analysis reveals that the asymmetric unit contains one (C6H5)4As+ cation and one half [Ni(NCS)2Br2]2− anion, the latter lying on a crystallographic twofold axis.
Crystal Engineering, Dec 1, 2000
WORLD SCIENTIFIC eBooks, Feb 1, 1995
In this paper we report on the first mesoporous catalyst based on SBA-15 incorporating simultaneo... more In this paper we report on the first mesoporous catalyst based on SBA-15 incorporating simultaneously basic and acid functions able to promote the Friedländer reaction between 2-aminoaryl ketones and ethyl acetoacetate leading to quinolines 1 with high yields. From 2-aminobenzophenone (3a) it is possible to prepare quinoline 1a with the highest selectivity (86%) as compared with other mesoporous acidic catalysts. In contrast, the reaction catalyzed by amine-grafted SBA-15 yielded selectively (98%) the corresponding quinolone 2a in accordance with our previous results. Experimental results have been justified by theoretical calculations as function of the stability of reaction intermediate species, which could be involved in the process.
Journal of Molecular Structure
Acta Crystallographica Section A Foundations and Advances
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Acta Crystallographica Section A Foundations and Advances, 2017
There is considerable interest in seeking new dielectric materials due to their potential applica... more There is considerable interest in seeking new dielectric materials due to their potential applications in modern electronic devices such as memory elements, high performance insulators and resonators.1 Search for new dielectric materials still poses formidable challenge owing to stringent permittivity requirements imposed by operative frequency, power levels, types of application and stability.2 Recently, CPs/MOFs are being sought as low dielectric constant (low-κ) materials for interlayer dielectrics with high thermal stability, electrically insulating property.3 Alkaline-earth metal coordination polymers are promising candidates for exploring dielectric and ferroelectric properties. Since the framework lacks positional freedom, dielectric constants of these solids are expected to be very low and mostly arise from mobile solvent molecules and polarizability of the organic linkers. In this work, we attempted to explore the structural landscape of calcium or strontium based dicarboxylates under solvothermal condition with an objective was to study the influence of selected aromatic dicarboxylic acid based ligands and polar aprotic solvents in dictating the crystal structures of the final solids. In this poster, we report crystal structure, photoluminescence and dielectric properties of several new alkaline-earth CPs.
Acta Crystallographica Section A Foundations and Advances, Dec 1, 2017
Nonsteroidal anti-inflammatory drugs (nsaids) are among the most commonly used pharmaceutical sol... more Nonsteroidal anti-inflammatory drugs (nsaids) are among the most commonly used pharmaceutical solids and primarily used as anti-inflammatory, analgesic, and antipyretic agents.1 In this study we focused on two nsaids molecules Niflumic acid (Nif) and Mefenamic acid (Mef) which are BCS (Biopharmaceutical classification system) class II drug with poor solubility and high permeability.2 Both these molecules have important pharmacological activity. The first drug Nif used in rheumatoid arthritis and arthrosis the second drug Mef prescribed in conditions of dental pain, premenstrual syndrome, headache and postoperative surgeries. Recently Mef is also found to have therapeutic effect in Alzheimer's diseases and anti-cancer activity (colon and liver cancer).3 We extended our approach to exploit acid•••pyridine synthon to obtain new multicomponent solids based on Nif and Mef. In this poster, we discuss the design strategy, comparative structural features of twelve new solids based on Nif and Mef.
Inorganica Chimica Acta, 2019
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Chemischer Informationsdienst, 1984
ChemInform Abstract Die Titelwolframate (Darstellung durch Fällung aus wässrigen Lösungen) mit x ... more ChemInform Abstract Die Titelwolframate (Darstellung durch Fällung aus wässrigen Lösungen) mit x bis zu 0.5 kristallisieren in der orthorhombischen BiZWOÖ-Struktur. Bi,"5Fe"5WO" wandelt sich bei hohen Temp. irreversibel in eine monokline Scheelit-artige Struktur um. Die Proben mit x = l kristallisieren in einer defekten Pyrochlorstruktur und wandeln sich bei ca. 1270 K in eine Struktur vom tetragonalen W-Bronze-Typ um (Elektronen-und Röntgen-Beugung, elektronenmikroskopische Untersuchungen, IR-und diffuse Reflexionsspektren, magnetische Suszeptibilitäten.