Akella Sivaramakrishna | VIT University (original) (raw)

Papers by Akella Sivaramakrishna

Research paper thumbnail of Domino and Multicomponent Reactions by Graphene-Based Carbocatalysts – A Boon for Organic Transformations

BENTHAM SCIENCE PUBLISHERS eBooks, May 1, 2023

Research paper thumbnail of Synthesis and antibacterial studies of novel hydrazide based thorium(IV) and lanthanum(III) complexes

Zenodo (CERN European Organization for Nuclear Research), May 1, 2015

A bstract : N ovel complexes of thorium(IV) and lanthanum(III) have been synthesized by their act... more A bstract : N ovel complexes of thorium(IV) and lanthanum(III) have been synthesized by their action w ith triphenylphosphinimino-N group ligands, namely (i) N-(triphenylphosphoranylidene)acetohydrazide and (ii) N-(triphenylphosphoranylidene)nicotinohydrazide. The present work describes the studies on the coordination behaviour of all these complexes and they have been characterized by the FT-IR, 1 H, 13 C and 31 P NMR spectroscopic techniques. Further these complexes were tested against antibacterial activities.

Research paper thumbnail of Molecular Incorganic Silicon Chemistry ‐ Part 3

Research paper thumbnail of Alkali solubilized nickel(II)-dimethylglyoxime as a new redox indicator

Research paper thumbnail of Investigations on synthesis and bioactivity of novel organometallic complexes

Pharmaceutical regulatory affairs, Jul 9, 2013

Research paper thumbnail of Room Temperature Catalytic Synthesis of Biaryl and Benzimidazole Derivatives - Triggered by Nano-Sized Pd-Loaded-Modified Chitosan Polyurethane Foams

Journal of Catalysis, Oct 1, 2023

Research paper thumbnail of ChemInform Abstract: Synthesis, Structure, Chemistry, and Applications of Tetravalent Nickel Complexes

Research paper thumbnail of Recent Advances in the Synthesis, Properties, and Applications of Modified Chitosan Derivatives: Challenges and Opportunities

Topics in Current Chemistry, Apr 8, 2021

Since its first fabrication by exfoliation in 2014, phosphorene has been the focus of rapidly exp... more Since its first fabrication by exfoliation in 2014, phosphorene has been the focus of rapidly expanding research activities. The number of phosphorene publications has been increasing at a rate exceeding that of other two-dimensional materials. This tremendous level of excitement arises from the unique properties of phosphorene, including its puckered layer structure. With its widely tunable band gap, strong in-plane anisotropy, and high carrier mobility, phosphorene is at the center of numerous fundamental studies and applications spanning from electronic, optoelectronic, and spintronic devices to sensors, actuators, and thermoelectrics to energy conversion, and storage devices. Here, we review the most significant recent studies in the field of phosphorene research and technology. Our focus is on the synthesis and layer number determination, anisotropic properties, tuning of the band gap and related properties, strain engineering, and applications in electronics, thermoelectrics, and energy storage. The current needs and likely future research directions for phosphorene are also discussed.

Research paper thumbnail of Poly(ionic liquids) as “smart” stabilizers for metal nanoparticles

European Polymer Journal, Nov 1, 2014

Poly(ionic liquids)(PILs) of the types poly(1-vinyl-3-alkyl imidazolium)X (where alkyl = ethyl, b... more Poly(ionic liquids)(PILs) of the types poly(1-vinyl-3-alkyl imidazolium)X (where alkyl = ethyl, butyl & pentyl; X = Br À or OH À) are synthesized and used for the preparation of stable silver, gold and nickel nanoparticles in solution. Studies pertaining to the dispersion of metal NP stabilized by PILs are discussed. The role of PILs is prominent as carriers towards reversible ''solubility switch'' of synthesized metal nanoparticles between aqueous and organic media by simple anionic metathesis. These PIL stabilized nanoparticles show great stability for longer period without agglomeration. At another role of employed PIL is the ability to tune the size of the metal NP, depending on the length of alkyl chains of PIL. UV-Visible, SEM and TEM techniques are used for the characterization and morphological study. PIL stabilized Ag NP shows very good antimicrobial activity at lower concentrations against Escherichia coli and Staphylococcus aureus. Ag NP are used in the catalytic reduction of aromatic nitro compounds with NaBH 4 and that of Ni NP for hydrogen transfer reduction of acetophenone in quantitative yields.

Research paper thumbnail of The recent advances in cobalt-catalyzed C(sp<sup>3</sup>)–H functionalization reactions

Organic and Biomolecular Chemistry, 2023

Functionalization of unactivated C(sp3)–H bonds represents one of the interesting transformations... more Functionalization of unactivated C(sp3)–H bonds represents one of the interesting transformations in organic synthesis. This review highlights the most recent developments in the cobalt-catalyzed functionalization of unactivated C(sp3)–H bonds.

Research paper thumbnail of Functionalized Triazines and Tetrazines: Synthesis and Applications

Topics in Current Chemistry, Jun 23, 2022

Research paper thumbnail of Recent advances in biodegradable polymers – Properties, applications and future prospects

Research paper thumbnail of CCDC 1403608: Experimental Crystal Structure Determination

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.

Research paper thumbnail of CCDC 1455699: Experimental Crystal Structure Determination

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.

Research paper thumbnail of Carbamoylmethylphosphine Oxide-Functionalized MIL-101(Cr) as Highly Selective Uranium Adsorbent

Analytical chemistry, Jan 6, 2017

The carbamoylmethylphosphine oxide (CMPO) functionalized MIL-101(Cr) was investigated as a potent... more The carbamoylmethylphosphine oxide (CMPO) functionalized MIL-101(Cr) was investigated as a potential uranium scavenger. This metal-organic framework-based adsorbent shows very high selectivity toward uranium, as well as thorium, in competition with various rare earth metals. Furthermore, it showed rapid adsorption kinetics, in both batch conditions and a dynamic (column) setup. The adsorbent is fully regenerable, using oxalate solution. Fast elution kinetics in the column setup were observed during the regeneration. In addition, reusability studies were performed under dynamic conditions. Five consecutive adsorption/desorption cycles were carried out, showing a consistent 100% recovery, at pH 4, using 0.1 M oxalate solution as an effective stripping agent. Additionally, the successive use over various adsorption/desorption cycles with constant performance proves the high stability of this adsorbent in an acidic, aqueous environment.

Research paper thumbnail of Detecting phase transitions in a CaCl_2–H_2O system at low temperatures using a fiber-optic Fresnel reflection sensor

Applied Optics, 2017

Temperature-induced crystallization events in an aqueous calcium chloride solution in the concent... more Temperature-induced crystallization events in an aqueous calcium chloride solution in the concentration range of 15-40 mass% are monitored using an optical fiber Fresnel reflection sensor in the temperature range of 30°C to -200°C. The deviation of the phase boundary from equilibrium and the formation of an eutectic mixture followed by its densification during rapid cooling are inferred from the distinct signatures of the optical fiber sensor via the changes in refractive index. During the natural heating at laboratory ambient conditions, the optical signals impart the completion of dissolution of ice and CaCl&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;·6H&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;O. The corresponding temperatures have been used in Linke&amp;amp;amp;amp;#39;s equations to obtain the salinities, which are in good agreement with the intended solution concentrations. The sensor signal imparts simultaneous melting of the constituents of the eutectic mixture of a 29.7 mass% solution during the natural heating phase. The persistence of the metastable liquid phase at -200°C for tens of minutes followed by solidification is observed at all the concentrations studied. Finally, the feasibility of monitoring phase transitions in a NaCl-CaCl&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;-H&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;O system has been demonstrated.

Research paper thumbnail of Development of highly selective chemosensor for Al3+: Effect of substituent and biological application

Sensors and Actuators B: Chemical, 2015

Research Highlights  The ligand L allow naked eye detection of thorium ions  The chemosensor sh... more Research Highlights  The ligand L allow naked eye detection of thorium ions  The chemosensor shows unique selectivity towards Th(IV) ion in semi-aqueous media.  By spectrophotometric method the lowest detection limit for thorium is 2 ppm Abstract A rapid and sensitive spectrophotometric method has been developed for the determination of Th 4+ ions using tetra butyl 2,2'-bipyridine-5,5'-diylbis(methylene) diphosphonate (L) as a chemosensor. The selective complexation of L was examined with various f-metal ions like Th 4+ , U 6+ and Ln's(III) ions and other selected metal ions (from s, p, and d-block elements). The chemosensor L selectively portrayed a naked-eye detectable colour change from colourless to pink with an appearance of a new charge transfer band at 320 nm and 525 nm. No noticeable spectral and colour changes of L were observed with other tested metal ions. This confirms high selectivity of L towards Th 4+ ions. The Job's plot delineated the formation of a host-guest complex between L and Th 4+ in 1:1 binding stoichiometry. The binding constant for the complexation of L-Th 4+ was calculated from Benesi-Hildebrand (BH) plot and was found to be 6×10 3 M-1. The complexing ability L with Th 4+ was supported by 31 P NMR, FT-IR, UV-DRS, vibrating sample magnetometery and mass spectral data. The limit of detection (LOD) and limit of quantification (LOQ) of L for the analysis of Th 4+ was calculated to be 2.02 µM and 6.1 µM, respectively. Finally, the chemosensor L was successfully applied for the quantification of Th 4+ contents present in monazite sand, gas mantels and different water samples.

Research paper thumbnail of Combustion, Performance and Emission Characteristics of Diesel Engine with Neem Oil Methyl Ester and Its Diesel Blends

American Journal of Applied Sciences, 2013

Biodiesel, an alternative fuel is derived from the fats of animals and plants. As energy demands ... more Biodiesel, an alternative fuel is derived from the fats of animals and plants. As energy demands increase and fossil fuels are limited, research is directed towards alternative renewable fuels. The main advantages of using this alternative fuel are its renewability, biodegradability and better quality of exhaust gases. It is technically competitive and environmentally friendly alternative to conventional petro-diesel fuel for use in Compression Ignition (CI) engines. The use of biodiesel reduces the dependence on imported fossil fuels which continue to decrease in availability and affordability. An experimental investigation has been carried out to evaluate the combustion, performance and emission characteristics of a diesel engine with the effect of using neem oil methyl ester and its diesel blends at different loads. The results showed that maximum cylinder pressure and maximum rate of heat release increased with the increase in bio diesel blends. The carbon monoxide (CO) and smoke emissions were found significantly lower when operating on biodieseldiesel blends, but Nitrogen Oxide (NOx) emissions are found to be higher at full load.

Research paper thumbnail of Synthesis and characterization of platinacyclosulfides derived from platinum based heterobimetallic carbonyl clusters

Zenodo (CERN European Organization for Nuclear Research), May 1, 2015

The present paper describes the synthesis and reactivity of platinum based trinuclear carbonyl cl... more The present paper describes the synthesis and reactivity of platinum based trinuclear carbonyl clusters of the type L 2 PtRu 2 (CO) 8 where L 2 = 1,3-bis(diphenylphosphino)propane (dppp) and 1,2-bis(diphenylphosphino)butane (dppe). Reaction of these trinuclear clusters with elemental sulfur yielded the unexpected formation of platinacyclosulfides. The products were isolated and identified as platinacyclodisulfide and platinacyclotetrasulfide by analytical and spectroscopic techniques.

Research paper thumbnail of Studies on synthesis and coordination chemistry of catechol based phosphine oxides

Zenodo (CERN European Organization for Nuclear Research), May 1, 2015

Two different types of catechol based phosphine oxides are prepared by the condensation reaction ... more Two different types of catechol based phosphine oxides are prepared by the condensation reaction of phenyldichloro phosphine oxide and the corresponding catechol derivatives in the presence of triethylamine. These compounds are used for the preparation of their corresponding La III and Th IV complexes. All these products were characterized by spectroscopic data.

Research paper thumbnail of Domino and Multicomponent Reactions by Graphene-Based Carbocatalysts – A Boon for Organic Transformations

BENTHAM SCIENCE PUBLISHERS eBooks, May 1, 2023

Research paper thumbnail of Synthesis and antibacterial studies of novel hydrazide based thorium(IV) and lanthanum(III) complexes

Zenodo (CERN European Organization for Nuclear Research), May 1, 2015

A bstract : N ovel complexes of thorium(IV) and lanthanum(III) have been synthesized by their act... more A bstract : N ovel complexes of thorium(IV) and lanthanum(III) have been synthesized by their action w ith triphenylphosphinimino-N group ligands, namely (i) N-(triphenylphosphoranylidene)acetohydrazide and (ii) N-(triphenylphosphoranylidene)nicotinohydrazide. The present work describes the studies on the coordination behaviour of all these complexes and they have been characterized by the FT-IR, 1 H, 13 C and 31 P NMR spectroscopic techniques. Further these complexes were tested against antibacterial activities.

Research paper thumbnail of Molecular Incorganic Silicon Chemistry ‐ Part 3

Research paper thumbnail of Alkali solubilized nickel(II)-dimethylglyoxime as a new redox indicator

Research paper thumbnail of Investigations on synthesis and bioactivity of novel organometallic complexes

Pharmaceutical regulatory affairs, Jul 9, 2013

Research paper thumbnail of Room Temperature Catalytic Synthesis of Biaryl and Benzimidazole Derivatives - Triggered by Nano-Sized Pd-Loaded-Modified Chitosan Polyurethane Foams

Journal of Catalysis, Oct 1, 2023

Research paper thumbnail of ChemInform Abstract: Synthesis, Structure, Chemistry, and Applications of Tetravalent Nickel Complexes

Research paper thumbnail of Recent Advances in the Synthesis, Properties, and Applications of Modified Chitosan Derivatives: Challenges and Opportunities

Topics in Current Chemistry, Apr 8, 2021

Since its first fabrication by exfoliation in 2014, phosphorene has been the focus of rapidly exp... more Since its first fabrication by exfoliation in 2014, phosphorene has been the focus of rapidly expanding research activities. The number of phosphorene publications has been increasing at a rate exceeding that of other two-dimensional materials. This tremendous level of excitement arises from the unique properties of phosphorene, including its puckered layer structure. With its widely tunable band gap, strong in-plane anisotropy, and high carrier mobility, phosphorene is at the center of numerous fundamental studies and applications spanning from electronic, optoelectronic, and spintronic devices to sensors, actuators, and thermoelectrics to energy conversion, and storage devices. Here, we review the most significant recent studies in the field of phosphorene research and technology. Our focus is on the synthesis and layer number determination, anisotropic properties, tuning of the band gap and related properties, strain engineering, and applications in electronics, thermoelectrics, and energy storage. The current needs and likely future research directions for phosphorene are also discussed.

Research paper thumbnail of Poly(ionic liquids) as “smart” stabilizers for metal nanoparticles

European Polymer Journal, Nov 1, 2014

Poly(ionic liquids)(PILs) of the types poly(1-vinyl-3-alkyl imidazolium)X (where alkyl = ethyl, b... more Poly(ionic liquids)(PILs) of the types poly(1-vinyl-3-alkyl imidazolium)X (where alkyl = ethyl, butyl & pentyl; X = Br À or OH À) are synthesized and used for the preparation of stable silver, gold and nickel nanoparticles in solution. Studies pertaining to the dispersion of metal NP stabilized by PILs are discussed. The role of PILs is prominent as carriers towards reversible ''solubility switch'' of synthesized metal nanoparticles between aqueous and organic media by simple anionic metathesis. These PIL stabilized nanoparticles show great stability for longer period without agglomeration. At another role of employed PIL is the ability to tune the size of the metal NP, depending on the length of alkyl chains of PIL. UV-Visible, SEM and TEM techniques are used for the characterization and morphological study. PIL stabilized Ag NP shows very good antimicrobial activity at lower concentrations against Escherichia coli and Staphylococcus aureus. Ag NP are used in the catalytic reduction of aromatic nitro compounds with NaBH 4 and that of Ni NP for hydrogen transfer reduction of acetophenone in quantitative yields.

Research paper thumbnail of The recent advances in cobalt-catalyzed C(sp<sup>3</sup>)–H functionalization reactions

Organic and Biomolecular Chemistry, 2023

Functionalization of unactivated C(sp3)–H bonds represents one of the interesting transformations... more Functionalization of unactivated C(sp3)–H bonds represents one of the interesting transformations in organic synthesis. This review highlights the most recent developments in the cobalt-catalyzed functionalization of unactivated C(sp3)–H bonds.

Research paper thumbnail of Functionalized Triazines and Tetrazines: Synthesis and Applications

Topics in Current Chemistry, Jun 23, 2022

Research paper thumbnail of Recent advances in biodegradable polymers – Properties, applications and future prospects

Research paper thumbnail of CCDC 1403608: Experimental Crystal Structure Determination

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.

Research paper thumbnail of CCDC 1455699: Experimental Crystal Structure Determination

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.

Research paper thumbnail of Carbamoylmethylphosphine Oxide-Functionalized MIL-101(Cr) as Highly Selective Uranium Adsorbent

Analytical chemistry, Jan 6, 2017

The carbamoylmethylphosphine oxide (CMPO) functionalized MIL-101(Cr) was investigated as a potent... more The carbamoylmethylphosphine oxide (CMPO) functionalized MIL-101(Cr) was investigated as a potential uranium scavenger. This metal-organic framework-based adsorbent shows very high selectivity toward uranium, as well as thorium, in competition with various rare earth metals. Furthermore, it showed rapid adsorption kinetics, in both batch conditions and a dynamic (column) setup. The adsorbent is fully regenerable, using oxalate solution. Fast elution kinetics in the column setup were observed during the regeneration. In addition, reusability studies were performed under dynamic conditions. Five consecutive adsorption/desorption cycles were carried out, showing a consistent 100% recovery, at pH 4, using 0.1 M oxalate solution as an effective stripping agent. Additionally, the successive use over various adsorption/desorption cycles with constant performance proves the high stability of this adsorbent in an acidic, aqueous environment.

Research paper thumbnail of Detecting phase transitions in a CaCl_2–H_2O system at low temperatures using a fiber-optic Fresnel reflection sensor

Applied Optics, 2017

Temperature-induced crystallization events in an aqueous calcium chloride solution in the concent... more Temperature-induced crystallization events in an aqueous calcium chloride solution in the concentration range of 15-40 mass% are monitored using an optical fiber Fresnel reflection sensor in the temperature range of 30°C to -200°C. The deviation of the phase boundary from equilibrium and the formation of an eutectic mixture followed by its densification during rapid cooling are inferred from the distinct signatures of the optical fiber sensor via the changes in refractive index. During the natural heating at laboratory ambient conditions, the optical signals impart the completion of dissolution of ice and CaCl&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;·6H&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;O. The corresponding temperatures have been used in Linke&amp;amp;amp;amp;#39;s equations to obtain the salinities, which are in good agreement with the intended solution concentrations. The sensor signal imparts simultaneous melting of the constituents of the eutectic mixture of a 29.7 mass% solution during the natural heating phase. The persistence of the metastable liquid phase at -200°C for tens of minutes followed by solidification is observed at all the concentrations studied. Finally, the feasibility of monitoring phase transitions in a NaCl-CaCl&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;-H&amp;amp;amp;amp;lt;sub&amp;amp;amp;amp;gt;2&amp;amp;amp;amp;lt;/sub&amp;amp;amp;amp;gt;O system has been demonstrated.

Research paper thumbnail of Development of highly selective chemosensor for Al3+: Effect of substituent and biological application

Sensors and Actuators B: Chemical, 2015

Research Highlights  The ligand L allow naked eye detection of thorium ions  The chemosensor sh... more Research Highlights  The ligand L allow naked eye detection of thorium ions  The chemosensor shows unique selectivity towards Th(IV) ion in semi-aqueous media.  By spectrophotometric method the lowest detection limit for thorium is 2 ppm Abstract A rapid and sensitive spectrophotometric method has been developed for the determination of Th 4+ ions using tetra butyl 2,2'-bipyridine-5,5'-diylbis(methylene) diphosphonate (L) as a chemosensor. The selective complexation of L was examined with various f-metal ions like Th 4+ , U 6+ and Ln's(III) ions and other selected metal ions (from s, p, and d-block elements). The chemosensor L selectively portrayed a naked-eye detectable colour change from colourless to pink with an appearance of a new charge transfer band at 320 nm and 525 nm. No noticeable spectral and colour changes of L were observed with other tested metal ions. This confirms high selectivity of L towards Th 4+ ions. The Job's plot delineated the formation of a host-guest complex between L and Th 4+ in 1:1 binding stoichiometry. The binding constant for the complexation of L-Th 4+ was calculated from Benesi-Hildebrand (BH) plot and was found to be 6×10 3 M-1. The complexing ability L with Th 4+ was supported by 31 P NMR, FT-IR, UV-DRS, vibrating sample magnetometery and mass spectral data. The limit of detection (LOD) and limit of quantification (LOQ) of L for the analysis of Th 4+ was calculated to be 2.02 µM and 6.1 µM, respectively. Finally, the chemosensor L was successfully applied for the quantification of Th 4+ contents present in monazite sand, gas mantels and different water samples.

Research paper thumbnail of Combustion, Performance and Emission Characteristics of Diesel Engine with Neem Oil Methyl Ester and Its Diesel Blends

American Journal of Applied Sciences, 2013

Biodiesel, an alternative fuel is derived from the fats of animals and plants. As energy demands ... more Biodiesel, an alternative fuel is derived from the fats of animals and plants. As energy demands increase and fossil fuels are limited, research is directed towards alternative renewable fuels. The main advantages of using this alternative fuel are its renewability, biodegradability and better quality of exhaust gases. It is technically competitive and environmentally friendly alternative to conventional petro-diesel fuel for use in Compression Ignition (CI) engines. The use of biodiesel reduces the dependence on imported fossil fuels which continue to decrease in availability and affordability. An experimental investigation has been carried out to evaluate the combustion, performance and emission characteristics of a diesel engine with the effect of using neem oil methyl ester and its diesel blends at different loads. The results showed that maximum cylinder pressure and maximum rate of heat release increased with the increase in bio diesel blends. The carbon monoxide (CO) and smoke emissions were found significantly lower when operating on biodieseldiesel blends, but Nitrogen Oxide (NOx) emissions are found to be higher at full load.

Research paper thumbnail of Synthesis and characterization of platinacyclosulfides derived from platinum based heterobimetallic carbonyl clusters

Zenodo (CERN European Organization for Nuclear Research), May 1, 2015

The present paper describes the synthesis and reactivity of platinum based trinuclear carbonyl cl... more The present paper describes the synthesis and reactivity of platinum based trinuclear carbonyl clusters of the type L 2 PtRu 2 (CO) 8 where L 2 = 1,3-bis(diphenylphosphino)propane (dppp) and 1,2-bis(diphenylphosphino)butane (dppe). Reaction of these trinuclear clusters with elemental sulfur yielded the unexpected formation of platinacyclosulfides. The products were isolated and identified as platinacyclodisulfide and platinacyclotetrasulfide by analytical and spectroscopic techniques.

Research paper thumbnail of Studies on synthesis and coordination chemistry of catechol based phosphine oxides

Zenodo (CERN European Organization for Nuclear Research), May 1, 2015

Two different types of catechol based phosphine oxides are prepared by the condensation reaction ... more Two different types of catechol based phosphine oxides are prepared by the condensation reaction of phenyldichloro phosphine oxide and the corresponding catechol derivatives in the presence of triethylamine. These compounds are used for the preparation of their corresponding La III and Th IV complexes. All these products were characterized by spectroscopic data.

Research paper thumbnail of Dono r-stab ilized hyper coordinated silic on (IV) chelat es wi th cyclohe xylid en eimino-N ligand gr ou p: Rol e of substi tuents on i oni zatio n

N - C yclo hexyli den eimino- O -(trime t h yl s ily l) acylimid ates react smoothly with XSiCl3 ... more N - C yclo hexyli den eimino- O -(trime t h yl s ily l) acylimid ates react smoothly with XSiCl3 (X = M e , Ph, v i nyl
and C l) i n a transsi lyla tion re actio n pr od ucing ionic pentacoord inate b ischelates and neutral hexaco ordi -
nat e d co mplexes de pe n ding o n the e lectronic and s teric b ehavior of the lig ands . These hyp ercoord inated
si licon co mplexes are cha racte rized by UV–V is , FT- IR and N MR s pectroscop i c techni ques. A neutral hexa-
coordi nate sil icon comple x with dich lor o ligands was char acter iz ed by s ingle cry stal X- ray analy sis. The
UV–Vi s ab sor pti on da ta sh owed a sig nificant bathochr omic s hift of k max in hyp e r c o o rd inat e d s i li c o n c o m -
plexes on com p ar is o n with th e ir co rres ponding hydr azide lig ands . The 29Si N M R che m i cal shifts s tro ngl y
de pend on n atur e of X gro up directly attached to the central s ilicon atom towar d io nizati o n.