Scientometric profile of solar energy research in India

An analysis of the Indian literature output scanned in Web of Science during 1999–2011 on solar energy research indicates that the growth of the literature. The area of solar fuels and Material sciences multidisciplinary has received maximum attention. Publication output of literature by different countries collaboration follows the trend in basic sciences with USA and South Korea being the major producers with India. The contribution of Indian Institutions and Global Citation Scores, h-index, g-index and gh-index has been analysed

Phosphorus-supported ligands for the assembly of multimetal architectures

Modeled after boron-based scorpionate ligands, acyclic and cyclic phosphorus-containing compounds possessing reactive groups can serve as excellent precursors for the assembly of novel phosphorus-supported ligands that can coordinate multiple sites. In such ligands, the phosphorus atom does not have any role in coordination but is used as a structural support to assemble one or more coordination platforms. In this Account, we describe the utility of inorganic heterocyclic rings such as cyclophosphazenes and carbophosphazenes as well as acyclic phosphorus-containing compounds such as (S)PCl<SUB>3</SUB>, RP(O)Cl<SUB>2</SUB>, and R<SUB>2</SUB>P(O)Cl for building such multisite coordination platforms. We can modulate the number and orientation of such coordination platforms through the choice of the phosphorus-containing precursor. This methodology is quite general and modular and allows the creation of well-defined libraries of multisite coordination ligands. Phosphorus-supported pyrazolyl ligands are quite useful for building multimetallic architectures. Some of these ligands are prone to P-N bond hydrolysis upon metalation, but we have exploited the P-N bond sensitivity to generate hydrolyzed ligands in situ, which are useful to build multimetal assemblies. In addition, the intimate relationship between small molecule cyclophosphazenes and the corresponding pendant cyclophosphazene-containing polymer systems facilitated our design of polymer-supported catalysts for phosphate ester hydrolysis, plasmid DNA modification, and C-C bond formation reactions. Phosphorus hydrazides containing reactive amine groups are ideal precursors for integration into more complex ligand systems. The ligand (S)P[N(Me)N-CH-C<SUB>6</SUB>H<SUB>4</SUB>-2-OH]<SUB>3</SUB> (LH<SUB>3</SUB>) contains six coordination sites, and its coordination response depends upon the oxidation state of the metal ion employed. LH<SUB>3</SUB> reacts with divalent transition metal ions to afford neutral trimetallic derivatives L<SUB>2</SUB>M<SUB>3</SUB>, where the three metal ions are arranged in a perfectly linear manner in many cases. Incorporating an additional methoxy group into LH<SUB>3</SUB> affords the ligand (S)P[N(Me)N-CH-C<SUB>6</SUB>H<SUB>3</SUB>-2-OH-3-OMe]<SUB>3</SUB> (L'H<SUB>3</SUB>), which contains nine coordination sites: three imino nitrogen atoms, three phenolate oxygen atoms, and three methoxy oxygen atoms. The reaction of L'H<SUB>3</SUB> with transition metal salts in 1:1 ratio leads to the in situ formation of a metalloligand (L'M), which on further treatment with lanthanide salts gives heterobimetallic trinuclear cationic complexes [L'<SUB>2</SUB>M<SUB>2</SUB>Ln]<SUP>+</SUP> containing a M-Ln-M linear array (M = transition metal ion in a +2 oxidation state). Many of these 3d-4f compounds behave as single-molecule magnets at low temperatures. Although challenges remain in the development of synthetic methods and in the architectural control of the coordination platforms, we see opportunities for further research into coordination platforms supported by main group elements such as phosphorus. As we have shown in this Account, one potential disadvantage, sensitivity of P-N bonds to hydrolysis, can be used successfully to build larger assemblies

Multifunctional behavior of bis-acylhydrazone: Real-time detection of moisture in organic solvents, halochromism and aggregation induced emission

A versatile novel indenopyrazine/indenoquinoxaline appended acylhydrazones (1 and 2) have been designed and synthesized successfully. Compounds 1 and 2 are designed such that, it comprises of acylhydrazone, which is responsible for moisture detection via deprotonation of the original molecule, pyrazine, pyridine and hydrazone unit which is responsible for halochromism via protonation and deprotonation, further the integrated twisted molecular structure results in the aggregation-induced emission features. Successive treatment of Fˉ and moisture to compound 1 and 2 produce reversible colorimetric responses that are easily visualized by the naked eye. Further, the corresponding mechanism was effectively confirmed by 1H NMR spectral analysis. The inherent halochromic features of appended unique pyrazine and pyridine core in compounds 1 and 2 were studied by the sequential addition of trifluoroacetic acid (TFA) and triethylamine (TEA) which is authenticated by reversible colorimetric changes as well as absorption spectral studies. Compound 1 adopts a twisted scissor-like structure and due to multiple weak interactions results in an interesting supramolecular network. Furthermore, both compound 1 and 2 exhibits the aggregation-induced emission features in DMF/water mixture, which was expansively confirmed through DLS particle analysis and TEM images. The integration of three distinct features into a single molecule are scarce

Dihaloborenium cations stabilized by a four-membered N-heterocyclic carbene : electron deficiency compensation by asymmetric structural changes

The synthesis, characterization and X-ray analysis of dichloro- and dibromo-borenium cations stabilized by a 4-membered carbene are reported. The ligand's structural changes, atypical for similar systems, were caused by coordination to electron deficient fragments and its CN2P ring strain.ASTAR (Agency for Sci., Tech. and Research, S’pore)Accepted versio

(Iminophosphoranyl)(thiophosphoranyl)methanide {CH(PPh₂NSiMe₃)(Ph₂PS)}⁻ as a Ligand in Rare-Earth-Element Chemistry

The (iminophosphoranyl)­(thiophosphoranyl)­methanide {CH­(PPh₂NSiMe₃)­(PPh₂S)}⁻ has been introduced as a ligand into the chemistry of yttrium and the lanthanides. First, the bimetallic potassium reagent [K­{CH­(PPh₂NSiMe₃)­(PPh₂S)}]₂ was synthesized by deprotonation of [CH₂(PPh₂NSiMe₃)­(PPh₂S)] with KH. [K­{CH­(PPh₂NSiMe₃)­(PPh₂S)}]₂ forms a dimeric structure in the solid state. The potassium atoms are bridged by the sulfur atom of the ligand. Moreover, an η⁶ coordination of one phenyl ring is observed. The salt metathesis of [K­{CH­(PPh₂NSiMe₃)­(PPh₂S)}]₂ with LnCl₃ led to the dichloro complexes [{CH­(PPh₂NSiMe₃)­(PPh₂S)}­LnCl₂(THF)] (Ln = Dy, Er). The bis­(amido) compounds [{CH­(PPh₂NSiMe₃)­(PPh₂S)}­Ln­{N­(SiHMe₂)₂}₂] (Ln = Y, Sm, Er, Lu) were obtained by amine elimination from [CH₂(PPh₂NSiMe₃)­(PPh₂S)] and [Ln­{N­(SiHMe₂)₂}₃(THF)₂]. The amido complex [{CH­(PPh₂NSiMe₃)­(PPh₂S)}­Er­{N­(SiHMe₂)₂}₂] could also be accessed by the reaction of [{CH­(PPh₂NSiMe₃)­(PPh₂S)}­ErCl₂(THF)] with KN­(SiHMe₂)₂