Narayan S. Hosmane

Magnetic Nanocomposites: A New Perspective in Catalysis

In recent years, the synthesis and applications of magnetic nanoparticles (MNPs) have attracted increasing interest in catalysis research, and MNP‐derived catalysts have been employed in such industrially important reactions as hydrogenation, hydroformylation, Suzuki–Miyaura and Heck couplings, and olefin metathesis. The hybrid nanocomposite species display sustainable catalytic activities and great advantages concerning catalyst recycling processes. A number of examples using these innovative hybrids in catalysis have been reported with promising results. This Minireview primarily addresses recent catalytic applications of magnetic nanocomposites, including a discussion of the synthetic methodologies that are commonly used.

Synthesis and Properties of Carborane-Appended C3-Symmetrical Extended π Systems

A series of C(3)-symmetric pi-conjugated compounds containing three to six o-carborane clusters have been synthesized by employing palladium-catalyzed Suzuki coupling reactions and palladium-catalyzed acetylation reactions, followed by silicon tetrachloride mediated trimerization reactions. Carborane-containing extended trimers were found to emit blue light. Incorporation of o-carborane clusters into extended pi-conjugated systems led to 22-70% enhancement of their relative fluorescence quantum yields. Decapitation of o-carborane clusters made these extended trimers water soluble, and their aqueous solutions were also found to be fluorescent, but with a reduced fluorescence intensity. The carborane-appended pi-conjugated compounds are found to be extremely thermally stable, and for some of these compounds only 10% mass loss occurred at temperatures close to 500 degrees C. The DSC thermograms of smaller C(cage)-appended trimers indicate the occurrence of solid-solid phase transitions.

Conversion of carbon dioxide to few-layer graphene

Burning magnesium metal in dry ice resulted in few-layer nanosheets of graphene in high yields. These carbon nanomaterials were characterized by Raman spectroscopy, energy-dispersive X-ray analysis, X-ray powder diffraction and transmission electron microscopy. This work provides an innovative route for producing one of the most promising carbon nanostructures by capturing carbon dioxide that is popularly known as the greenhouse gas.

Visible-light-driven photocatalytic S- and C- codoped meso/nanoporous TiO2

The first facile and efficient soft synthesis for fabricating S- and C- co-doped hierarchically meso/nanoporous TiO2 is hereby presented. The doping of sulfur is achieved through a counter strategy, in which the precursor of TiO2 is added to the sulfur hydrosol. The sulfur nanoparticles in the sulfur hydrosol serve as the seeds for the formation of bimodal meso/nanopores TiO2 upon calcination treatment. The prepared anatase TiO2 exhibited excellent thermal stability and photocatalytic activity. In comparison to commercial P25 TiO2, our S- and C- codoped meso/nanoporous anatase TiO2 exhibits remarkably enhanced visible light-driven photocatalytic activity on the decomposition of methylene blue (MB). The samples also showed excellent cyclic stability in the photocatalytic activity of degrading MB. The formation mechanism of these S-, C- codoped hierarchically meso/nanoporous TiO2 spheres is also discussed. The high photocatalytic activity in the visible light region is attributed to numerous oxygen vacancies, acidic sites on the surface of TiO2, and large specific surface area.

Polyhedral boron clusters in materials science

Robust three-dimensional structure, aromaticity, high chemical and thermal stability of polyhedral boron clusters make them promising candidates for use in materials science. Boron clusters have been used for the synthesis of luminescent materials, polymers, coordination polymers or metal–organic frameworks, dendrimers, liquid crystals, and nonlinear optical materials. Some of these clusters have been used as molecular building blocks in nanoscience. This review summarizes the applications of polyhedral boron clusters in materials science.

Enhanced π-Conjugation and Emission via Icosahedral Carboranes: Synthetic and Spectroscopic Investigation

The ability of ortho-, meta- and para-carboranes to enhance the emission intensity has been compared. For this purpose a series of carborane-appended 1,3,5-triphenylbenzene (TB) and 1,3,5- tris(biphenyl-4-yl)benzene (TBB) containing three ortho-, meta- and para-carborane clusters directly attached to the conjugated cores have been synthesized employing Suzuki, Heck, and trimerization reactions. The incorporation of the icosahedral carboranes was associated with a red shift in the UV absorption spectrum of up to 13 nm as well as enhancements of the emission intensities of up to 154%. The presence of ortho-carboranes showed the maximum red shift in the UV spectrum whereas the maximum enhancement of the emission intensity was observed in the presence of meta-carborane clusters. The order of π-conjugation extension is found to be ortho > meta ≈ para. A comparative thermal analysis indicated o-carborane-appended trimers to be the most thermally stable in the series. Proton NMR spectra of reported carborane-appended trimers indicated that ortho- and meta-carborane cages have benzenelike characteristics.

Boron Atoms as Spin Carriers in Two‐ and Three‐Dimensional Systems

Paramagnetic compounds with at least partially boron-centered electron spin can be constructed using either the prototypically electron-accepting boron atoms bridged by planar pi-conjugated organic systems, or by taking advantage of the three-dimensional delocalized bonding in oligonuclear borane, haloborane, or carborane clusters. The concept of mixed valency can thus be transferred from organic and transition-metal chemistry to main-group-element molecules, and density functional theory is capable of reproducing the variable spin distribution.

Organometallic derivatives of diphosphinoamines, X2PN(R)PX2. Reactions with carbonyl derivatives of group 6 metals and iron pentacarbonyl. The crystal structures of [Mo(CO)4PhN(P(OPh)2)2] and [W(CO)4iPrN(PPh2)2]

The diphosphinoamines

Boron and gadolinium neutron capture therapy for cancer treatment

X_2PN(R)PX_2 (L) (R = Me or Ph, X = OCH_2CF_3

Catalytic Phenylborylation Reaction by Iridium(0) Nanoparticles Produced from Hydridoiridium Carborane

or OPh;