Organometallic Synthesis

Magnetic and semiconductor nanomaterials exhibit novel magnetic and optical properties owing to their unique size and shape-dependent effects. With shrinking the size down to nanoscale region, various anomalous properties that normally not present in bulk start to dominate. Ability in harnessing of these anomalous properties for the design of various advance electronic devices is strictly dependent on synthetic strategies. Hence, current research has focused on developing a rational synthetic control to produce high quality nanocrystals by using organometallic approach to tune both size and shape of the nanomaterials. In order to elucidate the growth mechanism, transmission electron microscopy was employed as a powerful tool in performing real time-resolved morphologies and structural characterization of magnetic (Fe3O4) and semiconductor (ZnO) nanocrystals. The current synthetic approach is found able to produce nanostructures with well-defined shapes. We have found that oleic acid...

In an attempt to establish the structures of the product formed in the reaction of PdCl2 and diphenylacetylene in polar organic solvents, the reactions were carried out in alcohols, acetonitrile and tetrahydrofuran at room temperature. The reactions in protic solvents such as primary and secondary alcohols resulted in the cyclic dimerization of diphenylacetylene to yield the corresponding dimeric endo‐4‐alkoxy‐π‐1,2,3,4‐tetraphenylcyclobutenypalladium(II) chloride complexes 1–4 in good yields. In these complexes the tetraphenylcyclobutenyl moieties are coordinated to palladium atoms in η3‐mode and are bridged by two chlorides as confirmed by the single crystal X‐ray analysis of complexes 1, 2 and 4. In all these complexes, the coordination of cyclobutenyl moieties to palladium atoms are similar but a marked difference was observed for the Pd2Cl2 core which is planar in complex 1 but puckered in complexes 2 and 4 resulting in shorter Pd⋅⋅⋅Pd distances. The same reaction under solvent...

In an attempt to establish the structures of the product formed in the reaction of PdCl2 and diphenylacetylene in polar organic solvents, the reactions were carried out in alcohols, acetonitrile and tetrahydrofuran at room temperature. The reactions in protic solvents such as primary and secondary alcohols resulted in the cyclic dimerization of diphenylacetylene to yield the corresponding dimeric endo‐4‐alkoxy‐π‐1,2,3,4‐tetraphenylcyclobutenypalladium(II) chloride complexes 1–4 in good yields. In these complexes the tetraphenylcyclobutenyl moieties are coordinated to palladium atoms in η3‐mode and are bridged by two chlorides as confirmed by the single crystal X‐ray analysis of complexes 1, 2 and 4. In all these complexes, the coordination of cyclobutenyl moieties to palladium atoms are similar but a marked difference was observed for the Pd2Cl2 core which is planar in complex 1 but puckered in complexes 2 and 4 resulting in shorter Pd⋅⋅⋅Pd distances. The same reaction under solvent...

We report the magnetic hyperthermia properties of chemically synthesized ferromagnetic 11 and 16 nm Fe nanocubes displaying the saturation magnetization of bulk iron. The specific absorption rate measured on 16 nm nanocubes is 1690±160 W/g at 300 kHz and 66 mT. The influence of magnetic interactions on their magnetic properties and on their efficiency for hyperthermia is discussed. Based on the Stoner-Wohlfarth model, conditions on their diameter and on their coating are derived to further increase their efficiency.

The solid-state pyrolysis of organometallic derivatives of a cyclotriphosphazene is demonstrated to be a new, simple and versatile solid-sate templating method for obtaining single crystal micro-and nanocrystals of transition and valve metal oxides. The technique, when applied to Mo-containing organometallics N 3 P 3 [OC 6 H 4 CH 2 CN⋅Mo(CO) 5 ] 6 and N 3 P 3 [OC 6 H 4 CH 2 CN⋅Mo(CO) 4 py] 6 , results in standalone and surface-deposited lamellar MoO 3 single crystals, as determined by electron and atomic force microscopies and X-ray diffraction. The size and morphology of the resulting crystals can be tuned by the composition of the precursor. X-ray photoelectron and infrared spectroscopies indicate that the deposition of highly lamellar MoO 3 directly on an oxidized (400 nm SiO 2) surface or (100) single crystal silicon surfaces yields a layered uniphasic single-crystal film formed by cluster diffusion on the surface during pyrolysis of the metal carbonyl derivatives. For MoO 3 in its layered form, this provides a new route to an important intercalation material for high energy density battery materials.

In an attempt to establish the structures of the product formed in the reaction of PdCl 2 and diphenylacetylene in polar organic solvents, the reactions were carried out in alcohols, acetonitrile and tetrahydrofuran at room temperature. The reactions in protic solvents such as primary and secondary alcohols resulted in the cyclic dimerization of diphenylacetylene to yield the corresponding dimeric endo-4-alkoxy-p-1,2,3,4-tetraphenylcyclobutenypalladium(II) chloride complexes 1-4 in good yields. In these complexes the tetraphenylcyclobutenyl moieties are coordinated to palladium atoms in h 3-mode and are bridged by two chlorides as confirmed by the single crystal X-ray analysis of complexes 1, 2 and 4. In all these complexes, the coordination of cyclobutenyl moieties to palladium atoms are similar but a marked difference was observed for the Pd 2 Cl 2 core which is planar in complex 1 but puckered in complexes 2 and 4 resulting in shorter Pd•••Pd distances. The same reaction under solvent free ball milling condition yielded hexaphenylbenzene by the cyclic trimerization while that in the presence of ethanol and n-butanol produced complexes 1 and 3, respectively, as major and hexaphenylbenzene as minor product. An efficient catalytic synthesis of hexaphenylbenzene using PdCl 2 was developed using ball milling condition which has several advantages over the existing catalytic systems.

The solid-state pyrolysis of organometallic derivatives of a cyclotriphosphazene is demonstrated to be a new, simple and versatile solid-sate templating method for obtaining single crystal micro-and nanocrystals of transition and valve metal oxides. The technique, when applied to Mo-containing organometallics N 3 P 3 [OC 6 H 4 CH 2 CN⋅Mo(CO) 5 ] 6 and N 3 P 3 [OC 6 H 4 CH 2 CN⋅Mo(CO) 4 py] 6 , results in standalone and surface-deposited lamellar MoO 3 single crystals, as determined by electron and atomic force microscopies and X-ray diffraction. The size and morphology of the resulting crystals can be tuned by the composition of the precursor. X-ray photoelectron and infrared spectroscopies indicate that the deposition of highly lamellar MoO 3 directly on an oxidized (400 nm SiO 2) surface or (100) single crystal silicon surfaces yields a layered uniphasic single-crystal film formed by cluster diffusion on the surface during pyrolysis of the metal carbonyl derivatives. For MoO 3 in its layered form, this provides a new route to an important intercalation material for high energy density battery materials.

We report the magnetic hyperthermia properties of chemically synthesized ferromagnetic 11 and 16 nm Fe nanocubes displaying the saturation magnetization of bulk iron. The specific absorption rate measured on 16 nm nanocubes is 1690±160 W/g at 300 kHz and 66 mT. The influence of magnetic interactions on their magnetic properties and on their efficiency for hyperthermia is discussed. Based on the Stoner-Wohlfarth model, conditions on their diameter and on their coating are derived to further increase their efficiency.

After the development of diketopyrrolopyrrole (DPP) in 1974, its derivatives have been widely explored
for optoelectronic applications. In this review we discuss various donor/acceptor functionalized DPPs
which have been recently published and systematically compare their properties. The modification of
donor functionalized DPPs to tetracyanobutadiene (TCBD) bridged derivatives with improved acceptor
strength and absorption in the near infra-red region has shown some exciting advancement in nonfullerene acceptors for organic solar cells and therapeutic agents in photothermal therapy and these are
also described. The optoelectronic properties in relation to structural changes such as changes of the
end capping groups, donor–acceptor moieties, aromatic moiety in the DPP core and number of DPP
units in the molecular structure are discussed. We are expecting that the current review will provide
guidelines for the exploration of new DPP based efficient materials for photovoltaic and biomedical
applications.