Krishanu Sarkar

A new functionalized mesoporous matrix supported Pd(II)-Schiff base complex: an efficient catalyst for the Suzuki-Miyaura coupling reaction.

A new Pd(II) bounded 2D-hexagonally ordered functionalized MCM-41 type material (IV) has been synthesized. Functionalization was carried out by the anchoring of 3-aminopropyltriethoxysilane in the MCM-41 type mesoporous material, followed by grafting with 2,6-diacetylpyridine (DAP) to give a N3-type Schiff base chelating attachment for the Pd(II) species. Fourier transform infrared (FTIR), powder X-ray diffraction (PXRD) and high resolution transmission electron microscopy (HRTEM) studies have been used to characterize the material. Material IV behaves as a highly active catalyst towards Suzuki-Miyaura cross-coupling reaction for the synthesis of biaryl organics. In addition, IV acts as a true heterogeneous catalyst in coupling reaction. It was found that this catalyst is highly efficient and recyclable towards Suzuki-Miyaura reaction with high turn over frequencies. X-Ray photoelectron spectroscopic (XPS) analysis was employed to understand the oxidation state of the palladium atom in the catalyst (IV) and its loading in the material.

Highly ordered acid functionalized SBA-15: a novel organocatalyst for the preparation of xanthenes.

Post-synthesis modification of SBA-15 has been carried out to design highly ordered acid functionalized hybrid mesoporous organosilica, AFS-1. This material has been used as an efficient heterogeneous organocatalyst for the syntheses of xanthenes under mild conditions in the absence of any other metal co-catalyst.

A new extra large pore organic–inorganic hybrid silicoaluminophosphate

A new extra large pore organic–inorganic hybrid silicoaluminophosphate (HSAPO-1) has been synthesized hydrothermally at 443 K by using 4,4′-trimethylene-dipiperidine (TMDP) as the single molecule template and bis(triethoxysilyl)ethane (BTEE) as the hybrid silicon precursor at almost neutral pH. The use of the organic-free silica precursor tetraethyl orthosilicate (TEOS) instead of BTEE in an otherwise identical synthesis gel also leads to the formation of a novel microporous silicoaluminophosphate (SAPO-L). Powder XRD, TEM-EDS, N2 sorption, TGA, CHN and ICP-AES chemical analysis, 13C, 29Si, 27Al and 31P MAS NMR and FTIR spectroscopic tools were employed to characterize these novel materials.