Selective and solventless oxidation of organic sulfides and alcohols using new supported molybdenum (VI) complex in microwave and conventional methods

Abstract

A new dioxo‐molybdenum (VI) complex supported on functionalized Merrifield resin (MR‐Mo) has been synthesized and characterized by elemental, scanning electron mcroscopy, energy‐dispersive X‐ray analysis, TGA, Brunauer–Emmett–Teller method, powder‐X‐ray diffraction, Fourier transform infrared, X‐ray photoelectron spectroscopy and DRS–UV–vis analysis. The virgin Merrifield resin (MR) was functionalized by carbonylation followed by Schiff base formation with ethanolamine (MR‐SB). Experimental data showed that the Schiff base coordinated with the MoO22+ moiety via O‐ and N‐atoms. The catalytic activity of MR‐Mo was explored under solventless conditions toward the oxidation of organic sulfides and alcohols using 30% aqueous H2O2 as oxidant. The oxidation reactions were conducted under microwave and conventional methods. The microwave‐assisted oxidation reactions were found to be many times faster than the conventional methods. The oxidation reactions were selective and formed sulfoxides or aldehydes as the sole product with superior TOF values among the molybdenum (VI)‐based complexes. Besides these, the MR‐Mo was purely heterogeneous in nature and can be recycled for at least five reaction cycles without the loss of catalytic efficiency and product selectivity.

A Comparative Study on Interactions of Ternary Copper(II) Complexes and Their Analogues Anchored Polymer (BPEI) with Serum Albumins

“…Moreover, the g k values are also greatly influenced by the donor types, the hard donors as well as distorted geometry cause g k to increase whereas soft donors and planar geometry cause g k to decrease. [34] Hence, the found g k values for the ternary copper(II) complexes anchored BPEI (1)(2)(3)(4)(5) are in the range of 2.2 À 2.4, confirming the presence of CÀ O and CÀ N bonds. All above spectral results confirms the proposed structure of ternary copper(II) complexes anchored BPEI (1-5) as mentioned in Scheme 1S.…”

“…As seen from Table S1, the zeta potential values of all the complexes (1-5) increase with increasing degree of anchoring due to charge enhancement at the surface of BPEI. It shows that higher is the value of zeta potential higher is the degree of anchoring in complexes (1)(2)(3)(4)(5). It is due to presence of an increasing amount of positively charged copper(II) complexes in ternary copper(II) complexes anchored BPEI.…”

“…[31] The band observed in the range of 1617-1633 cm À 1 and 1464-1472 cm À 1 can be associated with NÀ H asymmetric bending and CÀ H bending respectively. The bands around 852 cm À 1 and 730 cm À 1 observed for 1,10-phenanthroline ligand were red shifted in the range of 842-831 cm À 1 and 730-698 cm À 1 respectively in the complexes (1)(2)(3)(4)(5). These shifts could be explained by the fact that each of the two nitrogen atoms of phenanthroline ligands donates a pair of electrons to the central copper atom forming coordinate bond.…”

“…The ternary copper(II) complex units anchored to polymer was confirmed by comparison of UV-visible spectra of BPEI, precursor ternary copper(II) complexes and ternary copper(II) complexes anchored BPEI (3) as shown in Figure 2. Similarly, all the ternary copper(II) complexes anchored BPEI (1)(2)(3)(4)(5)…”

“…The metal complexes anchored polymer is a coordination complex, in which the metal complex is anchored to a polymer matrix through either one or more of its ligands by a coordinate bond. Many of them are used as catalysts for the synthesis of organic compounds of industrial and scientific importance, [1][2][3][4][5][6] but the studies on biological applications of the metal complexes anchored polymers were limited. [7,8] In our previous works, we have investigated cytotoxic property of several copper(II) and cobalt(III) metal complexes anchored polymers.…”