No abstract

No abstract

The crystal structure of sodium hydrogen fumarate, NaC4H304, has been determined using threedimensional data and least-squares refinements with individual anisotropic temperature factors for each atom, giving R=0.105. In a triclinic unit-cell in space group PT (a=6.623, b=7"946, c=5"343/~, a= 87.8, fl= 112.8 y= 98.4 °) containing two molecules, fumarate groups are aligned in extensive chains along the [010] axis, adjacent neighbours being linked by H-bonds of 2.51 A between the oxygen atoms of the contiguous COOH groups. The fumarate group, unlike the fumaric acid molecule, is non-planar and one of the COOH groups is twisted by 40 ° out of the plane of the rest of the molecule. Na÷-O contacts range from 2-38 to 2.64/~ with a mean value of 2-44/~, giving a sixfold coordination.

Though concept of oxygen bridged bimetallic catalyst for organic reaction is not well understood. Herein, we have tried to explain the concept by experimental as well as its support by full DFT study. We report here a competent protocol for dehydrogenative oxidation of benzylic alcohol using an oxygen bridged bimetallic CuMoO 4 nano catalyst. Careful demonstration reveals that oxidation is not effective either with mono-metallic Cu (II) or Mo(VI); instead combination of both the metals through the oxygen bridge [CuÀ OÀ Mo] unexpectedly and interestingly catalyzed the reaction efficiently. The new concept is strongly supported by computational DFT study. DFT study reveals dehydrogenative oxidation is preferred at copper centre over molybdenum and aromatic benzyl alcohols are greatly stabilised. Interaction barrier energy of monometallic CuO and MoO 3 catalyst is much higher than bimetallic CuMoO 4 . Hydrogen transfer has larger barrier heights for CuO (31.5 kcal/mol) and MoO 3 (40.3 kcal/mol) than bimetallic CuMoO 4 .

No abstract