Co-Mo complex

This reaction was first reported in the early 1970s as an unexpected result in search for the synthesis of new organometallic cobalt complexes [13-18]. Dicobalt octacarbonyl was the only cluster used in its beginnings, although now, many cobalt species and other metal complexes are able to mediate or catalyze this reaction. Thus, the stoichiometric reaction has been performed with Zr, Ni, Fe, Ti, W and Mo derivatives. In addition, heterobimetallic Co - W and Co - Mo complexes (1), are suitable precursors for the PKR and impart a high degree of selectivity in the process giving exclusively endo adducts 2 (Scheme 2) [19,20]. 

ABSTRACT New catalysts for hydrogenolysis of C-O bond are proposed. The catalysts were prepared by anchoring of Mo, (Ni,Mo) and (Co,Mo) complexes to the surface of a new carbon support Sibunit. Two types of the active component were prepared - oxide and sulfide forms. The catalysts were tested in a model reaction of tetrahydroftiran hydrogenolysis. As shown, the catalysts are active in the purposeful reaction of C-O- bond hydrogenolysis and do not catalyze the side reactions -polymerization and dehydration of tetrahydrofuran. 

Bimetallic Co-Mo-complexes with optimal localization on the support surface A way for highly active hydrodesulfurization catalysts preparation for different petroleum distillates... 

Synthesis of the bimetallic Co-Mo complexes with a different molecule size in aqueous solution with Co and Mo stoichiometry that is optimal for the active sites of hydrotreating catalysts ... 

Bimetallic Co-Mo-complexes with optimal localization on the support surface... 

Thus, the use of bimetallic Co-Mo complexes for the catalysts preparation allows to obtain high active hydrotreating catalysts, which mainly contain Co-Mo-S phase type n inside of the pores exposed to the reacting heteroatomic molecules of the feedstock. Depending on the molecules size of supported Co-Mo complex, the proposed method can be used for the preparation of hydrotreating catalysts both for light and heavy petroleum distillates. 

Trost and Hachiya [140] studied asymmetric molybdenum-catalyzed alkylations. Interestingly, they noticed that the regioselectivity of this transformation performed with a non-symmetric allylic substrate varied according to the nature of the metal Pd-catalyzed substitutions on aryl-substituted allyl systems led to attack at the less substituted carbon, whereas molybdenum catalysis afforded the more substituted product. They prepared the bis(pyridylamide) ligand 105 (Scheme 55) and synthesized the corresponding Mo-complex from (C2H5 - CN)3Mo(CO)3. With such a catalyst, the allylic... 

The results with Mo(CO)s were similar to Trost s report. Reactions with S,S-ligand 31 yielded the S-products predominantly. It is interesting to point out that entry 1 and entry 2 should give the same result if this reaction was going through the same tr-allyl Mo complex. However, branched carbonate (entry 1) gave slightly... 

Thus, we prepared Mo complex 70 having four carbon monoxides from (nob) Mo(CO)4 with ligand 64. 

Mo complex 70 (2 mole) were reacted with 1 mole of carbonate L-C to generate lmole of tt-allyl Mo complex 71, lmole of free ligand 64, lmole of Mo(CO)6,... 

The catalyst effectiveness decreased upon increasing the concentration of the intercalated complexes via aggregation of the closely associated complexes.164 Sulfides were also oxidized by heterogeneous Co(II) complexes.163 Catalytic oxidation of thiols was mediated by Mo complex intercalated in a layered double hydroxide.166... 

The previous EXAFS studies were restricted to supported catalysts. Furthermore, the structural properties determined by MES and EXAFS were mainly related to the HDS activity and not to the other catalytic functions. Presently, we will report EXAFS (both Mo and Co), MES, HDS and hydrogenation activity studies of unsupported Co-Mo catalysts. These catalysts have been prepared by the homogeneous sulfide precipitation method (l8) which permits large amounts of Co to be present as Co-Mo-S. The choice of unsupported catalysts allows one to avoid some of the effects which inherently will be present in alumina supported catalysts, where support interactions may result in both structural and catalytic complexities. 

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