Molybdenum complexes derivatives

Abdul-Raman, A., Amoroso, A.A., Branston, T.N., Das, A., Mahler, J.P., McCleverty, J.A., Ward, M.D. and Wlodarczyk, A. (1997) Dinuclear molybdenum complexes derived from diphenols Electrochemical interactions and reduced species. Polyhedron, 16, 4353-62. 

As in the molybdenum complexes derived from MgXg units some of the additional six ligands may be, for example, H2O molecules, and this is so in Ta6Cli4. 7 H2O, in which the structural unit is [Ta6Cli2(Cl2)(H20)4]. The basic structure of this unit had been deduced earlier from X-ray diffraction data obtained from a concentrated alcoholic solution of the compound. 

Y. Ishii, K. Yamawaki, T. Yoshida, T. Ura, M. Ogawa, Oxidation of olefins and alcohols by peroxo-molybdenum complex derived from tris(cetylpyridinium) 12-molybdophosphate and hydrogen peroxide, /. Org. Chem. 52 (1987) 1868. 

When methylene chloride was used as a solvent, it was found that 28 are obtained in minor amounts, while the dominating product is the -coordinated chloro-carbyne species [(> -Tp )Mo(CO)2(=CCl)], whose yield increases abruptly with substitution in the pyrazol-l-yl fragments (3-methyl-, 3,4,5-trimethyl-, and 3,5-dimethyl-4-chloro derivatives) [90AX(C)59,95JCS(D) 1709]. The tungsten analog can be prepared similarly. The chlorocarbyne molybdenum complex follows also from the reaction of the parent anion with triphenylsulfonium cation but conducted in dichloromethane. The bromo- and iodocarbyne derivatives are made similarly. 

Allyl(dicarbonyl)molybdenum complexes 5 are also prepared from 4 via the methyl derivative... 

Interesting results of NMR study of Schiff base molybdenum(VI) ds-dioxo complexes, derivatives of a or p-D-glucosamines [36] have been published by Zhao et al.87... 

The formation of 2H-pyrroles (21) and a pyrrole derivative (22) from the reaction of 3-phenyl-2//-azirines and acetylenic esters in the presence of molybdenum hexacarbonyl is intriguing mechanistically (Schemes 24, 25).53 Carbon-nitrogen bond cleavage must occur perhaps via a molybdenum complex (cf. 23 in Scheme 26) but intermediate organometallic species have not yet been isolated.53 Despite the relatively poor yields of 2H-pyrrole products, the process is synthetically valuable since the equivalent uncatalyzed photochemical process produces isomeric 2H-pyrroles from a primary reaction of azirine C—C cleavage54 (Scheme 24). 

Indirect electroreduction with Ni, Co, and Fe complexes has been well studied, and will be discussed first. Furthermore, the synthetic use of palladium, rhodium, and ruthenium complexes as mediators in the electroreduction of organic compounds are finding increasing apphcations. Metallic complexes derived from chromium, manganese, molybdenum, tungsten, and rhenium have also been used as mediators for special conversions. Recently, tin, zinc, and mercury... 

Using this method, the electrophilic aromatic substitution of the electron-rich arylamine 578 by the molybdenum-complexed cation 577 affords regio- and stereoselectively the molybdenum complexes 579. Cyclization with concomitant aromatization and demetalation using activated manganese dioxide leads to the carbazole derivatives 568 (8,10,560) (Scheme 5.26). 

The reactions of dinuclear thioaldehyde and -ketone complexes with PR3 take a different course. When the dimeric complexes 112 are treated with PMe3 a Ti-S bond in 112 is cleaved and the monomeric complexes 113 are reversibly formed (see Scheme 26), 69 The reaction of 112 with benzene-thiol led to a Ti-C cleavage and formation of 1,3-propanedithiolato-(phenylthiolato) complex.69 The reaction of binuclear p-191 rf-thioketone molybdenum complexes related to 115 (M = Mo, E = S, R = Aryl) with P(OEt)3 also gave mononuclear complexes [Mo(CO)2(Et) i72-S = C(Aryl)2 (i75-C5H5)] by a rather complicated reaction sequence. When other phosphites were employed additionally binuclear complexes derived from addition of the phosphite to one molybdenum atom were isolated.225... 

Certain molybdenum complexes, such as MoO(02)(PhCONPhO)22 and the peroxo-molybdenum compound derived from tris(cetylpyridinium) 12-molybdophosphate and hydrogen peroxide (PCMP),28 are able to selectively oxidize secondary alcohols. PCMP is able to perform selective oxidations in catalytic amounts in the presence of hydrogen peroxide as secondary oxidant.29... 

Synthetic protein-like polymers containing amino acids find pharmaceutical and biological applications and display self-assembly properties [174], In this aspect, both ROMP and ADMET have been used as tools for the polymerization of amino acid-based monomers. Early ROMP examples date back to 1994 with the synthesis and ROMP of amino acid-derived homochiral norbomene monomers by Coles et al [175], The molybdenum complex [Mo(=CHCMe2Ph)(=NC6H3Pr,2-2,6)(OBu )2]... 

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