Molybdenum, chloro

CO-RMs 14-18 were prepared hy reaction of a terminal allqrne with a tricarbonyl chloro molybdenum complex (13) in the presence of Cul to activate the allgme, with NHEta as a base. This reaction is veiy versatile and produces a structurally diverse selection of potentially therapeutic CO-RMs. The most promising of these CO-RMs is 16. This CO-RM is water soluble presumably because of the p-D-fructopyranose group. This group significantly increases the polarity and therefore water solubility of the complex. 

Divalent molybdenum compounds occur in mononuclear, dinuclear, and hexanuclear forms. Selected examples are shown in Figure 6. The mononuclear compounds are mostiy in the realm of organometaUic chemistry (30—32). Seven-coordinate complexes are common and include MoX2(CO)2(PR3)2, where X = Cl, Br, and I, and R = alkyl MoCl2(P(CH3)3)4, heptakis(isonitrile) complexes of the form Mo(CNR) 2 (Fig. 6d), and their chloro-substituted derivatives, eg, Mo(CNR)3CR. The latter undergo reductive coupling to form C—C bonds in the molybdenum coordination sphere (33). 

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. 

The fact that the pH values of the pure metals were lower than the theoretical values was attributed to the formation of hydroxy-chloro complexes of the metal and to the high chloride ion concentration in the pit, and the results highlight the very pronounced decrease in pH that can occur in an occluded cell, particularly when the alloy contains high concentrations of chromium and molybdenum. They also showed that migration of chloride ions into the solution in the pit can result in a 7-12-fold increase in concentration, and that the potential in the pit is in the active region. 

The solution should be free from the following, which either interfere or lead to an unsatisfactory deposit silver, mercury, bismuth, selenium, tellurium, arsenic, antimony, tin, molybdenum, gold and the platinum metals, thiocyanate, chloride, oxidising agents such as oxides of nitrogen, or excessive amounts of iron(III), nitrate or nitric acid. Chloride ion is avoided because Cu( I) is stabilised as a chloro-complex and remains in solution to be re-oxidised at the anode unless hydrazinium chloride is added as depolariser. 

I.3.4.2.6. Compounds with Unusual Double Bonds 1,3-Dipolar cycloaddition of l-chloro-2-phenyl-2-trimetkylsilyl-l-phosphaethene with nitrile oxides, followed by elimination of Me SiCl, results in 3,5-diphenyl-l,4,2-oxaphosphazole 190 (356). Chromium, molybdenum, and tungsten pentacarbonyls of 3,5-diphenyl-).3-phosphinins react with nitrile oxides to give the corresponding 1,3-dipolar cycloadducts, at the P = C bond, see 191 (Ar = Ph, Mes) (357). 

The phthalic anhydride/urea process may also be employed to convert tetra-chloro phthalic anhydride to green copper hexadecachloro phthalocyanine by condensation. In this case, titanium or zirconium dioxides, particularly in the form of hydrated gels, are used instead of the molybdenum salts which are used in the phthalic anhydride process [23]. There is a certain disadvantage to the fact that the products lack brilliance and require additional purification. 

The molybdenum-mediated arylamine cyclization was also applied to the total synthesis of pyrano[3,2-a]carbazole alkaloids (Scheme 26). Reaction of the 5-aminochromene 71 with the complex salt 62 affords the complex 72, which on oxidative cyclization provides girinimbine 73, a key compound for the transformation into further pyrano[3,2-a] carbazole alkaloids. Oxidation of 73 with DDQ leads to murrayacine 74, while epoxidation of 73 using meta-chloro-perbenzoic acid (MCPBA) followed by hydrolysis provides dihydroxygirinim-bine75 [113]. 

Preparation of tricesium di-p-chloro-hexachloro-p-hydrido-dimolybdate-(3 ), Cs3[Mo2ClgH]. Molybdenum(II) acetate (10.0 g, 23.4 mmole) is placed in a three-necked, 500-mL flask containing a Teflon-coated stirrer bar. The flask is capped with three rubber septums, and a thermometer is inserted through one of the septums. After the flask and its contents have... 

A molybdenum oxychloride-based catalyst system, MoOCl4- -Bu4Sn-EtOH, is more active than Mods ones. " In the polymerization of 1-chloro-l-octyne by the oxychloride-based catalyst, propagation rate is improved to be faster and MWD of the formed polymer is smaller. This ternary catalyst also induces living polymerization of... 

In the course of a study of the formation of fluorophosphoranes from chloro-phosphines (22) we observed one exception in the compound chloromethyldi-chlorophosphine, which reacted smoothly with antimony trifluoride to give the flammable fluorophosphine, C1CH2PF2, under conditions where many other chloro-phosphines were invariably converted into fluorophosphoranes. As this fluorophosphine is readily available, its interaction with a metal carbonyl derivative was studied, and cycloheptatriene molybdenum tricarbonyl, obtained from the reaction of molybdenum hexacarbonyl with cycloheptatriene (I, 2), was chosen as a starting compound. 

The substituents fluoro. chloro, bromo, cyano, nitro, alkoxycarbonyl, A.yV-dialkylaminocar-bonyl and dialkylphosphonyl do not interfere with the molybdenum(Vl) fluoride reactions, but hydroxy, alkoxy, amino, dialkylamino and alkene groups do.9,10... 

The reaction of Mo(CO)6 and acetic acid is still the most convenient preparative route known for condensing two monomeric units into a compound containing a quadruple bond. In fact, facile conversion of Mo2(02CCH3)4 to chloro species occurs in concentrated hydrochloric acid to form the Mo2 Clj ion (36), which is isostructural with the Re2Clg ion. The eclipsed configuration of Mo2Clg" and the molybdenum atom separation of 2.14 A are entirely consistent with a quadruple bond in the anion as expected (33). 

Notably, early attempts to similarly prepare cyclopropenyl complexes of group 6 molybdenum and tungsten, using [CpM(CO),] anions (M = Mo, W) and [C,(Bu-/),]BF4, resulted in the electrophilic attack of the cyclopropenium cation on the peripheral cyclopentadienyl ligand, to give hydride complexes (equation 196)270. These air-sensitive hydride complexes readily react with CC14, to afford the corresponding air-stable chloro complexes. 

Carbonyl(pentasulfur pentanitrido)molybdenum, 0532 5-Chloro-l,2,3-thiadiazole, 0651... 

Bis(r -benzene)molybdenum(0), 3508 Bis(p3-methylidyne)rnart M/otris(pentamethylcyclopentadienylrhodium), 3907 Chloro(r 8 l,3,5,7-cyclooctatetraene)(tetrahydrofuran)lutetium, 3530... 

Two processes are commonly used for the production of copper phthalocyanine the phthalic anhydride-urea process patented by ICI [33,34] and the I.G. Farben dinitrile process [48], Both can be carried out continuously or batchwise in a solvent or by melting the starting materials together (bake process). The type and amount of catalyst used are crucial for the yield. Especially effective as catalysts are molybdenum(iv) oxide and ammonium molybdate. Copper salts or copper powder is used as the copper source [35-37] use of copper(i) chloride results in a very smooth synthesis. Use of copper(i) chloride as starting material leads to the formation of small amounts of chloro CuPc. In the absence of base, especially in the bake process, up to 0.5 mol of chlorine can be introduced per mole of CuPc with CuCl, and up to 1 mol with CuCl2. 

---