Tungsten, chloro

Trimethyl aluminium reacts with Tp M02Cl [M = Mo and W, Tp = T 3-HB(3,5-Me2pz)3] to give Tp M02Me. The tungsten-chloro complex is alkylated by RMgBr, to yield Tp W02R (R =... 

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. 

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). 

C1C2Hj, Acetic acid, chloro-ruthenium complex, 26 256 02C1,WC,Hi, Tungsten(VI), trichloro(l,2-dimethoxyethane)(2,2-dimethylpro-pylidyne)-, 26 50... 

Into the tared flask are placed 126.5 g. (1 mole) of />-chloro-toluene (Org. Syn. 3, 34) and 3.8 g. of phosphorus pen bichloride. The flask is he ated in a bath kept at 160-170° (Note 2), and while illuminated with direct sunlight or with an un frosted 100-watt tungsten lamp, a rapid stream of chlorine is introduced directly from a cylinder until the gain in weight is 55-66 g (Note 3). 

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. 

In a third class of 7t-cyclopentadienyl complexes, compounds of type LVIII are bound to a transition metal via the lone pair at the germanium atom. The first compounds in this series, the pentacarbonyl-[chloro(pentamethylcyclopentadienyl)germylene]chromium(0) (LIXa) and -tungsten(O) (LIXb) were synthesized by alkylation of the ylide complexes (CO)5M—GeCl2 THF according to Eq. (22) (201). Nucleophilic substitution reactions of LIXb lead to the alkyl- and amino-substituted complexes LIXc-e [Eq. (23)] (202). 

The chemistry of the dicarbonyl(7 -cyclopentadienyl)nitrosyl and the chloro-(i7 -cyclopentadienyl)dinitrosyl complexes of chromium, molybdenum, and tungsten [i.e., fT -CsHs)M(CO)j(NO)] and [(i7 -CsHs)M(NO)2Cl] has not been studied extensively, partly because of the various difficulties associated with their preparation. The procedures described below are of general applicability to all three metals and lead to the desired compounds in high yields. The carbonyl nitrosyl complexes are the synthetic precursors of the chloro nitrosyl complexes and so their preparation is described first. 

B. CHLORO(t7 -CYCLOPENTADIENYL)DINITROSYL complexes of CHROMIUM, MOLYBDENUM, AND TUNGSTEN... 

All three (t7 CsH5)M(NO)2C1 complexes are prepared in a similar manner, but to achieve maximum yields of the chromium and tungsten compounds, the reactions must be performed at -78°. The molybdenum complex (chloro(Tj -cyclopentadienyl)nitrosylmolybdenum), on the other hand, can be obtained in excellent yields even at room temperature and its preparation is detailed below. 

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