Carbonyl halides metal

Ir and Pt atoms with oxalyl chloride gives metal chlorocarbonyl derivatives used as precursors to Re2(C0)eCl2 o-[Ru2(C0)6Cl2(u-Cl)2] Rh2(C0) ( -C )2 and ois-Pt(C0)2Cl2. The role of rhodium carbonyl iodides in the catalytic reactions of MeOH with CO has also received attention.  

Calderazzo and G. Pampaloni, Inorg. Synth.. lS65. 23, 34 H70. Gillone, ibid., p.27 F. Calderazzo, R. Polland and D. Vitali, ibid., p.32  

Barrett arid D.J. Co1e-Hami1ton, J. Chem. Soc., Chem. Commun.. 1985. 1557. 

Daniel, I. Hyla-Kryspin, 0. Demuynck and A. Veillard, Nouv. J. Chem.. 1985, 9, 581. 

Church, F-W. Grevels, H. Hermann and K. Sctia fner, Inorg. Chem., 

Fachinetti, F. Del Cima, G. Braca and T. Funaioli, J. Organomet. Chem., 

C40t 1549. P. Braunstein and J. Rose, J. Organomet. Chem., 1984, 262, 223. M.P. Gomez-Sal, B.F.G. Johnson, J. Lewis, P.R. Raithby and S.N.A.B. Syed-Mustaffa, ibid., 272, C21. P. Braunstein, J. Rose, A. Tiripicchio and M. Tiripicchio-Camelleni, J. Chem, Soc, Chem, Commun, 1984, 391. 

Oxidation with I2 of [Mo(ii -arene)(00)3] yields [Mo(n -arene)(C0)3l]-[Mo2l5(C0)6], which contains a novel anion of approximately C2y symmetry. 

Each Mo atom in the anion is 7-co-ordinate, being bonded to three bridging and one terminal I atom, and three terminal CO ligands. The analogous tungsten anion was also prepared. The synthesis and reactivities of salts of fao-and mer-[Ru(C0)3l3] have been examined. On heating the /ac-isomer in an argon atmosphere, the dimeric dianion [Ru2(C0)i,l6]2- of 2 symmetry is formed.is  

High yield syntheses of [0s2(C0)6( i-I)2] and [0s2(C0)bI2] have been reported, and a facile synthesis of M05M0 containing species described starting from [Mo2(C0)eU].i 2 

Henrick, M. McP-artlin and J. Morris, Anqew. Chem. Int. Ed. Engl., 

Hoffmann, S.D. Wijeyeskera and S-S. Sung, Pure Appl. Chem.. 1986, 58 481 6. Bor, ibid. 1986, 58, 543 F. Calderazzo and 0. Belli Dell Amico, ibid, 1986, 561 S.P.Tubin, ibid, 1986, M, 567 J. Halpem, ibid. 

Abel and M. M. Bhatti, Inorg. Nucl. Chem. Lett., 1980, 16, 117. 

Longoni, S. Campanella, A. Ceriotti, P. Chini, V. G. Albano, and D. Braga, /. Chem. Soc., Dalton Trans., 1980, 1816. 

Other published work relevant to this Chapter includes  

Jemmis, A. R. Pinhas, and R. Hoffmann, /. Am. Chem. Soc., 1980, 102, 2576. Semibridging CO ligands in binuclear carbonyl complexes. 

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It has generally been concluded that the photoinitiation of polymerization by the transition metal carbonyls/ halide system may occur by three routes (1) electron transfer to an organic halide with rupture of C—Cl bond, (2) electron transfer to a strong-attracting monomer such as C2F4, probably with scission of-bond, and (3) halogen atom transfer from monomer molecule or solvent to a photoexcited metal carbonyl species. Of these, (1) is the most frequently encountered. 

The block copolymer produced by Bamford s metal carbonyl/halide-terminated polymers photoinitiating systems are, therefore, more versatile than those based on anionic polymerization, since a wide range of monomers may be incorporated into the block. Although the mean block length is controllable through the parameters that normally determine the mean kinetic chain length in a free radical polymerization, the molecular weight distributions are, of course, much broader than with ionic polymerization and the polymers are, therefore, less well defined,... 

The reaction of CO with some metal halides results in the formation of metal carbonyl halides directly, as illustrated in the following examples ... 

Table 12a. Standard enthalpy of formation, A/ff(g), enthalpy of disruption, AHjy, and metal-halogen bond enthalpy contribution, (M-X), in metal carbonyl halides (kJ mol-1)...

In a similar manner, Jt-allyl complexes of manganese, iron, and molybdenum carbonyls have been obtained from the corresponding metal carbonyl halides [5], In the case of the reaction of dicarbonyl(r 5-cyclopentadienyl)molybdenum bromide with allyl bromide, the c-allyl derivative is obtained in 75% yield in dichloromethane, but the Jt-allyl complex is the sole product (95%), when the reaction is conducted in a watenbenzene two-phase system. Similar solvent effects are observed in the corresponding reaction of the iron compound. As with the cobalt tetracarbonyl anion, it is... 

Method A TEBA-Cl (0.33 g, 1.5 mmol) in aqueous NaOH (5M, 45 ml) is added with stirring to CH2=CHCH2Br (1.8 g, 15 mmol) and the metal carbonyl halide (3 mmol) in PhH or CH2C12 (10 ml). The mixture is stirred at room temperature for ca. 20 min and then worked up and converted into the triphenylphosphine derivative by the procedure described in 8.1.1. 

Metal carbonyl halide Method (solvent) Reaction time % yield... 

A very versatile preparation seems to be the elimination of organotin halides in the reaction of organostannyl-organosilylcyclopentadienes with metal carbonyl halides. This reaction is very selective and only Sn—C bonds are cleaved with formation of 7)5-cyclopentadienyl complexes (7) ... 

Bromopentacarbonylmanganese, Mn(CO)5Br (1). This yellow metal carbonyl halide is obtained in 73% yield by reaction of manganese carbonyl with Br2 in CC14 at 40°.1... 

Metal carbonyl halides, as metal vapor synthesis milestone,... 

G. Mass Spectra of Metal Carbonyl Halides and Metal Carbonyl Hydrides. . 107... 

The mass spectra of some metal carbonyl halides with it-cyclopen-tadienyl, 7t-cycloheptatrienyl, 7i-allyl and Tt-indenyl ligands have been investigated 52,38) The usual losses of carbonyl groups and C2H2 fragments are observed. The mass spectra of the chlorides exhibited a strong iodine memory effect, since ions expected for the corresponding iodides were also observed in their mass spectra. Pyrolysis of the halides... 

Recently we have been interested in phosphine-containing carbonyl cations of the noble metals (55) such as [M(CO)3(PR3)2X]+ (M = Fe, Ru, Os X = halogen) and [M(CO)2(PR3)2]+ (M = Rh, Ir) which we prepared from the corresponding metal carbonyl halides under atmospheric CO pressure. 

In this manner, the field of metal carbonyl halides was initiated (57). Using low temperatures, we were able to make the addition compounds Fe(CO)5X2, which subsequent work revealed were intermediary in the exchange of 14CO with the carbonyl groups of Fe(CO)4X2 (58). Meanwhile, Fe2(CO)8I2 has also been described (59). 

In recent years more and more emphasis has been laid on the chemistry of cyclopentadienyl metal carbonyls. In this field the reactions of cyclopentadienyl metal carbonyl halides with electron donors deserve special attention. Many of these reactions yield cations by replacement of halogen. In the following report, general procedures will be described by which substituted cyclopentadienyliron dicarbonyl cations of the type [C5H5Fe(CO)2L]+ can be prepared. 

Reaction of Metal Carbonyl Halides with Allyl Halides, NaOH, and PhCH2N(C2H5)3+CL... 

Elimination of hydrogen halides, particularly in the presence of base, is also a common reachon (equation 54). The actual mechanism of these reactions could involve nucleophihc displacement of halide by the metal carbonyl halide that is formed in situ from the hydride (equations 55 and 56). 

Deviating from the route via nucleophilic attack of the carbanion at the carbon atom of a CO ligand and then reaction of the acylmetallate with an electrophile are those methods which involve (a) addition of the carbanion to the carbon atom of a carbyne ligand, (b) displacement of halides from transition-metal carbonyl halides by cyclohepta-trienyllithium, or derivatives thereof, followed by hydride abstraction or (c) substitution of a coordinated solvent from a metal-carbonyl complex (see also reaction of LiR with carbene complexes). 

These anionic complexes may also be prepared by reactions of metal carbonyl halides with a reducing agent, e.g. ... 

Reactions of metal carbonyl anions with 1,1- or 1,2-dihaloalkanes also do not yield an alkyl metal product, owing to rapid 1,1- or 1,2-M—X elimination e.g., the reaction of Na[Mn(CO)5] and 1,2-dibromoethane produces MnBrfCO), and C2H4, rather than Mn(CH2CHjBr)(CO)5 or (OC)5MnCH2CH2Mn(CO)s. Reactions of metal carbonyl anions with perfluoroalkyl halides produce metal carbonyl halides, rather than perfluoro-alkyl-metal species. This is because of the reverse polarity of the C—X bond . 

Transition metal carbonyl derivatives of magnesium can be prepared readily by the reductive cleavage of the metal-metal bond in numerous dimeric transition metal carbonyl complexes or by the removal of halogen from transition metal carbonyl halide complexes with an excess of 1 % magnesium amalgam in the presence of a Lewis base. These preparations may be represented by the general equations... 

Since these important findings near the end of the last century, metal carbonyls of a majority of the transition metals have been isolated and characterized. Many of these compounds are pure metal carbonyls, containing only the metal and CO. Many other types are also known, including metal carbonyl-halides, -hydrides, -anions, -7r-cyclopentadienyls, etc. A number of earlier reviews dealing primarily with metal carbonyls has been published 169, 197). Fortunately, there are also two recent reviews on the subject by Abel ) and Hileman ISO). A useful, recent... 

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