Mass spectra of metal carbonyls

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

The facile loss of carbonyl groups in the mass spectra of metal carbonyls permits the generation of novel bare metal cluster ions Mj in the mass spectra of polynuclear metal carbonyls of the type Mx(CO)y. Thus in the mass spectra of Mn2(CO)io and Co2(C0)s all carbonyl groups are lost before rupture of the metal-metal bond resulting in the production of the bimetallic ions Mn and Co 2, respectively 14>. 

The investigations of mass spectra of metal carbonyls were started by Aston in the 1920s and 1930s in order to determine the isotopic distribution of metals. Later, metal carbonyls were used for electromagnetic separation and preparation of larger quantities of particular metal isotopes. 

The mass spectra of bimetallic carbonyl metal compounds with cyclic arsine ligands have been discussed (Table 10). Molecular ion peaks are present for the pentamethyl-cyclopentaarsine containing complexes of chromium and tungsten, (AsMe)5[M(CO)]2 (186,188). Their decomposition includes CO and/or M(CO)5 loss giving rise to the ions (AsMe)sM2(CO) + (n = 0-9), (AsMe)sM(CO)/ (n = 0-5), M As Me-" and MAs Me+ (m = 2-4), MjAs Me, M AsMe -" (m = 2-4), MAs (w = 2-5), MAsjCH and AsMOj The latter is the most abundant in the mass spectra . ... 

Keto Derivatives of Group IV Organometalloids, 7, 95 Lewis Base-Metal Carbonyl Complexes, 3, 181 Ligand Substitution in Transition Metal ir-Complexes, 10, 347 Literature of Organo-Transition Metal Chemistry 1950-1970, 10, 273 Literature of Organo-Transition Metal Chemistry 1971,11, 447 Literature of Organo-Transition Metal Chemistry 1972, 12, 379 Mass Spectra of Metallocenes and Related Compounds, 8, 211 Mass Spectra of Organometallic Compounds, 6, 273... 

Miller (90), King (209, 210), and Bruce (211) first observed the formation of neutral metal fluoride species and metal fluoride-containing ions in the mass spectra of pentafluorophenyl derivatives of phosphorus, germanium, silicon, and phosphido-bridged iron carbonyls (90) and aliphatic and aromatic fluorocarbon derivatives of iron, cobalt (209-211),... 

The already voluminous review literature on clusters will be considered as a basis for this review. The topics treated so far are clusters in general (109, 241) and in connection with metal-metal bonding (30, 338, 380), special types of clusters like those with TT-acceptor ligands (231), hydrides (233), carbonyls (85, 86) or methinyl tricobalt enneacarbonyls (313, 317) properties of clusters like structures (56, 316), fluxionality (110), mass spectra (226), vibrational spectra (365), and redox behavior (292). Clusters have been treated in the context of metal carbonyls (3, 4), metal sulfur complexes (2, 381), and in relation to coordination polyhedra (297). Reviews... 

The most characteristic feature in the mass spectra of the metal carbonyls and their derivatives is the successive loss of CO groups to give a series of... 

C. Mass Spectra of Polynuclear Metal Carbonyl Derivatives. 95... 

E. Mass Spectra of Olefin Metal Carbonyl Derivatives. 103... 

F. Mass Spectra of Tertiary Phosphine Derivatives of Metal Carbonyls. 105... 

The metal-n-cyclopenladienyl bond is somewhat stronger in n-cyclo-pentadienyl derivatives than the metal-carbon bond in metal carbonyl derivatives. However, stepwise loss of 7t-cyclopentadienyl ligands occurs in the mass spectra of 7t-cyclopentadienyl derivatives 24>. The following fragmentation of ferrocene is particularly important because of the occurrence of ferrocene as a pyrolysis product in numerous mass spectra ... 

The mass spectra of binuclear cyclopentadienylmetal carbonyl derivatives of chromium and molybdenum provide useful indications of the relative strengths of the metal-metal bonds in various compound types. The mass spectrum of [C5H5Cr(CO)3]2 (S. M = Cr) exhibits no bimetallic ions but only monometallic ions such as CsHsC CO) (n = 3,... 

The mass spectra of monometallic olefin derivatives of metal carbonyls of the following types have been investigated ... 

Another process of interest in the mass spectra of tris(dimethyl-amino)phosphine derivatives is the elimination of a CH3NCH2 (azapro-pene) fragment. This occurs in ions containing first-row transition metals but no carbonyl groups, e.g. 

The mass spectra of certain metal carbonyl complexes of triphenyl-phosphine and l,2-bis(diphenylphosphino)ethane (Pf-Pf) have been investigated 48>. Besides the usual stepwise loss of carbonyl groups, cleavage of the phosphorus-carbon bond occurs. Thus triphenylphosphine complexes exhibit cleavage of the phenyl-phosphorus bond after all carbonyl groups are lost. The 1,2- bis(diphenylphosphino)ethane complexes (e.g. (Pf-Pf)[W(CO)5]2 and (Pf-Pf)M(CO)4) exhibit elimination of the ethylene bridge between two phosphorus atoms. 

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... 

The mass spectra of several substituted butadieneiron tricarbonyl compounds [(CI)-(CVII)] have been reported (136), and the migration of the carbonyl substituent, R1, to the metal atom giving the fragment [FeR ] + was observed in all cases. 

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