Ligand Substitution in Transition Metal w-Complexes

Keto Derivatives of Group IV Organometalloids, 7,95 Lewis Base-Metal Carbonyl Complexes, 3,181 Ligand Substitution in Transition Metal w-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... 

The properties of siloxide as ancillary ligand in the system TM-O-SiRs can be effectively utilized in molecular catalysis, but predominantly by early transition metal complexes. Mono- and di-substituted branched siloxy ligands (e.g., incompletely condensed silsesquioxanes) have been employed as more advanced models of the silanol sites on silica surface for catalytically active centers of early TM (Ti, W, V) that could be effectively used in polymerization [5], metathesis [6] and epoxidation [7] of alkenes as well as dehydrogenative coupling of silanes [8]. 

A cationic Sb(III) ligand is part of the tungsten complex [Cp(CO)2(Me3P)WSb(Me)-(Cl)Bu ]I, which was prepared from tr ns-Cp(CO)2(MeP)WSb(Cl)Bu and Mel in Et20 . The first transition metal complexes containing a metal-arsenic double bond were synthesized in 1983 . Transition metal substituted arsines of the type Cp(CO)3M—AsBu 2 (M = Mo, W) show increased Lewis basicity compared with triorganoarsines R3AS. From the above-mentioned complex one carbonyl is cleavable already at 60 °C (equation 35). 

In contrast to the typical behavior of organic compounds discussed above, many photoreactions of transition metal complexes have wavelength-dependent quantum yields (7). Generally, these wavelength effects have been interpreted in terms of more than one reactive excited state of the photolyzed species. The photoreactivity of V(CO) L (L = amine), for example, has been interpreted in this manner with the previously mentioned model of substitutional photoreactivity proposed by Wrighton et al. (42, 49,73). Assuming ligand dissociation to be the only primary photochemical process (Section III-B-1), photolysis of W(C0)5L could produce three primary products ... 

The group of potential 0,N-two-center ligands includes oximes (>C=N-OH), as well as hydroxylamine NH2OH, and its derivatives. The iri -coordination of simple oximes and substituted hydroxylamines in d transition metal complexes was reported almost simultaneously in Russia [9] and elsewhere [42,43]. More speciflcally, it was found [9,44,45] that the flnal product of the reaction between tungsten (molybdenum) oxotetrafluoride and simple oximes and p-phenylhydroxylamine is a complex anion with the deprotonated organic ligand [M0F4L] (where M=Mo, W HL stands for acetoxime, acetaldoxime, benzal-doxime, 2- and 4-pyridinaldoxime, and p-phenylhydroxylamine). 

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