Halide alkoxides

Mixed Halide Alkoxides. Metal chlorides, hydrogen chloride, and carboxyUc acid chlorides convert metal alkoxides to metal chloride alkoxides. 

In contrast, the bulkier ferf-butylamidinate [Bu C(NAr)2] allowed tin(II) mono-halide, -alkoxide, and -amide complexes to be isolated cleanly in high yields. The preparative routes are summarized in Scheme 50. ... 

Indeed, nucleophilic attack at Ca is the most widely observed single reaction of Fischer carbenes. Substituent substitution is favored when one of the substituents on the carbene carbon is a good leaving group, e.g., halide, alkoxide, etc. Aminolysis of complex 41 typifies this mode of reaction (17),... 

Amphoteric molecules of this type, where the acidic and basic sites are relatively close to each other but cannot interact directly, can heterolytically cleave H-X and C-X bonds where X is a halide, alkoxide, amide, alcohol, thiol, trimethylsilyl, or alkyl group.18,18a The ability to effect changes in the reactivity of borollide complexes by adjusting metal oxidation states and ligands allows fine-tuning of catalytic and other properties, which in turn advances the application of these compounds in synthesis. 

Treatment of the halide alkoxides with (NEt4)Cl afforded crystalline... 

With the exception of nitrogen, all of the Group Vb elements are expected to form pentacoordinate compounds in their 5+ oxidation state, and this is, indeed, the case with some of the halides, alkoxides, etc. It was not until the pioneering work of Georg Wittig and his collaborators, however, that the first examples of pentaorganyls of these borderline elements between metals and metalloids were reported (95-99, 102, 104). In this early investigation, a complete set of the pentaphenyls could be obtained and characterized (95-99, 102), but apart from the pentamethyl-antimony case, all attempts for the preparation of pentaalkyl derivatives failed (104). 

Alkyne adducts of M0CI4 were reported in 1973 by Greco et al. (221). An array of monomeric (222) and dimeric (223) d2 W(IV) complexes related to [W(C1C=CC1)C15] has been reported by Dehnicke. Schrock has prepared Mo(IV) and W(IV) alkyne derivatives with halide, alkoxide (224), and thiolate (225) ligands present. Other d2 monomers with alkyne ligands have terminal oxo (226,227), nitrene (228), and sulfido (61) ligands. 

Photoelectron spectroscopy (PES) has been shown to provide a convenient probe of metal ion effective nuclear charge and the nature of the metal-ligand bond via the energy of valence-electron photoionizations (16, 20, 22, 284, 285, 312, 332-334). Recently, PES spectroscopy has been employed in the study of oxo-molybdenum compounds of the type (L-A5)MoE(X,Y) [E = O, S, NO X, Y = halide, alkoxide, or thiolate] in order to evaluate the synergy between the axial (E) and equatorial (X,Y) donors in affecting the ionization energy of the HOMO localized on the Mo center (16, 284, 334). These studies have conclusively shown that equatorial dithiolene coordination electronically bulfers the Mo center in (L-A pMoEttdt) (Fig. 13) from the severe electronic perturbations associated with the enormous variation in the Ji-donor/acceptor properties... 

A very large series of nitrosyl complexes, [Mo(NO)Tp X Y] has been described where X and Y are halide, alkoxide, aryloxide, alkyl or arylamide, alkyl or aryl thiolate groups. These diamagnetic Mo(NO) + species are regarded as containing 16 valence electrons, with a formal metal oxidation state of 11, assuming NO+ binding, and the metal center could... 

The largest families stem from substituted py, bipy, phen, and DAB but virtually any kind of O, N, S or P donor can be used. Both the nature of the hgands and their substituents as well as the nature of X (halide, alkoxide, alkyl, alkynyl) have been used as handles for tuning the photophysical properties of the excited state and emission of these complexes. 

Lanthanide alkoxide complexes can be prepared using a number of methods. The key difference lies in the nature of lanthanide starting materials. These include elemental metals, halides, alkoxides, amides, carboxylates, hydrides, and organometallic species [1, 11], The organic ligands come from aliphatic alcohols, phenols, or their metal salts. 

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