ion. The oxidative addition mechanism was originally proposed22i because of the lack of a strong rate dependence on polar factors and on the acidity of the medium. Later, however, the electrophilic substitution mechanism also was proposed. Recently, the oxidative addition mechanism was confirmed by investigations into the decomposition and protonolysis of alkylplatinum complexes, which are the reverse of alkane activation. There are two routes which operate in the decomposition of the dimethylplatinum(IV) complex Cs2Pt(CH3)2Cl4. The first route leads to chloride-induced reductive elimination and produces methyl chloride and methane. The second route leads to the formation of ethane. There is strong kinetic evidence that the ethane is produced by the decomposition of an ethylhydridoplatinum(IV) complex formed from the initial dimethylplatinum(IV) complex. In D2O-DCl, the ethane which is formed contains several D atoms and has practically the same multiple exchange parameter and distribution as does an ethane which has undergone platinum(II)-catalyzed H-D exchange with D2O. Moreover, ethyl chloride is formed competitively with H-D exchange in the presence of platinum(IV). From the principle of microscopic reversibility it follows that the same ethylhydridoplatinum(IV) complex is the intermediate in the reaction of ethane with platinum(II). Important results were obtained by Labinger and Bercaw62c in the investigation of the protonolysis mechanism of several alkylplatinum(II) complexes at low temperatures. These reactions are important because they could model the microscopic reverse of C-H activation by platinum(II) complexes. Alkylhydridoplatinum(IV) complexes were observed as intermediates in certain cases, such as when the complex (tmeda)Pt(CH2Ph)Cl or (tmeda)PtMe2 (tmeda ) N,N,N′,N′-tetramethylenediamine) was treated with HCl in CD2Cl2 or CD3OD, respectively. In some cases H-D exchange took place between the methyl groups on platinum and the, CD3OD prior to methane loss. On the basis of the kinetic results, a common mechanism was proposed to operate in all the reactions: (1) protonation of Pt(II) to generate an alkylhydridoplatinum(IV) intermediate, (2) dissociation of solvent or chloride to generate a cationic, fivecoordinate platinum(IV) species, (3) reductive C-H bond formation, producing a platinum(II) alkane σ-complex, and (4) loss of the alkane either through an associative or dissociative substitution pathway. These results implicate the presence of both alkane σ-complexes and alkylhydridoplatinum(IV) complexes as intermediates in the Pt(II)-induced C-H activation reactions. Thus, the first step in the alkane activation reaction is formation of a σ-complex with the alkane, which then undergoes oxidative addition to produce an alkylhydrido complex. Reversible interconversion of these intermediates, together with reversible deprotonation of the alkylhydridoplatinum(IV) complexes, leads to multiple H-D exchange

Activation of c-h bonds by metal complexes

C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material sciences, crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these C–H functionalizations required precious 4d or 5d transition metal catalysts. Given the cost-effective and sustainable nature of earth-abundant first row transition metals, the development of less toxic, inexpensive 3d metal catalysts for C–H activation has gained considerable recent momentum as a significantly more environmentally-benign and economically-attractive alternative. Herein, we provide a comprehensive overview on first row transition metal catalysts for C–H activation until summer 2018.

3d Transition Metals for C-H Activation.

6.1.2. Aqueous V(III) Chemistry 877 6.1.3. Oxidation State of Vanadium in Tunicates 878 6.1.4. Uptake of Vanadate into Tunicates 879 6.1.5. Vanadium Binding Proteins: Vanabins 879 6.1.6. Model Complexes and Their Chemistry 880 6.1.7. Catechol-Based Model Chemistry 880 6.1.8. Vanadium Sulfate Complexes 881 6.2. Fan Worm Pseudopotamilla occelata 883 7. Vanadium Nitrogenase 883 7.1. Nitrogenases 883 7.2. Biochemistry of Nitrogenase 884 7.3. Clusters in Nitrogenase and Model Systems: Structure and Reactivity 885

/pdf/the-chemistry-and-biochemistry-of-vanadium-and-the-4v5q292kxm.pdf

The chemistry and biochemistry of vanadium and the biological activities exerted by vanadium compounds.

Nitric Oxide Donors: Chemical Activities and Biological Applications

http://alpha.chem.umb.edu/chemistry/ch611/documents/C-Htransitionmetalbonds.pdf

Carbonhydrogen-transition metal bonds

Vanadium(V) peroxy complexes. New versatile biomimetic reagents for epoxidation of olefins and hydroxylation of alkanes and aromatic hydrocarbons

Novel unusually stable peroxotitanium(IV) compounds. Molecular and crystal structure of peroxobis(picolinato)(hexamethylphosphoric triamide)titanium(IV)

Fluorocarbon emulsions comprising a stabilizing, particle size controlling fluorophilic/hydrophilic compound which can have the formula R.sub.F.sup.1 --W--R.sub.H.sup.1 (I) wherein RF 1 is a linear, branched or cyclic C2-14 fluorocarbon group; RH 1 is a linear, branched or cyclic C2-18 saturated or unsaturated hydrocarbon group; and W is absent or is a bivalent species chosen from the group consisting of --O--, --S--, or various fluorinated structures. Use of the fluorophilic/lipophilic compound in the dispersions of the invention provides stable particle size and efficient emulsification. The dispersions of the invention can comprise biologically useful additive and can be used for various purposes, as oxygen carriers, contrast agents, or diagnostic agents.

Preparations comprising a fluorocarbon or highly fluorinated compound and a lipophilic/fluorophilic organic compound, and their uses

On observe pour la premiere fois le spectre RMN de 17 O a haute resolution pour des atomes O peroxydiques lies a des metaux de transition dans le compose [(CN) 4 OMo−O−O] [N(PPh 3 ) 2 ] 2 enrichi a 17 O ainsi que pour les composes alkylperoxo non enrichis du platine. Interpretation des resultats

Oxygen-17 NMR as a tool for studying oxygenated transition-metal derivatives: first direct oxygen-17 NMR observations of transition-metal-bonded peroxidic oxygen atoms. Evidence for the absence of oxo-peroxo oxygen exchange in molybdenum(VI) compounds

Michèle Postel

Papers

Vanadium(V) peroxy complexes. New versatile biomimetic reagents for epoxidation of olefins and hydroxylation of alkanes and aromatic hydrocarbons

Novel unusually stable peroxotitanium(IV) compounds. Molecular and crystal structure of peroxobis(picolinato)(hexamethylphosphoric triamide)titanium(IV)

Preparations comprising a fluorocarbon or highly fluorinated compound and a lipophilic/fluorophilic organic compound, and their uses

Oxygen-17 NMR as a tool for studying oxygenated transition-metal derivatives: first direct oxygen-17 NMR observations of transition-metal-bonded peroxidic oxygen atoms. Evidence for the absence of oxo-peroxo oxygen exchange in molybdenum(VI) compounds

FeCl3H2O: a specific system for arylacetylene hydration