Acetonitrile ligand exchange reactions

This is a new entry for alkylation of benzene, though the applicability of this reaction is narrow. These authors proposed that a catalytic cycle involves olefin/acetonitrile ligand exchange followed by olefin insertion into the Ru-Ar bond. The C-H bond activation in another arene allows elimination of alkylbenzenes. 

Ru(Me)(Tp)(CO)(NCMe)] reacts with arenes to initiate C-H activation and loss of methane via initial arene/acetonitrile ligand exchange. This reaction produces the active catalyst [Ru(Ph)-(Tp)(CO)(NCMe)] (Fig. 2.75). Subsequent C-H activation of another... 

Various [hydroxy(tosyloxy)iodo]arenes 64 can be conveniently prepared by a ligand-exchange reaction of (diacetoxyiodo)arenes with p-toluenesulfonic acid monohydrate in acetonitrile (Scheme 2.26). This method has been apphed to the synthesis of derivatives with various substituted aromatic groups [150,166,186,209, 210], [hydroxy(tosyloxy)iodo]heteroarenes [206] and the recyclable hypervalent iodine reagents 65-68 (also see Chapter 5) [154,155,158]. Similarly, numerous polylluoroalkyl derivatives of the types C F2 +iI(OH)OTs [135,176,211] andC F2 +iCH2l(OH)OTs [176,212] can be prepared from the respective bis(trifluoroacetates) and p-toluenesulfonic acid. 

The rates of ligand-exchange reactions of solvent molecules bound in the first coordination sphere of nickel(II) ions depend on the natures of the other ligands attached to the metal [Hu 71]. By means of N NMR measurements in systems containing nitrogen donor atoms, Lincoln and West [Li 74] studied how various chelate-forming ligands affect the lability of acetonitrile solvent molecules... 

Most of the transition metal cations are strongly bonded to six dimethyl sulphoxide molecules making ligand exchange reactions more difficult to accomplish than for example in acetonitrile. Iodides, bromides and many chlorides of class (a) metals such as FeCla 27,148 and VOCI2 are considerably ionized in this solvent and the formation of the corresponding halide complex anions is not possible. 

Antimony.— The kinetics of ligand exchange reactions in a number of antimony(m) complexes have been measured. The elimination of methyl bromide from [PhaSbMej+Br" in acetonitrile has been studied, and after allowance for salt effects and for ion-pairing the results fit second-order kinetics. The solvolysis of PhiSbAr (Ar = p-tolyl, /n-chlorophenyl- or /i-anisyl) in octan-2-ol occurs by parallel iSNl(Sb) mechanisms, with the formation of benzene and ArH. The presence of the alkoxide ion of octan-2-ol causes a marked change in the product ratio, and a bimolecular process may then be involved. 

---