Metathetical substitution

Late-transition-metal-amido complexes have been prepared by metathetical substitution reactions, or-bonded ligand exchange, deprotonation of amine complexes, and oxidative addition of N-H bonds. Metathetical substitution is the most common route to late-metal-alkylamido complexes, whereas metathetical substitution and a-bonded ligand exchange have both been used commonly to prepare arylamido compounds. 

Metathetic substitution with alkali metal salts of transition metal complexes ... 

II Metathetic substitution with sodium salt of iron tetra-carbonyl. 

I Metathetic substitution with sodium salts of metal coordination compounds RnGeXi-n + NaR - RnGeXniR o n + m + o =... 

II Metathetic substitution reactions with organolead halides ... 

The complexes [Cu(NHC)(MeCN)][BF ], NHC = IPr, SIPr, IMes, catalyse the diboration of styrene with (Bcat) in high conversions (5 mol%, THF, rt or reflux). The (BcaO /styrene ratio has also an important effect on chemoselectivity (mono-versus di-substituted borylated species). Use of equimolecular ratios or excess of BCcat) results in the diborylated product, while higher alkene B(cat)j ratios lead selectively to mono-borylated species. Alkynes (phenylacetylene, diphenylacety-lene) are converted selectively (90-95%) to the c/x-di-borylated products under the same conditions. The mechanism of the reaction possibly involves a-bond metathetical reactions, but no oxidative addition at the copper. This mechanistic model was supported by DFT calculations [68]. 

Nitrite complexes can be simply prepared by metathetical replacement with nitrite ion.1163 The structure of n-anj-Pt(N02)2 P-(p-tol)3 2 has a Pt—N distance of 2.030(5) A and N—O distances of 1.228(8) A and 1.98(7) A.11 4 Chemical shift (5 Pt) and coupling constant data have been tabulated for a large group of platinum(II) and (IV) nitro complexes. Both chemical shift and coupling constant changes upon ligand substitution are dominated by the nature of the trans ligand/165... 

The formation of chloroimino ligands has been proposed solely on weak v(C=N) vibrations in the 1600-1750 cm-1 IR region. A repeat of the vanadium reaction by other workers (109) found the product of their reaction to be VC13(CNBu )3, so some caution should be applied to the formulation of the proposed vanadium dimer at least. Substitution reactions on these compounds with a series of mono- and bidentate tertiary phosphorus ligands and metathetical replacements with lithium quinolin-8-olate and sodium diethyl dithiocarbamate have given a range of neutral and cationic products (204, 483). 

Acetylene-vinylidene rearrangements of silylacetylene-iron carbonyl complexes have been observed,537 while iron-acetylide hydride complexes of the type [Fe(H)(C=CR)(dmpe)2], where dmpe=l,2-bis(dimethylphosphino)ethane, have been found to react with anions to afford substituted alkenyl complexes. It has been proposed538 that a likely reaction course for this latter rearrangement involves initial protonation of the cr-bound acetylide ligand at the carbon (I to the metal centre to form a vinylidene complex. Metal-to-carbon hydride migration in this vinylidene complex with attack by the anion would then lead to the neutral complex (see Scheme 106). A detailed mechanistic investigation has been carried out539 on the novel metathetical... 

The hexacarbonyl and substituted carbonyl cations react with a variety of anionic nucleophiles to produce neutral species. The metathetical reaction of metal carbonylate salts with those of the cationic carbonyls yield primarily a mixed metal carbonyl salt however, on warming, anionic attack may cause expulsion of carbon monoxide and the formation of a metal-metal bond (174-176). 

---