By ligand exchange

On the way to cydo-Cig, l,6-bis(triisopropylsilyl)-l,3,5-hexatriyne (2) [50] was subjected to reaction with [Co2(CO)8], followed by ligand exchange with the bridging bis(diphenyphosphino)methane (dppm) ligand, whereupon smooth deprotection yielded the stable dark-red dicobalt complex 3 (Scheme 1). Oxida-... 

It has already been shown above that the radicals are most probably produced at the TMA - TiCl4/MgCl2 interface, where an alkylation of the TiCU by ligand exchange is supposed to happen (see reaction scheme above). Assuming this ligand exchange occurs, the primary radical would be a methyl... 

In a study of the reactions oi acyclic o-methoxyphenyl-phosphinites (45a), phosphonites (45b) and phosphites (45c) with halogens,the intermediate halogenophosphonium salts (46) are stabilised either by ligand exchange with starting material (not shown) or by elimination of methyl halides to form cyclic phosphoranes ( 47 ) 3 7. ... 

The synthesis of asymmetrically substituted stannylenes is most efficiently achieved by ligand exchange reactions between two stannylenes, SnXj and SnY2 (see Chapter 4). For example, the stannylenes [(Me3Si)2NJClSn and (C5H5)ClSn can be synthesized according to Eqs. (36) and (37) 86,93 94). 

Tetrachlorooxotechnetate(V) results from action of cone. HC1 on perteeh-netate at ambient temperatures and is preferably isolated as the tetrabutyl-ammonium salt [19]. Tetrabromooxotechnetate(V) was similarly obtained with hydrobromic add at 0 °C [8]. The molecular structures of both compounds are reported in [20,21]. The analogous iodo complex, tetraiodooxotechnetate(V), was synthesized by ligand exchange of the chloro compound with sodium iodide in acetone [22]. However, it suffers from considerable decomposition during isolation. 

L)AuC=CR complexes can also be obtained by ligand exchange starting from precursors with homoleptic substitution (PPN+= (Ph3P)2N+ Equation (19)).71... 

Another method to prepare mixed Li/Al derivatives has been developed by ligand-exchange reactions, starting from the A14N4 cube 39 and LiPHR (R = cyclohexyl) (68). Thus, the outcome of the latter is the rhombododecahedral Li4Al4P6 cluster 40, which bears exohedral THF donor ligands at the lithium centers (Eq. 23) (68). 

Scheme 11.8. Preparation of substituted cyclopropanols by ligand exchange. For details, see Table 11.5.

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