Alkynyl complexes neutral

As in alkynyl complexes, Cp is electron rich and thus reacts readily with electrophiles. These reactions proceed more readily with neutral rather than cationic vinylidenes. 

Tazelaar, C.GJ., Bambirra, S., van Leusen, D. et al. (2004) Neutral and cationic alkyl and alkynyl complexes of lanthanum synthesis, stabiUty, and cis-selective linear alkyne dimerization. Organometallics, 23, 936. 

A cationic trifluoromethylplatinum solvent complex reacts with phenylacetylene and 2-chloroethanol to form a neutral /3-alkoxyalkenylplatinum complex 149 via nucleophilic attack of the alcohol to the initially formed alkynyl complex (Equation (34)) The reaction is unique to the complex having an electron-withdrawing GF3 ligand, and a cationic methylplatinum(ii) complex with a similar structure reacts with phenylacetylide to yield the cationic complex with a carbene ligand (150, Equation (35)). 

Deprotonation of isolated cationic monosubstituted vinylidenes [M] =G=C(FI)R (see Section 6.15.2.8) has also been widely used for the preparation of neutral alkynyl complexes. Examples include the following ... 

Disubstituted neutral vinylidenes 220 have been prepared by reaction of the cr-alkynyl complex [Ru(G=GPh)Gp(PPh3) P(OMe)3 ] 219 with organic halides XGH2R via electrophilic addition of the methylenic GH2R unit to the G j-atom of the phenylacetylide chain and subsequent Arbuzov-like dealkylation of the phosphite ligand (Scheme 22). The formation of minor amounts of vinylidenes 221 in the reactions of 219 with isothiocyanates has also been reported. ... 

Complexes of the type [AuRL] may contain a great variety of organic ligands such as alkyl, aryl, vinyl, or alkynyl, whereas the neutral donor ligand L is most commonly a tertiary phosphine. Also many polynuclear complexes are known which have the C-Au-L moiety with bridging polyfunctional ligands. Alkyl- or aryl-gold(I) complexes are usually synthesized... 

---