Vinylidene complexes physical properties

Highly reactive organic vinylidene and allenylidene species can be stabilized upon coordination to a metal center [1]. In 1979, Bruce et al. [2] reported the first ruthenium vinylidene complex from phenylacetylene and [RuCpCl(PPh3)2] in the presence of NH4PF6. Following this report, various mthenium vinylidene complexes have been isolated and their physical and chemical properties have been extensively elucidated [3]. As the a-carbon of ruthenium vinylidenes and the a and y-carbon of ruthenium allenylidenes are electrophilic in nature [4], the direct formation of ruthenium vinylidene and ruthenium allenylidene species, respectively, from terminal alkynes and propargylic alcohols provides easy access to numerous catalytic reactions since nucleophilic addition at these carbons is a viable route for new catalysis (Scheme 6.1). 

All known vinylidene and propadienylidene complexes are listed in Tables IV-VII, together with some salient physical properties. In their IR spectra, v(CC) generally occurs between 1590 and 1660 cm-1 in their Raman spectra, strong v(CC) bands are found at 1590 and 1594 cm-1 for... 

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