An extended range of novel ruthenium phosphaalkene complexes of the type [Ru{η 1 -N:η 2 -P,C-P(pz )=CH(SiMe 2 R)}(CO)(PPh 3 ) 2 ] (R = Tol, C 6 H 4 CF 3 -p; pz = pz Me2 , pz CF3 , pz Me,CF3 ; R = Me, C 6 H 4 CF 3 -p; pz = pz Ph ) have been prepared from the respective ruthenaphosphaalkenyls [Ru{P=CH(SiMe 2 R)}Cl(CO)(PPh 3 ) 2 ] upon treatment with Lipz . Where R = C 6 H 4 CF 3 -p and pz = pz Me2 the complex is characterized by single crystal X-ray diffraction, only the second example of such species being structurally characterized. This indicates enhanced pyramidalisation of the alkenic carbon center when compared with precedent data (R = Me, pz = pz) implying an enhanced Ru→π* PC contribution, which can be correlated with the greater donor power of pz Me2 . This is similarly reflected in spectroscopic data that reveal significant influence of the pyrazolyl substituents upon the phosphaalkene, stronger donors imparting significantly enhanced shielding to phosphorus; in contrast, a much lesser influence if noted for the silyl substituents.