[ReBr(CO)(5)] reacts with the iminophosphorane phosphine ligands Ph2PCH2P(=NR)Ph-2 (R = P(=O)(OEt)(2) (1a), P(=O)(OPh)(2) (1b), P(=S)(OEt)(2) (1c), P(=S)(OPh)(2) (1d), 4-C6F4CHO (1e), 4-C6F4CN (1f), 4-C5F4N (1g)) affording the neutral complexes [ReBr(kappa(2)-P,X-Ph2PCH2P{=NP(=X)(OR)(2)}Ph-2)(CO)(3)] (X = O, R = Et (2a), Ph (2b); X = S, R = Et (2c), Ph (2d)) and [ReBr{kappa(2)-P,N-Ph2PCH2P(=NR)Ph-2}(CO)(3)] (R = P(=O)(OEt)(2) (3a), P(=O)(OPh)(2) (3b), 4-C6F4CHO (3e), 4-C6F4CN (3f), 4-C5F4N (3g)). The reactivity of the cationic complex [Re(kappa(3)-P,N,S-Ph2PCH2P{=NP(=S)(OPh)(2)}Ph-2)(CO)(3)][SbF6] (4d) has been explored allowing the synthesis of the cationic [Re(L)(kappa(2)-P,S-Ph2PCH2P=NP(=S)(OPh)(2)}Ph-2)(CO)(3)][SbF6] (L = acetone (5a), CH3C N (5b), pyridine (5c), PPh3 (5d)) and the neutral [ReY(kappa(2)-P,S-Ph2PCH2P{=NP(=S)(OPh)(2)}Ph-2)(CO)(3)] (Y = Cl (6a), I (6h), N-3 (6c)) complexes. The catalytic activity of complex 4d in the regioselective isomerization of terminal propargylic alcohols HC (CCRR2)-R-1(OH) into alpha,beta-unsaturated aldehydes (RRC)-R-1-C-2=CHCHO or ketones (RRC)-R-3-C-4=(CRCOMe)-C-1 (if R-2 = (CHRR4)-R-3) under neutral conditions in ionic liquids has being studied. Isolation and X-ray characterization of the key intermediate rhenium(I) oxocyclocarbene complex [Re{=C(CH2)(3)O}(kappa(2)-P,S-Ph2PCH2P{=NP(=S)(OPh)(2)}Ph-2)(CO)(3)][SbF6] (5e) seems to indicate that the catalytic reaction proceeds through tautomerization of the terminal alkynols to yield vinilydene-type species.