The fulvene complex (η6-C5Me4CH2 )Re(CO)2(C6F5) 1a reacts with alkyl phosphines to yield the zwitterionic species (η5-C5Me4CH2 PR3)Re(CO)2(C6F 5) 2 (R = Me, Et, iPr). Reaction of the analogous iodo complex (η6-C5Me4CH2 )Re(CO)2I, 1b, with PMe3 and PEt3 affords the cationic species [(η5-C5Me4CH2 (PR3))Re(CO)2(PR3)] + I- 3 (R = Me, Et). However, reaction of 1b with Pi Pr3 yields the zwitterion (η5-C5Me4CH2 PiPr3)Re(CO)2 (I) 4. Trimethyl phosphite reacts with both 1a and 1b to afford the phosphonate complexes (η5-C5Me4CH2 P(O)(OMe)2)Re(CO)2(P(OMe) 3) 5a and trans-(η5C5Me4 CH2P(O)(OMe)2)Re(CO)2 (C6F5)(Me) 5b respectively. The complex [(η5-C5Me4CH2 (PMe3))Re(CO)2(PMe3 )]+ I- 3a has been characterized by X-ray structural analysis.fulvene complexes, functionalized cyclopentadienyl complexes.Peer reviewed