Hydride complexes [ReH(CO)₄L] 1, [ReH(CO)₃L₂] 2, [ReH(CO)₂L₃] 3 and [ReH(CO)L₄] 4 [L = P(OEt)₃ a, PPh(OEt)₂ b, PPh₂(OEt) c or PPh₂(OMe) d] were prepared by treating [ReH(CO)₅] with the appropriate phosphite under UV irradiation or reflux. The complexes were characterised by IR, ¹H, ¹³C and ³¹P NMR spectroscopy and by crystal structure determinations of 1d and 2d. Protonation of the monocarbonyls [ReH(CO)L₄] 4 in CD₂Cl₂ with HBF₄·Et₂O resulted in an equilibrium mixture of the classical dihydride complexes [ReH₂(CO)L₄]⁺BF₄^– and their non-classical tautomers [Re(η²-H₂)(CO)L₄]⁺BF₄^–. The dihydride [ReH₂(CO){PPh(OEt)₂}₄]BPh₄ was also isolated as a solid by protonation of [ReH(CO){PPh(OEt)₂}₄] in ethanol. Thermally unstable [Re(η²-H₂)(CO)₄L]⁺, [Re(η²-H₂)(CO)₃L₂]⁺ and [Re(η²-H₂)(CO)₂L₃]⁺ 7 cations were also prepared by protonation of the corresponding monohydrides 1, 2 and 3 and fully characterised in solution. The unsaturated complexes [Re(CO)₂L₃]BPh₄ and [Re(CO)L₄]BPh₄ 11 and the triflate [Re(η¹-OSO₂CF₃)(CO)₃L₂] were obtained from the η²-H₂ derivatives by evolution of H₂. The new complexes [Re(CCPh)(CO)₃L₂], [Re(CCPh)(CO)L₄] 13, [Re(4-MeC₆H₄CN)(CO)₂L₃]BPh₄, [Re(4-MeC₆H₄NC)(CO)₂L₃]BPh₄ and [Re(4-MeC₆H₄NC)(CO)L₄]BPh₄ were prepared by treating the triflate compounds or the unsaturated compounds [Re(CO)₂L₃]BPh₄ and [Re(CO)L₄]BPh₄ with Li⁺CCPh^– or with the appropriate ligand.