The synthesis of Re(III), Re(I) and Mn(I) compounds of the macrocyclic phosphine ligand 1,5,9-trialkyl-1,5,9-triphosphacyclododecane, 12[ane]P₃R₃ (R = Et, ⁱBu) is described. The reaction of 12[ane]P₃R₃ with ReCl₃(PPh₃)₂(CH₃CN) or ReCl₃(PPhMe₂)₃ gives rise to the octahedral d⁴ complexes (12[ane]P₃R₃)ReCl₃ (1^R). Reduction of 1^iBu with Na/Hg under a CO atmosphere gives the rhenium(I) compound (12[ane]P₃R₃)Re(CO)₂Cl, 2^R which undergoes further reactivity to give hydride (3^R), vinylidene (4^R) and allenylidene (5^R) compounds. With Mn(CO)₅Br, 12[ane]P₃Et₃ gives the octahedral d⁶ complex, (12[ane]P₃Et₃)Mn(CO)₂Br, 6^Et. The crystal structures of (12[ane]P₃ ⁱBu₃)ReCl₃ and (12[ane]P₃Et₃)Mn(CO)₂Br are presented.