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, Bu-i) is described. The reaction of 12[ane] P3R3 with ReCl3 (PPh3)(2) ( CH3CN) or ReCl3 (PPhMe2)(3) gives rise to the octahedral d(4) 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)(2)Cl, 2(R) which undergoes further reactivity to give hydride (3(R)), vinylidene (4(R)) and allenylidene (5(R)) compounds. With Mn(CO)(5)Br, 12[ane] P3Et3 gives the octahedral d(6) complex, (12[ane] P3Et3)Mn(CO)(2)Br, 6(Et). The crystal structures of (12[ane] (P3Bu3)-Bu-i)ReCl3 and (12[ane] P3Et3)Mn(CO)(2)Br are presented.