The first tritertiary (1,5,9-triphosphacyclododecane)chromium(0) complexes have been prepared from the secondary phosphine macrocycle precursor complex tricarbonyl(1,5,9-stiphosphacyclododecane)chromium(0), and the range of molybdenum(0) complexes with tritertiary 1,5,9-triphosphacyclododecane ligands has been extended. The synthetic routes involve either deprotonation of the secondary phosphine precursor followed by alkylation with alkyl halide or by radical-catalysed hydrophosphination of selected alkenes. These routes are general and allow access to a range of macrocyclic triphosphines with alkyl functions or with alkyl arms containing pendant donor functions (N, P, O, S) attached to phosphorus fdr both chromium and molybdenum. All compounds have been spectroscopically and analytically characterised.

The free macrocyclic 1,5,9-tris(2-propyl)-1,5,9-triphosphacyclododecane (Pr-3(i)[12]aneP(3), L) has been used for the first time to prepare a range of metal complexes. Reaction of L with RhCl3 . 3H(2)O yields the six-co-ordinate fac-octahedral complex [RhCl3(L)], which has been structurally characterises and is also used to prepare the analogous rhodium(III)-trihydrido and -triiodo complexes. The half-sandwich complex, [Fe(eta(5)-C5H5)(Lj)]PF6 was prepared from [Fe(eta(5)-G(5)H(5))(eta(6)-C6H5)]PF6 and L. The ruthenium complexes [RuCl2(dmso)(L)] (dmso = dimethyl sulfoxide) and [Ru-2(mu-Cl)(3)(L)(2)]Cl were also formed from the reaction of L with [RuCl2(dmso)(4)] and [RuCl2-(eta(6)-C6H4Me-4-Pr-i-1)](2) respectively.

1,5,9-Triphospha-1,5,9-tris(2-propyl)cyclododecane is liberated from the molybdenum template upon which it is formed by action of aqueous base and after oxidation of the metal with halogens.

The reaction of fac-[Cr(CO)(3)(MeCN)(3)] with primary allyl- and vinyl-phosphines gave rise to the corresponding tris(primary phosphine)chromium tricarbonyl complexes. Radical-catalysed coupling of the allyl functions with PH groups in the tris(allylphosphine) complex led to the chromium tricarbonyl complex of 1,5,9-triphosphacyclododecane. The molybdenum analogue of the chromium prop-2-enylphosphine complex has also been prepared. Radical-catalysed coupling of the vinyl functions with PH groups in these complexes resulted in new complexes with multidentate ligand systems but not in complexes of new macrocycles. The crystal structures of the new 1,5,9-triphosphacyclododecane and prop-2-enylphosphine complexes have been determined and Structural implications for these template cyclisation reactions investigated.

Selective oxidation of Mo(CO)(3) complexes of tritertiary 1,5,9-triphosphacyclododecane macrocycles (R(3)L) by halogens (X(2) = Cl-2, Br-2, I-2) to Mo(II) triphospha macrocycle complexes of the type (R(3)L)Mo(CO)(2)X(2) [R = (CH3)(2)CH (2), (CH3)(3)SiCH2 (3), C2H5 (4), (CH3)(2)CHCH2 (5)] allows the high yield and stereoselective liberation of the corresponding tritertiary macrocycles [syn,syn-R(3)L, R = (CH3)(2)CH (6), (CH3)(3)SiCH2 (7), C2H5 (8), (CH3)(2)CHCH2 (9)] in good yield (75-80%) by digestion in strong base. This method fails for the parent trisecondary macrocycle (H(3)L) and also for the intermediate Mo(II) salts, [(R(3)L)Mo(CO)(3)X]A(-) [X = halide, A(-) = halide, BPh(4) (1)]. Addition of halogen to (H(3)L)Cr(CO)(3) gives rise to the new blue-violet complexes (H(3)L)Cr(CO)(2)X(2) [X = Cl-2 (11), Br-2 (12)]. Paramagnetic susceptibilities indicate that 11 and 12 are low-spin d(4) six coordinate dicarbonyl halo-halide complexes of the type [(H(3)L)Cr(CO)(2)X]X. In this case, the trisecondary 1,5,9-triphosphacyclododecane (H(3)L, 13) may be liberated stereoselectively and in reasonable yield (60-70%) from 11 or 12. The macrocycles may alternatively be liberated from the Mo(II) dihalo complexes by action of CN-. The free trisecondary macrocycle can be alkylated nonstereoselectively to give the tritertiary macrocycles [syn,-anti-R(3)L; R = CH3 (24), C2H5 (8b), (CH3)(3)C (25)]. The inversion of phosphorus in the syn,syn isomer 8 to its syn,anti analogue, 8b, was shown to be slow at 156 degrees C. Exhaustive oxidation of the Mo(0) macrocycle complexes with H2O2 Or O-3 results in liberation of the corresponding macrocycle trioxides in good yield. All free macrocycles (and oxides) have been characterized by spectroscopic methods and as the hydrochlorides for selected ligands.

The first tritertiary 1,5,9-triphosphacyclododecane ligand complexes of molybdenum were prepared from the trisecondary 1,5,9-triphosphacyclododecane precursor. The tungsten trisecondary 1,5,9-triphosphacyclododecane analogue has been synthesised and also serves as an intermediate to the first tungsten complexes of the tertiary phosphine macrocyclic ligands. The synthetic routes are general and allow access to a range of macrocyclic triphosphines with alkyl, omega-aminoalkyl and alkenyl functions on phosphorus. All the compounds have been characterised spectroscopically and the molybdenum triisopropyl derivative. [Mo(CO)(3){cyclo-(PrPC3H6)(3)}], structurally.

New triphosphamacrocycle complexes of molybdenum(ii) and tungsten(ll) have been prepared by oxidative addition of halogens to molybdenum and tungsten tricarbonyl complexes of 1,5,9-triphosphacyclododecane and tritertiary phosphine analogues. The behaviour of these macrocycle complexes is similar to that of previously reported examples with monodentate tertiary phosphines and the metal(0) precursors give rise initially to seven-co-ordinate salts containing a [M(CO)(3)X(L)](+) cation (L = tridentate triphosphamacrocycle) with a halide anion which may be exchanged for other counter ions. The seven-co-ordinate complexes are all fluxional in solution and give rise to temperature-variant NMR spectra. At the low-temperature limit an AB(2) pattern was observed in the P-31 NMR spectra of all the new complexes. The salts all convert slowly into the neutral seven-coordinate dicarbonyldihalogeno complexes [M(CO)(2)X(2)(L)] in solution. These are the first examples of metal complexes of the 1,5,9-triphosphacyclododecane family other than the metal(o) tricarbonyl template complexes upon which the macrocyclic ligands were originally made.