38900-82-2

Upstream product

• 81097-61-2 W(CO)3(1,1,4,7,7-pentamethyldiethylenetriamine) 
• 1486-28-8 diphenyl(methyl)phosphine 
• 36351-36-7 tetrahydridotetrakis(methyldiphenylphosphine)tungsten(IV) 
• 81097-61-2 fac-W(CO)3(PMTA) 

Downstream Products

• 136546-86-6 W(CO)3{(P(C₆H₅)2(CH₃))3(H)}⁽¹⁺⁾*CF₃SO₃^(1-)=W(CO)3{(P(C₆H₅)2(CH₃))3(H)}(CF₃SO₃) 

Relevant academic research and scientific papers

Steric and electronic effects of mono- and tridentate phosphine ligands on the basicities of the metal in tungsten tris(phosphine) tricarbonyl complexes

Titration calorimetry has been used to determine the heats of protonation (ΔHHM) of the fac-W(CO)3(PR3)3 (PR3 = PMePh2 (1), PEtPh2 (2), PMe2Ph (3), PEt2Ph (4), PMe3 (5), PEt3 (6)) and fac-W(CO)3(L3) (L3 = PhP(CH2CH2PPh2)2 (7), MeC(CH2PPh2)3 (8)) complexes with CF3SO3H in 1,2-dichloroethane solvent at 25.0°C. The W(CO)3(PR3)3 and W(CO)3(L3) complexes undergo protonation at the tungsten with 1 equiv of CF3SO3H to form [W(H)(CO)3(PR3)3]CF3SO 3(1H+-6H+) and [W(H)(CO)3(L3)]CF3SO3(7H +,8H+), respectively. For the W(CO)3(PR3)3 (1-6) complexes, the metal basicity (-ΔHHM) generally increases as phosphine basicity (-ΔHHP) increases; the ΔHHM values range from -15.1 kcal mol-1 (PR3 = PMePh2) to -25.0 kcal mol-1 (PR3 = PEt3). However, the trend in the ΔHHM values is also influenced by the steric bulk of the phosphine ligand. Steric crowding in the fac-W(CO)3(PR3)3 complexes is relieved when the complexes are protonated and the phosphine ligands adopt a less crowded arrangement in which they are approximately coplanar with the metal; metal basicity increases as the cone angle (θ) of the phosphine increases. ΔHHM of the tridentate phosphine complex 8 (-10.5 kcal mol-1) with the facially coordinating MeC(CH2PPh2)3 ligand is 6.2 kcal mol-1 less exothermic than that of 7 (-16.7 kcal mol-1) with the flexible PhP(CH2CH2PPh2)2 ligand. The lower basicity of 8 is attributed to a destabilization of the 8H+ product, which is forced by the MeC(CH2PPh2)3 ligand to adopt a structure less favorable than that of 7H+. The ΔHHM values (-18.3 and-20.1 kcal mol-1, respectively) of the Cp*Re(CO)2(PR3) (PR3 = PMe2Ph (9), PMe3 (10)) complexes have also been determined.

W(CO)3(PMTA) (PMTA = MeN(CH2CH2NMe2)2) as a starting material for syntheses of W(CO)3(PR3)3, W(CO)3(η6-arene), and the protonated W(H)(CO)3(PR3)3+ complexes

A new and improved method for the synthesis of M(CO)3(PMTA) (M = W, Mo) from M(CO)6 and PMTA (MeN(CH2CH2NMe2)2) is described.The tridentate nitrogen ligand in W(CO)3(PMTA) is replaced, under relatively mild conditions, by tertiary phosphines (PMe3, PEt3, PMe2Ph, PMePh2, PhP(CH2CH2PPh2)2, CH3C(CH2PPh2)3, and Ph2P(CH2)nPPh2 where n = 1, 2) and arenes (C6H6, MeC6H5, p-Me2C6H4, C6Me6, C6H5Cl), which provides a general synthetic method for the preparation of W(CO)3(PR3)3 and W(CO)3(η6-arene) complexes.The reactions of W(CO)3(L)3 with CF3SO3H in CH2Cl2 solution yield the hydrido derivatives W(H)(CO)3(L)3+ which were characterized by their 1H and 31P NMR spectra at different temperatures.These studies show the W(H)(CO)3(L)3+ complexes to be fluxional as a result of both hydride and phosphine ligand migration.