Intermolecular hydrogen bonding of acidic alcohols (PhOH, (CF3)2CHOH (HFIP), (CF3)3CHOH (PFTB)) to the hydride ligand of WH(CO)2(NO)L2 (L = PMe3 (1), PEt3 (2), P(OiPr)3 (3), PPh3 (4)) has been observed and characterized by IR and NMR spectroscopy in hexane, toluene-d 8, and CD2Cl2 solutions. The H-bonding is an equilibrium process with medium −ΔH° of 4.1−6.9 kcal/mol; the enthalpy increases on going from 4 to 1, i.e., the strongest bonding is found for the smallest and the most basic L = PMe3. The value of −ΔH° depends on the pK a of the proton donors, increasing as the acidity does (PhOH < HFIP < PFTB). The IR and NMR data suggest C 2 v symmetry around tungsten in the ROH···HW(CO)2(NO)L2 adduct, with the H···H distance of 1.77 Å (L = PMe3) estimated from the hydride T 1min relaxation time. The relevance of the hydrogen bonding to the mechanism of protonation of metal hydrides is suggested.

No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

No abstract