The association constants and enthalpies for the binding of hydrogen bond donors to group 10 transition metal complexes featuring a single fluoride ligand (trans-[Ni(F)(2-C<inf>5</inf>NF<inf>4</inf>)(PR<inf>3</inf>)<inf>2</inf>], R = Et 1a, Cy 1b, trans-[Pd(F)(4-C<inf>5</inf>NF<inf>4</inf>)(PCy<inf>3</inf>)<inf>2</inf>] 2, trans-[Pt(F){2-C<inf>5</inf>NF<inf>2</inf>H(CF<inf>3</inf>)}(PCy<inf>3</inf>)<inf>2</inf>] 3 and of group 4 difluorides (Cp<inf>2</inf>MF<inf>2</inf>, M = Ti 4a, Zr 5a, Hf 6a; Cp<inf>2</inf>MF<inf>2</inf>, M = Ti 4b, Zr 5b, Hf 6b) are reported. These measurements allow placement of these fluoride ligands on the scales of organic H-bond acceptor strength. The H-bond acceptor capability β (Hunter scale) for the group 10 metal fluorides is far greater (1a 12.1, 1b 9.7, 2 11.6, 3 11.0) than that for group 4 metal fluorides (4a 5.8, 5a 4.7, 6a 4.7, 4b 6.9, 5b 5.6, 6b 5.4), demonstrating that the group 10 fluorides are comparable to the strongest organic H-bond acceptors, such as Me<inf>3</inf>NO, whereas group 4 fluorides fall in the same range as N-bases aniline through pyridine. Additionally, the measurement of the binding enthalpy of 4-fluorophenol to 1a in carbon tetrachloride (?23.5 ± 0.3 kJ mol<sup>-1</sup>) interlocks our study with Laurence's scale of H-bond basicity of organic molecules. The much greater polarity of group 10 metal fluorides than that of the group 4 metal fluorides is consistent with the importance of p?-d? bonding in the latter. The polarity of the group 10 metal fluorides indicates their potential as building blocks for hydrogen-bonded assemblies. The synthesis of trans-[Ni(F){2-C<inf>5</inf>NF<inf>3</inf>(NH<inf>2</inf>)}(PEt<inf>3</inf>)<inf>2</inf>], which exhibits an extended chain structure assembled by hydrogen bonds between the amine and metal-fluoride groups, confirms this hypothesis.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)