Reductively Stable Hydrogen-Bonding Ligands Featuring Appended Cf2-H Units

We present the development of ligands featuring the unconventional hydrogen bond donor, -CF2H, within a metal's secondary coordination sphere. When metalated with palladium, o-CF2H-functionalized 1,10-phenanthroline provides highly directed H-bonding interactions with Pd-coordinated substrates. Spectroscopic and computational analyses with a series of X-type ligand acceptors (-F, -Cl, -Br, -OR) establish the H-bonding interaction strength for the -CF2H group (similar to 3 kcal/mol). The synthesis of Pd-0/Ni-0 complexes and subsequent coupling (Ni) highlight the unique reductive and base compatibility of the -CF2H hydrogen bond donor group.