Hydride ligands spectroscopic properties

The spectroscopic properties and the reactivity towards low-valent metal fragments of these cationic alkylidyne salts mirror those of the pyrazolylborate analogues, with one notable exception being that pyrazolylmethane ligands exhibit a (protic) reactivity at the bridgehead carbon, allowing for modification of the ligand within the alkylidyne complex (Section IV.E), a phenomenon which has not been similarly documented for Tp L M( = CR) complexes (hydridic B-H bond). 

---