Trispyrazolylborate degradation in rhodium complexes, crystal structure of [Rh(e-But-C3N2H2)(NBD) (3-But-C3N2H3)]

The reaction of [Rh(μ-Cl)(NBD)] 2 (NBD = 2,5-norbornadiene) and [TpBu t ] − (TpBu t = hydrotris(3- tert -butylpyrazol-1-yl)borate, HB[3-Bu t pz] 3 0 yields [Rh(3-Bu t pz) (NDB)(3-Bu t pzH)] (pz = C 3 N 2 H 2 ) instead of the expected complex [Rh(TpBu t )(NBD)]. The crystal structure of the title compound shows the presence of an asymmetric H bond between the two pyrazole rings. The formation of the pyrazole/pyrazolate complex implies a degradation reaction of the ligand.