Magnetic behavior and Mössbauer spectra of spin-crossover pyrazolate bridged dinuclear diiron(<scp>ii</scp>) complexes: X-ray structures of high-spin and low-spin [{Fe(NCBH<sub>3</sub>)(py)}<sub>2</sub>(μ-bpypz)<sub>2</sub>]
characterization of new spin-crossover pyrazolato bridged dinuclear [(FeII(NCS)(py))2(mu-bpypz)2] and the corresponding cyanotrihydroborato-kappaN complexes are described together with the X-ray crystal analysis of the latter in both the high-spin and low-spin states as well as the variable temperature magnetic susceptibility and/or Mossbauer spectra demonstrating the spin-crossover which exhibits an one-step