Direct two-step spin-crossover through [HS-HS]center dot center dot center dot[LS-LS] at the plateau in dinuclear diiron(II) complex [{Fe(NCBH3)(4phpy)}(2)(mu-bpypz)(2)]

The variable temperature magnetic susceptibility, X-ray crystallography, and IR and Raman spectra of a new dinuclear complex [{Fe-II(NCBH3)(4-phpy)}(2)(mu-bpypz)(2)] demonstrated the first two-step spin-crossover associated with a 1 : 1 mixture of high-spin pair [HS-HS] and low-spin pair [LS-LS] at the plateau.