Two 2D spin-crossover coordination polymers constructed by [Pd(SCN) 4 ] 2- building blocks.

Two new two-dimensional (2D) coordination polymers, [Fe II (L) 2 {Pd II (SCN) 4 }] (L 1 = 2-methoxypyrazine, 1; and L 2 = ( E )-3-(phenyldiazenyl)pyridine, 2), were successfully constructed by using square-planar [Pd(SCN) 4 ] 2- building blocks. Complex 1 exhibits complete and one-step spin-crossover (SCO) behavior, while 2 exhibits incomplete and two-step SCO behavior. Further structural insight into this synergy reveals that the flat/flexing [Fe{Pd(SCN) 4 }] ∞ sheets in 1 and 2 are stabilized by interlayered/intralayered supramolecular interactions.