Unique spin transition and wide thermal hysteresis loop for a cobalt(II) compound with long alkyl chain

The cobalt(II) compounds with long alkyl chains, [Co(C12-terpy)(2)](BF4)(2)center dot EtOH center dot 0.5H(2)O(1 center dot EtOH center dot 0.5H(2)O) and [Co(C12-terpy)(2)](BF4)(2) (1) was synthesized and characterized. The compound 1 center dot EtOH center dot 0.5H(2)O exhibits a re-entrant spin crossover. The compound 1 exhibits the re-entrant spin crossover and multi phase transitions with a wide thermal hysteresis loop.