Readily prepared metallo-supramolecular triple helicates designed to exhibit spin-crossover behaviour.
New dinuclear supramolecular cylinders have been designed to exhibit spin-crossover behaviour, a form of molecular bistability. This has been achieved within the framework of our imine-based approach to supramolecular architecture by switching from pyridylimine systems to imidazolimines. Spin-crossover behaviour is achieved while retaining the simplicity and ease-of-synthesis of our molecular design. The imidazole groups used also introduce additional NH groups that engage in hydrogen-bonding to anions and solvents. In the case of the iron(II) tetrafluoroborate complex this hydrogen bonding links supramolecular cylinders into an extended two-dimensional array. Consistent with this, a sharper spin-crossover transition is observed for this compound than for the corresponding hexafluorophosphate salt. More subtle anion effects are indicated in the perchlorate salt which gives a two-step spin conversion, thereby displaying tristability.
Centre for Supramolecular and Macromolecular Chemistry, Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
Floriana
F
Tuna
Martin R
MR
Lees
Guy J
GJ
Clarkson
Michael J
MJ
Hannon