Spin-Crossover in Iron(II) Complexes of N,N′-Disubstituted 2,6-Bis(Pyrazol-3-yl)Pyridines: An Effect of a Distal Substituent in the 2,6-Dibromophenyl Group
Igor A. Nikovskiy,
Alexander V. Polezhaev,
Valentin V. Novikov,
Dmitry Yu. Aleshin,
Rinat R. Aysin,
Elizaveta K. Melnikova,
Luca M. Carrella,
Eva Rentschler,
Yulia V. Nelyubina
Affiliations
Igor A. Nikovskiy
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
Alexander V. Polezhaev
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
Valentin V. Novikov
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
Dmitry Yu. Aleshin
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
Rinat R. Aysin
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
Elizaveta K. Melnikova
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
Luca M. Carrella
Johannes Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, Germany
Eva Rentschler
Johannes Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, Germany
Yulia V. Nelyubina
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
A series of new bis(pyrazol-3-yl)pyridines (LR) N,N′-disubstituted by 4-functionalized 2,6-dibromophenyl groups have been synthesized to study the effect of a distal substituent on the spin-crossover (SCO) behaviour of the iron(II) complexes [Fe(LR)2](ClO4)2 by variable-temperature magnetometry, NMR spectroscopy, and X-ray diffraction. The SCO-assisting tendency of the substituents with different electronic and steric properties (i.e., the bromine atom and the methyl group) in the para-position of the 2,6-dibromophenyl group is discussed. Together with earlier reported SCO-active iron(II) complexes with N,N′-disubstituted bis(pyrazol-3-yl)pyridines, these new complexes open the way for this family of SCO compounds to emerge as an effective ‘tool’ in revealing structure–function relations, a prerequisite for successful molecular design of switchable materials for future breakthrough applications in sensing, switching, and memory devices.
