Cyanido-Bridged FeII–MI Dimetallic Hofmann-Like Spin-Crossover Coordination Polymers Based on 2,6-Naphthyridine

5 years ago

Cyanido-Bridged FeII–MI Dimetallic Hofmann-Like Spin-Crossover Coordination Polymers Based on 2,6-Naphthyridine

José Antonio Real, M. Carmen Muñoz, Carlos Bartual-Murgui, Lucía Piñeiro-López, Maksym Seredyuk, Francisco Javier-Valverde-Muñoz

Two new 3D spin-crossover (SCO) Hofmann-type coordination polymers {Fe(2,6-naphthy)[Ag(CN)2][Ag2(CN)3]} (1; 2,6-naphthy = 2,6-naphthyridine) and {Fe(2,6-naphthy)[Au(CN)2]2}·0.5PhNO2 (2) were synthesized and characterized. Both derivatives are made up of infinite stacks of {Fe[Ag(CN)2]2[Ag2(CN)3]}n and {Fe[Au(CN)2]2}n layered grids connected by pillars of 2,6-naphthy ligands coordinated to the axial positions of the FeII centers of alternate layers. The in situ generated [Ag2(CN)3]– linkers define wide rectangular windows that favor the interpenetration of three identical 3D networks, strong argentophilic interactions between them, and the generation of a densely packed structure without accessible void spaces. In contrast, the smaller rhombus-shaped window in 2 affords a structure made up of doubly interpenetrated 3D networks with strong aurophilic interactions between them and accessible voids partially occupied by nitrobenzene molecules. Compound 1 displays a relatively abrupt two-step SCO in the temperature interval 150–215 K, whereas 2 features an incomplete one-step SCO behavior (T1/2 = 166 K) that extends over 150 K.The synthesis, structure, magnetic, and calorimetric spin-crossover (SCO) properties of doubly and triply interlocked iron(II) frameworks based on the bis-monodentate 2,6-naphthyridine ligand are described and discussed in the context of Hofmann-like clathrate SCO compounds.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/ejic.201700920