[M₆M′₄] Cage Compounds with Chiral Bidentate Ligands

Abstract

Two decanuclear cyanide-bridged cage compounds were synthesized through the combination of chiral bidentate ligand-capped transition metal building blocks with hexacyanometalate ions, and their structural and magnetic properties were investigated.

Cyanide-Bridged Decanuclear Cobalt–Iron Cage

“…Single-crystal X-ray analysis reveals that 1 crystallized in the orthorhombic space group P 2 1 2 1 2 1 and has a cage structure constructed from six [Co(L R ) 2 ] and four hexacyanoferrate units, within which one tetraethylammonium cation is encapsulated. The metal arrangement is adamantane-like in topology: very close to that of the reported [Ni 6 Fe 4 ] cage molecules . The cobalt ions have octahedral coordination geometries with four nitrogen donor atoms from two chiral bidentate ligands and two nitrogen donor atoms from two neighboring hexacyanoferrate units.…”

“…We previously reported [Ni 6 Fe 4 ] and [Co 10 ] cage molecules, which were obtained by the self-assembly of chiral bidentate ligands with nickel or cobalt ions and hexacyanometalate units . The [Ni 6 Fe 4 ] complexes show ferromagnetic interactions between Ni II and low-spin Fe III ions because of the orthogonality of their magnetic orbitals and constitute a rare example of magnetic cage molecules.…”

Site Selectivity for the Spin States and Spin Crossover in Undecanuclear Heterometallic Cyanido-Bridged Clusters

“…64 Thus, in a further pursuit to activate as much as possible potential SCO sites and appointing the new topologies of heterometallic clusters of modular potential, we exploited the self-assembly between [W(CN) 8 ] 3− and Fe II , Co II , or Ni II complexes with bulky N donors of various degrees of flexibility, commonly used to construct SCO complexes. 67,68 As a result, here we present an unprecedented series of cyanido-bridged clusters realizing new undecanuclear topology: Fe II 18MeOH (1), S15−S17). For the sake of simplicity, we will consider the M 7 W 4 forms as the fundamental structural components (see further description).…”

“…This feature definitely precluded the observation of multistability, although multichannel bistability was achieved through a solid/solution approach. , Furthermore, the weakly bonded MeOH molecules on the surface of a cluster allow facile ligand substitution chemistry at these specific positions to create extended clusters and polymers. − However, until now, only the use of dedicated capping 1,4,7-trimethyl-1,4,7-triazacyclononane (Me 3 tacn) ligands allowed one to extend the SCO behavior onto the peripheral cluster areas . Thus, in a further pursuit to activate as much as possible potential SCO sites and appointing the new topologies of heterometallic clusters of modular potential, we exploited the self-assembly between [W­(CN) 8 ] 3– and Fe II , Co II , or Ni II complexes with bulky N donors of various degrees of flexibility, commonly used to construct SCO complexes. , As a result, here we present an unprecedented series of cyanido-bridged clusters realizing new undecanuclear topology: Fe II [Fe II (bzbpen)] 6 [W V (CN) 8 ] 2 [W IV (CN) 8 ] 2 ·18MeOH ( 1 ), Na I [Co II (bzbpen)] 6 [W V (CN) 8 ] 3 [W IV (CN) 8 ]·28MeOH ( 2 ), Na I [Ni II (bzbpen)] 6 [W V (CN) 8 ] 3 [W IV (CN) 8 ]·27MeOH ( 3 ) (group I ), and Co II [Co II ( R / S -pabh) 2 ] 6 [W V (CN) 8 ] 2 [W IV (CN) 8 ] 2 ·26MeOH [ 4 R and 4 S ) (group II ); bzbpen = N 1 , N 2 -dibenzyl- N 1 , N 2 -bis­(pyridin-2-ylmethyl)­ethane-1,2-diamine; R / S -pabh = ( R / S )- N -(1-naphthyl)-1-(pyridin-2-yl)­methanimine]. The series was characterized by scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), flame atomic absorption spectroscopy (FAAS), single-crystal X-ray diffraction (XRD), powder XRD (PXRD), superconducting quantum interference device (SQUID) magnetometry, UV–vis–NIR (in the solid state and in solution), IR and 57 Fe Mössbauer spectroscopic techniques, and electrospray ionization mass spectrometry (ESI MS).…”