Diversity in the ½ spin arrangement of [Ni(dmit)2]– anions in divalent Ca2+(crown ether) supramolecular cation salts

Abstract

Calcium ion (Ca 2z ) and crown ethers, 12-crown-4, 15-crown-5, 1-aza-18-crown-6 (A18-crown-6) and 1,10diaza-18-crown-6 (DA18-crown-6), were assembled into divalent supramolecular cation (SC 2z ) structures in the monovalent [Ni(dmit) 2 ] 2 salts (dmit 22 ~2-thioxo-1,3-dithiole-4,5-dithiolate), which regulate the arrangement of the [Ni(dmit) 2 ] 2 anions in the crystal. The divalent SC 2z -[Ni(dmit) 2 ] 2 system showed a larger diversity of crystal structures compared with the monovalent SC z system. Peculiar magnetic behavior was observed depending on the arrangement of the S~1 2 spins on the [Ni(dmit) 2 ] 2 anions. Single crystals of Ca 2z (12-crown-4) 2 [Ni(dmit) 2 ] 2 (1) and Ca 2z (15-crown-5) 2 [Ni(dmit) 2 ] 2 (CH 3 CN) 0.7 (2) had a typical sandwich-type Ca 2z (crown ether) 2 structure, which included the formation of p-p dimers and monomers of [Ni(dmit) 2 ] 2 anions in the crystal. The temperature-dependent magnetic susceptibility (x m ) of salt 1 showed a magnetic transition at 190 K, at which temperature the spins on each [Ni(dmit) 2 ] 2 dimer formed a singlet pair. On the other hand, the magnetic behavior of salt 2 obeyed the Curie-Weiss law. The Ca 2z ions in the isostructural single crystals of Ca 2z (A18-crown-6)[Ni(dmit) 2 ] 2 (CH 3 CN) 2 (3) and Ca 2z (DA18-crown-6)[Ni(dmit) 2 ] 2 (CH 3 CN) 2 (4) were completely included into the 18-crown-6 cavity, and further interacted with two CH 3 CN molecules from the axial position. The resultant Ca 2z (18-crown-6)(CH 3 CN) 2 cations induced the formation of uniform zig-zag chains of the [Ni(dmit) 2 ] 2 anions, the magnetic susceptibility of which were explained by a one-dimensional Heisenberg antiferromagnetic linear chain. The magnetism of these salts was discussed in terms of the intermolecular transfer integral t.

Two electroactive ferrocenyl chalcones as original optical chemosensors for Ca2+ and Ba2+ cations in CH3CN

“…The first value can be explained by the fact that the crown ring fits well the calcium ion [18]. This 2M species is probably formed by a Ca 2+ cation sandwiched between two crown rings of the ligand [19]. Actually, the value of the 2M association constant is two order of magnitude higher than that obtained for the monosubstituted azacrown counterpart 5 (2.0 · 10 3 mol L À1 ).…”

Tridentate phosphine ligands bearing aza-crown ether lariats

“…The (P 3 )MoCl 3 cores in ( 8a [Ca(OTf) 2 (THF)])MoCl 3 and [( 8b [Na])MoCl 3 ][NTf 2 ] are nearly isostructural and are similar to other ( mer -triphosphine)MoCl 3 complexes,[36–39] where the Mo-Cl distances are all between 2.38–2.44 Å and the Mo-P distances are between 2.46–2.47 Å for the central phosphine and 2.55–2.57 Å for the distal phosphine arms (see Table 1). The calcium complex ( 8a [Ca(OTf) 2 (THF)])MoCl 3 bears an eight-coordinate calcium atom (best described as a square-faced bicapped trigonal prism) that binds both triflate anions and a THF molecule, a coordination geometry that appears to be common for Ca 2+ complexes of 15-crown-5 derivatives [3,40–42]. The cation/crown size mismatch of the Ca 2+ complex is notable, as engineering such “destabilized” systems may prove critical for the type of secondary coordination sphere interactions we are investigating.…”

Asymmetrical [Ni(dmit)2]− Arrangements Induced by (1R,2R)-Cyclohexanediammonium - Crown Ether Supramolecules

“…Calcd for salt 1, C 21.5 -H 32. 5 Crystal Structure Determination. Crystallographic data (Table 1) were collected by a Rigaku RAXIS-RAPID diffractometer using Mo-KR (λ = 0.71073 Å ) radiation from a graphite monochromator.…”