A new 2D coordination polymer Co₃(OH)₂(pa)₂(ina)₂ (1, pa = 3-(1H-benzimidazol-2-yl) propanoic carboxylate, ina = isonicotinate) contained uncommon, linear Co(II) trimers of mixed T_d–O_h–T_d geometries, exhibits spin canting below 20 K. Such magnetic behavior mainly arises from the Dzyaloshinski–Moriya interaction from the anisotropic, mixed geometries trimeric Co(II) ions to the crimpled 2D network based on the nature of the binding modes of Co(II)-carboxylate trimer and the effect of the intertrimers arrangement of 1. The mixed single-carboxylate-aromatic amine ligands bridged metal systems display a new structurally authenticated example of a thick 2D layer, and also indicate homometallic Co(II) clusters with T_d–O_h–T_d mixed-geometries can result in relatively obvious noncompensation moments, according to different efficient spins of Co(II) at very low temperature, in spite of antiferromagnetic intracluster interactions.

Four couples of enantiomerically pure chiral seven-coordinated mononuclear lanthanide complexes, [(L_OEt)Dy((R,R)-Salphen)]₂·3H₂O (1, L_OEt = [(Cp)Co(P(O)(OEt)₂)₃], Cp = cyclopentadiene, Salphen = N,N′-1,2-diphenylethylenebis(salicylideneiminato) dianion), [(L_OEt)Dy((S,S)-Salphen)]₂·3H₂O (2), [(L_OEt)Dy((R,R)-5-Cl-Salcy)]·CH₃OH·1/8H₂O (3, Salcy = N,N′-(1,2-cyclohexanediylethylene)bis(salicylideneiminato) dianion), [(L_OEt)Dy((S,S)-5-Cl-Salcy)]·CH₃OH·1/8H₂O (4), [(L_OEt)Tb((R,R)-5-Cl-Salcy)]·CH₃OH·1/8H₂O (5), [(L_OEt)Tb((S,S)-5-Cl-Salcy)]·CH₃OH·1/8H₂O (6), [(L_OEt)Ho((R,R)-5-Cl-Salcy)]·CH₃OH·1/8H₂O (7) and [(L_OEt)Ho((S,S)-5-Cl-Salcy)]·CH₃OH·1/8H₂O (8), have been successfully synthesized by using tetradentate chiral salen-type ligands and the Kläui's tripodal ligand of L_OEt. Structural analyses reveal that all compounds have a typical double-decker sandwich structure, and the Ln(III) ions exhibit a rare seven-coordinated mode, situating in a distorted monocapped triangular prism polyhedron. Circular dichroism (CD) spectra confirm the enantiomeric nature of the optically active complexes and demonstrate that the chirality is successfully transferred from the ligand to the coordination environment of the Ln(III) ions. Field-induced slow relaxation of the magnetization is observed for complexes 1–4, suggesting that they can be rare chiral single-ion magnets (SIMs) based on the seven-coordinated lanthanide ions.