Terbium and Europium Chlorocyananilate-Based 2D Coordination Polymers.

Two-dimensional layered coordination polymers based on the hetero-substituted 3-chloro-6-cyano-2,5-dihydroxybenzoquinone ligands, hereafter ClCNAn 2- anilate, and Ln III ions (Tb and Eu) are reported. Compounds 1 and 2 , formulated as Ln 2 (ClCNAn) 3 (DMSO) 6 (Ln III = Tb, 1 ; Eu, 2 ), and their related intermediates 1' and 2' , formulated as Ln 2 (ClCNAn) 3 (H 2 O) x ·yH 2 O (x + y likely = 12, Ln = Tb, 1' ; and Eu, 2' ), were prepared by a conventional one-pot reaction (the latter) and recrystallized from DMSO solvent (the former). Polyhydrated intermediates 1' and 2' show very similar XRPD patterns, while, despite their common stoichiometry, 1 and 2 are not isostructural. Compound 1 consists of a 2D coordination framework of 3,6 topology, where [Tb(DMSO) 3 ] III moieties are bridged by three bis-chelating ClCNAn 2- ligands, forming distorted hexagons. Ultrathin nanosheets of 1 were obtained by exfoliation via the liquid-assisted sonication method and characterized by atomic force microscopy, confirming the 2D nature of 1 . The crystal structure of 2 , still showing the presence of 2D sheets with a "hexagonal" mesh and a common (3,6) connectivity, is based onto flat, non-corrugated slabs. Indeed, at a larger scale, the different "rectangular tiles" show clear roofing in 1 , which is totally absent in 2 . The magnetic behavior of 1 very likely indicates depopulation of the highest crystal-field levels, as expected for Tb III compounds.