New Metal‐Organic Frameworks with Large Cavities: Selective Sorption and Desorption of Solvent Molecules

Abstract

Five novel transition metal complexes [Cd(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (1), [Cu(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (2), [Ni(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (3), [Cd(II) (2)(tpba-2)(SCN)(3)]ClO(4) (4), [Cu(I) (3)(SCN)(6)(H(3)tpba-2)] (5) [TPBA-2 = N',N'',N'''-tris(pyrid-2-ylmethyl)-1,3,5-benzenetricarboxamide, THF=tetrahydrofuran] were obtained by reactions of the corresponding transition metal salts with TPBA-2 ligand in the presence of NH(4)SCN using layering or solvothermal method, respectively. The results of X-ray crystallographic analysis showed that complexes 1, 2 and 3 are isostructural and have the same 2D honeycomb network structure with Kagomé lattice, in which all the M(II) (M = Cd, Cu, Ni) atoms are six-coordinated, and the TPBA-2 ligands adopt cis,cis,cis conformation while the thiocyanate anions act as terminal ligands. Capsule-like motifs are found in 1, 2 and 3, in which six THF molecules are hosted, and the results of XPRD and solid-state (13)C NMR spectral measurements showed that the compound 1 can selectively desorb and adsorb THF molecules occurring along with the re-establishment of its crystallinity. In contrast to 1, 2 and 3, complex 4 has different 2D network structure, resulting from TPBA-2 ligands with cis,trans,trans conformation, thiocyanate anions serving as end-to-end bridging ligands, and the incomplete replacement of perchlorate anions, which further link the 2D layers into 3D framework by the hydrogen bonds. In complex 5, the Cu(II) atoms are reduced to Cu(I) during the process of solvothermal reaction, and the Cu(I) atoms are connected by thiocyanate anions to form a 3D porous framework, in which the protonated TPBA-2 ligands are hosted in the cavities as templates.

Crystal structure of [(1,4-di(1-imidazolyl)benzene-κ2N:N´)(μ2-5-iso nicotinamidoisophthalato-κ2O1,O3)cop per(II)], C26H18CuN6O5

“…Particularly,c opper complexes containing heterocycles have been investigatedextensivelytodate [3,4]. On the other hand, it is well known that carboxylate and pyridine groups have good coordination capacities as well as the amide group, af ascinating functional groupw itht wo differentt ypes of hydrogen bonding sites: the -NH moiety which acts as an electron acceptor while the -C=O groupactsasanelectron donor [5][6][7][8]. So we have recently prepared an ew two-dimensional copper(II) coordination polymer, [Cu(dib)(iaip)] n ,(I), with iaip, dib and copper acetate.…”

Crystal structure of diaqua(hydrogen 5-isonicotinamidoisophthalato)- (μ2-5-isonicotinamidoisophthalato-k2O1,O3)praseodymium(III) monohydrate, Pr(H2O)2(C14H9N2O5)(C14H8O5N2) · H2O

“…However, the design and control over high-dimensional lanthanide frameworks are rarely reported [2,3]. On the other hand, it is well known that carboxylate and pyridine groups have good coordination capacities as well as the amide group, afascinating functional group with two different types of hydrogen bonding sites: the -NH moiety which acts as an electron acceptor while the -C=O group acts as an electron donor [4][5][6]. …”

Crystal structure of aqua(1H-imidazol)-(μ3-5-isonicotinamidoisophthalato- k2O1,O3-k1N1)iron(II) monohydrate, Fe(H2O)(C3H4N2)(C14H8N2O5) · H2O

“…Particularly, iron(II) complexes with the heterocycle carboxylate have been investigated rarely to date [2][3][4]. However, it is well known that carboxylate pyridine as well as the amide groups have good coordination capacity [5][6][7][8].…”