A new ZnII metallocryptand with unprecedented diflexure helix induced by V-shaped diimidazole building blocks

Taking advantage of V-shaped ligands, a Zn^II metallocryptand, namely {[Zn₂(didp)₂(m-bdc)₂]}_n, (1) [didp = 2,8-di(1H-imidazol-1-yl)-dibenzothiophene and m-H₂bdc = isophthalic acid], has been hydrothermally synthesized. Single-crystal X-ray diffraction analysis reveals a 26-membered butterfly-type metallomacrocycle [Zn₂(didp)₂]. One m-bdc^2- ligand bridges [Zn₂(didp)₂] units to form a laterally non-symmetric [Zn₂(didp)₂(m-bdc)] metallocryptand with an exo-exo conformation. Another crystallographically independent m-bdc^2- functions as a secondary synthon to bridge discrete metallocryptands into a 1D zigzag chain architecture. Undoubtedly, the choice of two matched ligands in this work is crucial for metallocryptand construction and structure expansion. Interestingly, a rare helical chain with two flexures in one single L and/or R strand is observed. Another important feature is the C-O...π interactions, by which the dimensionality extension of (1) can be induced. Fluorescence measurements and density functional theory (DFT) calculations illustrate that the emission of (1) can probably be attributed to ligand-to-ligand charge transfer (LLCT).

Synthesis, Crystal Structure, and Properties of a Zn(II) Coordination Polymer Based on a Difunctional Ligand Containing Triazolyl and Carboxyl Groups

A new compound, namely, [Zn(L)2]n (1) was obtained by the reaction of 2-methyl-4-(4H-1,2,4-triazol-4-yl) benzoic acid (HL) with ZnSO4·7H2O, and the compound was characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, powder X-ray diffraction (PXRD), and thermogravimetric analysis. The linear HL ligands were deprotonated to be L− anions and act as two-connectors to link Zn2+ to form a two-dimensional (2D) lay structure with (4, 4) topology. The large vacancy of 2D framework allows another layer structure to interpenetrate, resulting in the formation of 2D + 2D → 2D parallel interpenetration in 1. The weak interactions, such as hydrogen bonding and π–π stacking interactions, connect the adjacent 2D layers into a three-dimensional (3D) coordination polymer. The solid-state UV-visible spectroscopy and luminescent property have also been studied.

Synthesis, structures and photoluminescence properties of mixed ligand divalent metal–organic frameworks

Crystal engineering is an effective route for synthesis of mixed ligand metal–organic frameworks with attractive topologies and versatile potential applications.

Crystal structure of poly[diacetato(μ2-1,4-bis(1H-imidazol-1-yl)benzene-κ 2 N:N′)nickel(II)], C26H22N8NiO4

C26H22N8NiO4, monoclinic, P21/c (no. 14), a = 7.520(5) Å, b = 11.662(7) Å, c = 13.666(9) Å, β = 98.519(8)°, V = 1185.3(13) Å3, Z = 2, R gt (F) = 0.0345, wR ref (F 2 ) = 0.1007, T = 293 K.

Synthesis, structure and adsorption properties of lanthanide-organic frameworks with pyridine-3,5-bis(phenyl-4-carboxylate)

Under solvothermal conditions, reactions of pyridine-3,5-bis(phenyl-4-carboxylic acid) (H2L) with lanthanide metal salts give rise to three new metal-organic frameworks (MOFs) with the formula {[Ln4(L)3(μ3-OH)4(H2O)4]·(NO3)2·solvent}n [Ln = Er (1), Yb (2) and Lu (3)]. The complexes were characterized by single crystal and powder X-ray diffraction, IR and thermogravimetric analyses. They have the same two-fold interpenetrating three-dimensional (3D) framework structures with [Ln4(COO)6(μ3-OH)4(H2O)4] clusters as secondary building units (SBUs) and a rare 6-connected lcy topology with the point (Schläfli) symbol of {3(3)·5(9)·6(3)}. Interestingly, 1-3 show selective and hysteretic sorption of CO2 over N2, and the photoluminescence properties of the complexes were also investigated.

The crystal structure, luminescence and nitrobenzene-sensing properties of a two-dimensional Mn(II) coordination polymer based on 2,6-bis(imidazol-1-yl)pyridine

A two-dimensional Mn(II) coordination polymer (CP), poly[bis[μ2-2,6-bis(imidazol-1-yl)pyridine-κ(2)N(3):N(3')]bis(thiocyanato-κN)manganese] [Mn(NCS)2(C11H9N5)2]n, (I), has been obtained by the self-assembly reaction of Mn(ClO4)2·6H2O, NH4SCN and bent 2,6-bis(imidazol-1-yl)pyridine (2,6-bip). CP (I) was characterized by FT-IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The crystal structure features a unique two-dimensional (4,4) network with one-dimensional channels. The luminescence and nitrobenzene-sensing properties were explored in a DMF suspension, revealing that CP (I) shows a strong luminescence emission and is highly sensitive for nitrobenzene detection.

Controlled in situ reaction for the assembly of Cu(ii) mixed-ligand coordination polymers: synthesis, structure, mechanistic insights, magnetism and catalysis

Controlled in situ nucleophilic addition reaction results in two Cu(ii) mixed-ligand coordination polymers, and the one-step nucleophilic addition for in situ reaction is proposed.