Bis(imidazole-κN³)bis(nitrato-κO)zinc(II)

Abstract

Key indicators: single-crystal X-ray study; T = 293 K; mean (C-C) = 0.005 Å; R factor = 0.044; wR factor = 0.127; data-to-parameter ratio = 17.7.The title complex, [Zn(NO 3 ) 2 (C 3 H 4 N 2 ) 2 ], contains a Zn II centre with a slightly distorted tetrahedral coordination environment, involving two N atoms from imidazole ligands and two O atoms from nitrate anions. The imino NH groups participate in intermolecular N-HÁ Á ÁO hydrogen bonds. Related literature

Fabrication of Super‐Sized Metal Inorganic‐Organic Hybrid Glass with Supramolecular Network via Crystallization‐Suppressing Approach

“…Due to the high similarity between ZnÀ N and ZnÀ O bond lengths in the tetrahedral configuration, we could not precisely calculate the ZnÀ O bond length for the glassy samples, where the ZnÀ O distance is comparable to the ZnÀ N distance (i.e., ZnÀ N=ZnÀ O � 2 Å) in the zinc nitrate imidazole complex. [35] To further investigate and compare the local structure of the crystalline and glassy samples, X-ray total scattering experiments were conducted on the MIOC glass and ZIF-7-III crystal. The pair distribution function (PDF) D(r) data of the MIOC glass and ZIF-7-III crystal (Figure 3b) suggest that the correlations between Zn and Hbim remain intact in the MIOC glass, since the observed CÀ N, ZnÀ N, and ZnÀ C correlations in the glass sample are similar to those in ZIF-7-III crystal.…”

“…Unlike the crystal spectra, the 67 Zn MAS NMR spectra of the MIOC glass show a significantly broader peak for the higher field, indicating a rather large broadening contribution from the chemical shift distribution, implying a high degree of short-range disorder around ZnN 2 O 2 as well from the presence of multiple sites of Zn with different degree of distortion. [51,52,35] The H-bonding in the networks of glassy MIOC samples was evaluated by Raman measurement (Figure S20 Table S4, and Supporting Text III). [53] As the T g value of the as-synthesized MIOC glass is below 273 K, MIOC glass is dynamically flexible at RT and it can be drawn to a fiber using a tapered rod.…”

“…The fitting results of the EXAFS spectra (Figure S16 and Table S3) show that the Zn−N bond length is about 2 Å for the ZIF‐7‐III crystal and MIOC glasses. Due to the high similarity between Zn−N and Zn−O bond lengths in the tetrahedral configuration, we could not precisely calculate the Zn−O bond length for the glassy samples, where the Zn−O distance is comparable to the Zn−N distance (i.e., Zn−N=Zn−O≈2 Å) in the zinc nitrate imidazole complex [35] . To further investigate and compare the local structure of the crystalline and glassy samples, X‐ray total scattering experiments were conducted on the MIOC glass and ZIF‐7‐III crystal.…”

“…In this network, Zn is coordinated tetrahedrally to two NO 3 and two Hbim, and the Zn(NO 3 ) 2 -(Hbim) 2 molecules are connected to each other through Hbonding (i.e., NÀ H•••O). [35] However, the prolonged drying of the undried MIOC glass at 323 K for 1 month led to the evaporation of excess solvent and hence the formation of transparent bulk glass (labeled as MIOC glass). It is interesting to note that the large-sized MIOC glass can be synthesized by casting the glass into a silicone mold with a rectangular shape and then cooling it at 273 K to maintain its structural rigidity.…”

“…Here, we demonstrate a synthetic approach to prepare large-sized MCC glass in air and at low temperature (i.e., < 373 K). Using this approach, we synthesize a novel hydrogen-bonded MIOC glass (i.e., Zn(NO 3 ) 2 (Hbim) 2 , Hbim = protonated benzimidazole) [35] through suppressing the crystallization of non-meltable 2D zeolitic-imidazolate framework-7-III (ZIF-7-III) [24] (i.e., Zn 2 (bim) 4 , bim = benzimidazole; ZIFs are a sub-set of MOFs [36] ) in a solution, rather than the commonly used direct melt-quenching of MCCs. [2] It is expected that molecules including ethanol and nitric acid insert into the ZIF network, coordinate with the metal centers, and distort the framework by interrupting its structural periodicity, thereby transforming the framework into a hydrogen-bonded MIOC network.…”