From 1D to 2D Cd(II) and Zn(II) Coordination Networks by Replacing Monocarboxylate with Dicarboxylates in Partnership with Azine Ligands: Synthesis, Crystal Structures, Inclusion, and Emission Properties.

Victor Ch Kravtsov,Nikita Siminel,Marina S Fonari,Eduard B Coropceanu,Natalia V Costriucova,Vasile Lozovan,Olga V Kulikova

doi:10.3390/molecules25235616

Abstract

Eight mixed-ligand coordination networks, [Cd(2-aba)(NO3)(4-bphz)3/2]n·n(dmf) (1), [Cd(2-aba)2(4-bphz)]n·0.75n(dmf) (2), [Cd(seb)(4-bphz)]n·n(H2O) (3), [Cd(seb)(4-bpmhz)]n·n(H2O) (4), [Cd(hpa)(3-bphz)]n (5), [Zn(1,3-bdc)(3-bpmhz)]n·n(MeOH) (6), [Cd(1,3-bdc)(3-bpmhz)]n ·0.5n(H2O)·0.5n(EtOH) (7), and [Cd(NO3)2(3-bphz)(bpe)]n·n(3-bphz) (8) were obtained by interplay of cadmium nitrate tetrahydrate or zinc nitrate hexahydrate with 2-aminobenzenecarboxylic acid (H(2-aba)), three dicarboxylic acids, sebacic (decanedioic acid, H2seb), homophthalic (2-(carboxymethyl)benzoic acid, H2hpa), isophthalic (1,3-benzenedicarboxylic acid, H2(1,3-bdc)) acids, bis(4-pyridyl)ethane (bpe) and with four azine ligands, 1,2-bis(pyridin-4-ylmethylene)hydrazine (4-bphz), 1,2-bis(1-(pyridin-4-yl)ethylidene) hydrazine (4-bpmhz), 1,2-bis(pyridin-3-ylmethylene)hydrazine (3-bphz), and 1,2-bis(1-(pyridin-3-yl) ethylidene)hydrazine (3-bpmhz). Compounds 1 and 2 are 1D coordination polymers, while compounds 3–8 are 2D coordination polymers. All compounds were characterized by spectroscopic and X-ray diffraction methods of analysis. The solvent uptakes and stabilities to the guest evacuation were studied and compared for 1D and 2D coordination networks. The de-solvated forms revealed a significant increase of emission in comparison with the as-synthesized crystals.

Highlights

Having been launched as intriguing adsorption materials with the possibility to be applied in gas storage due to the exceptional low density, large surface area, pore function regulation, and structural flexibility [1,2], currently, the coordination polymers (CP) demonstrate their significance as materials for luminescence [3], catalysis [4], magnetism [5], optics [6], electric conductivity [7], and so on.The pore regulation by design can be considered as an advantage of CPs compared to the traditional porous materials such as zeolites and activated carbons
The strategy of replacing monocarboxylic acids (2-aminobenzoic) by three dicarboxylic acids with different skeleton flexibilities in a blend with N, N0 -diazine ligands has succeeded for extending the dimensionality of coordination polymers from 1D to 2D while keeping invariable the coordination polymeric chains originated from azine ligands
The five topologically similar 2D networks 3–7 are built in the same way from a ladder-type chain based on [M2 (CO2 )4 ]

Summary

Introduction

Having been launched as intriguing adsorption materials with the possibility to be applied in gas storage due to the exceptional low density, large surface area, pore function regulation, and structural flexibility [1,2], currently, the coordination polymers (CP) demonstrate their significance as materials for luminescence [3], catalysis [4], magnetism [5], optics [6], electric conductivity [7], and so on.The pore regulation by design can be considered as an advantage of CPs compared to the traditional porous materials such as zeolites and activated carbons. Having been launched as intriguing adsorption materials with the possibility to be applied in gas storage due to the exceptional low density, large surface area, pore function regulation, and structural flexibility [1,2], currently, the coordination polymers (CP) demonstrate their significance as materials for luminescence [3], catalysis [4], magnetism [5], optics [6], electric conductivity [7], and so on. Molecules 2020, 25, 5616 adsorption properties accompanied by the guest selectivity were reported for 1D and 2D coordination networks [10,11,12]. The carboxylates are among the most demanded ligands in the synthesis of homo-ligand and hetero-ligand CPs with either rigid or flexible coordination backbones [13]. The rational choice of the metal provides the ability of the carboxylic group to coordinate to the metal in different ways and ensures the formation of coordination networks with different dimensionality and complexity [14,15,16]

Methods

Results

Conclusion