The Positional Isomeric Effect on the Structural Diversity of Cd(II) Coordination Polymers, Using Flexible Positional Isomeric Ligands Containing Pyridyl, Triazole, and Carboxylate Fragments

Abstract

To systematically investigate the influence of the positional isomeric effect on the structures of polymer complexes, we prepared two new polymers containing the two positional isomers ethyl 5-methyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-3-carboxylate (L1) and ethyl-5-methyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-4-carboxylate (L2), as well as Cd(II) ions. The structures of the metal–organic frameworks were determined by a single crystal XRD analysis. The compound [Cd(L1)2·4H2O] (1), is a hydrogen bond-induced coordination polymer, whereas the compound [Cd(L2)4·5H2O]n (2) is a three-dimensional (3-D) coordination polymer. Their structures and properties are tuned by the variable N-donor positions of the ligand isomers. This work indicates that the isomeric effect of the ligand isomers plays an important role in the construction of the Cd(II) complexes. In addition, the thermal and luminescent properties are reported in detail.

Crystallization Induced Enhanced Emission in Two New Zn(II) and Cd(II) Supramolecular Coordination Complexes with the 1-(3,4-Dimethylphenyl)-5-Methyl-1H-1,2,3-Triazole-4-Carboxylate Ligand

“…Neutral mononuclear complexes with general formula [M(L) 2 ·(H 2 O) 2 ] were obtained according to the procedure previously reported (see Figure 1 ) [ 38 ]. Slow diffusion of the reactants in immiscible liquids ( n -BuOH/H 2 O) resulted in the formation at the interphase of single crystals suitable for XRD analysis.…”

“…grade and used without further purification (Sigma-Aldrich, St. Louis, MO, United States). The syntheses of the ester precursor and the sodium salt of the carboxylate ligands were carried according to the procedure previously described by Brito et al and reported elsewhere [ 38 ]. On the other hand, the 1-bis-ethyl 1-(3,4-dimethylphenyl)-5-methyl-1 H -1,2,3-triazol-4-carboxylate diacquo Zn(II) or Cd(II) complexes (compounds 1 and 2, respectively), were obtained by double layer solution diffusion in crystallization at room temperature using a test tube (15 cm length by 1.5 cm diameter) between 50 mg (0.197 mmol, 2 eq.)…”

“…Taking these facts into account, multidentate ligands based on 1,2,3-triazole may be considered as versatile building blocks for new functional materials with emerging properties that can be fine-tuned just by a judicious choice of the substituents on the triazole rings. The incorporation of carboxylate groups enhances the coordination capability, enabling the growth of the coordination network in the coordination compounds [ 38 , 39 , 40 ]. Interactions between this type of ligands and metal centers could give information about their synergistic capability, on the antenna effect, charge transfer transitions, or π-system extension that have been studied previously in other systems [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ].…”

Synthesis, Crystal Structure and Hirshfeld Surface Analysis of a New Coordination Polymer: Strontium Benzilate

“…In continuation of our previous investigation on coordination polymers 13,14,[24][25][26][27] , in this work, we present the synthesis, structural characterization and energetic properties of the new coordination polymer strontium benzilate. Hirshfeld surface analysis 28 was used for visually analyzing intermolecular interactions in the crystal structure.…”

The Methylene Spacer Matters: The Structural and Luminescent Effects of Positional Isomerism of n-Methylpyridyltriazole Carboxylate Semi-Rigid Ligands in the Structure of Zn(II) Based Coordination Polymers

“…The fine selection of positionally isomeric organic ligands, and their role in the structure of the CP, is a relevant aspect to study since it can also affect their physical properties. For instance, the isomeric effect [ 28 , 29 , 30 ] over coordination metal complexes can generate the difference between molecular or extended solids [ 25 , 30 , 31 ] and can affect the luminescent and thermal properties. Specifically, the luminescent properties could be modified on demand by appropriately selecting these building blocks.…”