Group Position-Dependent Structurally Diverse Coordination Compounds Based on Isomeric Ligands

Abstract

Two isomeric ligands Htzpya and Hpytza (Htzpya ¼ 3-(5-tetrazolyl)pyridine-1-acetic acid, Hpytza ¼ 5-(3-pyridyl) tetrazole-2-acetic acid) have been selected to react with DyCl 3 Á6H 2 O or PrCl 3 Á6H 2 O under hydrothermal conditions, resulting in the formation of four new coordination compounds, mononuclear [Dy(tzpya) 2 (H 2 O) 5 ]ClÁ4H 2 O (1), dinuclear [Pr 2 (tzpya) 2 (H 2 O) 12 ]Cl 4 Á2H 2 O (2), and two one-dimensional polymers [Dy(pytza) 2 Cl(H 2 O) 2 ] n (3) and [Pr(pytza) 2 Cl (H 2 O) 2 ] n (4), whose structures are controlled by the different positions of the carboxylate group. These compounds were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Compounds 1-4 are self-assembled to form three-dimensional network structures by hydrogen bonding interactions. Furthermore, the luminescence properties were also investigated at room temperature in the solid state.

Synthesis, Characterization and Properties of TbIII and DyIII Coordination Compounds based on Isomeric Ligands

“…Therefore, compound 2 displays a mononuclear structure. Compared to the previously reported Dy III compounds based on isomeric ligands Hpytza and Htzpya [Hpytza = 5‐(3‐pyridyl)tetrazole‐acetic acid, Htzpya = 3‐(5‐tetrazolyl)pyridine‐1‐acetic acid)],17 the structure of compound 2 is analogous to that of [Dy(tzpya) 2 (H 2 O) 5 ]Cl · 4H 2 O while is different from the 1D polymer [Dy(pytza) 2 Cl(H 2 O) 2 ] since each pytza ligand acts as a bidentate ligand by its carboxylate group in a μ 1,3 ‐COO bridging mode. It is worthwhile to point out that an uncoordinated pztza anion in the molecule plays a role of balancing the charge, which is relatively rare.…”

“…These emissions are tentatively attributed to the ligand centered luminescence. Generally, the intraligand fluorescence emission wavelength is determined by the energy gap between the π and π* molecular orbitals of the free ligand, which is related to the extent of π conjugation17 (see Figure 7, Figure 8, and Figure 9).…”

“…In addition, investigation on coordination compounds derived from tetrazole‐carboxylate ligands receives increasing attention since these bifunctional ligands with abundant nitrogen and oxygen atoms can display various coordination modes and are very likely to form diverse structures, thus leading us to this interesting and challenging field 14–16. However, researches concerning coordination compounds based on isomeric tetrazole‐carboxylate ligands are limited 17–19…”

Two copper(II) compounds derived from tetrazole carboxylates for chemodynamic therapy against hepatocellular carcinoma cells

“…Tetrazole carboxylates are bi-functional ligands with either flexible carboxylate groups or rigid tetrazole rings that have great potential for constructing a variety of coordination architectures. These ligands with abundant nitrogen and oxygen atoms have a high possibility to show diverse coordination modes, and the CH 2 is capable of favoring the carboxylate with flexible orientations, contributing to the formation of novel crystal structures ( Zou et al, 2014b ; Zou et al, 2014c ; Zou et al, 2014d ; Zou et al, 2015b ; Dai et al, 2021 ). In the previous study, tetrazole-based ligands have been universally employed as multi-building blocks for the construction of novel coordination architectures and in the fields of luminescence ( Zou et al, 2014b ; Zou et al, 2014c ; Zou et al, 2014d ; Yang et al, 2014 ; Zou et al, 2015b ; Sun et al, 2016 ; Zhang et al, 2016 ; Dai et al, 2021 ), catalysis ( Zou et al, 2015a ), and adsorption ( Wriedt et al, 2012 ).…”

pH Dependent Synthesis of NdIII Coordination Compounds Based on Bifunctional 5‐(4‐Pyridyl)tetrazole‐2‐acetic Acid

“…The selection of ligand is also one of the key factors for the final structures of the targeted coordination compounds. Tetrazole‐carboxylate ligands with both flexible carboxylate group and rigid tetrazolyl ring have been widely investigated, for instance, 5‐aminotetrazole‐1‐acetic acid, 5‐(2‐pyridyl) tetrazole‐2‐acetic acid, 5‐(3‐pyridyl) tetrazole‐2‐acetic acid, etc., have been employed in the construction of the coordination compounds.…”