Tetrazole Carboxylate Ligands Research Articles

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

Two Cu(II) compounds based on tetrazole-carboxylate ligands, [Cu(phtza)2(H2O)2]∙3H2O (1) and [Cu(atzipa)2]∙2H2O (2) (phtza = 2,2'-(5,5'-(1,3-phenylene)bis(2H-tetrazole-5,2-diyl))diacetate, atzipa = 3-(5-amino-1H-tetrazol-1-yl)isopropanoic anion), were designed and synthesized by hydrothermal reactions. The X-ray diffraction results show that the two compounds show two-dimensional (2D) layer structures. Nanoprecipitation with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG-2000) contributes to the formation of the nanoparticles (NPs) with excellent water dispersity. In vitro study indicates that the two NPs exert considerable cytotoxicity toward human hepatocellular carcinoma cells (HepG2 and Huh7) with low half-maximal inhibitory concentration (IC50). However, the cytotoxicity of such NPs is negligible in normal cells (HL-7702). The cytotoxicity of these NPs was also investigated by the flow cytometry and Calcein-AM/PI (live/dead) co-stained experiments. The results promise the great potential of these NPs for chemodynamic therapy against cancer cells.

Bifunctional tetrazole-carboxylate ligand based Zn(ii) complexes: synthesis and their excellent potential anticancer properties.

Transition metal coordination complexes have provided cancer treatment with new insights to overcome the limitations of current chemotherapeutic agents. Utilization of bifunctional tetrazole-carboxylate ligands with Zn(ii) obtained two self-assembled complexes [Zn(HL1)(bipy)3/2(H2O)]·CH3OH·4(H2O) (1) (H3L1 = 1,3,5-tri(2-carboxymethyltetrazol-5-yl) benzene) and [Zn(L2)2(H2O)2]2·2H2O (2) (HL2 = (5-pyridin-3-yl-tetrazol-2-yl)-acetic acid). The X-ray diffraction results showed that the two complexes displayed a two-dimensional (2D) layer structure and a one-dimensional (1D) layer structure. Nanocoprecipitation with DSPE-PEG-2000 resulted in the formation of complex nanoparticles (NPS) with excellent water dispersion. In vitro CCK-8 assay indicated the two NPs exert high cytotoxicity and sensitivity and a low half-maximum inhibitory concentration (IC50) towards HeLa than HepG2 cells. In addition, the cytotoxicity was also confirmed by live/dead co-stained experiments. The presented experimental results showed the 1 and 2 NPs were capable of inhibiting cell proliferation in vitro and may help design coordination complex-based anticancer candidates for cancer cells.

Two luminescent cadmium(II) coordination compounds based on tetrazole–carboxylates

Tetrazole–carboxylate ligands are excellent building blocks to construct novel coordination architectures. 5-Aminotetrazole-1-isopropionic acid (Hatzipa) and 3,3-di(1H-tetrazol-5-yl)pentanedioic acid (H4dtzpda) were prepared. And reactions of the two ligands with CdCl2·2.5H2O afforded [Cd(atzipa)2(H2O)(EtOH)] (1) and [Cd2(H2dtzpda)2(H2O)3]·3H2O (2), respectively. Compound 1 shows a two-dimensional layer structure, whereas compound 2 is a three-dimensional network composed of Cd2+ and octa-dentate H2dtzpda2− via the tetrazole-N and the carboxylate group in a μ1,1,3-COO mode. The luminescence properties of Hatzipa, H4dtzpda and the compounds were investigated at room temperature in the solid state.

Synthesis and anticancer property of three new Ca (II) compounds derived from tetrazole carboxylate ligands

Three new Ca (II) coordination polymers derived from different tetrazole-carboxylate ligands, namely [Ca(pztzma)2(H2O)2] (1), [Ca(pytza)2(H2O)2] (2), [Ca(tzpha)(4,4′-bipy)3/2(H2O)]·2H2O (3) have been prepared and characterized, where pztzma (pztzma = 2-(5-pyrazin-2-yl-tetrazol-2-yl)-propionic anion, pytza (pytza = 2-(5-pyridin-4-yl-tetrazol-2-yl)-propionic anion), tzpha (tzpha = {5-[3,5-Bis-(2-methoxycarbonylmethyl-2H-tetrazol-5-yl)-phenyl]-tetrazol-2-yl}-acetato). Nanoparticles (NPs) of the three compounds can be prepared by PEG-5000 (Polyethylene glycol-5000) co-precipitation method. And [Ca(tzpha)(4,4′-bipy)3/2(H2O)]·2H2O (3) NPs has a relatively low IC50 (half maximal inhibitory concentration) of 42 μg/mL (5.6 μM) on HeLa cells is superior to [Ca(pytza)2(H2O)2] (2) 40 μg/mL (7.8 μM) and [Ca(pztzma)2(H2O)2] (1) NPs of 33 μg/mL (6.4 μM). The migration of HeLa cells is inhibited by NPs of the three compounds. The results show that [Ca(pztzma)2 (H2O)2] (1), [Ca(pytza)2(H2O)2] (2) and [Ca(tzpha)(4,4′-bipy)3/2(H2O)]·2H2O (3) NPs can inhibit cell proliferation and migration in vitro.

Synthesis, crystal structure and thermal behavior of two Ba(II) compounds derived from tetrazole-carboxylate ligands

Here we report two Ba(II) coordination compounds, 2D [Ba(btzphda)(H2O)4] (1) and 3D [Ba2(pytzipa)4(H2O)3]·2H2O (2) derived from 1,3-bis(tetrazol-5-yl)benzene-N2,N2′-diacetic acid (H2btzphda) and 5-(4-pyridyl)tetrazole-2-isopropionic acid (Hpytzipa). Furthermore, differential scanning calorimetry (DSC) and thermogravimetric-differential thermogravimetric (TG-DTG) analyses were applied to evaluate the thermal decomposition behavior of such compounds. The relevant thermodynamic parameters (ΔH, ΔS, and ΔG) of the decomposition process of compounds 1 and 2 were calculated, as well.

Synthesis and anticancer property of Zn(II) compounds nanoparticles based on tetrazole carboxylate ligands

Two new coordination compounds, [Zn(pytzipa)2(H2O)4]·2H2O (1) and [Zn2(dtzpda)(H2O)5]·3H2O (2) have been synthesized by solvothermal reactions of Zn(NO3)2·6H2O with Hpytzipa or H4dtzpda, respectively (Hpytzipa = 5-(3-pyridyl)tetrazole-2-isoproponaic acid, H4dtzpda = 3,3-di(1H-tetrazol-5-yl)pentanedioic acid). The X-ray diffraction results reveal that compound 1 is a linear chain in which pytzipa acts as a bidentate ligand to bridge adjacent Zn2+ ions by the nitrogen atom of the pyridine ring and the oxygen atom of the carboxylate group. In compound 2, dtzpda4− acts as a hepta-dentate ligand to bridge adjacent Zn2+ ions by the nitrogen atoms of the tetrazole rings and the oxygen atoms of the carboxylate in a chelating mode. Furthermore, nanoparticles (NPs) of the two compounds were prepared by co-precipitation with PEG-5000(poly(ethyleneglycol-5000)). Both two NPs show considerable cytotoxicity towards HeLa cells but Hpytzipa and H4dtzpda are non-toxic in nature. The results show that coordination Zn(II) with Hpytzipa or H4dtzpda can improve the toxicity of the NPs significantly and the NPs of the compounds are potential candidates for treatment of cancer cells.

Synthesis and anticancer property of one Fe(II) compound based on 5-(3-pyridyl)tetrazole-2-acetic acid

Tetrazole-carboxylate ligands are universally considered as multi-functional candidates for the construction of coordination architectures. A 1-D [Fe(pytza)2(H2O)2]n·2nH2O (pytza = 5-(3-pyridyl)tetrazole-acetato) has been prepared. In vitro study on Hela cells show that Hpytza is naturally nontoxic while [Fe(pytza)2(H2O)2]n·2nH2O shows high toxicity with a half-maximal inhibitory concentration (IC50) of 6.3 × 10−5 M. In addition, the compound can effectively inhibit the migration of Hela cells.

Four new samarium(III) compounds based on different tetrazole–carboxylate ligands

Tetrazole–carboxylate ligands with both rigid tetrazole ring and flexible carboxylate group have a great potential in the construction of coordination architectures. Here, we report four new samarium(III) compounds based on four tetrazole–carboxylate ligands 5-(2-pyrimidyl)tetrazole-2-acetic acid (Hpmtza), 5-aminotetrazole-1-propanoic acid (Hatzpa), 5-(4-pyridyl)tetrazole-2-acetic acid (Hpytza), and 3,3-di(1H-tetrazol-5-yl)pentanedioic acid (H4dtzpda), namely mononuclear [Sm(pmtza)2(H2O)6]Cl·3H2O (1), binuclear [Sm2(atzpa)4(H2O)8](NO3)2·2H2O (2), one-dimensional [Sm(pytza)3(H2O)2]·2H2O (3) and [Sm(Hdtzpda)(H2O)4]·4H2O (4). The effect of different counter anion (ClO4 −, Cl−, NO3 −) on the formation of such compounds was also investigated. Furthermore, the luminescence of compounds 1–4 shows intraligand emission, whereas the characteristic peaks of Sm3+ may be overlapped.

Coordination Architectures of energetic Cd (II) coordination polymers constructed by the bifunctional substituted-tetrazole-carboxylate ligands

Three different tetrazole-carboxylate ligands, monotetrazole-carboxylate H2tza (H2tza=1,5-tetrazole-diacetic acid), Hpztza (Hpztza=5-(2-pyrazinyl)tetrazole-2(1-methyl)acetic acid), ditetrazole-carboxylate H2tzpha (H2tzpha=1,3-di(tetrazole-5-yl)benzene-N2,N2′-diacetic acid) have been chosen to react with CdCl2·6H2O, resulting in the formation of three new compounds [Cd2(tza)2] (1), [Cd(pztza)2] (2) and [Cd(tzpha)(CH3OH)2] (3). The coordinate sites of the three ligands are major influenced by the different substituted group of tetrazole ring. These compounds have been characterized by elemental analysis, IR and single crystal X-ray diffraction. Compound 1 displays a complex 3D structure; compound 2 shows a 3D network and compound 3 features a 2D layer network. Furthermore, the luminescence properties investigated at room temperature in the solid state showed excellent ligand-centered luminescence. The obvious enhancement in luminescence makes these compounds potential materials for optical use. The differential scanning calorimetry (DSC) and thermogravimetric-differential thermogravimetric (TG-DTG) analyses were applied to evaluate the thermal decomposition behavior of such compounds, showing that compounds 2 and 3 can be used as potential energetic materials. The relevant thermodynamic parameters ΔH, ΔS and ΔG were calculated as well.

Two SrII coordination compounds based on tetrazole-carboxylate ligands

Abstract Two novel coordination compounds, [Sr(atzp)2(H2O)2]·CH3OH (1) and [Sr(dtzpha)(H2O)3]·4H2O (2) [Hatzp=5-aminotetrazole-1-propionic acid, H2dtzpha=1,3-di(tetrazol-5-yl)benzene-N2,N2′-diacetic acid)], have been generated by using 5-aminotetrazole-1-propionic acid and 1,3-di(tetrazol-5-yl)benzene-N2,N2′-diacetic acid to react with strontium salts, respectively. X-ray diffraction analysis reveals that carboxylic groups of two ligands show the same coordination mode (the μ 1,1,3-COO coordination mode), compound 1 displays a 1D structure while compound 2 shows a 2D structure, which implies the influence of the number of the carboxylic acid groups. Luminescence properties of 1 and 2 were investigated at room temperature in the solid state.

Substituted group-directed magnesium(II) coordination compounds based on the derivatives of tetrazole-2-acetic acid

The different substituted group will have a substantial effect on the crystal structures of the resulting compounds. Tetrazole–carboxylate ligands are outstanding blocks for construction of novel coordination architectures. Three derivative ligands of tetrazole-2-acetic acid, H3-pytza, H4-pytza and H3tzpha, where H3-pytza = 5-(3-pyridyl)tetrazole-2-acetic acid, H4-pytza = 5-(4-pyridyl)tetrazole-2-acetic acid and H3tzpha = 1,3,5-tris(tetrazol-5-yl)benzene-N2,N2′,N2″-triacetic acid, have been chosen to be reacted with Mg(NO3)2·6H2O, resulting in the formation of three new compounds, [Mg(H2O)6](3-pytza)2·2H2O (1), [Mg(4-pytza)2(H2O)4] (2) and [Mg3(tzpha)2(H2O)12]·10H2O (3). These compounds were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The X-ray diffraction reveals that compounds 1 and 2 are mononuclear structures, while compound 3 shows a one-dimensional chain. The structures of these compounds are controlled by not only the different 5-substituted group of the tetrazole-2-acetic acid, but also the complementary hydrogen bonds. Furthermore, the luminescence studies show that compounds 1–3 show stronger emission than the corresponding ligands. Three Mg(II) coordination compounds 5-substituted group derivative of tetrazole-2-acetic acid (H3-pytza, H4-pytza and H3tzpha) show different luminescence properties.

Isomer dependent assembly of Ce(III) and Gd(III) coordination polymers containing 5-(n-pyridyl)tetrazole-2-acetato (n = 3,4)

Isomer plays a vital role in the self assembly process of the coordination compounds. Tetrazole-carboxylate ligands with rich nitrogen and oxygen atoms are excellent candidates for the construction of novel coordination architectures. 5-(n-pyridyl)tetrazole-2-acetato potassium salt (denoted as Kn-pytza, n=3,4) was selected to be reacted with LnCl3·6H2O (Ln=Ce, Gd), resulting in the formation of [Ln(3-pytza)2Cl(H2O)2]n [Ln=Ce(1), Gd(2)] and [Ln(4-pytza)3(H2O)2]n·2nH2O [Ln=Ce(3), Gd(4)], respectively. The X-ray diffraction analysis reveals that compounds 1 and 2 are similar with one dimensional zigzag chains while compounds 3 and 4 are isomorphic with one dimensional ladder-like chains consisting of Ln2O6 (Ln=Ce, Gd) secondary building units (SBU) and the bridging 4-pytza, which can be attributed to the different coordination modes adopted by the isomeric ligands. In addition, the photoluminescence properties of the ligands and compounds 1–4 in the solid state were investigated at room temperature.

Counter anion and pH directed assembly of europium(III) compounds based on tetrazole containing carboxylic acids

Counter anion and pH play important roles in the self-assembly process of coordination compounds. Tetrazole carboxylate ligands are outstanding candidates for construction of coordination architectures. Four new compounds based on Htzpya, Hatzpa, Hpytza and europium(III) salts, namely mononuclear [Eu(tzpya)2(H2O)5]Cl·4H2O (1), binuclear [Eu2(atzpa)4(H2O)8](NO3)2·2H2O (2), one dimensional [Eu(pytza)3(H2O)2]n·2nH2O (3) and [Eu(pytza)2(H2O)4]nCln (4) were obtained, where Htzpya=3-(5-tetrazolyl)pyridine-1-acetic acid, Hatzpa=5-aminotetrazole-1-propanoic acid and Hpytza=5-(4-pyridyl) tetrazole-2-acetic acid. Different europium(III) salts EuX3·6H2O (X=Cl−, NO3−) and pH values were selected to investigate the influence of both the counter anions and the pH on the formation of such compounds. Furthermore, the luminescence properties of 1–4 in the solid state were also investigated at room temperature, showing both intraligand emission and characteristic peaks of Eu3+ for compounds 1–4.

Coordination Architectures of Lanthanum Complexes Based on Bifunctional 5‐Substituted Tetrazolecarboxylate Ligands

AbstractThree complexes of bifunctional 5‐substituted tetrazolatecarboxylate ligands [2‐(5‐(pyrazin‐2‐yl)‐2H‐tetrazol‐2‐yl)acetic acid (Hpztza), 3‐(5‐amino‐2H‐tetrazol‐1(5H)‐yl)propanoic acid (Hatzp), and N,N′‐bis(tetrazol‐5‐yl)anime‐N2,N2′‐diacetic acid (H2datza)], namely a mononuclear structure [La(pztza)2(H2O)5]·4H2O·pztza (1), a 1D polymeric chain structure [La2(atzp)4(H2O)8]·2NO3·2H2O (2), and a 2D layer network [La(datza)(H2O)3]·4H2O (3) were prepared and structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. The structures of these complexes are controlled not only by the number and different coordination modes of the tetrazole‐carboxylate ligands but also the different 5‐substituents of the tetrazole ring. The complexes show ligand‐centered luminescence at room temperature in the solid state. The obvious enhancements in luminescence make these complexes to be the potential materials for optical use.

Three new manganese(II) coordination complexes based on tetrazole carboxylate ligands

Reactions of three tetrazole carboxylate ligands, namely 5-(4-pyridyl)tetrazole-2-acetic acid (Hpytza), 1,3,5-tris(tetrazol-5-yl)benzene-N2,N2′,N2″-triacetic acid (H3tzpha) and 5-aminotetrazole-1-propanoic acid (Hatzpa) with Mn(NO3)2·6H2O in the presence of KOH afforded three new complexes, [Mn(pytza)2] (1), [Mn3(tzpha)2(H2O)12]·2CH3OH·10H2O (2) and [Mn(atzpa)2(H2O)2] (3), respectively. These complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 displays a three-dimensional network while 2 and 3 show one-dimensional chains. Furthermore, the luminescence properties of these complexes were investigated at room temperature in the solid state.

Coordination architectures of copper(II) coordination polymers constructed from bifunctional 5-substituted-tetrazole-carboxylate ligands

Three complexes of the bifunctional 5-substituted-tetrazolate-carboxylate ligands 3-(5-amino-2H-tetrazol-1(5H)-yl) propanoic acid (Hatzp), 5-(2-pyrimidyl)tetrazole-1-acetic acid (Hpymtza) and 1H-tetrazolate-5-acetic acid (Htza), namely mononuclear [Cu(atzp)2(H2O)4]·2H2O (1), a 1D polymeric chain structure [Cu(pymtza)2]·2H2O (2) and a 2D layer network [Cu(tza)2]·2DMF (3), were prepared and structurally characterized. The structures of these complexes are controlled by not only the different coordination modes of the tetrazole-carboxylate ligands but also the different 5-substituents of the tetrazole ring. Three different coordination modes of the tetrazolate-carboxylate ligands were observed: a tridentate N4-monodentate mode in complex 1, a tridentate N,N-chelated-O-bridged mode in complex 2 and a N,O-chelated-N-bridged mode in complex 3. Extensive hydrogen bonds play an important role in the construction of the supramolecular networks. The complexes show ligand-centered luminescence at room temperature in the solid state.

Substituted group directed assembly of zinc coordination compounds based on bifunctional ligands, from mono, di to tristetrazole–carboxylate

Four new tetrazole–carboxylate ligands have been reacted with zinc salts, resulting in the formation of four compounds with enhanced luminescence properties and structures that are controlled by the number, different coordination modes and substitution of the ligands.