Copper (II) complexes of 3,5‐di‐tert‐butyl‐2‐hydroxybenzoylhydrazones of 2‐formylpyridine and 2‐acetylpyridine, with tautomeric azine‐scaffold‐based architecture: Synthesis, crystal structures, the effect of counteranions on complexation, and their anti‐microbial and anti‐tuberculosis evaluation

Abstract

A series of air‐ and moisture‐stable copper (II) complexes of 3,5‐di‐tert‐butyl‐2‐hydroxy‐N′‐(pyridin‐2‐ylmethylene)benzohydrazide (L1H) and 3,5‐di‐tert‐butyl‐2‐hydroxy‐N′‐(1‐(pyridin‐2‐yl)ethylidene)benzohydrazide (L2H) were synthesized. The two newly designed hydrazone Schiff base ligands with the tautomeric azine‐scaffold involving N, N and O ligating architecture were derived from the condensation of 3,5‐di‐tert‐butyl‐2‐hydroxybenzoylhydrazide with 2‐formylpyridine and 2‐acetylpyridine, respectively. The resultant ligands and their copper complexes were characterized using various spectro‐analytical techniques, like infrared (IR), 1H‐NMR, 13C‐NMR, electron paramagnetic resonance, electronic spectroscopy, thermogravimetric analysis and conductance measurements. The interesting inter‐convertible E/Z geometrical isomeric forms of the ligand L1H was established by NMR and IR spectra. In addition, the molecular structures of L2H, C3 and C4 were unambiguously established using the single‐crystal X‐ray diffraction technique. The dichlorido‐bridged dinuclear square pyramidal complexes, with the [Cu2(μ‐Cl)2L2] type of core units, were resulted for the complexes C1 and C3, whereas z‐in compressed mononuclear 1:2 (M:L) octahedral complex geometries resulted for C2, C4 and the rest of the complexes even when various copper (II) precursor salts with different counteranions were used. The ligands and their complexes were investigated for the anti‐microbial activities against gram‐positive and gram‐negative bacteria. The ligand L2H and its complexes C3 and C4 exhibited better anti‐tuberculosis activity than the controls.

Inspecting the anti‐tuberculosis, antimicrobial, and anti‐inflammatory efficiency of newly synthesized Co (II), Ni (II), Cu (II) and Zn (II) complexes of hydrazone ligands: Characterization and computational studies

“…The compounds were dissolved in DMSO to obtain the 200-12.5 μg/mL concentration solutions with diluted phosphate buffer (0.2 M, pH 7.4). Then, the attained solutions S C H E M E 1 Synthesis of (HL 1 HL 2 ) hydrazone ligands (1-2) and their transition metal complexes (3)(4)(5)(6)(7)(8)(9)(10).…”

“…2 Therefore, the medicinal industries require a compound with good therapeutic index, low toxicity, and significant pharmacological properties for treatment of multidrug-resistant TB and extremely drug-resistant TB. 3 With the TB infection, patients also face many microbial and inflammation ailments as realized by health care, which subject the patients in very terrible conditions. 4 Thus, by analyzing the current situation, we have examined the antiinfectious potency of the newly synthesized transition metal complexes and their associated hydrazone ligands to ascertain a therapeutic drug for curing the TB, microbial, and inflammation ailments.…”

Ligational behavior of a new bis (bidentate NO) donor hydrazone towards Co (II), Ni (II), and Cu (II) ions: Preparation, spectral, thermal, biological, docking, and theoretical studies

“…[1] Upon complexation, hydrazones has the ability to give mononuclear, binuclear, trinuclear, and tetranuclear chelates according to some conditions concerning (a) characters of the hydrazone ligand and metal ion, (b) pH of the reaction medium and hydrazone to metal ratio, and (c) existence of additional donor atoms (normally oxygen, nitrogen, or sulfur) in a suitable location for chelation. [2] Hydrazones and their metal complexes own significant biological applications such as antibacterial and antifungal, [3][4][5][6] antiviral, [7] antioxidant, [8] antimalarial, [9] analgesic, antiinflammatory, antiplatelet, [10] antitubercular, [11] antitumor, [12][13][14][15][16][17][18][19] and other applications. [20][21][22][23][24][25][26][27][28][29][30][31] The ligational behavior of polydentate chelating agents, particularly those with dissimilar donor atoms, is of a great and increased attention.…”

A Set of phenyl sulfonate metal coordination complexes triggered Biginelli reaction for the high efficient synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions

“…[49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] The unique combinations of organic/inorganic building blocks make these materials generate diverse functions. [64][65][66][67] MCCs-based applications have gained extensively impacts in materials science and catalysis areas, which are involved in the fields of organic chemistry, physical chemistry, and environment science. [68][69][70][71][72][73][74] Indeed, Yaghi has recently explored a kind of cobaltbased porphyrin catalyst for reduction of CO 2 to CO under electronchemical conditions.…”