Silver(I)-pyridinyl Schiff base complexes: Synthesis, structural characterization and reactivity in ring-opening polymerisation of ε-caprolactone

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities

A series of fifteen silver (I) quinoline complexes Q1-Q15 have been synthesized and studied for their biological activities. Q1-Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1-L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1-Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3Q1, [Ag(L1)2]ClO4Q6, [Ag(L2)2]ClO4Q7, [Ag(L2)2]CF3SO3Q12 and [Ag(L4)2]CF3SO3Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes' moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.

Aryl variation and anion effect on CT-DNA binding and in vitro biological studies of pyridinyl Ag(I) complexes

Synthesis and spectroscopic characterization of five ligands ((E)-2-((pyridin-2-ylmethylene)amino)phenol L1, 2-(pyridin-2-yl)benzo[d]thiazole L2, (E)-N-(2-fluorophenyl)-1-(pyridin-2-yl)methanimine L3, (E)-1-(pyridin-2-yl)-N-(p-tolyl)methanimine L4 and (E)-1-(pyridin-2-yl)-N-(thiophen-2-ylmethyl)methanimine L5 along with fifteen silver(I) complexes of L1 - L5, with a general formula [AgL₂]⁺X^- (L = Schiff base and X = NO₃^-, ClO₄^- or CF₃SO₃^-) is reported. The structures of complexes [Ag(L4)₂]NO₃, [Ag(L5)₂]NO₃, [Ag(L3)₂]ClO₄, [Ag(L4)₂]ClO₄ and [Ag(L5)₂]CF₃SO₃ were determined unequivocally by single crystal X-ray diffraction analysis. Calf-thymus deoxyribonucleic acid (CT-DNA), bovine serum albumin (BSA) binding studies, antioxidant, and antibacterial studies were performed for all complexes. Complexes [Ag(L2)₂]NO₃, [Ag(L5)₂]NO₃, [Ag(L1)₂]ClO₄ and [Ag(L3)₂]ClO₄ whose ligands have an OH^- and F^- as substituents or with a thiophene or thiazole moiety showed better antibacterial activities with lower minimum inhibitory concentration (MIC) values compared to the standard ciprofloxacin, against most of the bacterial strains tested. Similarly, complexes [Ag(L1)₂]NO_3,[Ag(L2)₂]NO_3,[Ag(L3)₂]NO₃ and [Ag(L5)₂]NO₃ with the NO₃^- anion, [Ag(L1)₂]ClO₄ and [Ag(L2)₂]ClO₄ with ClO₄^- anion, and [Ag(L5)₂]CF₃SO₃ with CF₃SO₃^- anion showed higher activities for antioxidant studies. Complexes [Ag(L4)₂]ClO₄ and [Ag(L4)₂]CF₃SO₃ with the Methyl substituent and CF₃SO₃^- as the anion, displayed high antioxidant activities in FRAP (ferric reducing antioxidant power) than the standard ascorbic acid. Spectroscopic studies of all the complexes revealed their moderate to high interaction with calf thymus DNA via an intercalation mode. In addition, the relatively moderate interaction of most of the complexes with BSA was through a static quenching mechanism.

Crystal structure of dichlorido-bis((E)-2-((pyridin-4-ylmethylene)amino)phenol)zinc(II), C24H20Cl2N4O2Zn

C24H20Cl2N4O2Zn, triclinic, P1̄ (no. 2), a = 9.9265(6) Å, b = 15.368(1) Å, c = 16.636(1) Å, α = 102.760(1)°, β = 90.385(2)°, γ = 94.112(3)°, V = 2311.4(3) Å3, Z = 4, Rgt(F) = 0.0260, wRref(F2) = 0.0653, T = 100(2) K.

Advances in ligand-unsupported argentophilic interactions in crystal engineering: an emerging platform for supramolecular architectures

Ligand-unsupported argentophilic interactions are described, emphasizing reticular design and recent developments in advanced synthetic strategies, and highlighting diverse interactions that are useful for the construction of unmitigated networks.