Saira Nayab

In this study, 2‐(piperidin‐1‐ylmethyl)quinoline (L_A) and 1‐(naphthalen‐2‐ylmethyl)piperidine (L_B) ligands were utilized alongside palladium(II) acetate [Pd(OAc)₂] and N,N‐Dimethylanilinium tetrakis (pentafluorophenyl)borate as a cocatalyst for the in situ addition polymerization of norbornene (NB). The ligand L_B system demonstrated superior catalytic performance compared with that of the ligand L_A system, achieving 99% versus 94% conversion for NB to polynorbornene (PNB) at 25°C in chlorobenzene. To validate the catalytic activities of these in situ catalytic systems, Pd (II) complexes, [L_APd(OAc)₂] and [L_BPd(μ‐OAc)]₂, were synthesized and characterized. X‐ray structure analysis revealed that [L_APd(OAc)₂] adopted a square planar geometry, whereas [L_BPd(μ‐OAc)]₂ exhibited a distinctive clamshell structure. These complexes were also employed for the vinyl addition polymerization of NB under the same conditions as in situ catalytic systems. The active real Pd(II) complexes demonstrated slightly lower conversions compared with those of the in situ catalytic systems, achieving over 90% conversions for both [L_APd(OAc)₂] and [L_BPd(μ‐OAc)]₂. Furthermore, both catalytic systems were subsequently used for the (co)polymerization of NB and its derivatives, such as 5‐butylbicyclo[2.2.1]hept‐2‐ene (Bu‐NB), methyl bicyclo[2.2.1]hept‐5‐ene‐2‐carboxylate (Me‐NB), and bicyclo[2.2.1]hept‐5‐en‐2‐ylmethyl acetate (AAc‐NB), yielding relatively lower conversions.

Herein, Cu(II), Zn(II), and Cd(II) complexes with furan‐derived Schiff base ligand, (E)‐N¹,N¹‐diethyl‐N²‐(furan‐2‐ylmethylene)ethane‐1,2‐diamine(DEF), were synthesized. The synthesized ligand and M(II) (M = Cu, Zn, and Cd) complexes were characterized to confirm their purity and successful synthesis using ¹H NMR, ¹³C NMR, and FTIR spectroscopy. Thermal analysis demonstrated their stability, whereas UV‐Vis spectroscopy and molar conductance studies provided insights into their electronic properties and coordination behavior. Additionally, X‐ray diffraction studies indicated that the Zn(II) and Cd(II) complexes have distorted tetrahedral geometries, whereas the Cu(II) complex adopted distorted square planar geometry. The studied complexes showed remarkable free‐radical scavenging activity. Furthermore, they exhibited good inhibitory activity against urease and α‐amylose. In particular, [Cu(DEF)Cl₂] showed the best antioxidant activity, with an IC₅₀ of 3.21 ± 0.19 μM, and the highest α‐amylose inhibitory activities, with an IC₅₀ of 6.11 ± 0.33 μM. Moreover, [Cd(DEF)Br₂] proved to be more potent against Jack bean and Bacillus pasteurii ureases, with IC₅₀ values of 3.90 ± 0.11 μM and 6.01 ± 0.10 μM, respectively. Molecular docking studies showed a good correlation between the biological activities of the synthesized [M(DEF)X₂] complexes. Thus, the proposed compounds can serve as promising candidates for the treatment of infectious diseases.

A thiophene-derived Schiff base ligand (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine was used for the synthesis of M(II) complexes, [TEM(M)X₂] (M = Co, Cu, Zn; X = Cl; M = Cd, X = Br). Structural characterization of the synthesized complexes revealed distorted tetrahedral geometry around the M(II) center. In vitro investigation of the synthesized ligand and its M(II) complexes showed considerable anti-urease and leishmanicidal potential. The synthesized complexes also exhibited a significant inhibitory effect on urease, with IC₅₀ values in the range of 3.50–8.05 μM. In addition, the docking results were consistent with the experimental results. A preliminary study of human colorectal cancer (HCT), hepatic cancer (HepG2), and breast cancer (MCF-7) cell lines showed marked anticancer activities of these complexes.

Cobalt(II) and copper(II) complexes supported by 4‐(quinolin‐2‐ylmethyl)morpholine (L) were characterized, and their reactivity toward the ring‐opening polymerization (ROP) of rac‐lactide (rac‐LA) was studied. The use of [LMCl₂]/LiOⁱPr and [LMCl₂]/LiMe (M = Co, Cu) resulted in over 95% conversion within 10 min at 25 °C. The effect of the initiating group and geometry of the metal complexes steered the heterotactic enchainment of the resultant polylactide(PLA). The Co(II)/LiMe system represents the first example of the ROP of rac‐LA with high heterotactic enchainment (P_r = 0.92) with 98% conversion at 0 °C.

Herein, Cu (II), Zn (II), and Cd (II) complexes, [DEP(M)X₂], encompassing the pyridine‐derived Schiff‐base ligand DEP, where DEP is (E)‐N,N‐diethyl‐2‐([pyridine‐2‐ylmethylene]amino)ethane‐1‐amine, are synthesized. X‐ray diffraction studies reveal distorted square pyramidal geometries for the Cd (II) and Cu (II) complexes, whereas the geometry of [DEP (Zn)Cl₂] can best be described as trigonal bipyramidal. The antibacterial potential of DEP and its [DEP(M)X₂] complexes were evaluated against four bacterial strains: Salmonella typhi, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa; five fungal strains: Candida glabrata, Candida albicans, Microsporum canis, Fusarium solani, and Aspergillus flavus; and Leishmania major protozoan. Complexes exhibited superior bactericidal, fungicidal, and leishmanicidal inhibition potential against all tested microbes compared with the free ligand. The preliminary cytotoxic activity of [DEP(M)X₂] complexes on breast and colon carcinoma cells, that is, MCF‐7cell line and HCT‐116 cell line, respectively, revealed that studied complexes showed high cytotoxicity compared with ligand (DEP). Among the studied complexes, [DEP (Cd)Br₂] exhibited an excellent inhibitory profile, as confirmed by the docking study. The molecular docking studies showed a good correlation between the biological activities of synthesized metal complexes and docking studies. We have confidence in the contribution of these complexes toward the design of new metal‐derived candidates that can treat infectious diseases.

Dihydropyrazole (1-22) derivatives were synthesized from already synthesized chalcones. The structures of all of the synthesized compounds were confirmed by elemental analysis and various spectroscopic techniques. Furthermore, the synthesized compounds were screened against α amylase as well as investigated for antioxidant activities. The synthesized compounds demonstrate good to excellent antioxidant activities with IC₅₀ values ranging between 30.03 and 913.58 μM. Among the 22 evaluated compounds, 11 compounds exhibit excellent activity relative to the standard ascorbic acid IC₅₀ = 287.30 μM. Interestingly, all of the evaluated compounds show good to excellent α amylase activity with IC₅₀ values lying in the range between 0.5509 and 810.73 μM as compared to the standard acarbose IC₅₀ = 73.12 μM. Among the investigated compounds, five compounds demonstrate better activity compared to the standard. In order to investigate the binding interactions of the evaluated compounds with amylase protein, molecular docking studies were conducted, which show an excellent docking score as compared to the standard. Furthermore, the physiochemical properties, drug likeness, and ADMET were investigated, and it was found that none of the compounds violate Lipiniski's rule of five, which shows that this class of compounds has enough potential to be used as a drug candidate in the near future.