Hydrazone based spin crossover complexes: Behind the extra flexibility of the hydrazone moiety to switch the spin state

Soliman

et al. 2022

Applied Organom Chemis

The antimicrobial, anticancer, and antioxidant activities of four cobalt (III) complexes, [CoL2]X (X = ClO4¯ (1); OAc¯ (2), Cl¯ (3), or NO3¯ (4) with hydralazine Schiff base derivative (HL), were presented. The structure of the newly synthesized complexes 1 and 2 was confirmed utilizing FTIR, UV‐Vis, and NMR (1H and 13C) spectroscopy. In addition, single crystal X‐ray diffraction was used to approve the structure of complex 1. Based on Hirshfeld analysis, the molecular packing of 1 is controlled by short HH, OH, NH, and HC(π) interactions. The results of the X‐ray photoelectron spectroscopy (XPS) for the Co (III) complexes revealed the characteristic peaks of Co2p3/2 and Co2p1/2 with binding energy differences of 14.85–14.96 which greatly approved that the Co (III) complexes have been assembled successfully. Complex 4 (IC50 = 14.97 ± 0.59 μg/ml) has the highest cytotoxicity against lung carcinoma A‐549 cell line compared to the rest of the Co (III) complexes and the free ligand as well. Also, complex 4 has the best antioxidant activity with IC50 of 283.4 ± 12.3 μg/ml. The free ligand has broad spectrum of antibacterial and antifungal actions, while the studied Co (III) complexes have good antibacterial activity especially the chloride complex 3.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, structure, X‐ray photoelectron spectroscopy (XPS), and antimicrobial, anticancer, and antioxidant activities of Co (III) complexes based on the antihypertensive hydralazine

Soliman

et al. 2022

Applied Organom Chemis

“…Although solely light-driven bidirectional switching has not been achieved yet, separation of the absorptions in E and Z isomers is a bright direction worth exploring. The easy, scalable, and modular syntheses of acylhydrazone ligands − hold promising prospects toward this end. Future studies are ongoing in our laboratory.…”

Section: Discussionmentioning

confidence: 99%

Thermodriven, Acidity-Driven, and Photodriven Spin-State Switching in Pyridylacylhydrazoneiron(II) Complexes at or above Room Temperature

Shen

Zhang

et al. 2021

Inorg. Chem.

The magnetic bistability of spin-crossover (SCO) materials is highly appealing for applications as molecular switches and information storage. However, switching of the spin state around room temperature remains challenging. In this work, we reported the successful manipulation of the spin states of two iron(II) complexes (1-Fe and 2-Fe) based on pyridylacylhydrazone ligands in manifold ways. Both complexes are stabilized in the lowspin (LS) state at room temperature because of the strong ligandfield strength imposed by the ligands. 2-Fe shows thermoinduced SCO above room temperature with a very large and reproducible hysteresis (>50 K), while 1-Fe remains in the LS state up to 400 K. Acidity-driven spin-state switching of the two complexes was achieved at room temperature as a result of the complex dissociation and release of iron(II) in its high-spin (HS) state. Recovery of the complex is feasible upon further alkalization treatment in the case of 1-Fe, allowing bidirectional modulation of the spin state of the metal center. Light-driven one-way switching from LS to HS is also achieved by virtue of E-to-Z isomerization at the CN double bond, which results in dissociation of the complex because of the poor binding affinity in the Z configuration.

“…These tautomeric forms offer these molecules the possibility of coordinating in the neutral mode [12], in monoanionic mode [13], or dianionic mode [10,14]. These complexes often exhibit important properties for industries such as magnetism [15], luminescence [16], catalysis [17], and optics [18]. These metal transition coordination compounds obtained with hydrazone ligands are also studied because of their broad profile in the pharmacological field, with antitumor [19], antimicrobial [20,21] and anti-tuberculosis [22] potential.…”

Section: Introductionmentioning

confidence: 99%

Crystal structures of bis-{N-[1-(pyridin-2-yl-κN)ethylidene]nicotine hydrazide-κ2N’,O}cobalt(II)bis(perchlorate) dihydrate and bis-{N'-[1-(pyridin-2-yl-κN)ethylidene]nicotinohydrazide-κ2N',O}copper(II) perchlorate

et al. 2021

Complexes of Co(II), [Co(C26H24N8O2)]·(ClO4)2·(H2O)2 (1), and Cu(II), [Cu(C26H23N8O2)]·(ClO4) (2), have been synthesized. The prepared two compounds were characterized by elemental analysis, infrared and their structures were determined by single-crystal X-ray diffraction. The compound 1 crystallizes in the triclinic space group P-1 with the following unit cell parameters: a = 8.880 (5) Å, b = 10.529 (5) Å, c = 18.430 (5) Å, α = 99.407 (5)°, β = 102.174 (5)°, γ = 100.652 (5)°, V = 1618.2 (13) Å3, Z = 2, T = 293(2), μ(MoKα) = 0.77 mm-1, Dcalc = 1.582 g/cm3, 16135 reflections measured (5.050° ≤ 2q ≤ 59.152°), 7648 unique, Rint = 0.034 which were used in all calculations. The final R1 was 0.066 (I ≥ 2σ(I)) and wR2 was 0.22 (all data). The compound 2 crystallizes in the monoclinic space group P21/c with the following unit cell parameters : a = 11.652 (5) Å, b = 16.540 (5) Å, c = 14.512 (5) Å, β = 93.495 (5)°, V = 2791.6 (18) Å3, Z = 4, T = 293(2), μ(MoKα) = 1.05 mm-1, Dcalc = 1.768 g/cm3, 15592 reflections measured (5.624° ≤ 2θ ≤ 58.804°), 6630 unique, Rint = 0.025 which were used in all calculations. The final R1 was 0.050 (I ≥ 2σ(I)) and wR2 was 0.144 (all data). In both complexes, the ligand acts in a tridentate fashion. In the structure of the mononuclear complex 1, the Co(II) cation is coordinated by two ligand molecules. The basal plane around the Co(II) cation is occupied by two pyridine nitrogen atoms and two carbonyl oxygen atoms. Two imino nitrogen atoms occupy the apical positions of the distorted square-pyramidal geometry. The mononuclear 2 consists of a Cu(II) coordinated by one ligand and one monodeprotonated ligand molecule. The metal center lies in a distorted square bipyramidal environment. The basal plane around the Cu(II) is occupied by two pyridine nitrogen atoms and two carbonyl oxygen atoms, the apical position being occupied by the two imino nitrogen atoms.