Spectral, structural and DFT studies of platinum group metal 3,6-bis(2-pyridyl)-4-phenylpyridazine complexes and their ligand bonding modes

Prasad, Kota Thirumala; Gupta, Gajendra; Chandra, Asit K.; Pavan, M. Phani; Rao, Kollipara Mohan

doi:10.1016/j.jorganchem.2009.12.004

Cited by 18 publications

(1 citation statement)

References 73 publications

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“…Ruthenium half-sandwich complexes coordinated to N-donor ligands, such as 2,2′-bipyridine (bipy), have found uses as precatalysts for several transformations, including hydride transfer reactions or electrocatalysts for CO 2 reduction. , The substituents on the noninnocent N-donor ligand can be used to tune the reduction potential because they change the energy of the ligand’s lowest unoccupied molecular orbital (LUMO). − The heterocyclic 3-(pyrid-2-yl)-1,2,4,5-tetrazine (TzPy) ligand, isoelectronic to bipy, , can be modified after coordination by the addition of different dienophiles (Scheme ). , …”

Section: Introductionmentioning

confidence: 99%

[(η⁶-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]⁺, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

2021

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The bidentate ligand 3-(pyrid-2-yl)-1,2,4,5-tetrazine (TzPy) coordinated in the complex [CyRuCl(TzPy)]PF6 ([1]+; Cy = η6-p-cymene) shows noninnocent behavior and can be modified through the addition of dienophiles, vinylferrocene (ViFc) or ethynylferrocene (EthFc). The kinetics and transition-state thermodynamic analysis of the reaction of [1]+ + ViFc found ΔG ⧧(298 K) = 67 kJ mol–1, while that of [1]+ + EthFc was ΔG ⧧(298 K) = 83 kJ mol–1. The room temperature second-order rate of [1]+ + EthFc, k 2 = 1.51(4) × 10–2 M–1 s–1, was 3 orders of magnitude faster than that of EthFc + TzPy, k 2 = 1.05(15) × 10–4 M–1 s–1. The [1H2Fc]+ complex was converted to [1Fc]+ by oxidation with oxygen and 3,5-di-tert-butyl-o-quinone, and the molecular structure of [1Fc]+ was determined by single-crystal X-ray diffraction. The title complex [1]+ showed a quasi-reversible reduction in the cyclic voltammogram, and the electrochemical reduction mechanism was determined by UV–vis spectroelectrochemistry (SEC) experiments, as well as supported by density functional theory (DFT) calculations. The dihydropyridazine [1H2Fc]+ and pyridazine [1Fc]+ states of the ligand showed ligand noninnocence similar to that of the parent tetrazine but at a cathodically shifted potential. The dihydropyridazine [1H2Fc]+ showed a mixture of several products; however, upon oxidation, only a single product, [1Fc]+, was formed from the endo addition of the dienophile to [1]+. The electrochemical mechanism of [1Fc]+ was also studied by cyclic voltammetry and UV–vis SEC experiments, as well as supported by DFT calculations.

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Section: Introductionmentioning

confidence: 99%

[(η⁶-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]⁺, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

2021

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Half‐sandwich ruthenium, rhodium and iridium complexes featuring oxime ligands: Structural studies and preliminary investigation of in vitro and in vivo anti‐tumour activities

Palepu

Adhikari

et al. 2016

Applied Organom Chemis

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Half-sandwich ruthenium, rhodium and iridium complexes (1-12) were synthesized with aldoxime (L1), ketoxime (L2) and amidoxime (L3) ligands. Ligands have the general formula [PyC(R)NOH], where R = H (L1), R = CH 3 (L2) and R = NH 2 (L3). Reaction of [{(arene)MCl 2 } 2 ] (arene = p-cymene, benzene, Cp*; M = Ru, Rh, Ir) with ligands L1-L3 in 1:2 metal precursor-to-ligand ratio yielded complexes such as [{(arene)MLκ 2 (N∩N) Cl}]PF 6 . All the ligands act as bidentate chelating nitrogen donors in κ 2 (N∩N) fashion while forming complexes. In vitro anti-tumour activity of complexes 2 and 10 against HT-29 (human colorectal cancer), BE (human colorectal cancer) and MIA PaCa-2 (human pancreatic cancer) cell lines and non-cancer cell line ARPE-19 (human retinal epithelial cells) revealed a comparable activity although complex 2 demonstrated greater selectivity for MIA PaCa-2 cells than cisplatin. Further studies demonstrated that complexes 3, 6, 9 and 12 induced significant apoptosis in Dalton's ascites lymphoma (DL) cells. In vivo anti-tumour activity of complex 2 on DL-bearing mice revealed a statistically significant antitumour activity (P = 0.0052). Complexes 1-12 exhibit HOMO-LUMO energy gaps from 3.31 to 3.68 eV. Time-dependent density functional theory calculations explain the nature of electronic transitions and were in good agreement with experiments.

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Synthesis, Structural and Biological Studies of Some Half‐Sandwich d⁶‐Metal Complexes with Pyrimidine‐Based Ligands

et al. 2017

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The reaction of metal precursors {[Cp*MCl2]2 (M=Rh, Ir)} with 2‐aminopyrimidine (L1) gave binuclear complexes as [(Cp*MCl2)2(μ‐L1)], where L1 acted as a bridging ligand. While 2‐mercaptopyrimidine (L2) with [Cp*MCl2]2 {M=Rh(III), Ir(III)} formed mononuclear di substituted complexes as [Cp*M(L2)2], where L2 acted as a chelating as well as a monodentate ligand. The reaction of [CpRu(PPh3)2Cl] with 2‐mercaptopyrimidine (L2) led to the formation of mononuclear complex as general formula [CpRu(PPh3)(L2)] in presence of a base. 2‐Mercaptopyrimidine ligand resulted complexes with strained four‐membered metallacycle while 2‐aminopyrimidine yielded bridged complexes. HOMO‐LUMO energy gaps and UV‐Visible bands were additionally rationalised by the DFT studies. The binding ability of the complexes to the CT‐DNA was confirmed using UV‐Visible and fluorescence spectroscopy. In vitro antibacterial activity of the complexes was evaluated against human pathogenic bacteria. Cytotoxicity of the complexes was examined by the MTT assay over three cancerous and one non‐cancer cell lines viz., BE, HT‐29, MIA−Pa‐Ca2 and ARPE‐19.

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Spectral, structural and DFT studies of platinum group metal 3,6-bis(2-pyridyl)-4-phenylpyridazine complexes and their ligand bonding modes

Cited by 18 publications

References 73 publications

[(η⁶-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]⁺, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

[(η⁶-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]⁺, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

Half‐sandwich ruthenium, rhodium and iridium complexes featuring oxime ligands: Structural studies and preliminary investigation of in vitro and in vivo anti‐tumour activities

Synthesis, Structural and Biological Studies of Some Half‐Sandwich d⁶‐Metal Complexes with Pyrimidine‐Based Ligands

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Spectral, structural and DFT studies of platinum group metal 3,6-bis(2-pyridyl)-4-phenylpyridazine complexes and their ligand bonding modes

Cited by 18 publications

References 73 publications

[(η6-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]+, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

[(η6-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]+, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

Half‐sandwich ruthenium, rhodium and iridium complexes featuring oxime ligands: Structural studies and preliminary investigation of in vitro and in vivo anti‐tumour activities

Synthesis, Structural and Biological Studies of Some Half‐Sandwich d6‐Metal Complexes with Pyrimidine‐Based Ligands

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[(η⁶-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]⁺, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

[(η⁶-p-Cymene)[3-(pyrid-2-yl)-1,2,4,5-tetrazine]chlororuthenium(II)]⁺, Redox Noninnocence and Dienophile Addition to Coordinated Tetrazine

Synthesis, Structural and Biological Studies of Some Half‐Sandwich d⁶‐Metal Complexes with Pyrimidine‐Based Ligands