Chlorination of Platinum-Bound Salicylaldoxime. The First Example of a Structurally Characterized Monodentate Salicylaldoxime-Type Ligand

Kaplan, Savelii F.; Kukushkin, Vadim Yu.; Shova, Sergiu; Suwińska, Kinga; Wagner, Gabriele; Pombeiro, Armando J. L.

doi:10.1002/1099-0682(200104)2001:4<1031::aid-ejic1031>3.0.co;2-d

Cited by 17 publications

(4 citation statements)

References 34 publications

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“…The platinum satellites for the imine resonances (JHPt ~ 62 Hz) are consistent with other (salicylaldiminato)platinum complexes [18][19][20][21][22][23][24][25][26]. The FT-IR spectra show the expected decrease in the frequency of the C=N bond due to complexation, which is observed as the νC=N stretch shifts from ca.1632 cm -1 for the free ligands to ca.…”

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confidence: 81%

Synthesis, characterization, and anticancer properties of organometallic Schiff base platinum complexes

et al. 2015

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A small family of organometallic platinum complexes containing a chloride, ciscyclooctene, and a Schiff base ligand have been prepared and characterized fully. Three aliphatic amines and four aromatic amines were chosen as representative examples. All complexes were stable in air except for 7, derived from the pinacol-protected 4-aminophenylboronate ester 4-H2NC6H4Bpin (pin = 1,2-O2C2Me4), which decomposed via B-C bond cleavage.Both complex 4 (derived from aniline) and 7 were further characterized by single crystal X-ray diffraction studies and confirmed the square planar nature of the platinum center whereby the chloride ligand lies trans to the deprotonated hydroxyl group of the Schiff base ligand. The imine functionality is trans to the organic cyclooctene group. Complex 3, which contained the longest aliphatic chain studied (an octyl group), was the most promising for inducing apoptosis in the malignant MB231 breast cancer cell line. Conversely, complexes 4-6, which contained aromatic groups, were the most active against Renal Cell Carcinoma (RCC) cell lines. Graphical Abstract: Seven new organometallic (salicylaldiminato)platinum(II) complexes have been prepared, and characterized fully, whereupon six of these new compounds were examined for their in vitro cytotoxic properties against breast cancer cell line MB231 and Renal Cell Carcinoma (RCC) cell lines.

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confidence: 81%

Synthesis, characterization, and anticancer properties of organometallic Schiff base platinum complexes

et al. 2015

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“…Despite its spatial proximity to the Cu centre, the bridging H atom does not show the largest isotropic paramagnetic shift; it does show, however, the largest anisotropy by far (Tables and ), indicating that the shielding and deshielding effects in the principal components cancel to a large extent in the isotropic shift. The ability to calculate accurately the shift anisotropy may prove useful in assigning the NMR spectra of other paramagnetic solids, for which resonances may have similar isotropic shifts but different anisotropies (e.g., H5 and H(br) in 1 have an isotropic shift difference of just δ =3 ppm, but a difference in Ω of over δ =200 ppm).…”

Section: Resultsmentioning

confidence: 92%

Paramagnetic NMR of Phenolic Oxime Copper Complexes: A Joint Experimental and Density Functional Study

Bühl

Ashbrook

Dawson

et al. 2016

Chemistry A European J

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H and C pNMR properties of bis(salicylaldoximato)copper(II) were studied in the solid state using magic-angle-spinning NMR spectroscopy and, for the isolated complex and selected oligomers, using density-functional theory at the PBE0-1/3 //PBE0-D3 level. Large paramagnetic shifts are observed, up to δ( H)=272 ppm and δ( C)=1006 ppm (at 298 K), which are rationalised through spin delocalisation from the metal onto the organic ligand and the resulting contact shifts arising from hyperfine coupling. The observed shift ranges are best reproduced computationally using exchange-correlation functionals with a high fraction of exact exchange (such as PBE0-1/3 ). Through a combination of experimental techniques and first-principles computation, a near-complete assignment of the observed signals is possible. Intermolecular effects on the pNMR shifts, modelled computationally in the dimers and trimers through effective decoupling between the local spins via A-tensor and total spin rescaling in the pNMR expression, are indicated to be small. Addition of electron-donating substituents and benzannelation of the organic ligand is predicted computationally to induce notable changes in the NMR signal pattern, which suggests that pNMR spectroscopy can be a sensitive probe for the spin distribution in paramagnetic phenolic oxime copper complexes.

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“…Such chlorination and hydroxylation of the phenol rings is most surprising and rare, considering that almost all halogenation reactions developed so far are performed under photochemical conditions or involve the combination of stoichiometric amounts of oxidative halogenation reagents like H 2 O 2 , hypervalent iodine, and trimethylsilyl, under various thermal conditions. 15,[21][22][23][24] To the best of our knowledge, only one example of a relatively mild homogeneous chlorination of a pyrazole-based ligand coordinated to copper(II) has been reported so far. 25 The catalytic chlorination of phenols in heterogenized systems has been reported in a few cases.…”

Section: Introductionmentioning

confidence: 99%

Controlled Copper-Mediated Chlorination of Phenol Rings under Mild Conditions

et al. 2007

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The very unusual case of copper-mediated chlorination of phenol rings under mild conditions at room temperature is reported. Reaction of the ligand 1,7-bis(2-hydroxyphenyl)-2,6-diaza-4-hydroxylheptane (H3L1) with CuCl2 in acetonitrile leads to either the formation of a tetranuclear copper(II) complex [Cu4(HL3)2(mu-Cl)2Cl2](CH3CN) (1) or a linear trinuclear complex [Cu3(HL1)2Cl2(CH3CN)2](CH3CN)2 (2), depending on the reaction conditions. Both compounds have been fully characterized, including the determination of their 3D structures by X-ray diffraction. The unprecedented tetranuclear compound 1 is constituted of a dichlorido-bridged dimer of di-mu-phenoxido-dinuclear species, whereas the trinuclear complex 2 presents a linear array of copper(II) ions, held together through di-mu-phenoxido bridges of the central and external ions. The magnetic susceptibility of the two compounds was investigated, revealing either very strong (J<-500 cm-1) or strong (J value around -370(1) cm-1) antiferromagnetic dominant interactions among the CuII ions for 1 and 2, respectively. The tetranuclear complex 1 is obtained, under dry conditions, through the in situ formation of ligand HL3 (H3L3=1,7-bis(2-hydroxy-5-chlorophenyl)-2,6-diaza-4-hydroxylheptane) by oxidative chlorination of (HL1)2-. In the presence of traces of water, 1 is partially hydroxylated at the ortho position of one of the phenyl rings. The use of trimethylorthoformate as the dehydrating agent prevents the formation of hydroxylated ligands. Several partly chlorinated/hydroxylated products (identified as H3L2) have also been obtained through slight variations of the synthetic procedures (presence or absence of water and/or triethylamine in the reaction mixtures). These partially chlorinated and/or hydroxylated coordination species are mutually isomorphous to either 1 or 2. Several "modified" ligands have been isolated and characterized by 1H NMR and MS, after reaction with sodium sulfide of the complexes formed.

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Chlorination of Platinum-Bound Salicylaldoxime. The First Example of a Structurally Characterized Monodentate Salicylaldoxime-Type Ligand

Cited by 17 publications

References 34 publications

Synthesis, characterization, and anticancer properties of organometallic Schiff base platinum complexes

Synthesis, characterization, and anticancer properties of organometallic Schiff base platinum complexes

Paramagnetic NMR of Phenolic Oxime Copper Complexes: A Joint Experimental and Density Functional Study

Controlled Copper-Mediated Chlorination of Phenol Rings under Mild Conditions

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