Enthalpimetric titration of copper chelates with some adduct-forming ligands

Lahiri, Roma; Rao, G.N.

doi:10.1016/0040-6031(85)87083-0

Cited by 2 publications

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References 18 publications

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“…In view of the above importance, we report here in the syntheses, spectral, electrochemical, and biological studies and single crystal structures of Mn(II), Co(III), Ni(II), Cd(II) and Cu(II) complexes of Httfa using pyridine (py) /ethylenediamine (en) / bipyridyl (bpy) nitrogen donor secondary ligands. Although, complexes 1 , 2 and 5 have been reported earlier on the basis of their infrared spectra but no data pertaining to single X‐ray crystallography is available …”

Section: Introductionmentioning

confidence: 99%

Mn(II), Co(III), Ni(II), Cd(II) and Cu(II) Complexes of 2‐Thenoyltrifluoroacetone: Syntheses, Structures, Photoluminescence, Thermal, Electrochemical and Antitumor Studies on Dalton's Lymphoma Cells

et al. 2017

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Five complexes [Mn(ttfa)2(py)2] (1), [Co(ttfa)3] (2), [Ni(ttfa)2(en)] (3), [Cd(ttfa)2(bpy)] (4), and [Cu(ttfa)2(py)] (5) {where Httfa=2‐thenoyltrifluoroacetone} have been synthesized and characterized by elemental analyses, IR, UV‐Vis and single crystal X‐ray diffraction data. Both oxygen atoms of ttfa chelate with the metal ions forming six‐membered C3O2M chelate rings in the complexes. In complexes 1–4 the metal ion adopts a distorted octahedral geometry while the complex 5 is distorted square pyramidal. In the solid state, complexes are stabilized by various types of inter‐intramolecular interactions. Upon excitation at about 29500 cm−1, complexes 1, 2, 3 and 5 exhibit blue emissions while the complex 4 emits violet colour. Electrochemical studies of Httfa and complexes show irreversible redox behavior. Thermal degradation of the complexes as analyzed by TG‐DTA suggests the formation of their respective metal oxides as final thermally stable chemical entities. Httfa, complex 1 and 5 are studied for cytotoxicity on Dalton's lymphoma cells using MTT assay, apoptotic analysis and DNA fragmentation assay which reveals their order of activity as complex 5 > complex 1 > Httfa.

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Section: Introductionmentioning

confidence: 99%

Mn(II), Co(III), Ni(II), Cd(II) and Cu(II) Complexes of 2‐Thenoyltrifluoroacetone: Syntheses, Structures, Photoluminescence, Thermal, Electrochemical and Antitumor Studies on Dalton's Lymphoma Cells

et al. 2017

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Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Liu

McAllister

Miranda

et al. 2004

Chemistry A European J

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Reaction of CuX(2) (X(-)=Cl(-), Br(-), NO(3) (-)), NaOH, and 3[5]-tert-butylpyrazole (Hpz(tBu)) in a 1:1:2 molar ratio in MeOH at 293 K for three days affords [[Cu(3)(Hpz(tBu))(6)(mu(3)-X)(mu(3)-OH)(3)](2)Cu]X(6) (X(-)=Cl(-), 1; X(-)=Br(-), 2; X(-)=NO(3)(-), 3) in moderate yields. These compounds contain a centrosymmetric, vertex-sharing double-cubane [[Cu(3)(Hpz(tBu))(6)(mu(3)-X)(mu(3)-OH)(3)](2)Cu](6+) core, surrounded by a belt of six hydrogen-bonded X(-) ions. For 1 and 2, the ring of guest anions has near C(3) symmetry, that is slightly distorted owing to the axis of Jahn-Teller elongation at the central Cu ion. For 3 only, the NO(3)(-) guest ions are crystallographically disordered, reflecting their poor complimentarity with complex host. A similar reaction employing CuF(2) yields [[Cu(3)(Hpz(tBu))(4)(mu-pz(tBu))(2)(mu-F)(2)(mu(3)-F)](2)]F(2) (4), whose structure contains a cyclic hexacopper core with approximate C(2v) symmetry. Finally, an analogous reaction using Cu(NCS)(2) gives a mixture of trans-[Cu(NCS)(2)(Hpz(tBu))(2)] (5) and [Cu(2)(NCS)(2)(mu-pz(tBu))(2)(mu-Hpz(tBu))(Hpz(tBu))(2)] (6). The latter compound contains a Hpzt(Bu) ligand bridging the two Cu ions in an unusual kappa(1),mu-coordination mode. The variable temperature magnetic properties of 1-3 show antiferromagnetic behavior, leading to a S=1/2 ground state in which the seven copper(II) ions are associated into three mutually independent distinct spin systems. In confirmation of this interpretation, Q-band EPR spectra of solid 1 and 2 at 5 K also demonstrate a S= 1/2 spin system and exhibit hyperfine coupling to three (63,65)Cu nuclei. Unusually, the coupling is manifest as an eight-line splitting of the parallel feature, rather than the usual 10 lines. This has been rationalized by a spin-projection calculation, and results from the relative magnitudes of coupling to the three Cu nuclei. UV/Vis and mass spectrometric data show that 1-4 decompose to lower nuclearity species in solution.

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Enthalpimetric titration of copper chelates with some adduct-forming ligands

Cited by 2 publications

References 18 publications

Mn(II), Co(III), Ni(II), Cd(II) and Cu(II) Complexes of 2‐Thenoyltrifluoroacetone: Syntheses, Structures, Photoluminescence, Thermal, Electrochemical and Antitumor Studies on Dalton's Lymphoma Cells

Mn(II), Co(III), Ni(II), Cd(II) and Cu(II) Complexes of 2‐Thenoyltrifluoroacetone: Syntheses, Structures, Photoluminescence, Thermal, Electrochemical and Antitumor Studies on Dalton's Lymphoma Cells

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

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