| 1. |
- Davydov, Albert, et al.
(författare)
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Chemical reduction of the diferric/radical center in protein R2 from mouse ribonucleotide reductase is independent of the proposed radical transfer pathway
- 2002
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Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 331:1, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- The rates of reduction of the diferric/radical center in mouse ribonucleotide reductase protein R2 were studied by light absorption and EPR in the native protein and in three point mutants of conserved residues involved in the proposed radical transfer pathway (D266A, W103Y) or in the unstructured C terminal domain (Y370W). The pseudo-first order rate constants for chemical reduction of the tyrosyl radical and diferric center by hydroxyurea, sodium dithionite or the dihydro form of flavin adenine dinucleotide, were comparable with or higher (particularly D266A, by dithionite) than in native R2. Molecular modeling of the D266A mutant showed that the iron/radical site should be more accessible for external reductants in the mutant than in native R2. The results indicate that no specific pathway is required for the reduction. The dihydro form of flavin adenine dinucleotide was found to be a very efficient reductant in the studied proteins compared to dithionite alone. The EPR spectra of the mixed-valent Fe(II)Fe(III) sites formed by chemical reduction in the D266A and W103Y mutants were clearly different from the spectrum observed in the native protein, indicating that the structure of the diferric site was affected by the mutations, as also suggested by the modeling study. No difference was observed between the mixed-valent EPR spectra generated by chemical reduction in Y370W mutant and native mouse R2 protein
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| 2. |
- Gorlov, Mikhail, et al.
(författare)
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Binuclear palladium(I) and platinum(I) dimers stabilized by aromatic ligands : synthesis, structural characterization and reactivity with carbon monoxide
- 2003
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 350, s. 449-454
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Tidskriftsartikel (refereegranskat)abstract
- Reaction of PdCl2 with excess of GaCl3 in aromatic solvents leads to binuclear compounds of the general formula [Pd2X2(arene)(2)], where arene = C6H6, X- = GaCl7- (1); arene = C7H8, X- = GaCl4- (2). The solid-state structures of compounds 1 and 2 have been determined by X-ray crystallography. Two molecules of the arene are bound to the dipalladium unit. The compounds 1 and 2 do not react with triphenyl phosphine. Reaction of carbon monoxide with 1 in benzene solution yields [Pd-2(GaCl4)(2)(C6H6)(2)] (3), for which the crystal structure has also been determined. The compound [Pt-2(GaCl4)(2)(C10H10)(2)].2C(6)H(6) (4), which was obtained by reaction of K-2[PtCl4] with GaCl3 and naphthalene in a benzene solution, has a similar structure in the solid state.
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| 3. |
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| 4. |
- Huang, D. U., et al.
(författare)
-
Synthesis, structural characterization and magnetic properties of 2-pyrazinecarboxylate manganese compounds Mn(pyz)(2)(H2O)(4) and MnCl(pyz)(H2O) (n) (pyz=2-pyrazinecarboxylate)
- 2003
-
Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 353, s. 284-291
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Tidskriftsartikel (refereegranskat)abstract
- Two pyz complexes [Mn(pyz)(2)(H2O)(4)] (1) and [MnCl(pyz)(H2O)] (2) have been synthesized and structurally characterized. Complex 1 contains an eight-coordinate Mn(II) ion with square anti-prismatic geometry. The extensive intermolecular hydrogen-bonding interactions of O-carboxyl...H-O-aqua correlate the complex molecules, forming 2D polymeric layer structure. The structure of complex 2 contains 1D Mn/pyz chains, which link to each other by double mu(2)-Cl bridges to form 2D layer with Mn...Mn distance of 3.664 Angstrom. Hydrogen-bonding interactions of O-carboxyl...H-O-aqua are found between the layers to correlate the 2D layers to form a 3D framework. In addition, the variable temperature magnetic susceptibilities of complex 2 were measured and weak ferromagnetic exchange interactions between the neighboring magnetic species were found with J = 0.42 cm(-1).
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| 5. |
- Ivanov, Alexander V., et al.
(författare)
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Polycrystalline and surface O,O′-dialkyldithiophosphate zinc(II) complexes : preparation, 31P CP/MAS NMR and single-crystal X-ray diffraction studies
- 2001
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Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 315:1, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- Dithiophosphate zinc(II) complexes with eight different O,O′-dialkyldithiophosphate ligands have been prepared in solid/liquid states and as surface complexes on a synthetic sphalerite, and studied by means of 31P NMR spectroscopy. All 31P resonances, corresponding to dithiophosphate ligands with different structural functions (i.e. terminal chelating or bridging between two metal atoms in bi- and tetranuclear complexes), have been assigned on the basis of comparative analyses of chemical shift data for solid complexes, their melts and chloroform solutions at various concentrations. The bridging coordination of O,O′-dialkyldithiophosphate ligands by the two neighbouring zinc(II) atoms was established in the case of zinc(II) complexes formed at the surface of the synthetic sphalerite. In addition, novel molecular and crystal structures of the binuclear O,O′-di-cyclo-hexyldithiophosphate zinc(II) complex have been resolved by single-crystal X-ray diffraction data analysis, and useful correlations with 31P NMR data for this complex were obtained.
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| 6. |
- Ivanov, Alexander V., et al.
(författare)
-
The structural reorganisation of bis(diethyldithiocarbamato)morpholine-zinc(II) and -copper(II) in the course of solid-state solvation with morpholine and benzene molecules studied by ESR, solid-state 13C and 15N CP/MAS NMR spectroscopy and single-crystal X-ray diffraction
- 2001
-
Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 321:1-2, s. 63-64
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Tidskriftsartikel (refereegranskat)abstract
- Six forms of both non-solvated and solvated adducts of bis(diethyldithiocarbamato)–zinc(II) and –copper(II) with morpholine, of general formulas [M{O(CH2)4NH}{S2CN(C2H5)2}2] and [M{O(CH2)4NH}{S2CN(C2H5)2}2]·L (M=Zn(II) (1): L=O(CH2)4NH (2), C6H6 (3); M=Cu(II) (4): L=O(CH2)4NH (5), C6H6 (6)), have been prepared and studied by means of ESR, solid-state natural abundance 13C and 15N CP/MAS NMR spectroscopy and single crystal X-ray diffraction data. The existence of two conformers, which are correlated as rotation isomers, was unambiguously established for both zinc(II) and copper(II) non-solvated adducts 1 and 4. These two isomeric forms are characterised by different modes of spatial orientation of the non-planar morpholine ring relative to the two four-membered metallochelate rings. The geometry of the adduct molecules is close to square pyramidal, C4v, and therefore the ground state of the unpaired copper(II) electron corresponds to the 3dx2−y2 atomic orbital (AO). Solvation of the studied adducts in the solid state leads to their significant structural reorganisation at the molecular level, i.e. their structural unification yielding qualitatively new structural states with: (i) different lengths of the Zn---N bond; (ii) reoriented heterocyclic ring of the coordinated morpholine molecule; and (iii) an enhanced contribution of trigonal-bipyramidal character to the geometry of the coordination polyhedra of the central atom (from 7.5 and 22.7% in original adducts to 75% in solvated forms). The type of geometry of the coordination polyhedrons in the solvated forms of the adducts (intermediate between trigonal bipyramid D3h and square pyramid C4v) correlates with the fact that the ground state of the unpaired copper(II) electron is a mixture of 3dz2 and 3dx2−y2 AOs. All observed ESR and NMR resonances have been assigned and are in agreement with the structures obtained from X-ray diffraction data.
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| 7. |
- Kritikos, M., et al.
(författare)
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Novel bis(diethylenetriamine)thallium(III) complex. Synthesis and characterization in pyridine solution and in solid
- 2002
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Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 331, s. 224-231
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Tidskriftsartikel (refereegranskat)abstract
- A new complex of thallium(ill) with the nitrogen donor ligand diethylenetriamine (dien) has been prepared and characterized by multinuclear NMR (H-1, C-13. Tl-205), infrared and Raman spectroscopy. and X-ray diffraction. In solution, the symmetric s-facial isomer of [Tl(dien)(2)](3+) is formed. This is a fluxional molecule even at low temperature (235 K): therefore, the different rotamers cannot be observed separately. A complete characterization of the complex is given from its non-trivial NMR spectra. The crystal structure of [Tl(dien)(2)](ClO4)(3).H2O shows u-facial geometry. where the coordination environment around thallium can be described as a distorted trigonal prism.
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| 8. |
- Ma, G. B., et al.
(författare)
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Equilibrium and structure of thallium(III)-ethylenediamine complexes in pyridine solution and in solid
- 2001
-
Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 320:02-jan, s. 92-100
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Tidskriftsartikel (refereegranskat)abstract
- The formation of three [TI(en)(n)](3+) complexes (n = 1-3) in a pyridine solvent has been established by means of Tl-205 and H-1 NMR. Their stepwise stability constants based on concentrations, K-n = [Tl(en)(n)(3+)]/{[Tl(en)(n-1)(3+)](.)[en]}, at 298 K in 0.5 M NaClO4 ionic medium in pyridine, were calculated from Tl-205 NMR integrals: log K-1 = 7.6 +/- 0.7; log K-2 = 5.2 +/- 0.5 and log K-3 = 2.64 +/- 0.05. Linear correlation between both the Tl-205 NMR shifts and spin-spin coupling Tl-205-H-1 versus the stability constants has been found and discussed. A single crystal with the composition [Tl(en)(3)](ClO4)(3) was synthesized and its structure determined by X-ray diffraction. The Tl3+ ion is coordinated by three ethylenediamine ligands via six N-donor atoms in a distorted octahedral fashion.
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| 9. |
- Ma, G. B., et al.
(författare)
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Formation and structure of novel ternary complexes of thallium(III)cyanide-amine (ethylenediamine and triethylenetetramine) in solution and in solid
- 2003
-
Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 344, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- A novel ternary Tl(III) complex [Tl(en)(2)(CN)](2+) has been synthesized and characterized in solution by NMR and in solid by Raman spectroscopy. This complex has been prepared in the solid state, [Tl(en)(2)(CN)](ClO4)(2) (1), and the related [Tl(tren)(CN)(2)](ClO4) (2), and their crystal structures determined by X-ray diffraction. A linear cyano-bridged supramolecular complex exists in [Tl(en)(2)(CN)](ClO4)(2). In [Tl(tren)(CN)(2)](ClO4), the thallium ion exists in a distorted octahedral geometry cis coordinated cyanides.
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| 10. |
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| 11. |
- Agarwala, Hemlata
(författare)
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Probing valence and spin situations in selective ruthenium–iminoquinonoidframeworks. An experimental and DFT analysis
- 2011
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 374, s. 216-225
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Tidskriftsartikel (refereegranskat)abstract
- The ruthenium–iminoquinone complexes, [Ru(tpm)(Cl)(Q)]+ [tpm = tris(1-pyrazolyl)methane, Q = 3,5-di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine, where aryl = C6H5, [1]+; m-(OCH3)2C6H3, [2]+;m-(Cl)2C6H3, [3]+] have been synthesized. The sensitive bond distances of ‘‘Q’’ in [1](ClO4) and[2](ClO4), C–O: 1.294(8), 1.281(2) Å; C–N: 1.352(8), 1.335(2) Å; and C–C(meta): 1.366(10)/1.367(9) Å,1.364(2)/1.353(2) Å, respectively, and other analytical as well as theoretical (DFT) events suggest thevalence configuration of [RuIII(tpm)(Cl)(QSq)]+ for [1]+–[3]+. The paramagnetic [1]+–[3]+ show sharp1H NMR spectra with strikingly small J of 1.8–3.0 Hz. The DFT calculations on [1]+ predict that the triplet(S = 1) state exists above (1004 cm1) the singlet (S = 0) ground state. [1]+ exhibits l = 2.2 BM at 300 Kwhich diminishes to 0.3 BM near 2 K due to the steady decrease in the ratio of triplet to singlet populationwith the lowering of temperature. [1]+–[3]+ exhibit one oxidation and two successive reductions each inCH3CN. Experimental and DFT analyses collectively establish the valence configurations at thenon-innocent {Ru–Q} interface along the redox chain as [(tpm)(Cl)RuIII(QQo)]2+ ([1]2+–[3]2+)?[(tpm)(Cl)RuIII(QSq)]+ ([1]+–[3]+)?[(tpm)(Cl)RuII(QSq)]M[(tpm)(Cl)RuIII(QCat)] (1–3)?[(tpm)(Cl)-RuII(QCat)] ([1]–[3]). The spectral features of [1]n–[3]n (n = +2, +1, 0) have been addressed based onthe TD-DFT calculations on [1]n.
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| 12. |
- Ahlquist, Mårten, et al.
(författare)
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Rhodium(I) hydrogenation in water : Kinetic studies and the detection of an intermediate using C-13{H-1} PHIPNMR spectroscopy
- 2007
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 360:5, s. 1621-1627
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism for hydrogenation of dimethylmaleate in water using cationic rhodium complexes with water-soluble bi-dentate phosphines has been investigated using kinetics and a novel method for the indirect detection of intermediates in catalytic hydrogenation reactions, whereby a late intermediate was detected. A mechanism is proposed involving fast, irreversible substrate binding followed by a rate-determining reaction with dihydrogen.
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| 13. |
- Baryshnikova, A. T., et al.
(författare)
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Computational study of the structure and magnetic properties of the weakly-coupled tetranuclear square-planar complex of Cu(II) with a tetraporphyrin sheet
- 2019
-
Ingår i: Inorganica Chimica Acta. - : Elsevier S.A.. - 0020-1693 .- 1873-3255. ; 485, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- Owing to the fact that weakly-coupled Cu(II) complexes are potentially applicable in the fields of spintronics and single-molecule magnets we have studied one particularly conspicuous case – a tetranuclear square-planar complex of Cu(II) ions with a π-extended tetraporphyrin ligand (Tetrahedron, 2008, 64, 11433), the structural criteria of which, with very long distances between the paramagnetic centers, can sensibly define the exchange coupling constants and magnetic behaviour. We use the “broken symmetry” density functional theory formalism for various spin states (open-shell singlet, triplet and quintet states). The calculated value of the magnetic exchange integral corresponds to a very weak antiferromagnetic coupling between the neighboring Cu(II) ions (Jcalc = –1.48 cm−1(calculated) Jexp = −1.16 cm−1 (experiment)). The opposite Cu(II) ions are coupled ferromagnetically with an extremely small exchange constant (jcalc = 0.09 cm−1 (calculated) that corresponds to the open-shell singlet ground state of the following spin configuration↑↓↑↓. The exchange mechanism between the [Cu(n) + 4N] localized singly-occupied “magnetic” orbitals of the dxy(Cu) + 4sp2(N) nature indicates a diffuse non-zero overlap between them on the Carbon atoms of the organic ligand. The numerical analysis of atomic spin densities and corresponding decomposition coefficients for the singly-occupied “magnetic” orbitals confirm the proposed exchange mechanism. This superexchange pathway is mediated by the in-plane sp2-hybrid orbitals of the Carbon atoms that couple four [Cu + 4N] fragments by the σ-bond system. For more detailed characterization of the target system a topological analysis of electron density distributions in the high-spin quintet states has been carried out using the Bader's method “quantum theory of atoms in molecules”.
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| 14. |
- Bedin, Michele, et al.
(författare)
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Synthesis and properties of a heterobimetallic iron-manganese complex and its comparison with homobimetallic analogues
- 2019
-
Ingår i: Inorganica Chimica Acta. - : ELSEVIER SCIENCE SA. - 0020-1693 .- 1873-3255. ; 490, s. 254-260
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Tidskriftsartikel (refereegranskat)abstract
- Heterobimetallic cofactors containing one manganese and one iron ion have recently been found within the di-metal carboxylate protein family. Herein we report the synthesis and characterization of three binuclear metal complexes with Fe-Fe, Mn-Mn, and Fe-Mn metal composition. All three complexes use the same ligand framework, the BPMP ligand (HBPMP=2,6-bis[(bis (-2-pyridylmethyl)amine) methyl]-4-methylphenol)) with two additional acetate ligands bridging the two metals. In terms of stability towards metal exchange, the Fe-Mn is more stable than the Mn-Mn complex but less stable than the Fe-Fe complex. Cyclic voltammetry shows that the Fe-Mn complex behaves markedly different than the homobimetallic complexes. The Fe-Mn complex also shows higher reactivity with O-2 than both the Fe-Fe and the Mn-Mn counterparts.
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| 15. |
- Boschloo, Gerrit, et al.
(författare)
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Photoinduced absorption spectroscopy as a tool in the study of dye-sensitized solar cells
- 2008
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 361:3, s. 729-734
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Tidskriftsartikel (refereegranskat)abstract
- Photoinduced absorption (PIA) spectroscopy, where the excitation is provided by a square-wave modulated (on/off) monochromatic light source, is a versatile tool in the study of dye-sensitized solar cells. Spectra of transient species, such as the oxidized dye, can easily be obtained and their kinetics can be explored using frequency or time-resolved techniques. Experimental PIA conditions can be kept close to typical solar cell operating conditions, allowing extraction of relevant time constants. PIA is also a suitable method to study the quality of pore filling in case of solid hole conductors. Dye molecules that are not in direct contact with the hole conductor will have long lifetimes in their oxidized state and appear clearly in the PIA spectrum. The basic principles of PIA are explained using the example of electron injection and recombination in dye-sensitized TiO2 in the absence of redox electrolyte.
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| 16. |
- Clausing, Simon T., et al.
(författare)
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Preparation, photo- and electrochemical studies of a homoleptic imine-phosphaalkene Cu(I) complex
- 2020
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 513
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Tidskriftsartikel (refereegranskat)abstract
- A 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) functionalized phosphaalkene was used as a bidentate ligand towards a [Cu(I)L-2](+) complex. The spectroscopic, electrochemical and photophysical properties of the compound were studied revealing a rich redox chemistry indicative of ligand non-innocence. The compound is weakly emissive with excited state lifetimes of up to 9 ns. NMR and electrochemical analysis indicate a complex dynamic behavior of this photosensitizer in solution.
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| 17. |
- Duan, Lele, et al.
(författare)
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Synthesis, protonation and electrochemical properties of trinuclear NiFe2 complexes Fe-2(CO)(6)(mu(3)-S)(2) Ni(Ph2PCH2)(2)NR (R = n-Bu, Ph) with an internal pendant nitrogen base as a proton relay
- 2009
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 362:2, s. 372-376
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Tidskriftsartikel (refereegranskat)abstract
- Two trinuclear NiFe2 complexes Fe-2(CO)(6)(mu(3)-S)(2)[Ni(Ph2PCH2)(2)NR] (R = n-Bu, 1; Ph, 2) containing an internal base were prepared as biomimetic models for the active sites of FeFe and NiFe hydrogenases. Treatment of complex Fe-2(CO)(6)(mu(3)-S)(2)[Ni(Ph2PCH2)(2)N(n-Bu)] (1) with HOTf gave an N-protonated complex [Fe-2(CO)(6)(mu(3)-S)(2){Ni(Ph2PCH2)(2)NH(n-Bu)}][OTf] ([1H][OTf]). The structures of complexes 1, 2 and [1H][OTf] were determined by X-ray crystallography, which shows that the proton held by the N atom of [1H][OTf] lies in an equatorial position. Cyclic voltammograms of complexes 1 and [1H][OTf] were studied and compared with that of Fe-2(CO)(6)(mu(3)-S)(2)[Ni(dppe)].
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| 18. |
- Falkenström, Magnus, et al.
(författare)
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Light-induced charge separation in ruthenium based triads : New variations on an old theme
- 2007
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 360:3, s. 741-750
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Forskningsöversikt (refereegranskat)abstract
- Success with artificial photosynthesis requires control of the photoinduced electron transfer reactions leading to charge-separated states. In this review, some new ideas to optimize such charge-separated states in ruthenium(II) polypyridyl based three-component systems with respect to: (1) long lifetimes and (2) ability to store sufficient energy for catalytic water splitting, are presented. To form long-lived charge-separated states, a manganese complex as electron donor and potential catalyst for water oxidation has been used. The recombination reaction is unusually slow because it occurs deep down in the Marcus normal region as a consequence of the large bond reorganization following the manganese oxidation. For the creation of high energy charge-separated states, a strategy using bichromophoric systems is presented. By consecutive excitations of the two chromophores, the formation of charge-separated states that lie higher in energy than either of the two excited states could in theory be achieved, the first results of which will be discussed in this review.
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| 19. |
- Gao, W. M., et al.
(författare)
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Synthesis, structures and electrochemical properties of amino-derivatives of diiron azadithiolates as active site models of Fe-only hydrogenase
- 2006
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 359:4, s. 1071-1080
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Tidskriftsartikel (refereegranskat)abstract
- The preparation and characterization of two novel amino-incorporated sulfur-bridged dinuclear iron (I) complexes of the type [NR(mu-SCH2)2]Fe-2(CO)(6), one being amino protected [N(CH2CH2NHTs)(mu-SCH2)(2)]Fe-2(CO)(6) (8) and the other [(mu-SCH2)(2)Fe-2(-CO)(6)NCH2CH2N (mu-SCH2)(2)]Fe-2(CO)(6) (9) are described. These two complexes are readily prepared in a S(N)2 manner between double lithium anion and bis(chloromethyl) amine derivatives. The structures of 8 and 9 were characterized by IR, H-1, C-13 NMR, MS and HRMS spectra and further determined by X-ray analyses. Protonation of complex 8 gave the mono N-protonated product, while for 9 the protonation occurred in both of the N atoms. The redox properties were evaluated by cyclic voltammograms. It was shown that these two complexes can catalyze electrochemical reduction of proton to molecular hydrogen.
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| 20. |
- Gorlov, Mikhail, et al.
(författare)
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Dimeric palladium and platinum complexes isolated in Lewis-acidic media
- 2009
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 362:2, s. 605-609
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and X-ray characterization of binuclear dipalladium(I) and diplatinum(I) p-xylene complexes [Pd-2(eta(6)-C8H10)(2)(mu-Cl/Br)(2)(GaCl3)(2)] (1) and [Pt-2(eta(6)-C8H10)(2)(Ga2Br7)(2)] (5) are reported. It was established that the toluene ligands in the palladium complex [Pd-2(eta(6)-C7H8)(2)(GaCl4)(2)] (3) can be substituted by naphthalene without disruption of the metal-metal bond. The reaction of 3 with Pd(PPh3)(4) leads to the formation of a dipalladium(II) mu-diphenylphosphido compound [Pd2(mu- PPh2)(PPh3)(4)] (GaCl4)(2) center dot 4(C7H8) (4), most likely also involving a bridging mu-H ligand.
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| 21. |
- Gusev, Alexey, et al.
(författare)
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Structure-induced luminescence and bioactivities of Zinc(II) complexes with 2-(2,4-dichlorophenoxy)-N?-[pyridin-2-ylmethylene]acetohydrazide
- 2023
-
Ingår i: Inorganica Chimica Acta. - : ELSEVIER SCIENCE SA. - 0020-1693 .- 1873-3255. ; 551
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Tidskriftsartikel (refereegranskat)abstract
- The structure and photophysical properties of the series of Zn(II) complex with the hydrazone ligand, 2-(2,4dichlorophenoxy)-N -[1-pyridin-2-ylmethylene]acetohydrazide, and different counter anions have been synthesized and characterized by single crystal X-ray diffraction, FT-IR, elemental analyses and ESI-MS. X-ray crystallography has proved the neutral or monoanionic form of ligand upon coordination. All complexes are mononuclear with the tetra/penta/hexacoordinated zinc atoms. The diverse supramolecular architectures of the complexes show that counter-anions have significant impacts on the structures. Furthermore DFT, luminescence properties, antibacterial and herbicide activities of the complexes have been investigated were carried out as well.
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| 22. |
- Hasan, Md Nur, et al.
(författare)
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Functionalized nano-MOF for NIR induced bacterial remediation : A combined spectroscopic and computational study
- 2022
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Ingår i: Inorganica Chimica Acta. - : Elsevier. - 0020-1693 .- 1873-3255. ; 532
-
Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial infection has emerged as one of the principal health problems in the world that requires urgent effective prevention. In order to deal with this reality, antibacterial photodynamic therapy using photosensitizers such as IR820 is one of the most encouraging and innovative methodologies to combat bacteria-caused infections. However, their activity is limited due to low photostability, short circulation, and lack of targeted bio-distribution. Herein, we have developed a user-friendly and universal approach to overcome such limitations of cyanine dye IR820 by encapsulating it with zeolitic imidazolate framework-8 (ZIF-8) keeping its activity intact. The synthesized ZIF8-IR820 nano-MOFs are characterized using electron microscopic and optical spectroscopic techniques. Moreover, the formation of hybrids is confirmed from the charge transfer process obtained from time resolved fluorescence transient and first principles DFT based analysis. The ultrafast charge transfer dynamic enhances the red-light sensitive reactive oxygen species (ROS) production capability which is further catalyzed in acidic pH and DFT based calculation validates the experimental results. The enhanced ROS production of ZIF8-IR820 nano-MOFs makes it superior in NIR induced antibacterial activity. Overall, the study demonstrates a detailed physical understanding of photosensitizer encapsulated nano-MOF system which shows efficient NIR light induced photo-dose dependent antibacterial activity that can be beneficial for potential bacterial remediation.
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| 23. |
- Ivanov, Alexander, et al.
(författare)
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The unique alternation of conformationally different ('chair'-'saddle') eight-membered metallocycles [Cd2S4P2] in the chains of cadmium dialkyldithiophosphates : 13C, 31P, 113Cd CP/MAS NMR and single-crystal X-ray diffraction studies
- 2005
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 358:9, s. 2585-2594
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Tidskriftsartikel (refereegranskat)abstract
- O,O′-Dipropyldithiophosphate and O,O′-dibutyldithiophosphate (Dtph) cadmium(II) complexes were prepared and studied by means of heteronuclear 31P, 113Cd, 31C CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. Linear-chain polynuclear structures have been established for both cadmium(II) complexes, in which each pair of equivalent dithiophosphate groups, playing the same bridging structural function, asymmetrically links the neighbouring cadmium atoms. One remarkable structural feature of the synthesised cadmium(II) compounds is defined by the alternation of two types of conformationally different (‘chair'-‘saddle') eight-membered rings [Cd2S4P2] in the polymeric chains. Therefore, in both 31P NMR and XRD data, the bridging dithiophosphate ligands exhibit structural inequivalence in pairs. The structural states of both Dtph ligands and cadmium atoms have been characterised by the 31P and 113Cd chemical shift tensors, which display a profound axially symmetric and mainly rhombic characters, respectively. All experimental 31P resonances were assigned to the phosphorus structural sites in both resolved structures.
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| 24. |
- Ivanov, Alexander V., et al.
(författare)
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Conformational isomerism of the binuclear N,N-pentamethylenedithiocarbamate cadmium(II) complex, [Cd2{S2CN(CH2)5}4] on multinuclear (15N, 113Cd) CP/MAS NMR and single-crystal X-ray diffraction data
- 2006
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 359:12, s. 3855-3864
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Tidskriftsartikel (refereegranskat)abstract
- Crystalline N,N-cyclo-pentamethylenedithiocarbamate (PmDtc) cadmium(II) complex was prepared and studied by means of 15N, 113Cd CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. The unit cell of the cadmium(II) compound comprises two centrosymmetric isomeric binuclear molecules [Cd2{S2CN(CH2)5}4], which display structural inequivalence in both 15N and 113Cd NMR and XRD data. There are pairs of the dithiocarbamate ligands exhibiting different structural functions in both isomeric molecules. Each of the terminal ligands is bidentately coordinated to the cadmium atom and forms a planar four-membered chelate ring [CdS2C]; whereas pairs of the tridentate bridging ligands combine two neighbouring cadmium atoms forming an extended eight-membered tricyclic moieties [Cd2S4C2], whose geometry can be approximated by a ‘chair' conformation. The structural states of cadmium atoms were characterised by almost axially symmetric 113Cd chemical shift tensors. All experimental 15N resonance lines were assigned to the nitrogen structural sites in both isomeric binuclear molecules.
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| 25. |
- Ivanov, Maxim A., et al.
(författare)
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Preparation and structural organisation of heteroleptic tetraphenylantimony(V) complexes comprising unidentately and bidentately coordinated O,O'-dialkyldithiophosphate groups : multinuclear (C-13 P-31) CP/MAS NMR and single-crystal X-ray diffraction studies
- 2007
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 360:9, s. 2897-2904
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Tidskriftsartikel (refereegranskat)abstract
- O,O′-dipropyldithiophosphate and O,O′-di-iso-butyldithiophosphate (Dtph) tetraphenylantimony(V) complexes of the general formula [Sb(C6H5)4{S2P(OR)2}] (R = C3H7, i-C4H9) were prepared and studied by means of 13C, 31P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. Distorted octahedral and trigonal bipyramidal molecular structures have been established for prepared complexes. These unexpected structural distinctions between chemically related compounds are defined by the principally different coordination modes of O,O′-dipropyldithiophosphate and O,O′-di-iso-butyldithiophosphate ligands in their molecular structures (i.e., S,S′-bidentate chelating and S-unidentately coordinated, respectively). To characterise quantitatively phosphorus sites in both species of dithiophosphate ligands, 31P chemical shift anisotropy parameters (δaniso and η) were calculated from spinning sideband manifolds in MAS NMR spectra. The 31P chemical shift tensors for the bidentate chelating and unidentately coordinated dithiophosphate ligands display a profoundly rhombic and nearly axially symmetric characters, respectively.
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