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1.
The spectral and electrochemical properties of series of deformed iron(III) derivatives of short-chain basket-handle porphyrins
are reported. 1HNMR and optical studies demonstrated that deformation arises because of the bridging of opposite phenyl groups
by short chains. Axial ligation studies indicate that the straps present over both sides of the porphyrin ring do not prevent
the entry of small ligands. Electrochemistry in four different solvents suggests the stabilisation of Fe(II) and Fe(I) over
Fe(III) in strong coordinating solvents. 相似文献
2.
Eng MP Ljungdahl T Andréasson J Mårtensson J Albinsson B 《The journal of physical chemistry. A》2005,109(9):1776-1784
Gold porphyrins are often used as electron-accepting chromophores in donor-acceptor complexes for the study of photoinduced electron transfer, and they can also be involved in triplet-triplet energy-transfer interactions with other chromophores. Since the lowest excited singlet state is very short-lived (240 fs), the triplet state is usually the starting point for the transfer reactions, and it is therefore crucial to understand its photophysics. The triplet state of various gold porphyrins has been reported to have a lifetime of around 1.5 ns at room temperature and to have a biexponential decay both in emission and in transient absorption with decay times of around 10 and 100 micros at 80 K. In this paper, the triplet photophysics of two gold porphyrins (Au(III) 5,15-bis(3,5-di-tert-butylphenyl)-2,8,12,18-tetraethyl-3,7,13,17-tetramethylporphyrin and Au(III) 5,10,15,20-tetra(3,5-di-tert-butylphenyl)porphyrin) are studied by steady-state and time-resolved absorption and emission spectroscopy over a wide temperature range (4-300 K). The study reveals the existence of a dark state with an approximate lifetime of 50 ns, which was not previously observed. This state acts as an intermediate between the short-lived singlet and the triplet state manifold. In addition, we present DFT calculations, in which the core electrons of the central metal were replaced by a pseudopotential to account for the relativistic effects, which suggest that the lowest excited singlet state is an optically forbidden ligand-to-metal charge-transfer (LMCT) state. This LMCT state is an obvious candidate for the experimentally observed dark state, and it is shown to dictate the photophysical properties of gold porphyrins by acting as a gate for triplet state formation versus direct return to the ground state. 相似文献
3.
Lv H Yang B Jing J Yu Y Zhang J Zhang JL 《Dalton transactions (Cambridge, England : 2003)》2012,41(11):3116-3118
We have firstly demonstrated the dual facet of gold(III) in the reaction between gold(III) and porphyrins, which could be tuned through changing the counter ions, ligands and the electronic effect of the substituents of the porphyrins. 相似文献
4.
Data on the homo- and heteroleptic coordination compounds of indium(III) with halide, pseudo-halide, and N,O-donor ligands are generalized. Trends in the coordination numbers and coordination polyhedron geometries and the specifics
of formation of hybrid polymer structures are considered. 182 references. 相似文献
5.
《Journal of Coordination Chemistry》2012,65(19):3090-3098
AbstractA series of manganese(III) porphyrins with 4-methylimidazole have been prepared. These are high-spin complexes having general formula [MnIII(THMPP)X(4-MeIm)], where THMP?=?5,10,15,20-tetra(4-hydroxy-3-methoxyphenyl)porphine ligand, X?=?Cl?, Br?, NCS?, or N3? and 4-MeIm?=?4-methylimidazole. All the complexes have been characterized by UV-visible, FT-IR, ESI-MS spectra, elemental analyses and magnetic susceptibility measurements. These manganese(III) porphyrins oxidize aromatic alcohols to aldehydes. The oxidation reactions have been carried out at room temperature in the presence of oxidants such as NaIO4, H2O2, and NaOCl. The comparative studies proved that NaIO4 behaves as the most efficient oxidant in these oxidative transformation reactions. 相似文献
6.
Martí MA Bari SE Estrin DA Doctorovich F 《Journal of the American Chemical Society》2005,127(13):4680-4684
The water-soluble manganese(III) meso-tetrakis (N-ethylpyridinium-2-yl) porphyrin (Mn(III)TEPyP) and manganese(III) meso-(tetrakis(4-sulfonato-phenyl)) porphyrinate (Mn(III)TPPS) are able to chemically distinguish between HNO and NO donors, reacting with the former in a fast, efficient, and selective manner with concomitant formation of the {MnNO}(7) complex (k(on(HNO)) approximately equal to 10(5) M(-1) s(-1)), while they are inert or react very slowly with NO donors. DFT calculations and kinetic data suggest that HNO trapping is operative at least in the case of Mn(III)TPPS, while catalytic decomposition of the HNO donors (sodium trioxodinitrate and toluene sulfohydroxamic acid) seems to be the main pathway for Mn(III)TEPyP. In the presence of oxygen, the product Mn(II)TEPyP(NO) oxidizes back to Mn(III)TEPyP, making it possible to process large ratios of nitroxyl donor with small amounts of porphyrin. 相似文献
7.
E. Yu. Tyulyaeva O. V. Kosareva M. E. Klyueva T. N. Lomova 《Russian Journal of Inorganic Chemistry》2008,53(9):1405-1410
The speciation and reactions of palladium(II) complexes with meso-tetraphenylporphine (H2TPP) and meso-tetraphenyl-β-octaethylporphine (H2TetPOEP) were studied in H2SO4-H2O and H2SO4-HOAc protic solvents. H-associated species of PdTPP and PdTetPOEP were found to exist in sulfuric acid with concentrations of 16.33–17.38 and 17.48–18.22 mol/L, respectively. The kinetics of one-electron oxidation of complexes in the coordinated aromatic macrocycle were studied. A third-order rate equation was determined, and the mechanism of the oxidation reaction was substantiated with kinetically significant stages of dioxygen coordination, electron transfer from the macrocyclic aromatic system to dioxygen, and H-association equilibrium between the complex and sulfuric acid. The effects of peripheral ethyl substituents in the macrocyclic ligand on the reactivity of palladium(II)porphyrins were revealed. 相似文献
8.
Vermonden T van Steenbergen MJ Besseling NA Marcelis AT Hennink WE Sudhölter EJ Cohen Stuart MA 《Journal of the American Chemical Society》2004,126(48):15802-15808
The rheology of reversible coordination polymer networks in aqueous solution is studied. The polymers are formed by neodymium(III) ions and bifunctional ligands, consisting of two pyridine-2,6-dicarboxylate groups connected at the 4-positions by an ethylene oxide spacer. Neodymium(III) ions can bind three of these terdendate ligand groups. At high concentrations, the polymer networks yield viscoelastic materials, which can be described with the Maxwell model. The scaling of the elastic modulus, relaxation time, and zero-shear viscosity with concentration are in good agreement with the predictions of Cates' model that describes the dynamics of linear equilibrium polymers. This indicates that the networks have only few cross-links and can be described as linear equilibrium polymers. The gels are also thermo-reversible. At high temperatures, fast relaxation was found, resulting in liquidlike behavior. Upon cooling, the viscoelastic properties returned immediately. From the temperature dependence of the relaxation time, an activation energy of 49 kJ/mol was determined for the breaking and reptation of the polymers. 相似文献
9.
Jurij V. Brenčič Boris Čeh Ivan Leban 《Monatshefte für Chemie / Chemical Monthly》1981,112(12):1359-1368
Trans-[Cr(NH3)4F2]I·H2O (A) has monoclinic P2l/m (No. 11) space group witha=5.033 (3),b=16.333 (10),c=5.539 (3) Å and =98.47 (3)°,Z=2.Cis-[Cr(NH3)4F2]ClO4 (B) has tetragonal space group I4lmd (No. 109) witha=7.417 (1),c=16.610 (2) Å,Z=4. Cr–F and Cr–N bonding distances are 1.894 (3); 2.087 and 2.083 (5) Å for A and 1.887 (6); 2.062 (5) and 2.051 (7) Å for B. Octahedral angles within the cations are close to 90° for both compounds. Cr–N bondtrans to Cr–F bond in thecis compound is shorter. Structures were refined toR
2 values of 0.072 (A) and 0.058 (B).Trans-[Cr(NH3)4F2]I·H2O has weak N–H–F hydrogen bonds between the cations. None such interactions were found incis-[Cr(NH3)4F2]ClO4.
Fluorhältige Komplexe des Cr(III), 2. Mitt.: Kristall- und Molekülstruktur von trans-[Cr(NH3)4F2]I·H2O und cis-[Cr(NH3)4F2]ClO4
Zusammenfassung Trans-[Cr(NH3)4F2]I·H2O (A) kristallisiert in der Raumgruppe P2l/m (No. 11) mitZ=2 unda=5,033 (3),b=16,333 (10),c=5,539 (3) Å und =98,47 (3)°.Cis-[Cr(NH3)4F2]ClO4 (B) kristallisiert in der Raumgruppe I4lmd (No. 109) mitZ=4,a=7,417 (1) undc=16,610 (2) Å. Die Cr–F- und Cr–N-Abstände sind 1,894 (3); 2,087 (6), 2,083 (5) Å für A und 1,887 (6); 2,062 (5), 2,051 (7) Å für B. Die octaedrischen Bindungswinkel innerhalb der Kationen weichen nicht viel von 90° ab. Der Cr–N-Abstand intrans-Position der Cr–F-Bindung ist kürzer. Die Strukturen wurden bis zu GütefaktorenR 2 0,072 (A) und 0,058 (B) verfeinert. Bei der Verbindung A wurden schwache N–H ... F-Wasserstoff-Bindungen zwischen verschiedenen Kationen beobachtet, während bei der Verbindung B keine Wasserstoff-Bindungen vorhanden sind.相似文献
10.
The reaction of 2-hydroxy-N-phenylbenzamide with 2-aminobenzenethiol yielded 2-hydroxy-N-phenylbenzamidebenzothiazoline (H2-Saly · BTZ/HO⋂N⋂SH). The reaction of H2-Saly · BTZ with PhSbCl2, SbCl3, and BiCl3 under varied reaction conditions (microwave, as well as conventional method) gave corresponding antimony( III) and bismuth(III)
Schiff base compounds (substitution along with addition) in different coordination environments. These complexes were characterized
by elemental analysis, IR and NMR (1H and 13C) spectral studies. The ligand was found to bifunctional tridentate, as well as monodentate for different starting materials
of metal (Sb/Bi), as well as for different reaction conditions, hence, suitable coordination environments and pseudotrigonal
bipyramidal geometry for the antimony and bismuth complexes have been proposed. Their biological activities have also been
checked against many fungi and bacteria. The complexes were found to be more toxic than the corresponding ligand. The article
is published in the original.
The article is published in the original. 相似文献
11.
Lopes I Hillier AC Liu SY Domingos A Ascenso J Galvão A Sella A Marques N 《Inorganic chemistry》2001,40(6):1116-1125
[Sm(Tp(Me2)(2)(kappa(2)-S(2)CNR(2))] compounds (R = Et (1), Me (2); Tp(Me2) = HB(3,5-Me2pz)(3)) have been isolated from reaction of (R(2)NC(S)S)(2) with 2 equiv of [Sm(Tp(Me2)(2)]. Reductive cleavage of 2,2'-dipyridyl disulfide or 2,2'-dipyridyl diselenide by [Sm(Tp(Me2)(2)] afforded good yields of [Sm(Tp(Me2)(2)(kappa(2)-Y)] compounds (Y = 2-SC(5)H(4)N (3), 2-SeC(5)H(4)N (4)). 4 is the first selenopyridine complex of an f-block element. Sm(Tp(Me2)(2)(2-OC(5)H(4)N) (5) has been synthesized by salt metathesis of [Sm(Tp(Me2)(2)Cl] with the sodium salt of the 2-hydroxypyridine. The solid-state structures of 1, 3, 4, and 5 were determined by single-crystal X-ray diffraction analysis and revealed that the compounds are all eight-coordinate with dodecahedral geometry. The samarium atoms are bound in tridentate fashion to two pyrazolylborate ligands and in bidentate fashion by the third ligand. The solution behavior of the compounds was studied by (1)H NMR techniques. (1)H-(1)H exchange spectroscopy experiments give evidence for two distinct dynamic regimes occurring in solution. 相似文献
12.
The average magnetic susceptibility (1.2-100 K) and magnetisation (100–15000 Oe at 4.2 K) of two perchlorato manganese(III) porphyrins establish them to be high-spin, in contrast to the “anomalous” behaviour of analogous iron(III) porphyrins. An explanation of the origin of the zero-field splitting in high-spin manganese(III) porphyrins is presented. 相似文献
13.
14.
The recently defined Sparkle/AM1 model is now extended to Er(III) and Ce(III), using the same parameterization scheme. Thus, a set of fifteen complexes for each lanthanide ion, with various representative ligands of high crystallographic quality (R factor < 0.05 Å), and which possess oxygen and/or nitrogen as coordinating atoms, was used as the training set. In the validation procedure we used a set of twenty-two more complex structures for the Ce(III) ion and twenty-four more for the Er(III) ion, all of high crystallographic quality. For the thirty-seven cerium(III) complexes and thirty-nine erbium(III) complexes considered, the Sparkle/AM1 unsigned mean error, for all interatomic distances between the Ln(III) ion and the ligand atoms of the first sphere of coordination, is 0.08 and 0.06 Å, a level of accuracy comparable to present day ab initio/ECP geometries, while being hundreds of times faster. The Sparkle/AM1 model may thus prove useful for luminescent complex design. 相似文献
15.
The synthesis and crystal structures of two novel semicarbazones and four gold(III) compound derivatives of these semicarbazones are presented. A pattern in the formation of the semicarbazones shows the association of Cl– ions held together by intra- and intermolecular forces. [AuCl4]? and [AuBr4]? anions are co-crystallised with these semicarbazone ligands, and the packing architectures revealed by a single-crystal X-ray diffraction analysis showed the different influences of the anions and the association of these chemical species by intermolecular forces on the crystal packing. Crystal engineering led to gold(III) compounds that are stabilised by relevant hydrogen bonding networks, which demonstrated their importance to the supramolecular organisation of the studied compounds. Interestingly, Cl???Br interactions are observed and contribute to the formation of the supramolecular structures. Elemental analysis data and spectroscopic properties in the solid state and solution are also described. 相似文献
16.
Marianne Chateau-Gosselin Gary D. Christian Gaston J. Patriarche 《Mikrochimica acta》1979,71(5-6):415-421
Summary Electrogenerated AuCl4– in 0.02M HCl is used to titrate hydroquinone, ascorbic acid, phenylhydrazine, phenelzine sulphate and phenylsemicarbazide, with biamperometric end-point detection. Titration recoveries are reported and compared with results of coulometry with ceric sulphate oxidation. With less than 1 mg of sample, successive titrations can be performed in the same solution, in contrast to coulometry with ceric sulphate. Phenelzine sulphate reacts stoichiometrically, as opposed to its reactions with stronger oxidizing agents.
Zusammenfassung An der Elektrode entwickeltes AuCl4– in 0,02M HCl wurde für die Titration von Hydrochinon, Ascorbinsäure, Phenylhydrazin, Phenelzinsulfat und Phenylsemicarbazid mit biamperometrischer Endpunktanzeige verwendet. Die Ergebnisse wurden mitgeteilt und mit den Resultaten der Coulometrie mit Cersulfatoxydation verglichen. Im Gegensatz dazu können mit weniger als 1 mg Probe in derselben Lösung Folgetitrationen durchgeführt werden. Abweichend von seinem Verhalten gegenüber stärkeren Oxydationsmitteln reagiert Phenelzinsulfat stöchiometrisch.相似文献
17.
Machado AM Wypych F Drechsel SM Nakagaki S 《Journal of colloid and interface science》2002,254(1):158-164
Two samples of montmorillonite (one of Brazilian origin, BNC1 clay, and the other STX-1, supplied by the Clay Mineral Society Repository (University of Missouri, USA) were allowed to react with biomimetic metalloporphyrins of Fe(III) and Mn(III) in cationic form. The compounds were characterized by several techniques, showing that the metalloporphyrins molecules were adsorbed at the surface of the clay platelet crystals. The catalytic activities of the intercalated complexes for the oxidation of alkane were dependent upon the concentration of the porphyrin immobilized in the clay and factors such as the metal ion species in the porphyrins, choice of solvent, and concentration of the iodosylbenzene oxidant. Good selectivity to cyclohexanol instead of cyclohexanone was observed for the catalytic oxidation of cyclohexane by iodosylbenzene. 相似文献
18.
H Munakata T Kanzaki S Nakagawa H Imai Y Uemori 《Chemical & pharmaceutical bulletin》2001,49(12):1573-1580
We synthesized two water-soluble porphyrins appending platinum(II) complexes [alpha,beta-(4a) and alpha,alpha-(4b) 5,15-bis(2-trans-[PtCl(NH3)2]N-2-aminoethylaminocarbonylphenyl) 2,3,7,8,12,13,17,18-octamethylporphyrin] and studied their reactions with a variety of nucleic acids [disodium adenosine-5'-monophosphate (AMP), disodium guanosine-5'-monophosphate (GMP), disodium thymidine-5'-monophosphate (TMP), disodium cytidine-5'-monophosphate (CMP), synthetic polymer poly(dG)-poly(dC), poly(dA)-poly(dT)] by 1H-NMR, UV-vis and FAB-MS spectroscopies. Based on the denaturation experiments of synthetic nucleic acid polymers, we conclude that the presence of the porphyrins (5.6 microM) does not cause significant changes in the melting temperature of poly(dA)-poly(dT) (28 microM) (deltaT=1 degrees C) and shows reannealing. On the other hand, gradual melting of poly(dG)-poly(dC) (28 microM) occurs at a low temperature (deltaT= -27 degrees C) in the presence of the porphyrins (5.6 microM), and the solutions do not show reannealing phenomena. The results of UV-vis and 1H-NMR experiments revealed that the porphyrins bind to guanine bases and that the porphyrins bind to GMP more strongly than to the other nucleotides. The binding modes between the porphyrins and synthetic nucleic acids are affected more by the coordination of the nucleobase [poly(dG)-poly(dC)] to the Pt(II) in the porphyrins than by Coulomb and hydrophobic interactions. 相似文献
19.
Water-soluble cobalt porphyrin 1Co and imidazole ligand 2 were synthesized. 1Co binds dioxygen in the presence of imidazole ligand 2 in aqueous solution. The formation of the oxygen adduct 2-1Co(O(2)) was studied using UV-vis and EPR spectroscopy. The impact of pH on the kinetic stability of the oxygen adduct was examined. 相似文献
20.
D. E. Chirkst O. L. Lobacheva N. V. Dzhevaga 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(11):1872-1875
Conductometric and potentiometric titration experiments were performed to determine the pH values of hydroxo compound formation
in solutions of lanthanum(III) and holmium(III) nitrates. The instability constants of monohydroxo complexes, the solubility
product constants of hydroxides, and the Gibbs energies of formation of the corresponding compounds are calculated. 相似文献