Karl M. Kadish

University of Houston, Houston, Texas, United States

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Publications (548)2519.32 Total impact

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    ABSTRACT: Two heteroleptic corrole–phthalocyanine europium triple-decker complexes were fabricated into organic nanostructures by the standard phase-transfer method. The investigated compounds are represented by Eu2(Pc)2[Cor(ClPh)3] (1) and Eu2[Pc(OC8H17)8]2[Cor(ClPh)3] (2), where Pc represents the dianion of phthalocyanine and Cor(ClPh)3 the trianion of 5,10,15-tri(4-chlorophenyl)corrole. Both compounds 1 and 2 show typical electronic absorption spectra for a non-aggregated molecular structure in chloroform or toluene. However, in methanol compound 1 self-assembled into belt-like nanostructures while compound 2, which possesses long OC8H17 alkoxy side chains, self-assembled into large scale sheet-like nanostructures. The third-order nonlinear optical properties of both triple-decker compounds were also investigated in toluene by the Z-scan technique and characterized as showing nonlinear reverse saturation absorption and self-defocusing behavior. A third-order nonlinear optical susceptibility, χ(3), of 3.18 × 10−10 and 3.35 × 10−10 esu was obtained for 1 and 2, respectively, thus indicating the potential application of these compounds in the field of optical devices.
    Dyes and Pigments 10/2015; 121. DOI:10.1016/j.dyepig.2015.05.008 · 3.47 Impact Factor
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    ABSTRACT: Three meso-tetraaryl substituted N-5 sapphyrins were synthesized by a facile synthetic route from the corresponding open-chain pentapyrroles in high yield using acetic acid as the solvent and catalyst. Each compound was characterized by spectroscopic and electrochemical methods and the inverted pyrrole structure was confirmed in the solid state for the first time by single crystal X-ray analysis.
    Journal of Porphyrins and Phthalocyanines 06/2015; DOI:10.1142/S1088424615500558 · 1.36 Impact Factor
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    ABSTRACT: We recently reported the first example of a europium triple-decker tetrapyrrole with mixed corrole and phthalocyanine macrocycles and have now extended the synthetic method to prepare a series of rare earth corrole-phthalocyanine heteroleptic triple-decker complexes, which are characterized by spectroscopic and electrochemical methods. The examined complexes are represented as M2[Pc(OC4H9)8]2[Cor(ClPh)3], where Pc = phthalocyanine, Cor = corrole, and M is Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), or Tb(III). The Y(III) derivative with OC4H9 Pc substituents was obtained in too low a yield to characterize, but for the purpose of comparison, Y2[Pc(OC5H11)8]2[Cor(ClPh)3] was synthesized and characterized in a similar manner. The molecular structure of Eu2[Pc(OC4H9)8]2[Cor(ClPh)3] was determined by single-crystal X-ray diffraction and showed the corrole to be the central macrocycle of the triple-decker unit with a phthalocyanine on each end. Each triple-decker complex undergoes up to eight reversible or quasireversible one-electron oxidations and reductions with E1/2 values being linearly related to the ionic radius of the central ions. The energy (E) of the main Q-band is also linearly related to the radius of the metal. Comparisons are made between the physicochemical properties of the newly synthesized mixed corrole-phthalocyanine complexes and previously characterized double- and triple-decker derivatives with phthalocyanine and/or porphyrin macrocycles.
    Inorganic Chemistry 05/2015; 54(12). DOI:10.1021/acs.inorgchem.5b00477 · 4.79 Impact Factor
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    ABSTRACT: Two series of diphosphoryl-substituted porphyrins were synthesized and characterized by electrochemistry and spectroelectrochemistry in nonaqueous media containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). The investigated compounds are 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrins (Ph)2(P(O)(OEt)2)2PorM and 5,15-bis(diethoxyphosphoryl)-10,20-di(para-carbomethoxyphenyl)porphyrins (PhCOOMe)2(P(O)(OEt)2)2PorM where M = 2H, Co(II), Ni(II), Cu(II), Zn(II), Cd(II), or Pd(II). The free-base and five metalated porphyrins with nonredox active centers undergo two ring-centered oxidations and two ring-centered reductions, the latter of which is followed by a chemical reaction of the porphyrin dianion to give an anionic phlorin product. The phlorin anion is electroactive and can be reoxidized by two electrons to give back the starting porphyrin, or it can be reversibly reduced by one electron at more negative potentials to give a phlorin dianion. The chemical conversion of the porphyrin dianion to a phlorin anion proceeds at a rate that varies with the nature of the central metal ion and the solvent. This rate is slowest in the basic solvent pyridine as compared to CH2Cl2 and PhCN, giving further evidence for the involvement of protons in the chemical reaction leading to phlorin formation. Calculations of the electronic structure were performed on the Ni(II) porphyrin dianion, and the most favorable atoms for electrophilic attack were determined to be the two phosphorylated carbon atoms. Phlorin formation was not observed after the two-electron reduction of the cobalt porphyrins due to the different oxidation state assignment of the doubly reduced species, a Co(I) π anion radical in one case and an M(II) dianion for all of the other derivatives. Each redox reaction was monitored by thin-layer UV-visible spectroelectrochemistry, and an overall mechanism for each electron transfer is proposed on the basis of these data.
    Inorganic Chemistry 03/2015; 54(7). DOI:10.1021/acs.inorgchem.5b00067 · 4.79 Impact Factor
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    ABSTRACT: Photoexcitation of dichloromethane solutions of an uranyl macrocyclic complex with cyclo[1]furan[1]pyridine[4]-pyrrole (1) at the near-infrared (NIR) band (1177 nm) in the presence of electron donors and acceptors resulted in NIR-induced electron transfer without producing singlet oxygen via energy transfer.
    Chemical Communications 03/2015; 51(31). DOI:10.1039/C5CC00903K · 6.72 Impact Factor
  • Journal of Porphyrins and Phthalocyanines 03/2015; 19(01n03):1-10. DOI:10.1142/S1088424615500224 · 1.36 Impact Factor
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    ABSTRACT: The first europium triple-decker tetrapyrrole with mixed corrole and phthalocyanine macrocycles was synthesized and characterized by spectroscopic and electrochemical methods. The molecular structure was characterized by single-crystal X-ray diffraction and showed the corrole to be in the middle of the sandwich with phthalocyanine macrocycles at each extreme.
    Chemical Communications 01/2015; 51(12). DOI:10.1039/C4CC09755F · 6.72 Impact Factor
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    ABSTRACT: The protonation and deprotonation reactions for a series N-confused meso-tetraaryl-substituted free-base porphyrins containing electron-donating or electron-withdrawing substituents was monitored in CHCl3 and DMF by UV-visible spectroscopy during titrations with trifluoroacetic acid or tetra-n-butylammonium hydroxide. The spectroscopic data was also used to calculate equilibrium constants for these reactions. The examined compounds are represented as (XPh)4NCPH2, where "NCP" represents the N-confused porphyrin π-conjugated macrocycle and X is a CH3O, CH3, H or Clpara-substituent on the four meso-phenyl rings (Ph) of the compound. The porphyrins can exist in two tautomeric forms depending upon the solvent and each tautomer undergoes two stepwise protonation reactions leading to formation of the mono- and bis-protonated porphyrins, [(XPh)4NCPH3]+ and [(XPh)4NCPH4]2+. A single step deprotonation is observed for the same compounds in DMF and the product is assigned as [(XPh)4NCPH]-. Comparisons are made between UV-visible spectra of the protonated, neutral and deprotonated forms of the porphyrin and the effect of the porphyrin ring substituents and tautomeric form of the neutral porphyrin on the UV-visible spectra and protonation constants is discussed along with data from DFT calculations.
    Journal of Porphyrins and Phthalocyanines 01/2015; 19(01n03):251-260. DOI:10.1142/S1088424614501132 · 1.36 Impact Factor
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    ABSTRACT: The synthesis of unsymmetrical push-pull benzoporphyrins has been realized. UV-Vis and fluorescence spectroscopy, cyclic voltammetry and DFT calculations reveal subtle substituent effects on the electronic and optical properties of these porphyrins.
    RSC Advances 01/2015; 5(64):51489-51492. DOI:10.1039/C5RA09179A · 3.71 Impact Factor
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    ABSTRACT: A series of N-confused free-base meso-substituted tetraarylporphyrins was investigated by electrochemistry and spectroelectrochemistry in nonaqueous media containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) and added acid or base. The investigated compounds are represented as (XPh)4NcpH2, in which “Ncp” is the N-confused porphyrin macrocycle and X is a OCH3, CH3, H, or Cl substituent on the para position of each meso-phenyl ring of the macrocycle. Two distinct types of UV/Vis spectra are initially observed depending upon solvent, one corresponding to an inner-2H form and the other to an inner-3H form of the porphyrin. Both forms have an inverted pyrrole with a carbon inside the cavity and a nitrogen on the periphery of the π-system. Each porphyrin undergoes multiple irreversible reductions and oxidations. The first one-electron addition and first one-electron abstraction are located on the porphyrin π-ring system to give π-anion and π-cation radicals with a potential separation of 1.52 to 1.65 V between the two processes, but both electrogenerated products are unstable and undergo a rapid chemical reaction to give new electroactive species, which were characterized in the present study. The effect of the solvent and protonation/deprotonation reactions on the UV/Vis spectra, redox potentials and reduction/oxidation mechanisms is discussed with comparisons made to data and mechanisms for the structurally related free-base corroles and porphyrins.
    Chemistry - A European Journal 12/2014; 21(6). DOI:10.1002/chem.201405570 · 5.70 Impact Factor
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    ABSTRACT: Two series of substituted manganese triarylcorroles were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in CH2Cl2, CH3CN and pyridine. The investigated compounds are represented as (YPh)(3)CorMn(III) and (YPh)(3)CorMn(IV)Cl, where Cor is a trianion of the corrole and Y is a Cl, F, H or CH3 para-substituent on the three phenyl rings of the macrocycle. Each neutral Mn(III) corrole exists as a four-coordinate complex in CH2Cl2 and CH3CN and as a five-coordinate species in pyridine. (YPh)(3)CorMn(III) undergoes two oxidations to stepwise generate a Mn(IV) corrole and a Mn(IV) pi-cation radical. It also undergoes one reduction to generate a Mn(II) corrole in CH2Cl2 or CH3CN. In contrast, the reduction of (YPh)(3)CorMn(III) leads to a Mn(III) corrole pi-anion radical in pyridine. One oxidation is observed for (YPh)(3)CorMn(IV)Cl in CH2Cl2 and CH3CN to generate a Mn(IV) corrole pi-cation radical while Mn(III) and Mn(II) corroles are stepwise formed after reduction of the same compound. The second reduction of (YPh)(3)CorMn(IV)Cl in pyridine gives a Mn(III) pi-anion radical as opposed to a Mn(II) corrole with an unreduced pi-ring system. The neutral, reduced and oxidized forms of each corrole were characterized by electrochemistry and UV-visible spectroelectrochemistry and comparisons are made between the UV-visible spectra and redox potentials of the compounds in different central metal oxidation states. An overall reduction/oxidation mechanism in the three solvents is proposed.
    Journal of Porphyrins and Phthalocyanines 12/2014; 18(12):1131-1144. DOI:10.1142/S1088424614501119 · 1.36 Impact Factor
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    ABSTRACT: A cobalt(III) corrole, represented as (Cl2Ph)3CorCo(PPh3), where (Cl2Ph)3Cor is the trianion of 5,10,15-tri(2,4-dichlorophenyl)corrole, was synthesized and characterized as to its electrochemical and spectroelectrochemical properties. Single-crystal structure analysis showed the corrole to be monoclinic and have a space group P21/c with α = 13.441(3), b = 28.058(6), c = 27.584(6) Å, α = 90, β = 92.75(3), γ = 90°, Mr = 1144.38, V = 1039.1(4) Å3, Z = 8, Dc = 1.463 mg/cm3, μ = 0.816, F(000) = 4644, Rint = 0.0447, R(I > 4σ(I)) = 0.0769, wR(I > 4σ(I)) = 0.2104, R(all data) = 0.1214 and wR(all data) = 0.2705. The compound was also examined as a catalyst for the electroreduction of dioxygen when coated on an edge-plane pyrolytic graphite electrode in 1.0 M HClO4. Cyclic voltammetry and linear sweep voltammetry with a rotating disk electrode (RDE) or a rotating ring disk electrode (RRDE) were utilized to evaluate the catalytic activity of the corrole and elucidate the products of reduction, H2O or H2O2. Analysis of the data shows exclusively a two-electron transfer process to give 100% H2O2 as the product and no H2O was detectable.
    Journal of Porphyrins and Phthalocyanines 10/2014; 18(10n11):891-898. DOI:10.1142/S1088424614500734 · 1.36 Impact Factor
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    ABSTRACT: Electrochemical studies of the oxidation of dodecasubstituted and highly nonplanar nickel porphyrins in a noncoordinating solvent have previously revealed the first nickel(III) porphyrin dication. Herein, we investigate if these nonplanar porphyrins can also be used to detect the so far unobserved copper(III) porphyrin dication. Electrochemical studies of the oxidation of (DPP)Cu and (OETPP)Cu show three processes, the first two of which are macrocycle-centered to give the porphyrin dication followed by a Cu(II)/Cu(III) process at more positive potential. Support for the assignment of the Cu(II)/Cu(III) process comes from the linear relationships observed between E1/2 and the third ionization potential of the central metal ions for iron, cobalt, nickel, and copper complexes of (DPP)M and (OETPP)M. In addition, the oxidation behavior of additional nonplanar nickel porphyrins is investigated in a noncoordinating solvent, with nickel meso-tetraalkylporphyrins also being found to form nickel(III) porphyrin dications. Finally, examination of the nickel meso-tetraalkylporphyrins in a coordinating solvent (pyridine) reveals that the first oxidation becomes metal-centered under these conditions, as was previously noted for a range of nominally planar porphyrins.
    Inorganic Chemistry 09/2014; 53(19):10772–10778. DOI:10.1021/ic502162p · 4.79 Impact Factor
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    ABSTRACT: Electrochemical and UV/Vis spectral studies on the quinoxaline compound 2,3-di(2-pyridyl)-6,7-dicyano-1,4-quinoxaline, [(CN)2Py2Qx], its metallated derivatives [(CN)2Py2QxMCl2] (M = PdII, PtII) and their analogues sharing the dicyanopyrazine fragment are presented and discussed. X-ray work on the new quinoxaline complex [(CN)2Py2QxPtCl2] establishes that PtII is coordinated to the pyridine N atoms (“py–py” coordination). The spectra of the 1– charged quinoxaline and pyrazine compounds show new intense absorptions in the region of 500–900 nm, and redshifted bands in the 250–400 nm region. By using DFT/time-dependent DFT calculations, the spin density and spectral features of both couples of precursors and PtII derivatives were investigated in terms of single-electron excitations between the Kohn–Sham orbitals of the optimized structures in the gas and condensed phases. A detailed comparison is allowed of the experimental and calculated spectral features of the neutral and 1– charged species.
    Berichte der deutschen chemischen Gesellschaft 08/2014; 2014(22). DOI:10.1002/ejic.201402282
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    ABSTRACT: Five nitrophenylporphyrins were investigated as to their electrochemical properties in CH2Cl2 containing 0.1 M TBAP. The investigated compounds are represented as (NO2Ph)xPh4-xPorM, where Por represents the dianion of the porphyrin macrocycle, Ph is a phenyl group on meso-position of the macrocycle, NO2Ph is a meso-substituted nitrophenyl group, M = 2H, PdII or ZnII and x = 1 or 2. Each porphyrin undergoes an initial one electron reduction at E1/2 = -1.07 to -1.12 V where the added negative charge is almost totally localized on the meso-nitrophenyl group of the compound. This reversible reduction is then followed by one or more irreversible reductions of the nitrophenyl anion at more negative potentials which overlap with reduction of the conjugated porphyrin macrocycle. The initial one electron addition was monitored by thin-layer UV-vis spectroelectrochemistry which confirmed formation of a reduced nitrophenyl group in each case but also gave spectral evidence for a linkage of the one-electron reduction products in the case of the Zn derivatives, giving Zn porphyrin dimers or arrays which are characterized by a 14-15 nm red-shifted Soret band and two well-defined Q-bands, consistent with conversion from an unreduced four coordinate ZnII nitrophenylporphyrin to a five-coordinate ZnII complex with an unreduced porphyrin macrocycle.
    Journal of Porphyrins and Phthalocyanines 08/2014; 18(08n09):832-841. DOI:10.1142/S1088424614500540 · 1.36 Impact Factor
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    ABSTRACT: Cobalt porphyrins having 0-4 meso-substituted ferrocenyl groups were synthesized and examined as to their electrochemical properties in N,N'-dimethylformamide (DMF) containing 0.1 M tetra-n-butylammonium perchlorate as a supporting electrolyte. The examined compounds are represented as (Fc)n(CH3Ph)4-nPorCo, where Por is a dianion of the substituted porphyrin, Fc and CH3Ph represent ferrocenyl and/or p-CH3C6H4 groups linked at the four meso-positions of the macrocycle, and n varies from 0 to 4. Each porphyrin undergoes two reversible one-electron reductions and two to six one-electron oxidations in DMF, with the exact number depending upon the number of Fc groups on the compound. The first electron addition is metal-centered to generate a Co(I) porphyrin. The second is porphyrin ring-centered and leads to formation of a Co(I) π-anion radical. The first oxidation of each Co(II) porphyrin is metal-centered to generate a Co(III) derivative under the given solution conditions. Each ferrocenyl substituent can also be oxidized by one electron, and this occurs at more positive potentials. Each compound was investigated as a catalyst for the electoreduction of dioxygen when adsorbed on a graphite electrode in 1.0 M HClO4. The number of electrons transferred (n) during the catalytic reduction was 2.0 for the three ferrocenyl substituted compounds, consistent with only H2O2 being produced as a product of the reaction. Most monomeric cobalt porphyrins exhibit n values between 2.6 and 3.1 under the same solution conditions, giving a mixture of H2O and H2O2 as a reduction product, although some monomeric porphyrins can give an n value of 4.0. Our results in the current study indicate that appending ferrocene groups directly to the meso positions of a porphyrin macrocycle will increase the selectivity of the oxygen reduction, resulting in formation of only H2O2 as a reaction product. This selectivity of the electrocatalytic oxygen reduction reaction is explained on the basis of steric hindrance by the ferrocene substituents which prevent dimerization.
    Inorganic Chemistry 07/2014; 53(16). DOI:10.1021/ic501210t · 4.79 Impact Factor
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    ABSTRACT: Three related diruthenium complexes containing four symmetrical anionic bridging ligands were synthesized and characterized as to their electrochemical and spectroscopic properties. The examined compounds are represented as Ru2(dpb)4Cl, Ru2(dpb)4(CO), and Ru2(dpb)4(NO) in the solid state, where dpb = diphenylbenzamidinate anion. Different forms of Ru2(dpb)4Cl are observed in solution depending on the utilized solvent and the counteranion added to solution. Each Ru2(5+) form of the compound undergoes multiple redox processes involving the dimetal unit. The reversibility as well as potentials of these diruthenium-centered electrode reactions depends upon the solvent and the bound axial ligand. The Ru2(5+/4+) and Ru2(5+/6+) processes of Ru2(dpb)4Cl were monitored by UV-vis spectroscopy in both CH2Cl2 and PhCN. A conversion of Ru2(dpb)4Cl to [Ru2(dpb)4(CO)](+) was also carried out by simply bubbling CO gas through a CH2Cl2 solution of Ru2(dpb)4Cl at room temperature. The chemically generated [Ru2(dpb)4(CO)](+) complex undergoes several electron transfer processes in CH2Cl2 containing 0.1 M TBAClO4 under a CO atmosphere, and the same reactions were seen for a chemically synthesized sample of Ru2(dpf)4(CO) in CH2Cl2, 0.1 M TBAClO4 under a N2 atmosphere, where dpf = N,N'-diphenylformamidinate anion. Ru2(dpb)4(NO) undergoes two successive one-electron reductions and a single one-electron oxidation, all of which involve the diruthenium unit. The CO and NO adducts of Ru2(dpb)4 were further characterized by FTIR spectroelectrochemistry, and the IR spectral data of these compounds are discussed in light of results for previously characterized Ru2(dpf)4(CO) and Ru2(dpf)4(NO) derivatives under similar solution conditions.
    Inorganic Chemistry 07/2014; 53(14). DOI:10.1021/ic5007605 · 4.79 Impact Factor
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    ABSTRACT: Cobalt(III) triarylcorroles containing 0–3 nitro groups on the para-position of the three meso-phenyl rings of the macrocycle were synthesized and characterized by electrochemistry, mass spectrometry, UV-visible (UV–vis) and 1H NMR spectroscopy. The examined compounds are represented as (NO2Ph)nPh3-nCorCo(PPh3), where n varies from 0 to 3 and Cor represents the core of the corrole. Each compound can undergo two metal-centered one-electron reductions leading to formation of Co(II) and Co(I) derivatives in CH2Cl2 or pyridine containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). A stepwise two electron reduction of each NO2Ph group of the compound is also observed. This first is reversible and occurs in a single overlapping step at the same potential which involves an overall one-, two- or three-electron transfer process for compounds 2–4, respectively. This indicates the lack of an interaction between these redox active sites on the corroles. The second reduction of the NO2Ph groups is irreversible and located at a potential which overlaps the Co(II)/Co(I) process of the compounds. Thin-layer UV-visible spectroelectrochemical measurements in CH2Cl2, 0.1 M TBAP demonstrate the occurrence of an equilibrium between a Co(III) -anion radical and a Co(II) derivative with an uncharged macrocycle after the first controlled potential reduction of the nitro-substituted corroles. All four cobalt corroles were also examined as catalysts for the electroreduction of O2 when coated on an edge-plane pyrrolytic graphite electrode in 1.0 M HClO4. This study indicates that the larger the number of nitro-substituents on the cobalt corrole, the better the compound acts as a catalyst.
    Journal of inorganic biochemistry 07/2014; DOI:10.1016/j.jinorgbio.2013.12.014 · 3.27 Impact Factor
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    ABSTRACT: Two series of copper(I) complexes with diethoxyphosphoryl-substituted 1,10-phenanthroline ligands were synthesized and characterized in the solid state and in solution. The first comprised mixed-ligand CuI complexes with phenanthroline and triphenylphosphine. The second series includes bis-chelates with two phenanthroline ligands. According to the X-ray data for the six complexes, the ditopic phenanthroline ligands exhibit bidentate coordination to the copper(I) atom through two nitrogen atoms in both series. Solution equilibria involving different phenanthroline copper(I) species were studied by 1H and 31P NMR spectroscopy, electrochemistry, and spectroelectrochemistry. The solution speciation of these labile complexes is different for these two series and depends on the nature of solvent and the location of the phosphorus substituent on the phenanthroline backbone. Coordinating solvents can replace a bromide, triphenylphosphine, and even a phenanthroline ligand in the inner coordination sphere of the metal center. Copper(I) complexes with α-substituted phenanthrolines easily dissociate even in noncoordinating solvents such as CH2Cl2 and CHCl3. Ligand-exchange reactions leading to less sterically hindered species were observed under the utilized solution conditions. The coordination mode of the phenanthroline chelators does not change under any of the utilized solution conditions, and binding of the phosphoryl group to the metal center was never observed by spectroscopic or spectroelectrochemical methods.
    Berichte der deutschen chemischen Gesellschaft 07/2014; 2014(21). DOI:10.1002/ejic.201402161
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    ABSTRACT: The reaction of 5,10,15-tris(4-tert-butylphenyl)corrole with 2,3-bis(bromomethyl)-5,6-dicyanopyrazine provides a new example of corrole ring expansion to a hemiporphycene derivative. The ring expansion is regioselective, with insertion of the pyrazine derivative at the 5-position of the corrole ring, affording the corresponding 5-hemiporphycene. Different macrocyclic products accompany formation of the 5-hemiporphycene, depending on the reaction experimental conditions. Br-substitued 5-hemiporphycenes and the 2-Br substituted corrole were obtained in 1,2,4-trichlorobenzene, while in refluxing toluene traces of an inner core substituted corrole were observed together with a significant amount of the unreacted corrole. These results provide an important indication of the reaction pathway. The coordination behavior of the 5-hemiporphycene, together with detailed electrochemical characterization of the free-base and some metal complexes, provides evidence for the reactivity of the peripheral pyrazino group.
    Inorganic Chemistry 06/2014; 53(14). DOI:10.1021/ic500757a · 4.79 Impact Factor

Publication Stats

9k Citations
2,519.32 Total Impact Points


  • 1979–2015
    • University of Houston
      • Department of Chemistry
      Houston, Texas, United States
  • 2010
    • Osaka University
      • Department of Materials Engineering Science
      Suika, Ōsaka, Japan
  • 2001–2008
    • Roswell Park Cancer Institute
      • PDT Center
      Buffalo, New York, United States
  • 2007
    • Chinese Academy of Sciences
      • State Key Laboratory of Electroanalytical Chemistry
      Peping, Beijing, China
  • 2006–2007
    • Louisiana State University
      • Department of Chemistry
      Baton Rouge, Louisiana, United States
    • Louisiana State University Health Sciences Center New Orleans
      New Orleans, Louisiana, United States
  • 2003–2007
    • University of Texas at Austin
      • • Department of Chemistry and Biochemistry
      • • Institute for Cellular and Molecular Biology
      Austin, Texas, United States
    • Sapienza University of Rome
      • Department of Chemistry
      Roma, Latium, Italy
  • 2001–2007
    • Houston Baptist University
      Houston, Texas, United States
  • 2004–2006
    • University of Tsukuba
      • Graduate School of Pure and Applied Sciences
      Tsukuba, Ibaraki, Japan
  • 2005
    • University of Sydney
      • School of Chemistry
      Sydney, New South Wales, Australia
    • Tokyo Gakugei University
      Koganei, Tōkyō, Japan
  • 1993–2005
    • University of Burgundy
      Dijon, Bourgogne, France
  • 2003–2004
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 1994–2003
    • University of Cologne
      • Institute of Organic Chemistry
      Köln, North Rhine-Westphalia, Germany
  • 1993–1999
    • University of California, Davis
      • Department of Chemistry
      Davis, California, United States
    • University of Rome Tor Vergata
      Roma, Latium, Italy
  • 1996–1998
    • Wichita State University
      • Department of Chemistry
      Wichita, Kansas, United States
    • Hiroshima University
      • Division of Chemistry
      Hirosima, Hiroshima, Japan
  • 1987–1989
    • Mohammed V University of Rabat
      Rabat, Rabat-Salé-Zemmour-Zaër, Morocco
  • 1986–1989
    • Centre Hospitalier Universitaire de Dijon
      Dijon, Bourgogne, France
  • 1988
    • Princeton University
      • Department of Chemical and Biological Engineering
      Princeton, New Jersey, United States
  • 1980–1982
    • Houston Zoo
      Houston, Texas, United States
    • Rice University
      Houston, Texas, United States