Karl M. Kadish

University of Houston, Houston, Texas, United States

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Publications (586)2725.46 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The synthesis of a series of beta-functionalized push-pull dibenzoporphyrins was realized. These porphyrins display subtle push-pull effects, demonstrating the exceptional tunability of their electronic and electrochemical properties. The UV-Vis spectra of these porphyrins show unique absorption patterns and the fluorescence spectra of these porphyrins display strong near-IR emission bands. In particular, fluorescence quenching effect was observed for pyridyl carrying push-pull porphyrin 4c in the presence of an acid. The versatile synthetic methods developed in this work may open a door to access a large number of functionalized organic materials that are currently unavailable. The structure-property studies provided in this work may provide useful guidelines for the design of new generations of materials in dye-sensitized solar cells, in non-linear optical applications, as fluorescence probes, as well as sensitizers for photodynamic therapy.
    The Journal of Organic Chemistry 11/2015; DOI:10.1021/acs.joc.5b01906 · 4.72 Impact Factor

  • Chemistry - A European Journal 11/2015; 21(47):16701-16701. DOI:10.1002/chem.201584701 · 5.73 Impact Factor

  • Guifen Lu · Jing Li · Sen Yan · Cheng He · Mengying Shi · Weihua Zhu · Zhongping Ou · Karl M. Kadish ·
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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 · 3.97 Impact Factor
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    ABSTRACT: Complexes of 5,10,15-triferrocenylcorrole were synthesized from the crude free-base corrole product obtained by the reaction of ferrocenyl aldehyde and pyrrole. Direct formation of the complex in this manner leads to an increase of the reaction yield by protecting the corrole ring toward oxidative decomposition. The procedure was successful and gave the expected product in the case of the copper and triphenylphosphinecobalt complexes, but an unexpected result was obtained in the case of the nickel derivative, where metal insertion led to a ring opening of the macrocycle at the 5 position, giving as a final product a linear tetrapyrrole nickel complex bearing two ferrocenyl groups. The purified 5,10,15-triferrocenylcorrole complexes have been fully characterized by a combination of spectroscopic methods, electrochemistry, spectroelectrochemistry, and density functional theory calculations. Copper derivatives of 10-monoferrocenyl- and 5,15-diferrocenylcorrole were prepared to investigate how the number and position of the ferrocenyl groups influenced the spectroscopic and electrochemical properties of the resulting complexes. A complete assignment of resonances in the (1)H and (13)C NMR spectra was performed for the cobalt and nickel complexes, and detailed electrochemical characterization was carried out to provide additional insight into the degree of communication between the meso-ferrocenyl groups on the conjugated macrocycle and the central metal ion of the ferrocenylcorrole derivatives.
    Inorganic Chemistry 10/2015; DOI:10.1021/acs.inorgchem.5b01575 · 4.76 Impact Factor
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    ABSTRACT: Twelve structurally related pyridyl and meso-N-methylpyridylporphyrin derivatives are investigated by electrochemistry in different non-aqueous media. The UV/Vis spectrum of each newly investigated porphyrin was measured before and after electroreduction and, based on this data, the site of electron transfer is proposed. An interaction occurs between the meso-pyridyl or meso-N-alkyl-4-pyridyl substituents and the porphyrin π-ring system, the magnitude of which depends upon the number of linked pyridyl or N-alkyl-4-pyridyl groups on the compound, the solvent, the supporting electrolyte and/or other anions added to solution.
    10/2015; DOI:10.1002/celc.201500374
  • Guifen Lu · Jing Li · Xiaoqin Jiang · Zhongping Ou · Karl M Kadish ·
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    ABSTRACT: A series of europium triple-decker complexes containing phthalocyanine and nitrophenyl-corrole macrocycles were synthesized and characterized by spectroscopic and electrochemical methods in nonaqueous media. The examined compounds are represented as Eu2[Pc(OC4H9)8]2[Cor(Ph)n(NO2Ph)3-n], where n varies from 0 to 3, Pc(OC4H9)8 represents the phthalocyanine macrocycle, and Cor indicates the corrole macrocycle having phenyl (Ph) or nitrophenyl (NO2Ph) meso substituents. Three different methods were used for syntheses of the target complexes, two of which are reported here for the first time. Each examined compound undergoes five reversible one-electron oxidations and 3-5 one-electron reductions depending upon the number of NO2Ph substituents. The nitrophenyl groups on the meso positions of the corrole are highly electron-withdrawing, and this leads to a substantial positive shift in potential for the five oxidations and first reduction in CH2Cl2, PhCN, or pyridine as compared to the parent triple-decker compound with a triphenylcorrole macrocycle. The measured E1/2 values are linearly related to the number of NO2Ph groups on the corrole, and the relative magnitude of the shift in potential for each redox reaction was used in conjunction with the results from thin-layer spectro-electrochemistry to assign the initial site of oxidation or reduction on the molecule. The nitrophenyl substituents are also redox-active, and each is reduced to [C6H4NO2](-) in a separate one-electron transfer step at potentials between -1.12 and -1.42 V versus saturated calomel electrode.
    Inorganic Chemistry 09/2015; 54(18). DOI:10.1021/acs.inorgchem.5b01713 · 4.76 Impact Factor
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    ABSTRACT: A silver β-octabromo-meso-triarylcorrole has been found to exhibit a strongly saddled geometry, providing the first instance of a strongly saddled corrole complex involving a metal other than copper. The Soret maxima of the Ag octabromocorroles also redshift markedly in response to increasingly electron-donating para substituents on the meso-aryl groups. In both these respects, the Ag octabromocorroles differ from simple Ag triarylcorrole derivatives, which exhibit only mild saddling and substituent-insensitive Soret maxima. These results have been rationalized in terms of an innocent M(III) -corrole(3-) description for the simple Ag corroles and a noninnocent M(II) -corrole(.2-) description for the Ag octabromocorroles. In contrast, all copper corroles are thought to be noninnocent, while all gold corroles are innocent. Uniquely among metallocorroles, silver corroles thus seem poised on a knife-edge, so to speak, between innocent and noninnocent electronic structures and may tip either way, depending on the exact nature of the corrole ligand.
    Chemistry - A European Journal 09/2015; DOI:10.1002/chem.201502150 · 5.73 Impact Factor
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    ABSTRACT: Two series of copper tetraarylporphyrins containing β,β′-fused tetrabutano or tetrabenzo groups were synthesized and characterized as to their electrochemistry and spectroelectrochemistry in nonaqueous media. The examined compounds are represented as butano-(TpYPP)CuII and benzo-(TpYPP)CuII, where TpYPP is the porphyrin dianion and Y is a CH3, H or Cl substituent on the para-position of the four meso-phenyl rings of the compound. Each neutral porphyrin in the two series is ESR active and shows a typical d9 Cu(ii) signal in frozen CH2Cl2 solution. Each Cu(ii) porphyrin also undergoes two reversible one-electron reductions and two reversible one-electron oxidations in DMF or CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate to give a π-anion radical and dianion upon reduction and a π-cation radical and dication upon oxidation. A third one-electron oxidation is also observed for butano-(TpYPP)Cu (Y = CH3 and H) and benzo-(TPP)Cu in PhCN and this process is assigned to the CuII/CuIII transition. The reversible half-wave potential for the first oxidation of each compound in both series is shifted negatively by about 500 mV as compared to E1/2 values for oxidation of the related copper tetraarylporphyrin without the four fused benzo or butano rings while smaller positive shifts of 60 and 300 mV are seen for reduction of the tetrabenzotetraarylporphyrins and tetrabutaotetraarylporphyrins, respectively, as compared to the same redox reactions of the related tetraarylporphyrins. The electrochemically measured HOMO-LUMO gap averages 1.76 ± 0.05 V for benzo-(TpYPP)CuII, 2.04 ± 0.06 V for butano-(TpYPP)CuII and 2.33 ± 0.03 for (TpYPP)Cu in CH2Cl2. This journal is
    RSC Advances 09/2015; 5(94). DOI:10.1039/C5RA15593B · 3.84 Impact Factor
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    ABSTRACT: Four nitrated N-confused free-base tetraarylporphyrins were synthesized and characterized by electrochemistry and spectroelectrochemistry in nonaqueous media. The examined compounds are represented as NO2(Ar)4NcpH2, where NO2(Ar)4Ncp is the dianion of a tetraaryl N-confused porphyrin with an inner carbon bound NO2 group and Ar is a p-CH3OPh, p-CH3Ph, Ph or p-ClPh substituent on each meso-position of the macrocycle. UV/Vis spectra and NMR spectroscopy data indicate that the same form of the porphyrin exists in CH2Cl2 and DMF which is unlike the case of non-NO2 N-confused porphyrins. The Soret band of NO2(Ar)4NcpH2 exhibits a 30–36 nm red-shift in CH2Cl2 and DMF as compared to the spectrum of the non-NO2 N-confused porphyrins. The first two reductions and first oxidation of NO2(Ar)4NcpH2 are reversible in CH2Cl2 containing 0.1 M TBAP. The measured HOMO–LUMO gap averages 1.65 V in CH2Cl2 and 1.53 V in DMF, with both values being similar to those of the non-NO2 substituted compounds. The nitro group on the inverted pyrrole is itself not reduced within the negative potential limit of CH2Cl2 or DMF, but its presence significantly affects both the UV/Vis spectra and redox potentials.
    Chemistry - A European Journal 08/2015; 21(41). DOI:10.1002/chem.201501720 · 5.73 Impact Factor
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    ABSTRACT: The synthesis and physicochemical characterization of a new class of water soluble homo/heteropentanuclear porphyrazine complexes are described. The investigated compounds, prepared from the previously reported mononuclear species [LM].xH2O (L = tetrakis-2,3-[5,6-di(2-pyridyl) pyrazino]porphyrazinato dianion; M = MgII(H2O), ZnII, CuII, CoII, PdII, PtII;x =3-8) in DMSO under mild experimental conditions, are represented as [{Pd(OAc)2}4LM].xH2O (x=11-22) and bear four Pd(OAc)2 units, each externally coordinated at the vicinal pyridine N atoms of a single dipyridinopyrazine fragment of the porphyrazine macrocycle ("py-py" coordination). The newly synthesized compounds were examined by IR and magnetic susceptibility measurements in the solid state. Solution UV-visible spectral studies on all of the species were conducted in the low-donor organic solvents pyridine, dimethyl sulfoxide and dimethylformamide and in the water medium, whereas electrochemical measurements were performed in these media in the presence of tetrabutylammonium perchlorate (organic solvents) and KCl or NaOAc (water). Data on the photosensitizing activity for the generation of singlet oxygen, 1O2, of interest in photodynamic therapy, were also obtained in dimethylformammide solution on the compounds [{Pd(OAc)2}4LM] (M = MgII(H2O), ZnII, PdII, PtII) and the measured φΔ values are presented and discussed. NMR spectral data on the complex [{Pd(OAc)2}4LZn] are also included and discussed.
    Journal of Porphyrins and Phthalocyanines 08/2015; 19(08):903-919. DOI:10.1142/S1088424615500777 · 1.40 Impact Factor
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    ABSTRACT: Two-photon absorption and electrochemical properties of carbazole-linked porphyrin tweezers including a bisporphyrin dimer resulting from a Glaser homocoupling have been prepared and fully characterized by C. P. Gros, F. Bolze, K. M. Kadish, and co-workers. The dyads reported present a two-photon absorption maximum at 920 nm with two-photon absorption cross-section in the 1200 GM range. The comprehensive report can be found in the Full Paper on page 12018 ff.
    Chemistry - A European Journal 08/2015; 21(34):11910-11910. DOI:10.1002/chem.201590153 · 5.73 Impact Factor
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    ABSTRACT: Herein the synthesis, spectroscopic characterization, two-photon absorption and electrochemical properties of 3,6-disubstituted carbazole tweezers is reported. A dimer resulting from a Glaser homocoupling was isolated during a Sonogashira coupling reaction between a diethynyl-carbazole spacer and a 5-bromo-triarylporphyrin and the properties of this original compound were compared with the 3,6-disubstituted carbazole bisporphyrin tweezers. The dyads reported herein present a two-photon absorption maximum at 920 nm with two-photon absorption cross-section in the 1200 GM range. Despite a strong linear absorption in the Soret region and moderate fluorescence quantum yield, they both lead to a high brightness reaching 30 000 M(-1) cm(-1) . © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Chemistry - A European Journal 07/2015; 21(34). DOI:10.1002/chem.201501619 · 5.73 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 06/2015; 5(64):51489-51492. DOI:10.1039/C5RA09179A · 3.84 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; 19(06):1-9. DOI:10.1142/S1088424615500558 · 1.40 Impact Factor
  • Guifen Lu · Jing Li · Sen Yan · Weihua Zhu · Zhongping Ou · Karl M Kadish ·
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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 · 4.76 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 · 4.76 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 · 6.83 Impact Factor
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    ABSTRACT: Bis-porphyrins containing a β,β′-fused pyrazino (Pz) linking group were examined by electrochemistry and thin-layer UV-visible spectroelectrochemistry in PhCN containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) as supporting electrolyte. The investigated compounds are represented as M(TPP)-Pz-(TPP)M, where TPP is the dianion of tetraphenylporphyrin and M = Zn(II), Cu(II) or Ag(II). The effect of the linking Pz group on the redox potentials and UV-visible spectra of the neutral, electroreduced and electrooxidized bis-porphyrins is discussed and the data compared to what is observed for related monoporphyrins and earlier characterized bis-porphyrins containing a tetraazaanthracene (TA) linking group and the same central metal ions. The Cu(II) and Zn(II) Pz linked bis-porphyrins exhibit a relatively strong interaction between the two equivalent porphyrin macrocycles as evidenced by UV-visible spectra of the neutral compounds and characteristic splitting of redox processes for three of the four electron transfer reactions, the one exception being the first oxidation, where no splitting of potentials is observed in the formation of the bisporphyrin bis-cation radical, [M(TPP)-Pz-(TPP)M]2+. The first oxidation and first reduction of the bis-porphyrin with two Ag(II) central metal ions occurs via two overlapping one-electron transfer steps in each process indicating equivalent, but non-interacting redox centers. This difference in redox behavior is due to differences in the site of electron transfer, metal centered for the Ag(II) bisporphyrins, which undergo Ag(II)/Ag(III) and Ag(II)/Ag(I) processes as compared to only ring centered electron transfers for the Cu(II) and Zn(II) derivatives. The Pz-linked Zn(II) bis-porphyrins have a larger average HOMO–LUMO gap (2.01 V) as compared to related tetraazaanthracene linked bis-porphyrins (1.67 V), which were earlier characterized in the literature, but the gap is smaller than that for the mono-porphyrins with the same central metal ions (2.17 V). Each redox reaction of the investigated bisporphyrins was characterized by thin-layer spectroelectrochemistry.
    Journal of Porphyrins and Phthalocyanines 03/2015; 19(01n03):1-10. DOI:10.1142/S1088424615500224 · 1.40 Impact Factor
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    Guifen Lu · Sen Yan · Mengying Shi · Wenhan Yu · Jing Li · Weihua Zhu · Zhongping Ou · Karl M. Kadish ·
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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 · 6.83 Impact Factor

Publication Stats

14k Citations
2,725.46 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
  • 2003-2007
    • University of Texas at Austin
      • • Department of Chemistry and Biochemistry
      • • Institute for Cellular and Molecular Biology
      Austin, Texas, United States
    • Houston Baptist University
      Houston, Texas, United States
    • Sapienza University of Rome
      • Department of Chemistry
      Roma, Latium, Italy
  • 2006
    • Louisiana State University Health Sciences Center New Orleans
      New Orleans, Louisiana, 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
  • 2003-2004
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 1993-2004
    • University of Burgundy
      • Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB)
      Dijon, Bourgogne, France
  • 1994-2003
    • University of Cologne
      • Institute of Organic Chemistry
      Köln, North Rhine-Westphalia, Germany
  • 2001
    • Roswell Park Cancer Institute
      Buffalo, New York, United States
  • 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
  • 1987-1989
    • Centre Hospitalier Universitaire de Dijon
      Dijon, Bourgogne, France
  • 1988
    • Mohammed V University of Rabat
      Rabat, Rabat-Salé-Zemmour-Zaër, Morocco
    • 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
  • 1974-1977
    • California State University, Fullerton
      • Department of Chemistry & Biochemistry
      Fullerton, California, United States
  • 1972
    • Louisiana State University
      • Department of Chemistry
      Baton Rouge, Louisiana, United States