Frank R. Fronczek

Louisiana State University, Baton Rouge, Louisiana, United States

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Publications (894)2481.84 Total impact

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    Peumie L Abeyratne Kuragama · Frank R Fronczek · Andrzej Sygula ·

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    Peumie L Abeyratne Kuragama · Frank R Fronczek · Andrzej Sygula ·
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    ABSTRACT: Bis-corannulene receptors 4 and 5 with Klärner's tethers prepared by the Diels-Alder cycloaddition form inclusion complexes with C60 and C70, as evidenced by (1)H NMR titration. While 4 exhibits affinity toward fullerenes comparable to the previously reported corannulene-based receptors, 5 exceeds the performance of the former systems by ca. 2 orders of magnitude and, in addition, shows an enhanced preference for C70 over C60. The X-ray crystal structure of C60@5 and DFT calculations indicate that the tether in 5 not only preorganizes the pincers into a proper topology of the host but also contributes to the dispersion-based binding with the fullerene guests.
    Organic Letters 10/2015; DOI:10.1021/acs.orglett.5b02666 · 6.36 Impact Factor
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    ABSTRACT: The introduction of alkynyl groups at the β-pyrrolic positions of dibrominated corrole derivatives was attempted by using both Sonogashira and Stille coupling methodologies. An efficient bromination protocol was developed by using a silver corrolate, which enabled the regioselective preparation of the 3,17-Br2 isomer in high yield. Whereas unsatisfactory results were obtained by applying Sonogashira reaction conditions, the Stille methodology produced, for the first time, novel 3,17-diphenylethynylcorrole derivatives in good to excellent yields. A mild demetalation protocol of the silver complex led to the corresponding corrole free base, opening the way for the preparation of different metal complexes and further elaboration of the corrole platform by using alkyne chemistry.
    European Journal of Organic Chemistry 10/2015; 2015(31). DOI:10.1002/ejoc.201501138 · 3.07 Impact Factor
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    ABSTRACT: In the title compound, [Na2(H2O)9](C7H4ClO2)(C12H10ClN2O5S) {systematic name: catena-poly[[[triaquasodium(I)]-di-μ-aqua-[triaquasodium(I)]-μ-aqua] 3-chlorobenzoate 4-chloro-2-[(furan-2-ylmethyl)amino]-5-sulfamoylbenzoate]}, both the original m-chloro­benzoic acid and furosemide exist with deprotonated carboxyl­ates, and the sodium cations and water mol­ecules exist in chains with stoichiometry [Na2(OH2)9]2+ that propagate in the [-110] direction. Each of the two independent Na+ ions is coordinated by three monodentate water mol­ecules, two double-water bridges, and one single-water bridge. There is considerable cross-linking between the [Na2(OH2)9]2+ chains and to furosemide sulfonamide and carboxyl­ate by inter­molecular O—H⋯O hydrogen bonds. All hydrogen-bond donors participate in a complex two-dimensional array parallel to the ab plane. The furosemide NH group donates an intra­molecular hydrogen bond to the carboxyl­ate group, and the furosemide NH2 group donates an intra­molecular hydrogen bond to the Cl atom and an inter­molecular one to the m-chloro­benzoate O atom. The plethora of hydrogen-bond donors on the cation/water chain leads to many large rings, up to graph set R 4 4(24), involving two chains and two furosemide anions. The chloro­benzoate is involved in only one R 2 2(8) ring, with two water mol­ecules cis-coordinated to Na. The furan O atom is not hydrogen bonded.
    10/2015; 71(10):1266-1269. DOI:10.1107/S2056989015017430
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    Alfredo Peñaloza · Frank R Fronczek · Ralph Isovitsch ·
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    ABSTRACT: The title compound, [PdCl2(C28H24N2)]·CH3OH, was pre-pared from the reaction of PdCl2(DMSO)2 (DMSO is di-methyl sulfoxide) and N,N'-bis-(4-methyl-phen-yl)-1,2-di-phenyl-ethane-1,2-di-imine in methanol. The chelating di-imine core of the title compound deviates slightly from planarity, with an N-C-C-N torsion angle of 5.3 (3)°. Delocalization in the di-imine core is indicated by N-C and C-C bonds that are, respectively, longer and shorter than those found in related nonchelating di-imines. The distorted square-planar coordination environment around the Pd(II) atom is manifested as bond angles that are smaller and larger than 90°, and palladacycle torsion angles of -173.22 (16) and 167.06 (16)°. These deviations are attributed to the small bite angle of 79.13 (8)° of the di-imine chelate. The crystal packing exhibits weak inter-molecular hydrogen-bonding inter-actions involving aromatic H atoms, Cl atoms and inter-calated methanol solvent mol-ecules, defining layers parallel to (010).
    09/2015; 71(Pt 9):m164-5. DOI:10.1107/S2056989015014851
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    ABSTRACT: Bioassay-guided fractionation of the marine sponge Lendenfeldia dendyi and the soft coral Sinularia dura resulted in the isolation of five polybrominated diphenyl ethers (1–5). The structures of the isolated compounds were determined using spectroscopic methods (1D and 2D NMR) and HRMS analyses. The absolute structures of compounds 1 and 2 were confirmed by X-ray analysis. Antimicrobial testing of the isolated compounds along with the acetylated derivative of compound 2 (2a) indicated that they displayed a significant and selective activity against methicillin-resistant Staphylococcus aureus (MRSa) with IC50 values of <0.04–1.18 µM. The antimalarial and antileishmanial activities of the isolated compounds were also evaluated.
    Medicinal Chemistry Research 09/2015; 24(9). DOI:10.1007/s00044-015-1386-9 · 1.40 Impact Factor
  • Siva Murru · Charles Seth Lott · Frank R. Fronczek · Radhey S. Srivastava ·
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    ABSTRACT: Starting from 1,3-dicarbonyl compounds and arylhydroxylamines a convenient N-selective one step approach to α-amino carbonyl derivatives is examined.
    ChemInform 09/2015; 46(36). DOI:10.1002/chin.201536094
  • Alex L. Nguyen · Frank R. Fronczek · Kevin M. Smith · M. Graça H. Vicente ·

    Tetrahedron Letters 09/2015; DOI:10.1016/j.tetlet.2015.09.119 · 2.38 Impact Factor
  • Michael Yanney · Frank R. Fronczek · Andrzej Sygula ·
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    ABSTRACT: Buckycatcher II, a C51H24 hydrocarbon with two corannulene pincers on a dibenzonorbornadiene tether, exhibits an affinity toward C60 in organic solvents that is dramatically higher than the original buckycatcher C60H28 and other corannulene-based molecular receptors for fullerenes. In addition to the formation of an usual 1:1 C60@catcher inclusion complex, a trimeric C60@(catcher)2 assembly is detected in solutions and in the solid state. X-ray structure determination reveals a remarkable “universal joint” solvent-free crystal arrangement of the trimer, with a single fullerene cage wrapped by four corannulene subunits of two cooperating catcher receptors.
    Angewandte Chemie 08/2015; 54(38). DOI:10.1002/ange.201505327
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    ABSTRACT: Five functionalized bis(β-diketones) and their Cu(II) molecular squares are described. The new bis(β-diketones), m-pbhxH2 (3), 5-MeO-m-pbaH2 (4), 5-BuO-m-pbaH2 (5), 2-MeO-m-pbaH2 (6), and 2-MeO-m-pbprH2 (7), were prepared by reaction of the corresponding aldehydes with phospholenes, as we previously reported for m-pbaH2 (1) and m-pbprH2 (2). Ligand 3 has long alkyl chains in its β-diketone moieties, while ligands 4-7 have alkoxy substituents on their aromatic rings. When treated with Cu(2+), the new bis(β-diketones) 3, 4, 5, and 7 afford molecular squares, Cu4(m-pbhx)4 (10), Cu4(5-MeO-m-pba)4 (11), Cu4(5-BuO-m-pba)4 (12), and Cu4(2-MeO-m-pbpr)4 (13), respectively. Two of the new molecular squares, 10 and 12, contain longer-chain substituents and are soluble in a wider range of organic solvents. The other squares, 11 and 13, contain external and internal methoxy groups, respectively, and they show smaller changes in solubility. Single-crystal X-ray analyses are reported for three of the molecular squares without guest molecules, and for five adducts of the squares with σ- (polypyridine) and π-bonded (fullerene) guests. The Cu···Cu distances in the "empty" squares range from 14.047 to 14.904 Å; those in the adducts vary over a wider range depending on the guest molecule involved.
    Inorganic Chemistry 08/2015; 54(16). DOI:10.1021/acs.inorgchem.5b00792 · 4.76 Impact Factor
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    ABSTRACT: We describe a novel reactivity of benzylic-stabilized oxyallyl cations towards regioselective construction of carbon quaternary centers. These synthetically useful intermediates were readily generated upon ionization of aryl substituted α-hydroxy methylenol ethers with catalytic, mild Brønsted acid. The emerging unsymmetrical oxyallyl cations were then directly captured by indoles and other nucleophiles with exquisite control of regioselectivity, predictably at the electrophilic carbon bearing the alkyl substituent to produce highly functionalized, value-added enol ethers.
    Chemical Science 07/2015; 6(11). DOI:10.1039/C5SC01914A · 9.21 Impact Factor
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    ABSTRACT: An effective, stepwise methodology for polychlorination of BODIPY using trichloroisocyanuric acid (TCCA) in acetic acid was developed. In this way, selectively substituted di-, tri-, tetra- and penta-chloro-BODIPYs 2-5 were prepared. The pentachloro-BODIPY is shown to undergo regioselective Pd(0)-catalyzed Stille and Suzuki coupling reactions, first at the 8-position followed by the 3,5- and then the 2,6-positions; nucleophilic substitution reactions occur first at the 8- followed by the 3,5-positions, while the 2,6 are unreactive.
    The Journal of Organic Chemistry 07/2015; 80(16). DOI:10.1021/acs.joc.5b01147 · 4.72 Impact Factor
  • Khalid Alfooty · Yabing He · Frank R. Fronczek · Banglin Chen ·
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    ABSTRACT: Three coordination polymers were synthesized by solvothermal reaction of a C3-symmetrical organic ligand and metal ions (Zn2+, Cd2+, Mn2+). Single-crystal X-ray diffraction studies revealed that the compounds consist of trinuclear secondary building blocks connected by the organic linkers to form two-dimensional layers, which are packed together to form the final architectures, although they crystallized in the different space groups.
    Zeitschrift für anorganische Chemie 05/2015; 641(8-9). DOI:10.1002/zaac.201500060 · 1.16 Impact Factor
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    ABSTRACT: The insertion of a –NO2 group onto the corrole framework represents a key step for subsequent synthetic manipulation of the macrocycle based on the chemical versatility of such a functionality. Here we report results on the investigation of a copper 3-NO2-triarylcorrolate in nucleophilic aromatic substitution reactions with “active” methylene carbanions, namely diethyl malonate and diethyl 2-chloromalonate. Although similar reactions on nitroporphyrins afford chlorin derivatives, nucleophilic attack on carbon-2 of corrole produces 2,3-difunctionalized Cu corrolates in acceptable yields (ca. 30%), evidencing once again the erratic chemistry of this contracted porphyrinoid.
    Organic & Biomolecular Chemistry 05/2015; 13(23). DOI:10.1039/C5OB00659G · 3.56 Impact Factor
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    ABSTRACT: A series of four BODIPYs containing one or two ortho- or para-carborane clusters were synthesized using palladium(0)-catalyzed Suzuki cross-coupling or nucleophilic substitution reactions, at the 2,6- or the 8-positions of halogenated boron dipyrromethenes (BODIPYs). The spectroscopic, structural (including one X-ray) and in vitro BBB permeability of the BODIPYs using hCMEC/D3 brain endothelial cells were investigated.
    Journal of Organometallic Chemistry 05/2015; DOI:10.1016/j.jorganchem.2015.05.009 · 2.17 Impact Factor
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    ABSTRACT: Since the patent for the photodynamic therapy agent Talaporfin (mono-L-aspartylchlorin e6) was issued in 1987, confusion has existed regarding which of the three carboxylic acid groups in the chlorophyll degradation product, chlorin e6 (1), is modified in standard amino acid type conjugations (using DCC or EDC and an organic base) with amino acids and other biomolecules. Here it is shown that the site of conjugation is the central 152-carboxylic acid, such reactions proceeding in numerous examples via a 131:152-anhydride for which a high resolution X-ray structure is reported. Conjugation with eight oxygen and nitrogen nucleophiles, in every case, afforded the 152-conjugate, reinforcing the earlier conclusion that Talaporfin is the 152-aspartyl conjugate of chlorin e6 and suggesting that reports of 173-conjugation of chlorin e6 using stoichiometric peptide coupling procedures should be subjected to further scrutiny.
    European Journal of Organic Chemistry 04/2015; 2015(17). DOI:10.1002/ejoc.201500478 · 3.07 Impact Factor
  • Siva Murru · Charles Seth Lott · Frank R Fronczek · Radhey S Srivastava ·
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    ABSTRACT: A direct Fe-catalyzed α-amination of 1,3-dicarbonyl compounds has been accomplished using arylhydroxylamines as aminating agents. This novel protocol allows convenient access to α-amino carbonyl derivatives without the need for any postreaction manipulations. This is an operationally simple procedure that works at low temperatures in shorter reaction times and produces high yields with excellent N-selectivity.
    Organic Letters 04/2015; 17(9). DOI:10.1021/acs.orglett.5b00710 · 6.36 Impact Factor
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    ABSTRACT: A series of boron-disubstituted O-BODIPYs were synthesized, and their structures and spectroscopic properties were investigated using both computational and experimental methods. Three methods were investigated for the preparation of 4,4-dimethoxy-BODIPYs bearing electron-donating or electron-withdrawing 8-aryl groups: method A employs refluxing in the presence of NaOMe/MeOH, method B uses AlCl3 in refluxing dichloromethane followed by addition of methanol as nucleophile, and method C involves activation of the BODIPYs using TMSOTf in refluxing toluene followed by addition of methanol. The yields obtained depend on the method used and the structure of the starting BODIPYs; for example, 1a and 3a were most efficiently prepared using method C (98 and 70%, respectively), while 2a was best prepared by method A (50%). Methods B and C were employed for the synthesis of seven new 4,4-dialkoxy-BODIPYs. 4,4-Dipropargyloxy-BODIPY 1e reacted under Cu(I)-catalyzed alkyne-azide Huisgen cycloaddition conditions to produce 4,4-bis(1,2,3-triazole)-BODIPY 4 in 78% yield. The substitution of the fluorides for alkoxy groups on the BODIPYs had no significant effect on the absorption and emission wavelengths but altered their fluorescence quantum yields. Among this series of dialkoxy-BODIPYs, the 4,4-dipropargyloxy 1e and its corresponding bis(1,2,3-triazole) 4 show the largest quantum yields in toluene and THF, respectively.
    Inorganic Chemistry 03/2015; 54(7). DOI:10.1021/ic502821m · 4.76 Impact Factor
  • Ning Zhao · M Graça H Vicente · Frank R Fronczek · Kevin M Smith ·
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    ABSTRACT: The asymmetric BODIPY 1 a (BODIPY=4,4-difluoro-4-bora-3a,4a-diaza-s-indacene), containing two chloro substituents at the 3,8-positions and a reactive 5-methyl group, was synthesized from the asymmetric dipyrroketone 3, which was readily obtained from available pyrrole 2 a. The reactivity of 3,8-dichloro-6-ethyl-1,2,5,7-tetramethyl-BODIPY 1 a was investigated by using four types of reactions. This versatile BODIPY undergoes regioselective Pd(0) -catalyzed Stille coupling reactions and/or regioselective nucleophilic addition/elimination reactions, first at the 8-chloro and then at the 3-chloro group, using a variety of organostannanes and N-, O-, and S-centered nucleophiles. On the other hand, the more reactive 5-methyl group undergoes regioselective Knoevenagel condensation with an aryl aldehyde to produce a monostyryl-BODIPY, and oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) gives the corresponding 5-formyl-BODIPY. Investigation of the reactivity of asymmetric BODIPY 1 a led to the preparation of a variety of functionalized BODIPYs with λmax of absorption and emission in the ranges 487-587 and 521-617 nm, respectively. The longest absorbing/emitting compound was the monostyryl-BODIPY 16, and the largest Stokes shift (49 nm) and fluorescence quantum yield (0.94) were measured for 5-thienyl-8-phenoxy-BODIPY 15. The structural properties (including 16 X-ray structures) of the new series of BODIPYs were investigated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Chemistry - A European Journal 03/2015; 21(16). DOI:10.1002/chem.201406550 · 5.73 Impact Factor

Publication Stats

11k Citations
2,481.84 Total Impact Points


  • 1979-2015
    • Louisiana State University
      • Department of Chemistry
      Baton Rouge, Louisiana, United States
  • 2014
    • University of Chicago
      Chicago, Illinois, United States
  • 2013
    • Southwest University
      Kenner, Louisiana, United States
  • 2009-2011
    • Jackson State University
      • Department of Chemistry and Biochemistry
      Jackson, MS, United States
    • The University of Tampa
      Tampa, Florida, United States
  • 1990-2011
    • University of Victoria
      • Department of Chemistry
      Victoria, British Columbia, Canada
    • University of West London
      Londinium, England, United Kingdom
  • 2010
    • Moi University
      • Department of Chemistry and Biochemistry
      Nairoba, Nairobi Area, Kenya
  • 2000-2008
    • Universidad de Cádiz
      • Department of Organic Chemistry
      Puerto Real, Andalusia, Spain
  • 2007
    • International Union of Toxicology
      Reston, Virginia, United States
  • 2005
    • Virginia Polytechnic Institute and State University
      • Department of Chemistry
      Блэксбург, Virginia, United States
    • La Salle University
      • Department of Chemistry and Biochemistry
      Philadelphia, Pennsylvania, United States
  • 2003
    • University of Louisiana at Monroe
      • Department of Chemistry
      Louisiana, United States
  • 2002
    • Case Western Reserve University
      • Department of Chemistry
      Cleveland, OH, United States
  • 2000-2002
    • Iowa State University
      • Department of Chemistry
      Ames, Iowa, United States
  • 1995
    • University of St Andrews
      Saint Andrews, Scotland, United Kingdom
  • 1993
    • University of South Florida
      • Department of Chemistry
      Tampa, Florida, United States
  • 1988-1989
    • Washington University in St. Louis
      • Department of Chemistry
      San Luis, Missouri, United States
  • 1986-1989
    • University of Catania
      • Department of Chemical Sciences
      Catania, Sicily, Italy
  • 1987
    • Tulane University
      • Department of Chemistry
      New Orleans, Louisiana, United States
  • 1982
    • California Institute of Technology
      Pasadena, California, United States
  • 1975
    • Pasadena City College
      Pasadena, Texas, United States