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Papers by Robert Strongin

Journal of The American Chemical Society, 1995

Page 1. J. Am. Chem. Sac. 1995, 117, 9359-9360 9359 Synthesis of Oxo-and Methylene-Bridged Cm Dim... more Page 1. J. Am. Chem. Sac. 1995, 117, 9359-9360 9359 Synthesis of Oxo-and Methylene-Bridged Cm Dimers, the First Well-Characterized Species Containing Fullerene-Fullerene Bonds Amos B. Smith III,* Hidetoshi Tokuyama ...

Chemical Physics, 1993

The thermal behavior of solid CT0 has been studied by synchrotron X-ray powder diffraction and di... more The thermal behavior of solid CT0 has been studied by synchrotron X-ray powder diffraction and differential scanning calorimetry. The equilibrium solid state structures formed by C,a were solved by full profile refinement techniques in which orientational and packing disorder were explicitly accounted for. Above 345 R, CT0 forms a plastic crystal, with an equilibrium faceGentere.d cubic structure. At lower temperatures, orientational freezing occurs in two stages. Between 295 and 345 K, disorder persists only about the long axis of the molecule, and the lattice undergoes a rhombohedral distortion. Below 295 R, the rhombohedral lattice undergoes a further distortion, resulting in a previously unobserved monoclinic structure, in which the molecules are presumed to be essentially static. At all temperatures, however, the structure of CT0 retains an ABC packing sequence.

Journal of The American Chemical Society, 1993

Page 1. J. Am. Chem. SOC. 1993,115, 5829-5830 5829 1,2-Methanobuckminsterfderene (CalHz), the Par... more Page 1. J. Am. Chem. SOC. 1993,115, 5829-5830 5829 1,2-Methanobuckminsterfderene (CalHz), the Parent Fullerene Cyclopropane: Synthesis and Structure Amos B. Smith 111,' Robert M. Strongin, Laurent Brard, George T. Furst, and William J. Romanow ...

The Journal of Physical Chemistry, 1994

The infrared spectra of two fullerene derivatives, CwO and C61H2, have been measured in the 4000-... more The infrared spectra of two fullerene derivatives, CwO and C61H2, have been measured in the 4000-200cm-l frequency range between 10 K and room temperature. Due to symmetry lowering with respect to c60, the infrared activity favors the assignment of the Cm silent modes. The experimental results are compared with vibrational calculations based on semiempirical methods. The frequencies of the epoxide and CH2 bridges have been identified in the spectrum and correlated with calculated values. Both the 0 and CH2 bridges cause local perturbations of the Cw cluster and do not significantly change the vibrations of the cage. Temperature effects on the infrared spectra are briefly discussed.

Journal of Organic Chemistry, 1996

Journal of The American Chemical Society, 1995

... Amos B. Smith III,*$? ... AR; Romanow, WJ; Denenstein, AM; McCauley, JP, Jr.; Smith, AB, I11 ... more ... Amos B. Smith III,*$? ... AR; Romanow, WJ; Denenstein, AM; McCauley, JP, Jr.; Smith, AB, I11 Science 1991, 252, 12881; synthesis, structure, and bonding in superconducting alkali-metal-doped phases of Cm [McCauley, JP, Jr.; Zhu, Q.; Coustel, N.; Zhou, 0.; Vaughan, ...

Journal of The American Chemical Society, 1994

... Amos B. Smith 111,' Robert M. Strongin, Laurent Brard, and William J. Romanow De... more ... Amos B. Smith 111,' Robert M. Strongin, Laurent Brard, and William J. Romanow Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center University of Pennsylvania Philadelphia, Pennsylvania I91 04 ...

PLOS One, 2008

Background: In this pioneer study to the biological activity of organometallic compound Iron(III)... more Background: In this pioneer study to the biological activity of organometallic compound Iron(III)-salophene (Fe-SP) the specific effects of Fe-SP on viability, morphology, proliferation, and cell-cycle progression on platinum-resistant ovarian cancer cell lines were investigated.

Analytical Chemistry, 2006

The nucleophilic addition of the aminothiols homocysteine (HCY), cysteine (CYS), and glutathione ... more The nucleophilic addition of the aminothiols homocysteine (HCY), cysteine (CYS), and glutathione (GSH) to the electrogenerated quinone of fluorone black (1) via the ECE mechanism is reported. It is demonstrated that 1 selectively reacts with GSH to form the bis-GSH adduct, 1-(GSH) 2 , while only the monothiol adducts were generated in the presence of HCY and CYS (1-HCY and 1-CYS, respectively). The more anodic E pa of 1-(GSH) 2 relative to 1 and 1-GSH (ΔE pa ~ +0.14) is the voltammetric signature that allows the discrimination of GSH from HCY and CYS. It is also shown that the presence of structurally similar aminothiols-HCY and CYS-posed no interference to the signature voltammetric response of 1-(GSH) 2 .

Acta Crystallographica Section C-crystal Structure Communications, 2001

Author(s) of this paper may load this reprint on their own web site or institutional repository p... more Author(s) of this paper may load this reprint on their own web site or institutional repository provided that this cover page is retained. Republication of this article or its storage in electronic databases other than as specified above is not permitted without prior permission in writing from the IUCr.

Journal of Organic Chemistry, 1997

The resorcinarenes are unique three-dimensional cyclic aromatic tetramers. Their impact in the di... more The resorcinarenes are unique three-dimensional cyclic aromatic tetramers. Their impact in the disciplines of molecular recognition, supramolecular chemistry, and materials science has been the subject of extensive study and review. 1 Boronic acids have recently achieved great prominence as functional groups. They have been employed in palladium-mediated coupling reactions, 2 carbohydrate recognition and sensing, 3 enzyme inhibition, 4 and molecular transport studies. 5 They readily form strong (and reversible) covalent bonds to diols (the basis of carbohydrate affinity chromatography), 6 and boronate esters are utilized as efficient asymmetric homologation substrates 7 and catalysts. 8 The incorporation of arylboronic acid moieties into resorcinarene frameworks might thus afford access to an array of heterofunctional architectures. Herein we report our preliminary findings concerning the synthesis, derivatization, and properties of a new tetraarylboronic acid resorcinarene stereoisomeric molecular series 1a-d and 2a-d ( ) as well as cavitands 3 and 4 ( ).

Journal of The American Chemical Society, 2006

The synthesis of new benzo[a]-and [b]xanthene dye frameworks is described. A unique benzo-[a] xan... more The synthesis of new benzo[a]-and [b]xanthene dye frameworks is described. A unique benzo-[a] xanthene, seminaphtho[a]fluorone (SNAFR-1), is studied in a variety of media. The optimization of solution parameters and excitation wavelengths allows SNAFR-1 to display red, green, and blue emission bands of approximately equal intensities and also to produce white light. Ratiometric red (anion) and green (neutral) emissions are observed upon varying solution pH. A pH-independent violet-blue emission band is due to the addition of nucleophiles to the benzylic carbon of SNAFR-1.

Journal of The American Chemical Society, 2006

Several discreet sugar-boronate complexes exist in solution. This is due to the complex equilibri... more Several discreet sugar-boronate complexes exist in solution. This is due to the complex equilibria between isomeric species of even the simplest monosaccharides. In the current investigation, we determine the regio-and stereochemical features of the various equilibrating sugar isomers that induce signal transduction in boronic acid chemosensors such as 1 as well as 2 and 3. We present a unique example of a chemosensor (1) that is selective for ribose, adenosine, nucleotides, nucleosides, and congeners. As a result of this study, we are able to predict and achieve selective fluorescence and colorimetric responses to specific disaccharides as a consequence of their terminal sugar residue linkage patterns and configurations. We also find that the combined use of chemosensors exhibiting complementary reactivities may be used cooperatively to obtain enhanced selectivity for ribose and rare saccharides.

Journal of Organic Chemistry, 2005

A facile synthetic route utilizing readily available reagents affords a series of regioisomerical... more A facile synthetic route utilizing readily available reagents affords a series of regioisomerically pure xanthene dye derivatives. Advantages include relatively mild conditions and good to excellent yields. Nonpolar, highly crystalline intermediates are isolable by standard chromatographic techniques. The intermediates are in the requisite xanthene oxidation state, thus avoiding the need for relatively inefficient oxidation chemistry and/or harsh conditions. During the course of this work, a new boron-mediated 1,2-aryl migration reaction was discovered.

Journal of Organic Chemistry, 1998

A current challenge of fullerene chemistry 1 is the synthesis, isolation, and characterization of... more A current challenge of fullerene chemistry 1 is the synthesis, isolation, and characterization of new molecular carbon allotropes. Recent investigations include the formation of gas-phase clusters 2 as well as the solution-phase production of methanofullerene-acetylene hybrids 3 and all-carbon dimers. 4,5 Dimeric all-carbon fullerenes with appropriate bridging moieties might exhibit novel intercage electronic interactions or serve as precursors to coalesced fullerenes. Herein, we report the first isolation and characterization of the dimeric allotrope (C 60 ) 2 C 2 (1) obtained via a new reaction of [60]fullerene with the atomic carbon precursor diazotetrazole, 2 6 (Scheme 1).

Organic Letters, 2000

[structure: see text] Heating aqueous DMSO solutions of five saccharides in the presence of 1-3 r... more [structure: see text] Heating aqueous DMSO solutions of five saccharides in the presence of 1-3 reveals that each receptor promotes solution colors characteristic for each sugar. New compound 3 allows the direct correlation of sugar concentration with visible region absorbance and/or fluorescence intensities.

Journal of The American Chemical Society, 2004

Homocysteine (Hcy) is a biomarker for significant disorders including Alzheimer&a... more Homocysteine (Hcy) is a biomarker for significant disorders including Alzheimer's and cardiovascular disease. The monitoring of Hcy levels in plasma is of current concern. We describe highly selective colorimetric methods for the direct detection of Hcy. Inexpensive, commercially available materials are employed. The results show potential application for the detection of Hcy in human blood plasma.

Tetrahedron Letters, 2000

A novel palladium-catalyzed reaction of aryldiazonium tetra¯uoroborate salts with arylboronic est... more A novel palladium-catalyzed reaction of aryldiazonium tetra¯uoroborate salts with arylboronic esters furnishes cross-coupled products in moderate yields. The reaction proceeds at relatively mild temperatures and in aqueous media. #

Tetrahedron Letters, 2000

The first synthesis of arylboronic esters via the coupling of bis(pinacolato)diboron with easily ... more The first synthesis of arylboronic esters via the coupling of bis(pinacolato)diboron with easily prepared aryldiazonium tetrafluoroborate salts is reported. The palladium-catalyzed borylation reaction proceeds efficiently under mild reaction conditions in the absence of a base to afford various functionalized arylboronic esters in moderate to high yields.

Journal of The American Chemical Society, 2004

Homocysteine is a risk factor for disorders including cardiovascular 1 and Alzheimer's disease. 2... more Homocysteine is a risk factor for disorders including cardiovascular 1 and Alzheimer's disease. 2 Cysteine deficiency is involved in slowed growth, hair depigmentation, edema, lethargy, liver damage, muscle and fat loss, skin lesions, and weakness. 3 The detection of important biological thiols including cysteine and homocysteine has been the focus of numerous research efforts. The majority of the reported methods are based on redox chemistry or derivatization with chromophores or fluorophores. The determination of specific thiols is often carried out in conjunction with HPLC or capillary electrophoresis separations or via immunoassays. 4 Recent reports describe a need for much simpler methods that employ stable, nontoxic reagents 5a,b which are less sensitive to pH 5c and afford the requisite sensitivity 5d,6a as well as high selectivity. 6b

Journal of The American Chemical Society, 1995

Page 1. J. Am. Chem. Sac. 1995, 117, 9359-9360 9359 Synthesis of Oxo-and Methylene-Bridged Cm Dim... more Page 1. J. Am. Chem. Sac. 1995, 117, 9359-9360 9359 Synthesis of Oxo-and Methylene-Bridged Cm Dimers, the First Well-Characterized Species Containing Fullerene-Fullerene Bonds Amos B. Smith III,* Hidetoshi Tokuyama ...

Chemical Physics, 1993

The thermal behavior of solid CT0 has been studied by synchrotron X-ray powder diffraction and di... more The thermal behavior of solid CT0 has been studied by synchrotron X-ray powder diffraction and differential scanning calorimetry. The equilibrium solid state structures formed by C,a were solved by full profile refinement techniques in which orientational and packing disorder were explicitly accounted for. Above 345 R, CT0 forms a plastic crystal, with an equilibrium faceGentere.d cubic structure. At lower temperatures, orientational freezing occurs in two stages. Between 295 and 345 K, disorder persists only about the long axis of the molecule, and the lattice undergoes a rhombohedral distortion. Below 295 R, the rhombohedral lattice undergoes a further distortion, resulting in a previously unobserved monoclinic structure, in which the molecules are presumed to be essentially static. At all temperatures, however, the structure of CT0 retains an ABC packing sequence.

Journal of The American Chemical Society, 1993

Page 1. J. Am. Chem. SOC. 1993,115, 5829-5830 5829 1,2-Methanobuckminsterfderene (CalHz), the Par... more Page 1. J. Am. Chem. SOC. 1993,115, 5829-5830 5829 1,2-Methanobuckminsterfderene (CalHz), the Parent Fullerene Cyclopropane: Synthesis and Structure Amos B. Smith 111,' Robert M. Strongin, Laurent Brard, George T. Furst, and William J. Romanow ...

The Journal of Physical Chemistry, 1994

The infrared spectra of two fullerene derivatives, CwO and C61H2, have been measured in the 4000-... more The infrared spectra of two fullerene derivatives, CwO and C61H2, have been measured in the 4000-200cm-l frequency range between 10 K and room temperature. Due to symmetry lowering with respect to c60, the infrared activity favors the assignment of the Cm silent modes. The experimental results are compared with vibrational calculations based on semiempirical methods. The frequencies of the epoxide and CH2 bridges have been identified in the spectrum and correlated with calculated values. Both the 0 and CH2 bridges cause local perturbations of the Cw cluster and do not significantly change the vibrations of the cage. Temperature effects on the infrared spectra are briefly discussed.

Journal of Organic Chemistry, 1996

Journal of The American Chemical Society, 1995

... Amos B. Smith III,*$? ... AR; Romanow, WJ; Denenstein, AM; McCauley, JP, Jr.; Smith, AB, I11 ... more ... Amos B. Smith III,*$? ... AR; Romanow, WJ; Denenstein, AM; McCauley, JP, Jr.; Smith, AB, I11 Science 1991, 252, 12881; synthesis, structure, and bonding in superconducting alkali-metal-doped phases of Cm [McCauley, JP, Jr.; Zhu, Q.; Coustel, N.; Zhou, 0.; Vaughan, ...

Journal of The American Chemical Society, 1994

... Amos B. Smith 111,' Robert M. Strongin, Laurent Brard, and William J. Romanow De... more ... Amos B. Smith 111,' Robert M. Strongin, Laurent Brard, and William J. Romanow Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center University of Pennsylvania Philadelphia, Pennsylvania I91 04 ...

PLOS One, 2008

Background: In this pioneer study to the biological activity of organometallic compound Iron(III)... more Background: In this pioneer study to the biological activity of organometallic compound Iron(III)-salophene (Fe-SP) the specific effects of Fe-SP on viability, morphology, proliferation, and cell-cycle progression on platinum-resistant ovarian cancer cell lines were investigated.

Analytical Chemistry, 2006

The nucleophilic addition of the aminothiols homocysteine (HCY), cysteine (CYS), and glutathione ... more The nucleophilic addition of the aminothiols homocysteine (HCY), cysteine (CYS), and glutathione (GSH) to the electrogenerated quinone of fluorone black (1) via the ECE mechanism is reported. It is demonstrated that 1 selectively reacts with GSH to form the bis-GSH adduct, 1-(GSH) 2 , while only the monothiol adducts were generated in the presence of HCY and CYS (1-HCY and 1-CYS, respectively). The more anodic E pa of 1-(GSH) 2 relative to 1 and 1-GSH (ΔE pa ~ +0.14) is the voltammetric signature that allows the discrimination of GSH from HCY and CYS. It is also shown that the presence of structurally similar aminothiols-HCY and CYS-posed no interference to the signature voltammetric response of 1-(GSH) 2 .

Acta Crystallographica Section C-crystal Structure Communications, 2001

Author(s) of this paper may load this reprint on their own web site or institutional repository p... more Author(s) of this paper may load this reprint on their own web site or institutional repository provided that this cover page is retained. Republication of this article or its storage in electronic databases other than as specified above is not permitted without prior permission in writing from the IUCr.

Journal of Organic Chemistry, 1997

The resorcinarenes are unique three-dimensional cyclic aromatic tetramers. Their impact in the di... more The resorcinarenes are unique three-dimensional cyclic aromatic tetramers. Their impact in the disciplines of molecular recognition, supramolecular chemistry, and materials science has been the subject of extensive study and review. 1 Boronic acids have recently achieved great prominence as functional groups. They have been employed in palladium-mediated coupling reactions, 2 carbohydrate recognition and sensing, 3 enzyme inhibition, 4 and molecular transport studies. 5 They readily form strong (and reversible) covalent bonds to diols (the basis of carbohydrate affinity chromatography), 6 and boronate esters are utilized as efficient asymmetric homologation substrates 7 and catalysts. 8 The incorporation of arylboronic acid moieties into resorcinarene frameworks might thus afford access to an array of heterofunctional architectures. Herein we report our preliminary findings concerning the synthesis, derivatization, and properties of a new tetraarylboronic acid resorcinarene stereoisomeric molecular series 1a-d and 2a-d ( ) as well as cavitands 3 and 4 ( ).

Journal of The American Chemical Society, 2006

The synthesis of new benzo[a]-and [b]xanthene dye frameworks is described. A unique benzo-[a] xan... more The synthesis of new benzo[a]-and [b]xanthene dye frameworks is described. A unique benzo-[a] xanthene, seminaphtho[a]fluorone (SNAFR-1), is studied in a variety of media. The optimization of solution parameters and excitation wavelengths allows SNAFR-1 to display red, green, and blue emission bands of approximately equal intensities and also to produce white light. Ratiometric red (anion) and green (neutral) emissions are observed upon varying solution pH. A pH-independent violet-blue emission band is due to the addition of nucleophiles to the benzylic carbon of SNAFR-1.

Journal of The American Chemical Society, 2006

Several discreet sugar-boronate complexes exist in solution. This is due to the complex equilibri... more Several discreet sugar-boronate complexes exist in solution. This is due to the complex equilibria between isomeric species of even the simplest monosaccharides. In the current investigation, we determine the regio-and stereochemical features of the various equilibrating sugar isomers that induce signal transduction in boronic acid chemosensors such as 1 as well as 2 and 3. We present a unique example of a chemosensor (1) that is selective for ribose, adenosine, nucleotides, nucleosides, and congeners. As a result of this study, we are able to predict and achieve selective fluorescence and colorimetric responses to specific disaccharides as a consequence of their terminal sugar residue linkage patterns and configurations. We also find that the combined use of chemosensors exhibiting complementary reactivities may be used cooperatively to obtain enhanced selectivity for ribose and rare saccharides.

Journal of Organic Chemistry, 2005

A facile synthetic route utilizing readily available reagents affords a series of regioisomerical... more A facile synthetic route utilizing readily available reagents affords a series of regioisomerically pure xanthene dye derivatives. Advantages include relatively mild conditions and good to excellent yields. Nonpolar, highly crystalline intermediates are isolable by standard chromatographic techniques. The intermediates are in the requisite xanthene oxidation state, thus avoiding the need for relatively inefficient oxidation chemistry and/or harsh conditions. During the course of this work, a new boron-mediated 1,2-aryl migration reaction was discovered.

Journal of Organic Chemistry, 1998

A current challenge of fullerene chemistry 1 is the synthesis, isolation, and characterization of... more A current challenge of fullerene chemistry 1 is the synthesis, isolation, and characterization of new molecular carbon allotropes. Recent investigations include the formation of gas-phase clusters 2 as well as the solution-phase production of methanofullerene-acetylene hybrids 3 and all-carbon dimers. 4,5 Dimeric all-carbon fullerenes with appropriate bridging moieties might exhibit novel intercage electronic interactions or serve as precursors to coalesced fullerenes. Herein, we report the first isolation and characterization of the dimeric allotrope (C 60 ) 2 C 2 (1) obtained via a new reaction of [60]fullerene with the atomic carbon precursor diazotetrazole, 2 6 (Scheme 1).

Organic Letters, 2000

[structure: see text] Heating aqueous DMSO solutions of five saccharides in the presence of 1-3 r... more [structure: see text] Heating aqueous DMSO solutions of five saccharides in the presence of 1-3 reveals that each receptor promotes solution colors characteristic for each sugar. New compound 3 allows the direct correlation of sugar concentration with visible region absorbance and/or fluorescence intensities.

Journal of The American Chemical Society, 2004

Homocysteine (Hcy) is a biomarker for significant disorders including Alzheimer&a... more Homocysteine (Hcy) is a biomarker for significant disorders including Alzheimer's and cardiovascular disease. The monitoring of Hcy levels in plasma is of current concern. We describe highly selective colorimetric methods for the direct detection of Hcy. Inexpensive, commercially available materials are employed. The results show potential application for the detection of Hcy in human blood plasma.

Tetrahedron Letters, 2000

A novel palladium-catalyzed reaction of aryldiazonium tetra¯uoroborate salts with arylboronic est... more A novel palladium-catalyzed reaction of aryldiazonium tetra¯uoroborate salts with arylboronic esters furnishes cross-coupled products in moderate yields. The reaction proceeds at relatively mild temperatures and in aqueous media. #

Tetrahedron Letters, 2000

The first synthesis of arylboronic esters via the coupling of bis(pinacolato)diboron with easily ... more The first synthesis of arylboronic esters via the coupling of bis(pinacolato)diboron with easily prepared aryldiazonium tetrafluoroborate salts is reported. The palladium-catalyzed borylation reaction proceeds efficiently under mild reaction conditions in the absence of a base to afford various functionalized arylboronic esters in moderate to high yields.

Journal of The American Chemical Society, 2004

Homocysteine is a risk factor for disorders including cardiovascular 1 and Alzheimer's disease. 2... more Homocysteine is a risk factor for disorders including cardiovascular 1 and Alzheimer's disease. 2 Cysteine deficiency is involved in slowed growth, hair depigmentation, edema, lethargy, liver damage, muscle and fat loss, skin lesions, and weakness. 3 The detection of important biological thiols including cysteine and homocysteine has been the focus of numerous research efforts. The majority of the reported methods are based on redox chemistry or derivatization with chromophores or fluorophores. The determination of specific thiols is often carried out in conjunction with HPLC or capillary electrophoresis separations or via immunoassays. 4 Recent reports describe a need for much simpler methods that employ stable, nontoxic reagents 5a,b which are less sensitive to pH 5c and afford the requisite sensitivity 5d,6a as well as high selectivity. 6b