Absorption and redox properties of seven decakis(phenylthio)corannulene derivatives 3a–3g lead to a model for estimating material properties in persulfurated aromatic compounds. The same series is evaluated for performance in bulk... more
Absorption and redox properties of seven decakis(phenylthio)corannulene derivatives 3a–3g lead to a model for estimating material properties in persulfurated aromatic compounds. The same series is evaluated for performance in bulk heterojunction and perovskite photovoltaic devices.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Ten sym‐penta and deca‐X substituted corannulenes (1–10; X=H, F, CH3, or CF3) define a library of fluorous compounds comprising high symmetry non‐planar aromatic compunds. They provide a group of structurally similar, yet physically... more
Ten sym‐penta and deca‐X substituted corannulenes (1–10; X=H, F, CH3, or CF3) define a library of fluorous compounds comprising high symmetry non‐planar aromatic compunds. They provide a group of structurally similar, yet physically distinct structures manifesting special chemical behavior related to their degree of fluorination. Owing to their bowl forms, corannulene derivatives are distinct from planar polynuclear aromatic compounds; they have relatively high dipole moments, accept 1–4 electrons, and display room temperature fluorescence as well as low temp phosphorescence. Electronic structure theory predicts the bowl inversion barrier and physical properties. The syntheses of sym‐pentafluorocorannulene by an efficient late stage fluorination affords a key derivative to calibrate predictions.
Research Interests:
Research Interests:
Chiral corannulenes abound, but suffer generally from configurational lability associated with bowl‐to‐bowl inversion, thus obviating questions of stereogenicity and stereoelement construction. In contrast, peri‐annulated corannulenes... more
Chiral corannulenes abound, but suffer generally from configurational lability associated with bowl‐to‐bowl inversion, thus obviating questions of stereogenicity and stereoelement construction. In contrast, peri‐annulated corannulenes show greatly increased barriers for bowl‐to‐bowl inversion; specifically indenocorannulenes invert on a time scale too slow to observe by normal NMR methods and raise the possibility of creating chiral atropisomeric bowl‐shaped aromatics. Two methods for preparing indenocorannulene from simple 2‐haloarylcorannulenes—silyl cation C–F activation, and Pd‐mediated C–Cl activation[5]—enable the synthesis of an array of such chiral atropisomeric indenocorannulenes. Resolution of the enantiomers by high‐performance liquid chromatography over chiral support phases motivates the study of chiroptical properties, the assignment of absolute “Cartesian” configuration, and the assessment of configurational stability. These studies bring into question any systematic ...
Research Interests:
Research Interests: Engineering, Pharmacology, Biochemistry, Biophysics, Materials Science, and 12 moreChemistry, Technology, Biotechnology, Medicine, Transport Properties, Mechanical Properties of Materials, Intermolecular Interactions, CHEMICAL SCIENCES, Formation, Solid State, Component, and Optoelectronic Properties of Materials
Research Interests:
Silyl cation-promoted aryl C–F activation can lead to formal C–H activation and the formation of new C(ar)–C(alkyl) bonds.
Research Interests:
The structure and dynamics of five‐coordinate iridacyclopentadiene–chlorido and –hydrido complexes of the form [(PH3)2Ir(CY = CYCY′ = CY′)X] (X = Cl or H and Y = F and/or H) are investigated by M06‐2X/Def2‐TZVPP density functional theory... more
The structure and dynamics of five‐coordinate iridacyclopentadiene–chlorido and –hydrido complexes of the form [(PH3)2Ir(CY = CYCY′ = CY′)X] (X = Cl or H and Y = F and/or H) are investigated by M06‐2X/Def2‐TZVPP density functional theory computation. For the symmetrically substituted ring systems (Y = Y′ = H and Y = Y′ = F) the minimum energy chlorido structures are Y‐shaped trigonal bipyramids; whereas the hydrido complexes favor a T‐structure. Both the symmetrically and unsymmetrically (Y = H, Y′ = F) substituted hydrido complexes exhibit double well potentials for the hydrido ligand wag motion within the metallacycle ring plane, the depths of the well depending on the degree of steric, and electronic interactions within the particular constitutional isomer. Copyright © 2014 John Wiley & Sons, Ltd.
Research Interests:
Carbon fluorine bond activation produces phenyl cations that are effective electrophiles for a new synthesis of tetraarylammonium and triaryloxonium ions. In parallel with diazonium salt decomposition a robust and general method to these... more
Carbon fluorine bond activation produces phenyl cations that are effective electrophiles for a new synthesis of tetraarylammonium and triaryloxonium ions. In parallel with diazonium salt decomposition a robust and general method to these underrepresented cations is demonstrated in this work.
Research Interests:
Graph theory and isosteric replacement leads to the design and synthesis of (chiral) thiophene-fused indenocorannulenes with exceptional configurational stability and possible use as chiral catalysts, chiroptical materials, and sensors.
Research Interests:
Condensed phosphates may exist as linear, cyclic or branched structures. Due to their important role in nature, linear polyphosphates have been well studied. In contrast, branched phosphates (ultraphosphates) remain largely... more
Condensed phosphates may exist as linear, cyclic or branched structures. Due to their important role in nature, linear polyphosphates have been well studied. In contrast, branched phosphates (ultraphosphates) remain largely uncharacterised, because they were already described in 1950 as exceedingly unstable in the presence of water, epitomized in the antibranching-rule. This rule lacks experimental backup, since, to the best of our knowledge, no rational synthesis of defined ultraphosphates is known. Consequently, detailed studies of their chemical properties, reactivity and potential biological relevance remain elusive. Here, we introduce a general synthesis of monodisperse ultraphosphates. Hydrolysis half-lives up to days call the antibranching-rule into question. We provide evidence for the interaction of an enzyme with ultraphosphates and discover a rearrangement linearizing the branched structure. Moreover, ultraphosphate can phosphorylate nucleophiles such as amino acids and n...
Research Interests:
Research Interests:
Experimental optical absorption and photoconductivity spectra of thin films with GW–BSE theoretical predictions provide evidence for diffuse super atomic molecular orbitals (SAMOs) in corannulene, C20H10.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Jay S. Siegel received his Ph.D. from Princeton (1985), was a Swiss Universities Fellow at ETH Zurich (1983-4), and NSF–CNRS postdoctoral fellow at the University of Louis Pasteur in Strasbourg (1985-6). He began as Assistant Professor of... more
Jay S. Siegel received his Ph.D. from Princeton (1985), was a Swiss Universities Fellow at ETH Zurich (1983-4), and NSF–CNRS postdoctoral fellow at the University of Louis Pasteur in Strasbourg (1985-6). He began as Assistant Professor of Chemistry (1986) at UCSD, was promoted to Associate Professor (1992) and Full Professor (1996). In 2003, he was appointed as Professor and co-director of the Organic chemistry institute of the University of Zurich (UZH) and Director of its laboratory for process chemistry research (LPF). He served as Dean of Studies and Head of the Research Council for the Faculty of Sciences at UZH. He moved to Tianjin University in 2013 as dean and joined the Schools of Pharmaceutical and Life Sciences into a new Health Science Platform. His research is in the area of Stereochemistry and Physical Organic Chemistry.
Research Interests:
Integration of the human immunodeficiency virus type 1 (HIV-1) cDNA is a required step for viral replication. Integrase, the virus-encoded enzyme important for integration, has not yet been exploited as a target for clinically useful... more
Integration of the human immunodeficiency virus type 1 (HIV-1) cDNA is a required step for viral replication. Integrase, the virus-encoded enzyme important for integration, has not yet been exploited as a target for clinically useful inhibitors. Here we report on the identification of new polyhydroxylated aromatic inhibitors of integrase including ellagic acid, purpurogallin, 4,8,12-trioxatricornan, and hypericin, the last of which is known to inhibit viral replication. These compounds and others were characterized in assays with subviral preintegration complexes (PICs) isolated from HIV-1-infected cells. Hypericin was found to inhibit PIC assays, while the other compounds tested were inactive. Counterscreening of these and other integrase inhibitors against additional DNA-modifying enzymes revealed that none of the polyhydroxylated aromatic compounds are active against enzymes that do not require metals (methylases, a pox virus topoisomerase). However, all were cross-reactive with ...
Research Interests: Biochemistry, Microbiology, Medical Microbiology, Biology, Medicine, and 15 moreHIV, In Vitro, Integration, Enzyme, Human immunodeficiency virus, Anthraquinones, Replication, Integrase, Mechanism of action, Hiv Integrase Inhibitors, Perylene, Nucleotides, Ellagic acid, restriction enzyme, and Pharmacology and pharmaceutical sciences
So far, most reported open-shell singlet diradicaloids are based on planar π-conjugated molecules. Herein, we report the bridged corannulene dimer diradicaloids, and , both showing a three-dimensional curved π-conjugated structure. has a... more
So far, most reported open-shell singlet diradicaloids are based on planar π-conjugated molecules. Herein, we report the bridged corannulene dimer diradicaloids, and , both showing a three-dimensional curved π-conjugated structure. has a small diradical character ( = 5.4%) and behaves more like a closed-shell quinoidal compound at room temperature, while is a typical open-shell diradicaloid with a larger diradical character ( = 16.9%). Both compounds exhibited paramagnetic activity at elevated temperatures, with a singlet-triplet energy gap (Δ) of -8.4 and -3.0 kcal mol, respectively. X-ray crystallographic analysis revealed that both molecules have a dumbbell-shaped geometry, with the two terminal corannulene bowls bent to opposite directions. The spin is largely delocalized onto the two bowls in and there are multiple [CH···π] interactions between the neighboring bowls. Chemical oxidation/reduction to their respective dications/dianions results in global aromaticity with [4 + 2] π...
Research Interests:
Synthesis of double-threaded ruthenium(ii) ring-in-ring complexes and the Borromean link with three unequal rings detected by mass spectrometry.
Research Interests:
Annulated corannulenes 3-5 form via distinct synthetic pathways: (i) Pd-catalyzed spCH insertion, (ii) Pd-catalyzed aryl coupling, and (iii) silyl cation-promoted C-F activation/CH insertion. Crystal structure, redox, and photophysical... more
Annulated corannulenes 3-5 form via distinct synthetic pathways: (i) Pd-catalyzed spCH insertion, (ii) Pd-catalyzed aryl coupling, and (iii) silyl cation-promoted C-F activation/CH insertion. Crystal structure, redox, and photophysical studies elucidate the differing influence of 1,2,3- versus 1,2-indeno ring fusions. Mono and dianions of 3-5 are characterized. Resolution of 4 gives enantiopure forms, allowing assessment of the bowl-inversion barrier.
Research Interests:
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select... more
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
... K.; Al-Laham, MA; Zakrzewski, VG; Ortiz, JV; Foresman, JB; Cioslowski, J.; Stefanov, BB; Nanayakkara, A.; Challacombe, M.; Peng, CY; Ayala, PY; Chen, W ... Maricel Torrent, Miquel Duran, and Miquel Solà. Journal of the American... more
... K.; Al-Laham, MA; Zakrzewski, VG; Ortiz, JV; Foresman, JB; Cioslowski, J.; Stefanov, BB; Nanayakkara, A.; Challacombe, M.; Peng, CY; Ayala, PY; Chen, W ... Maricel Torrent, Miquel Duran, and Miquel Solà. Journal of the American Chemical Society 1999 121 (6), 1309-1316. ...
Research Interests:
Modification of metal electrode surfaces with functional organic molecules is an important step toward organic electronics. The interaction of the buckybowl indenocorannulene with a Cu(111) surface and the two-dimensional self-assembly on... more
Modification of metal electrode surfaces with functional organic molecules is an important step toward organic electronics. The interaction of the buckybowl indenocorannulene with a Cu(111) surface and the two-dimensional self-assembly on the same surface was studied by means of scanning tunneling microscopy and dispersion-enabled density functional theory. Based on the conjecture of maximizing van der Waals interaction with the surface one would expect the indeno group to be aligned parallel to the surface. Theoretical investigations predict a nonparallel arrangement with the benzo ring of the indeno group located higher above the surface than the bowl rim connected to the indeno group. This adsorbate geometry is due to strong electronic interaction between molecule and surface, including substantial Pauli repulsion. The long-range ordered monolayer shows differences for two molecules of the unit cell in scanning tunneling microscopy contrast, suggesting either different polar alignments, and therefore a different tilt of the indeno group, or occupation of different adsorption sites.
Research Interests:
Pentaindenocorannulene (C50 H20 , 1), a deep bowl polynuclear aromatic hydrocarbon, accepts 4 electrons, crystallizes in columnar bowl-in-bowl assemblies and forms a nested C60 @12 complex. Spectra, structures and computations are... more
Pentaindenocorannulene (C50 H20 , 1), a deep bowl polynuclear aromatic hydrocarbon, accepts 4 electrons, crystallizes in columnar bowl-in-bowl assemblies and forms a nested C60 @12 complex. Spectra, structures and computations are presented.
Research Interests:
Research Interests:
Research Interests:
A series of ML(2) coordination compounds of manisyl-substituted 2-pyridin-2-yl-1,10-phenanthrolines (pherpys) and... more
A series of ML(2) coordination compounds of manisyl-substituted 2-pyridin-2-yl-1,10-phenanthrolines (pherpys) and 2,2':6',2''-terpyridines (terpys) with Fe(ii), Co(ii), Ni(ii), Cu(ii), Zn(ii), Ru(ii), and Os(ii), were synthesized. The pyridyl-phenanthroline-metal complexes form isomorphous crystals (space group Pcca), except for the zinc complex, which is isostructural but not isomorphous (space group P2(1)/c). Traces of the Ru complex induce the Zn complex to crystallize in the Pcca modification. Terpyridine complexes are isostructural but divided into two subgroups (Pnna and C2/c). Within the crystal lattice, the dications arrange into two-dimensional sheets of interdigitated left- and right-handed double helices via CHpi and pi-pi interactions of the pendant manisyl functionalities. All of the complexes exhibit weak ligand charge transfer (LCT) emission in solution at room temperature and the osmium complexes possess an emissive metal to ligand charge transfer (MLCT) state.
Research Interests:
Research Interests: Biochemistry, Bioinformatics, Evolutionary Biology, Environmental Science, Developmental Biology, and 15 moreClimate Change, Computational Biology, Biotechnology, Cancer, Biology, Cell Cycle, Ecology, Drug Discovery, Evolution, Astrophysics, Functional Genomics, Astronomy, DNA, Cell Signalling, and Earth Science
A new life for Kurt... more
A new life for Kurt Mislow's authentic amines: Diaminobiphenyls were applied as the framework materials for the synthesis of axially chiral bichromophoric systems with strong CD and CPL effects.
Research Interests:
Variable-temperature NMR spectra of hexaalkylbenzenes containing both isopropyl and ethyl or cyclopropyl groups, in conjunction with empirical force-field calculations, have shown that the alkyl groups in these heterosubstituted benzenes... more
Variable-temperature NMR spectra of hexaalkylbenzenes containing both isopropyl and ethyl or cyclopropyl groups, in conjunction with empirical force-field calculations, have shown that the alkyl groups in these heterosubstituted benzenes retain the conformation ...
Research Interests:
High-resolution deuterium NMR spectra of 2-vinylanthracene-ad in dichloromethane were recorded. The observed quadrupolar splitting was used to calculate the torsional angle between the vinyl and anthracene planes. The potential energy... more
High-resolution deuterium NMR spectra of 2-vinylanthracene-ad in dichloromethane were recorded. The observed quadrupolar splitting was used to calculate the torsional angle between the vinyl and anthracene planes. The potential energy surface for rotation about the ...
Research Interests:
Research Interests:
Research Interests:
ABSTRACT