1
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Guo H, Lovell JB, Shu C, Pink M, Morton M, Rajca S, Rajca A. Chiral π-Conjugated Double Helical Aminyl Diradical with the Triplet Ground State. J Am Chem Soc 2024; 146:9422-9433. [PMID: 38501228 DOI: 10.1021/jacs.4c02057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
We report a neutral high-spin diradical of chiral C2-symmetric bis[5]diazahelicene with ΔEST ≈ 0.4 kcal mol-1, as determined by EPR spectroscopy/SQUID magnetometry. The diradical is the most persistent among all high-spin aminyl radicals reported to date by a factor of 20, with a half-life of up to 6 days in 2-MeTHF at room temperature. Its triplet ground state and excellent persistence may be associated with the unique spin density distribution within the dihydrophenazine moiety, which characterizes two effective 3-electron C-N bonds analogous to the N-O bond of a nitroxide radical. The enantiomerically enriched (ee ≥ 94%) (MM)- and (PP)-enantiomers of the precursors to the diradicals are obtained by either preparative chiral supercritical fluid chromatography or resolution via functionalization with the chiral auxiliary of the C2-symmetric racemic tetraamine. The barrier for the racemization of the solid tetraamine is ΔG‡ = 43 ± 0.01 kcal mol-1 in the 483-523 K range. The experimentally estimated lower limit of the barrier for the racemization of a diradical, ΔG‡ ≥ 26 kcal mol-1 in 2-MeTHF at 293 K, is comparable to the DFT-determined barrier of ΔG‡ = 31 kcal mol-1 in the gas phase at 298 K. While the enantiomerically pure tetraamine displays strong chiroptical properties, with anisotropy factor |g| = |Δε|/ε = 0.036 at 376 nm, |g| ≈ 0.005 at 548 nm of the high-spin diradical is comparable to that recently reported triplet ground-state diradical dication. Notably, the radical anion intermediate in the generation of diradical exhibits a large SOMO-HOMO inversion, SHI = 35 kcal mol-1.
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Affiliation(s)
- Haoxin Guo
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Joshua B Lovell
- Teledyne ISCO, 4700 Superior Street, Lincoln, Nebraska 68504-1328, United States
| | - Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Martha Morton
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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2
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Shu C, Yang Z, Rajca A. From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals. Chem Rev 2023; 123:11954-12003. [PMID: 37831948 DOI: 10.1021/acs.chemrev.3c00406] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
Stable radicals and thermally robust high-spin di- and triradicals have emerged as important organic materials due to their promising applications in diverse fields. New fundamental properties, such as SOMO/HOMO inversion of orbital energies, are explored for the design of new stable radicals, including highly luminescent ones with good photostability. A relation with the singlet-triplet energy gap in the corresponding diradicals is proposed. Thermally robust high-spin di- and triradicals, with energy gaps that are comparable to or greater than a thermal energy at room temperature, are more challenging to synthesize but more rewarding. We summarize a number of high-spin di- and triradicals, based on nitronyl nitroxides that provide a relation between the experimental pairwise exchange coupling constant J/k in the high-spin species vs experimental hyperfine coupling constants in the corresponding monoradicals. This relation allows us to identify outliers, which may correspond to radicals where J/k is not measured with sufficient accuracy. Double helical high-spin diradicals, in which spin density is delocalized over the chiral π-system, have been barely explored, with the sole example of such high-spin diradical possessing alternant π-system with Kekulé resonance form. Finally, we discuss a high-spin diradical with electrical conductivity and derivatives of triangulene diradicals.
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Affiliation(s)
- Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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3
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Zhang H, Pink M, Wang Y, Rajca S, Rajca A. High-Spin S = 3/2 Ground-State Aminyl Triradicals: Toward High-Spin Oligo-Aza Nanographenes. J Am Chem Soc 2022; 144:19576-19591. [PMID: 36251959 PMCID: PMC10438970 DOI: 10.1021/jacs.2c09241] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report high-spin aminyl triradicals with near-planar triphenylene backbones. Near-planarity of the fused aminyl radicals and the 2,6,10-triphenylene ferromagnetic coupling unit (FCU), magnetically equivalent to three fused 3,4'-biphenyl FCUs, assures an effective 2pπ-2pπ overlap within the cross-conjugated π-system, leading to an S = 3/2 (quartet) ground state that is well separated from low-spin excited doublet states. Thermal populations of the low-spin (S = 1/2) excited states are detectable both by SQUID magnetometry and electron paramagnetic resonance (EPR) spectroscopy, providing doublet-quartet energy gaps, ΔEDQ, corresponding to >85% population of the quartet ground states at room temperature. Notably, EPR-based determination of ΔEDQ relies on direct detection of the quartet ground state and doublet excited states. The ΔEDQ values are 1.0-1.1 kcal mol-1, with the more sterically shielded triradical having the larger value. The half-life of the more sterically shielded triradical in 2-methyltetrahydrofuran (2-MeTHF) is about 6 h at room temperature. The less sterically shielded triradical in 2-MeTHF decomposes at 158 K with a half-life of about 4 h, while at 195 K, the half-life is still about 2 h. The dominant products of the decay of triradicals are the corresponding triamines, suggesting hydrogen atom abstraction from the solvent as the primary mechanism. This study expands the frontier of the open-shell PAHs/nanographenes, of which the unique electronic, nonlinear optical, and magnetic properties could be useful in the development of novel organic electronics, photonics, and spintronics.
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Affiliation(s)
- Hui Zhang
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, United States
| | - Ying Wang
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
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Zhang S, Pink M, Junghoefer T, Zhao W, Hsu SN, Rajca S, Calzolari A, Boudouris BW, Casu MB, Rajca A. High-Spin ( S = 1) Blatter-Based Diradical with Robust Stability and Electrical Conductivity. J Am Chem Soc 2022; 144:6059-6070. [PMID: 35333507 PMCID: PMC10439714 DOI: 10.1021/jacs.2c01141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Triplet ground-state organic molecules are of interest with respect to several emerging technologies but usually show limited stability, especially as thin films. We report an organic diradical, consisting of two Blatter radicals, that possesses a triplet ground state with a singlet-triplet energy gap, ΔEST ≈ 0.4-0.5 kcal mol-1 (2J/k ≈ 220-275 K). The diradical possesses robust thermal stability, with an onset of decomposition above 264 °C (TGA). In toluene/chloroform, glassy matrix, and fluid solution, an equilibrium between two conformations with ΔEST ≈ 0.4 kcal mol-1 and ΔEST ≈ -0.7 kcal mol-1 is observed, favoring the triplet ground state over the singlet ground-state conformation in the 110-330 K temperature range. The diradical with the triplet ground-state conformation is found exclusively in crystals and in a polystyrene matrix. The crystalline neutral diradical is a good electrical conductor with conductivity comparable to the thoroughly optimized bis(thiazolyl)-related monoradicals. This is surprising because the triplet ground state implies that the underlying π-system is cross-conjugated and thus is not compatible with either good conductance or electron delocalization. The diradical is evaporated under ultra-high vacuum to form thin films, which are stable in air for at least 18 h, as demonstrated by X-ray photoelectron and electron paramagnetic resonance (EPR) spectroscopies.
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Affiliation(s)
- Shuyang Zhang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Tobias Junghoefer
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Wenchao Zhao
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, United States
| | - Sheng-Ning Hsu
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | | | - Bryan W. Boudouris
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, United States
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, United States
| | - Maria Benedetta Casu
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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5
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Kutin Y, Reitz J, Antoni PW, Savitsky A, Pantazis DA, Kasanmascheff M, Hansmann MM. Characterization of a Triplet Vinylidene. J Am Chem Soc 2021; 143:21410-21415. [PMID: 34898204 PMCID: PMC8704171 DOI: 10.1021/jacs.1c11062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
![]()
Singlet vinylidenes
(R2C=C:) are proposed as
intermediates in a series of organic reactions, and very few have
been studied by matrix isolation or gas-phase spectroscopy. Triplet
vinylidenes, however, featuring two unpaired electrons at a monosubstituted
carbon atom are thus far only predicted as electronically excited-state
species and represent an unexplored class of carbon-centered diradicals.
We report the photochemical generation and low-temperature EPR/ENDOR
characterization of the first ground-state high-spin (triplet) vinylidene.
The zero-field splitting parameters (D = 0.377 cm–1 and |E|/D = 0.028)
were determined, and the 13C hyperfine coupling tensor
was obtained by 13C-ENDOR measurements. Most strikingly,
the isotropic 13C hyperfine coupling constant (50 MHz)
is far smaller than the characteristic values of triplet carbenes,
demonstrating a unique electronic structure which is supported by
quantum chemical calculations.
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Affiliation(s)
- Yury Kutin
- Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Justus Reitz
- Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Patrick W Antoni
- Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Anton Savitsky
- Department of Physics, Technische Universität Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Müge Kasanmascheff
- Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Max M Hansmann
- Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
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6
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Pozharskii AF, Gulevskaya AV, Claramunt RM, Alkorta I, Elguero J. Perimidines: a unique π-amphoteric heteroaromatic system. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4963] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Data on the physicochemical characteristics, theoretical calculations, reactivity and synthetic methods for perimidines are summarized. Although perimidine and some of its simple 2-substituted derivatives were obtained by Sachs back in 1909, their chemistry and key physical properties remained unknown until the early 1970s. Subsequent studies revealed many fundamental features of the perimidine system, previously not encountered in the heterocyclic series. The first comprehensive review on perimidines was published forty years ago. The period that has passed since 1980 led to the emergence of new directions and trends. Several hundred new publications have appeared, the generalization of which has become the main purpose of this article. This primarily concerns the obtaining of highly nucleophilic and stable perimidine carbenes, new methods of electrophilic substitution and oxidation, establishment of a close relationship between perimidines and proton sponges, and modern theoretical calculations. Based on perimidines, many different polycondensed systems have been obtained. Applied research has developed especially rapidly in recent years. Many new compounds based on perimidines related to chemosensors, analytical reagents, dyes, metal catalysts, electronic devices, nanotechnology, and medical chemistry have been proposed. Some information under review is presented as Supplementary Materials. It contains six tables, which include data on the basicity constants of perimidines, details of some synthetic methods for perimidines and fused analogs and also a list of biological activities of perimidines.
The bibliography includes 387 references.
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7
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Xiao Z, Zeng J, Phan H, Herng TS, Gopalakrishna TY, Ding J, Zeng W, Wu J. A Stable Nitrogen‐centered Bis(imino)perylene Dimer‐based Diradicaloid. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zhanhui Xiao
- School of Materials Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China
| | - Jian Zeng
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Hoa Phan
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Tun Seng Herng
- Department of Materials Science and Engineering National University of Singapore 119260 Singapore Singapore
| | | | - Jun Ding
- Department of Materials Science and Engineering National University of Singapore 119260 Singapore Singapore
| | - Wangdong Zeng
- School of Materials Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Jishan Wu
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
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8
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Farghaly TA, Al-Hussain SA, Muhammad ZA, Abdallah MA, Zaki MEA. Synthesis and Reactions of Perimidines and Their Fused Systems. CURR ORG CHEM 2020. [DOI: 10.2174/1385272824999200622113807] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Perimidines are peri-naphtho-fused derivatives of pyrimidine. They are of particular
interest as they are a rare example of an azine in which the lone pair of electrons of
pyrrole-like nitrogen participates in the π-system of the molecule. Perimidine is an interesting
class of heterocyclic compounds. Various synthetic analogs of perimidines have been
prepared and evaluated for many pharmacological activities in different models with desired
findings. They exhibit biological activities as antitumor, antiulcer, antimicrobial, and antifungal
agents. This review is an attempt to organize the synthesis and chemical reactions of
perimidine analogs reported to date systematically since 1955. It should be noted that this
review is the first one that includes the preparation and reactions of the perimidine ring.
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Affiliation(s)
- Thoraya A. Farghaly
- Department of Chemistry, Faculty of Science, Cairo University, Giza, 12613, Egypt
| | - Sami A. Al-Hussain
- Department of Chemistry, Faculty of Science, Al-Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia
| | - Zeinab A. Muhammad
- Department of Organic Chemistry, National Organization for Drug Control and Research (NODCAR), Giza 12311, Egypt
| | - Magda A. Abdallah
- Department of Chemistry, Faculty of Science, Cairo University, Giza, 12613, Egypt
| | - Magdi E. A. Zaki
- Department of Chemistry, Faculty of Science, Al-Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia
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9
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Sadhukhan T, Beckett D, Thapa B, Raghavachari K. Coupling Constants, High Spin, and Broken Symmetry States of Organic Radicals: an Assessment of the Molecules-in-Molecules Fragmentation-Based Method. J Chem Theory Comput 2019; 15:5998-6009. [DOI: 10.1021/acs.jctc.9b00563] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Tumpa Sadhukhan
- Department of Chemistry, Indiana University, Bloomington, 47405 Indiana, United States
| | - Daniel Beckett
- Department of Chemistry, Indiana University, Bloomington, 47405 Indiana, United States
| | - Bishnu Thapa
- Department of Chemistry, Indiana University, Bloomington, 47405 Indiana, United States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, 47405 Indiana, United States
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10
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Song M, Song X, Bu Y. Spin coupling interactions in C[double bond, length as m-dash]C or B-B-cored porphyrin-mimetic graphene patch nitroxide diradicals. Phys Chem Chem Phys 2018. [PMID: 29517098 DOI: 10.1039/c8cp00105g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In view of the unique structures and promising applications of porphyrins and their derivatives, exploration of their various properties has continued to a hot topic. In this work, we combine porphyrin-mimetic graphene patches which are core-modified by a C[double bond, length as m-dash]C or a B-B unit and two nitroxide radical groups to construct a series of novel diradical molecules (the CC-cored or BB-cored molecules). The spin coupling constants (J) of diradicals were calculated at the (U)B3LYP/6-311G(d,p) level by considering the different linking modes of two nitroxide groups. The results indicate that different core modification considerably affects the J values of such diradicals, and the linking modes can tune the sizes and signs of J, changing their magnetic coupling interactions with different magnitudes and the signs of J from antiferromagnetic to ferromagnetic or vice versa. More interestingly and importantly, the spin coupling interactions of the CC-cored molecules can also be tuned by stretching the core unit C-C bond, suggesting the possibility of activating specific vibrational modes of the CC-cored diradicals by energy pulses to yield variable J coupling magnitudes. On the other hand, for the BB-cored molecules, two-electron reduction can switch or tune their magnetism from ferromagnetic to antiferromagnetic. The essence of all observations is further analyzed from the structural effects and orbital and spin density distributions. The findings about magnetic regulation in these core-modified porphyrin-mimetic graphene patch nitroxide diradicals further expand the field of molecular magnets and provide a rational theoretical basis for designing novel building blocks of magnetic functional molecular materials.
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Affiliation(s)
- Meiyu Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
| | - Xinyu Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
| | - Yuxiang Bu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China. and School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, People's Republic of China
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11
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Alkylation reactions of 5-amino-substituted tetrazolo[1,5-a][1,3,5]triazin-7(3H)-ones with alkyl halides. Chem Heterocycl Compd (N Y) 2017. [DOI: 10.1007/s10593-017-2007-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Olankitwanit A, Rajca S, Rajca A. Aza-m-Xylylene Diradical with Increased Steric Protection of the Aminyl Radicals. J Org Chem 2015; 80:5035-44. [DOI: 10.1021/acs.joc.5b00421] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arnon Olankitwanit
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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13
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Affiliation(s)
- Nolan M. Gallagher
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Arnon Olankitwanit
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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14
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Farghaly TA, Mahmoud HK. Site- and Regioselectivity of the Reaction of Hydrazonoyl Chlorides with Perimidine Ketene Aminal. Antimicrobial Evaluation of the Products. J Heterocycl Chem 2014. [DOI: 10.1002/jhet.1985] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Thoraya A. Farghaly
- Chemistry Department, Faculty of Science; University of Cairo; Giza 12613 Egypt
| | - Huda K. Mahmoud
- Chemistry Department, Faculty of Science; University of Cairo; Giza 12613 Egypt
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15
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Hibi D, Kitabayashi K, Shimizu A, Umeda R, Tobe Y. Synthesis and physical properties of zethrene derivatives bearing donor/acceptor substituents at 7,14-positions. Org Biomol Chem 2013; 11:8256-61. [DOI: 10.1039/c3ob41674g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Barone V, Boilleau C, Cacelli I, Ferretti A, Monti S, Prampolini G. Structure–Properties Relationships in Triplet Ground State Organic Diradicals: A Computational Study. J Chem Theory Comput 2012; 9:300-7. [DOI: 10.1021/ct300790c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, piazza
dei Cavalieri 7, I-56126 Pisa, Italy
| | - Corentin Boilleau
- Scuola Normale Superiore, piazza
dei Cavalieri 7, I-56126 Pisa, Italy
| | - Ivo Cacelli
- Dipartimento di Chimica e Chimica
Industriale, Università degli Studi di Pisa, via Risorgimento
35, I-56126 Pisa, Italy
| | - Alessandro Ferretti
- Istituto
di Chimica dei Composti
OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1,
I-56124 Pisa, Italy
| | - Susanna Monti
- Scuola Normale Superiore, piazza
dei Cavalieri 7, I-56126 Pisa, Italy
- Istituto
di Chimica dei Composti
OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1,
I-56124 Pisa, Italy
| | - Giacomo Prampolini
- Istituto
per i Processi Chimico-Fisici
(IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
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17
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Magnetism-Tunable Oligoacene Dioxide Diradicals: Promising Magnetic Oligoacene-Like Molecules. Chemphyschem 2012; 13:4148-54. [DOI: 10.1002/cphc.201200703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Indexed: 11/07/2022]
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18
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Matrix Isolation and Spectroscopic Characterization of 2,5,6-Trifluoropyridylnitren-3-yl. European J Org Chem 2012. [DOI: 10.1002/ejoc.201101866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Ikbal M, Jana A, Singh NP, Banerjee R, Dhara D. Photoacid generators (PAGs) based on N-acyl-N-phenylhydroxylamines for carboxylic and sulfonic acids. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.03.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Rajca A, Olankitwanit A, Rajca S. Triplet Ground State Derivative of Aza-m-xylylene Diradical with Large Singlet−Triplet Energy Gap. J Am Chem Soc 2011; 133:4750-3. [DOI: 10.1021/ja200708b] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Arnon Olankitwanit
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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Maji M, Mallick D, Mondal S, Anoop A, Bag SS, Basak A, Jemmis ED. Selectivity in Garratt−Braverman Cyclization: An Experimental and Computational Study. Org Lett 2011; 13:888-91. [DOI: 10.1021/ol102861j] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manasi Maji
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
| | - Dibyendu Mallick
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
| | - Sayantan Mondal
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
| | - Anakuthil Anoop
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
| | - Subhendu Sekhar Bag
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
| | - Amit Basak
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
| | - Eluvathingal D. Jemmis
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India, Department of Chemistry, Indian Institute of Technology, Guwahati India, and Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram, 695 016, Kerala, India
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Smellie IA, Fromm A, Moggach SA, Paton RM. Synthesis and structure of 2-pyransoylperimidines. Carbohydr Res 2011; 346:43-9. [DOI: 10.1016/j.carres.2010.09.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2010] [Revised: 09/17/2010] [Accepted: 09/23/2010] [Indexed: 11/26/2022]
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Neuhaus P, Sander W. Isolation and Characterization of the Triradical 1,3,5-Trimethylenebenzene. Angew Chem Int Ed Engl 2010; 49:7277-80. [DOI: 10.1002/anie.201001393] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Neuhaus P, Sander W. Isolation and Characterization of the Triradical 1,3,5-Trimethylenebenzene. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001393] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Boratyński P, Pink M, Rajca S, Rajca A. Isolation of the Triplet Ground State Aminyl Diradical. Angew Chem Int Ed Engl 2010; 49:5459-62. [DOI: 10.1002/anie.201002811] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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Boratyński P, Pink M, Rajca S, Rajca A. Isolation of the Triplet Ground State Aminyl Diradical. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201002811] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Vieille-Petit L, Clavier H, Linden A, Blumentritt S, Nolan SP, Dorta R. Ruthenium Olefin Metathesis Catalysts with N-Heterocyclic Carbene Ligands Bearing N-Naphthyl Side Chains. Organometallics 2010. [DOI: 10.1021/om9009697] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ludovic Vieille-Petit
- Organic Chemistry Institute, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Hervé Clavier
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, U.K
| | - Anthony Linden
- Organic Chemistry Institute, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Sascha Blumentritt
- Organic Chemistry Institute, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Steven P. Nolan
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, U.K
| | - Reto Dorta
- Organic Chemistry Institute, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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Dong H, Hrovat DA, Quast H, Borden WT. Calculations of the Relative Energies of the Low-Lying Electronic States of 2-Methylenedihydrophenalene-1,3-diyl: Effects of a 1,8-Naphtho Bridging Group on Trimethylenemethane and of a Vinylidene Bridging Group on 1,8-Naphthoquinodimethane. J Phys Chem A 2009; 113:895-901. [DOI: 10.1021/jp809715v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hao Dong
- Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, 305070, Denton, Texas 76203-5070, and Institut für Organische Chemie der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - David A. Hrovat
- Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, 305070, Denton, Texas 76203-5070, and Institut für Organische Chemie der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Helmut Quast
- Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, 305070, Denton, Texas 76203-5070, and Institut für Organische Chemie der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Weston Thatcher Borden
- Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, 305070, Denton, Texas 76203-5070, and Institut für Organische Chemie der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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