1
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Fahrenhorst-Jones T, Marshall DL, Burns JM, Pierens GK, Van Meurs DP, Kong D, Bernhardt PV, Blanksby SJ, Savage GP, Eaton PE, Williams CM. 9-Azahomo cubane. Chemistry 2024; 30:e202303133. [PMID: 37823679 DOI: 10.1002/chem.202303133] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/13/2023]
Abstract
Homocubane, a highly strained cage hydrocarbon, contains two very different positions for the introduction of a nitrogen atom into the skeleton, e. g., a position 1 exchange results in a tertiary amine whereas position 9 yields a secondary amine. Herein reported is the synthesis of 9-azahomocubane along with associated structural characterization, physical property analysis and chemical reactivity. Not only is 9-azahomocubane readily synthesized, and found to be stable as predicted, the basicity of the secondary amine was observed to be significantly lower than the structurally related azabicyclo[2.2.1]heptane, although similar to 1-azahomocubane.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - David L Marshall
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Gregory K Pierens
- Centre for Advanced imaging, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Derek P Van Meurs
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Dehui Kong
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria, Australia
| | - Philip E Eaton
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
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2
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Chan KY, Kinghorn AB, Hollenstein M, Tanner JA. Chemical modifications for a next generation of nucleic acid aptamers. Chembiochem 2022; 23:e202200006. [PMID: 35416400 DOI: 10.1002/cbic.202200006] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/11/2022] [Indexed: 11/08/2022]
Abstract
In the past three decades, in vitro systematic evolution of ligands by exponential enrichment (SELEX) has yielded many aptamers for translational applications in both research and clinical settings. Despite their promise as an alternative to antibodies, the low success rate of SELEX (~ 30%) has been a major bottleneck that hampers the further development of aptamers. One hurdle is the lack of chemical diversity in nucleic acids. To address this, the aptamer chemical repertoire has been extended by introducing exotic chemical groups, which provide novel binding functionalities. This review will focus on how modified aptamers can be selected and evolved, with illustration of some successful examples. In particular, unique chemistries are exemplified. Various strategies of incorporating modified building blocks into the standard SELEX protocol are highlighted, with a comparison of the differences between pre-SELEX and post-SELEX modifications. Nucleic acid aptamers with extended functionality evolved from non-natural chemistries will open up new vistas for function and application of nucleic acids.
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Affiliation(s)
- Kwing Yeung Chan
- The University of Hong Kong, School of Biomedical Sciences, HONG KONG
| | | | | | - Julian Alexander Tanner
- The University of Hong Kong, School of Biomedical Sciences, 3/F Laboratory Block, 21 Sassoon Road, 000000, Pokfulam, HONG KONG
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3
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Chachkov DV, Mikhailov OV. Cubic Octa-Carbon: Quantum-Chemical Design of Molecular Structure and Potential Way of Its Synthesis from Cubane. Int J Mol Sci 2021; 22:12067. [PMID: 34769494 DOI: 10.3390/ijms222112067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/30/2021] [Accepted: 11/05/2021] [Indexed: 11/17/2022] Open
Abstract
Quantum-chemical calculation of most important parameters of molecular and electronic structures of octa-carbon C8 having cubic form (bond lengths, bond and torsion angles) using CCSD(T)/QZVP and DFT B3PW91/QZVP methods, has been carried out. NBO analysis data and HOMO/LUMO images for this compound are presented, too. Good agreement was found between the structural data obtained using the above two quantum-chemical methods and, also, with corresponding experimental data. Also, the standard thermodynamic parameters of formation of cubic C8 considered here, and namely standard enthalpy ΔfH0(298K), entropy Sf0(298K) and Gibbs’ energy ΔfG0(298K) of formation for this compound were calculated. By using this data, a theoretically possible variant of the synthesis of this compound by dehydrogenation of cubane C8H8 is considered, and the thermodynamic characteristics of each of the four stages of this process have been calculated. It is noted that each of the four stages of this process is characterized by a very high (about 500 kJ/mol) enthalpy of activation, as a result of that, for their realization within a sufficiently short time, the use of appropriate catalysts is necessary.
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4
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Dallaston MA, Houston SD, Williams CM. Cubane, Bicyclo[1.1.1]pentane and Bicyclo[2.2.2]octane: Impact and Thermal Sensitiveness of Carboxyl-, Hydroxymethyl- and Iodo-substituents. Chemistry 2020; 26:11966-11970. [PMID: 32820575 DOI: 10.1002/chem.202001658] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/22/2020] [Indexed: 12/21/2022]
Abstract
With the burgeoning interest in cage motifs for bioactive molecule discovery, and the recent disclosure of 1,4-cubane-dicarboxylic acid impact sensitivity, more research into the safety profiles of cage scaffolds is required. Therefore, the impact sensitivity and thermal decomposition behavior of judiciously selected starting materials and synthetic intermediates of cubane, bicyclo[1.1.1]pentane (BCP), and bicyclo[2.2.2]octane (BCO) were evaluated via hammer test and sealed cell differential scanning calorimetry, respectively. Iodo-substituted systems were found to be more impact sensitive, whereas hydroxymethyl substitution led to more rapid thermodecomposition. Cubane was more likely to be impact sensitive with these substituents, followed by BCP, whereas all BCOs were unresponsive. The majority of derivatives were placed substantially above Yoshida thresholds-a computational indicator of sensitivity.
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Affiliation(s)
- Madeleine A Dallaston
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Sevan D Houston
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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5
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Cheung YW, Röthlisberger P, Mechaly AE, Weber P, Levi-Acobas F, Lo Y, Wong AWC, Kinghorn AB, Haouz A, Savage GP, Hollenstein M, Tanner JA. Evolution of abiotic cubane chemistries in a nucleic acid aptamer allows selective recognition of a malaria biomarker. Proc Natl Acad Sci U S A 2020; 117:16790-8. [PMID: 32631977 DOI: 10.1073/pnas.2003267117] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nucleic acid aptamers selected through systematic evolution of ligands by exponential enrichment (SELEX) fold into exquisite globular structures in complex with protein targets with diverse translational applications. Varying the chemistry of nucleotides allows evolution of nonnatural nucleic acids, but the extent to which exotic chemistries can be integrated into a SELEX selection to evolve nonnatural macromolecular binding interfaces is unclear. Here, we report the identification of a cubane-modified aptamer (cubamer) against the malaria biomarker Plasmodium vivax lactate dehydrogenase (PvLDH). The crystal structure of the complex reveals an unprecedented binding mechanism involving a multicubane cluster within a hydrophobic pocket. The binding interaction is further stabilized through hydrogen bonding via cubyl hydrogens, previously unobserved in macromolecular binding interfaces. This binding mechanism allows discriminatory recognition of P. vivax over Plasmodium falciparum lactate dehydrogenase, thereby distinguishing these highly conserved malaria biomarkers for diagnostic applications. Together, our data demonstrate that SELEX can be used to evolve exotic nucleic acids bearing chemical functional groups which enable remarkable binding mechanisms which have never been observed in biology. Extending to other exotic chemistries will open a myriad of possibilities for functional nucleic acids.
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6
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Grover N, Locke GM, Flanagan KJ, Beh MHR, Thompson A, Senge MO. Bridging and Conformational Control of Porphyrin Units through Non-Traditional Rigid Scaffolds. Chemistry 2020; 26:2405-2416. [PMID: 31697426 PMCID: PMC7064986 DOI: 10.1002/chem.201904199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Indexed: 12/21/2022]
Abstract
Connecting two porphyrin units in a rigid linear fashion, without any undesired electron delocalization or communication between the chromophores, remains a synthetic challenge. Herein, a broad library of functionally diverse multi-porphyrin arrays that incorporate the non-traditional rigid linker groups cubane and bicyclo[1.1.1]pentane (BCP) is described. A robust, reliable, and versatile synthetic procedure was employed to access porphyrin-cubane/BCP-porphyrin arrays, representing the largest non-polymeric structures available for cubane/BCP derivatives. These reactions demonstrate considerable substrate scope, from utilization of small phenyl moieties to large porphyrin rings, with varying lengths and different angles. To control conformational flexibility, amide bonds were introduced between the bridgehead carbon of BCP/cubane and the porphyrin rings. Through varying the orientation of the substituents around the amide bond of cubane/BCP, different intermolecular interactions were identified through single crystal X-ray analysis. These studies revealed non-covalent interactions that are the first-of-their-kind including a unique iodine-oxygen interaction between cubane units. These supramolecular architectures indicate the possibility to mimic a protein structure due to the sp3 rigid scaffolds (BCP or cubane) that exhibit the essential conformational space for protein function while simultaneously providing amide bonds for molecular recognition.
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Affiliation(s)
- Nitika Grover
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity College DublinTrinity Biomedical Sciences InstituteThe University of Dublin152-160 Pearse StreetDublin2Ireland
| | - Gemma M. Locke
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity College DublinTrinity Biomedical Sciences InstituteThe University of Dublin152-160 Pearse StreetDublin2Ireland
| | - Keith J. Flanagan
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity College DublinTrinity Biomedical Sciences InstituteThe University of Dublin152-160 Pearse StreetDublin2Ireland
| | - Michael H. R. Beh
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity College DublinTrinity Biomedical Sciences InstituteThe University of Dublin152-160 Pearse StreetDublin2Ireland
- Department of ChemistryDalhousie UniversityP.O. Box 15000Halifax, Nova ScotiaB3H 4R2Canada
| | - Alison Thompson
- Department of ChemistryDalhousie UniversityP.O. Box 15000Halifax, Nova ScotiaB3H 4R2Canada
| | - Mathias O. Senge
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity College DublinTrinity Biomedical Sciences InstituteThe University of Dublin152-160 Pearse StreetDublin2Ireland
- Physics Department E20Technische Universität MünchenJames-Franck-Str. 185748GarchingGermany
- Institute for Advanced Study (TUM-IAS)Technische Universität MünchenLichtenberg-Str. 2a85748GarchingGermany
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7
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Dallaston MA, Brusnahan JS, Wall C, Williams CM. Thermal and Sensitiveness Determination of Cubanes: Towards Cubane-Based Fuels for Infrared Countermeasures. Chemistry 2019; 25:8344-8352. [PMID: 31124182 DOI: 10.1002/chem.201901086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/17/2019] [Indexed: 11/06/2022]
Abstract
As infrared seeking technology evolves, threats are better able to distinguish defensive infrared (IR) flares from true targets. Spectrally matched flares, which generally employ carbon-based fuels, are better able to decoy some advanced missiles by more closely mimicking the IR emission of the target. Cubane is a high-energy carbon-based scaffold which may be suitable for use as a fuel in spectrally matched flares. The enthalpy of formation and strain energy of a series of cubanes was predicted in silico, and their thermal and impact stability examined. All were found to undergo highly exothermic decomposition in sealed cell differential scanning calorimetry, and two cubanes subsequently underwent quantitative sensitiveness testing. Despite their F of I values being in the secondary explosive range, cubane-1,4-dicarboxylic acid (F of I=70) and 4-carbamoylcubane-1-carboxylic acid (F of I=90) were identified as potentially useful fuels for pyrotechnic infrared countermeasure flare formulations.
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Affiliation(s)
- Madeleine A Dallaston
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Jason S Brusnahan
- Defence Science and Technology Group, Edinburgh, South Australia, 5111, Australia
| | - Craig Wall
- Defence Science and Technology Group, Edinburgh, South Australia, 5111, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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8
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Nguyen AI, Van Allsburg KM, Terban MW, Bajdich M, Oktawiec J, Amtawong J, Ziegler MS, Dombrowski JP, Lakshmi KV, Drisdell WS, Yano J, Billinge SJL, Tilley TD. Stabilization of reactive Co 4O 4 cubane oxygen-evolution catalysts within porous frameworks. Proc Natl Acad Sci U S A 2019; 116:11630-9. [PMID: 31142656 DOI: 10.1073/pnas.1815013116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A major challenge to the implementation of artificial photosynthesis (AP), in which fuels are produced from abundant materials (water and carbon dioxide) in an electrochemical cell through the action of sunlight, is the discovery of active, inexpensive, safe, and stable catalysts for the oxygen evolution reaction (OER). Multimetallic molecular catalysts, inspired by the natural photosynthetic enzyme, can provide important guidance for catalyst design, but the necessary mechanistic understanding has been elusive. In particular, fundamental transformations for reactive intermediates are difficult to observe, and well-defined molecular models of such species are highly prone to decomposition by intermolecular aggregation. Here, we present a general strategy for stabilization of the molecular cobalt-oxo cubane core (Co4O4) by immobilizing it as part of metal-organic frameworks, thus preventing intermolecular pathways of catalyst decomposition. These materials retain the OER activity and mechanism of the molecular Co4O4 analog yet demonstrate unprecedented long-term stability at pH 14. The organic linkers of the framework allow for chemical fine-tuning of activity and stability and, perhaps most importantly, provide "matrix isolation" that allows for observation and stabilization of intermediates in the water-splitting pathway.
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9
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Ohki Y, Uchida K, Hara R, Kachi M, Fujisawa M, Tada M, Sakai Y, Sameera WMC. Cubane-Type [Mo 3 S 4 M] Clusters with First-Row Groups 4-10 Transition-Metal Halides Supported by C 5 Me 5 Ligands on Molybdenum. Chemistry 2018; 24:17138-17147. [PMID: 30204282 DOI: 10.1002/chem.201804083] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Indexed: 02/02/2023]
Abstract
A synthetic protocol was developed for a series of cubane-type [Mo3 S4 M] clusters that incorporate halides of first-row transition metals (M) from Groups 4-10. This protocol is based on the anionic cluster platform [Cp*3 Mo3 S4 ]- ([1]- ; Cp*=η5 -C5 Me5 ), which crystallizes when K(18-crown-6) is used as the counter cation. Treatment of in situ-generated [1]- with such transition-metal halides led to the formation of [Mo3 S4 M] clusters, in which the M/halide ratio gradually changes from 1:2 to 1:1.5 and to 1:1, when moving from early to late transition metals. This trend suggests a tendency for early transition metals to tolerate higher oxidation states and adopt larger ionic radii relative to late transition metals. The properties of the [Mo3 S4 Fe] cluster 6 a were investigated in detail by using 57 Fe Mössbauer spectroscopy and computational methods.
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Affiliation(s)
- Yasuhiro Ohki
- Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Keisuke Uchida
- Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Ryota Hara
- Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Mami Kachi
- Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Mayu Fujisawa
- Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Mizuki Tada
- Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.,Research Center for Materials Science (RCMS) & Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Yoichi Sakai
- Department of Chemistry, Daido University, Takiharu-cho, Minami-ku, Nagoya, 457-8530, Japan
| | - W M C Sameera
- Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan
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10
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Schilling M, Hodel FH, Luber S. Discovery of Open Cubane Core Structures for Biomimetic LnCo 3 (OR) 4 Water Oxidation Catalysts. ChemSusChem 2017; 10:4561-4569. [PMID: 28941193 DOI: 10.1002/cssc.201701527] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Indexed: 06/07/2023]
Abstract
Bio-mimetic catalysts such as LnCo3 (OR)4 (Ln=Er, Tm; OR=alkoxide) cubanes have recently been in the focus of research for artificial water oxidation processes. Previously, the remarkable adaptability with respect to ligand shell, nuclear structure as well as protonation and oxidation states of those catalysts has been shown to be beneficial for the water oxidation process. We further explored the structural flexibility of those catalysts and present here a series of novel structures in which one metal center is pulled out of the cubane cage. This leads to an open cubane core, which is to some extent reminiscent of observed open/closed cubane-core forms of the oxygen-evolving complex in nature's photosystem II. We investigate how those open cubane core models alter the thermodynamics of the water oxidation cycle and how different solvation approaches influence their stability.
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Affiliation(s)
- Mauro Schilling
- Department of Chemistry C, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Florian H Hodel
- Department of Chemistry C, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Sandra Luber
- Department of Chemistry C, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
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11
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Elmehdawi RM, El-Kaheli MN, Abuhmaiera RG, Treish FA, Ben Younes MEM, Bazzicalupi C, Guerri A, Caneschi A, Amjad A. Synthesis, Crystal Structure, and Magnetic Properties of a New Mixed Metal (Co(II), Ni(II)) Cubane. Materials (Basel) 2017; 10:ma10020178. [PMID: 28772539 PMCID: PMC5459200 DOI: 10.3390/ma10020178] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 02/03/2017] [Accepted: 02/04/2017] [Indexed: 11/25/2022]
Abstract
The mixed Co(II)/Ni(II) complex, [Co2.67Ni1.33L4(CH3COO)2][BPh4]2·0.75H2O where HL = 4-(salicylaldimine)antipyrine, was isolated as an orange solid from the reaction of 4-(salicylaldimine)antipyrine, with mixed cobalt(II) acetate and nickel(II) acetate in ethanol. The complex was characterized by Frustrated Total Internal Reflection (FTIR), UltraViolet Visible spectroscopy (UV-Vis), X-ray single crystal diffraction, and by elemental analysis. The complex is composed of two symmetry independent cationic units, A and B. The two units are essentially isostructural; nevertheless, small differences exist between them. The units contain four metal atoms, arranged at the corners of a distorted cubane-like core alternately with phenoxy oxygen of the Schiff base. The overall eight corners occupied by metal ions in the asymmetric unit are shared between cobalt and nickel in a 5.33:2.67 ratio. Each metal divalent cation binds three coordinated sites from the corresponding tridentate Schiff base ligand, the fourth one is bound by the acetate oxygen, the fifth and the sixth donor sites come from the phenolate oxygens of other Schiff base ligands. Intermolecular hydrogen bonds join the complexes to the water molecules present in the crystal packing. The magnetic characterization was carried out for this new complex and for its isostructural counterpart containing only cobalt ions. The magnetic measurements for the cobalt(II)/nickel(II) mixed compound indicate either antiferromagnetic interactions among the two cubanes or an anisotropic contribution, whereas a ferromagnetic interaction is observed within the cubane, for both the complexes, as expected by geometrical considerations. A comparison between the magnetic properties of the pure cobalt(II) derivative and similar systems discussed in literature, is presented.
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Affiliation(s)
| | | | | | | | | | - Carla Bazzicalupi
- Chemistry Department, "U. Schiff", University of Florence, Sesto Fiorentino (Fl) 50019, Italy.
| | - Annalisa Guerri
- Chemistry Department, "U. Schiff", University of Florence, Sesto Fiorentino (Fl) 50019, Italy.
| | - Andrea Caneschi
- Chemistry Department, "U. Schiff", University of Florence, Sesto Fiorentino (Fl) 50019, Italy.
- INSTM-Research Unit at University of Florence, Sesto Fiorentino (Fl) 50019, Italy.
| | - Asma Amjad
- Chemistry Department, "U. Schiff", University of Florence, Sesto Fiorentino (Fl) 50019, Italy.
- INSTM-Research Unit at University of Florence, Sesto Fiorentino (Fl) 50019, Italy.
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12
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Chalmers BA, Xing H, Houston S, Clark C, Ghassabian S, Kuo A, Cao B, Reitsma A, Murray CEP, Stok JE, Boyle GM, Pierce CJ, Littler SW, Winkler DA, Bernhardt PV, Pasay C, De Voss JJ, McCarthy J, Parsons PG, Walter GH, Smith MT, Cooper HM, Nilsson SK, Tsanaktsidis J, Savage GP, Williams CM. Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere. Angew Chem Int Ed Engl 2016; 55:3580-5. [PMID: 26846616 DOI: 10.1002/anie.201510675] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 01/03/2016] [Indexed: 01/25/2023]
Abstract
Pharmaceutical and agrochemical discovery programs are under considerable pressure to meet increasing global demand and thus require constant innovation. Classical hydrocarbon scaffolds have long assisted in bringing new molecules to the market place, but an obvious omission is that of the Platonic solid cubane. Eaton, however, suggested that this molecule has the potential to act as a benzene bioisostere. Herein, we report the validation of Eaton's hypothesis with cubane derivatives of five molecules that are used clinically or as agrochemicals. Two cubane analogues showed increased bioactivity compared to their benzene counterparts whereas two further analogues displayed equal bioactivity, and the fifth one demonstrated only partial efficacy. Ramifications from this study are best realized by reflecting on the number of bioactive molecules that contain a benzene ring. Substitution with the cubane scaffold where possible could revitalize these systems, and thus expedite much needed lead candidate identification.
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Affiliation(s)
- Benjamin A Chalmers
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Hui Xing
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Sevan Houston
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | | | | | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, UQ, Australia
| | - Benjamin Cao
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Australian Regenerative Medicine Institute, Monash University (MU), Melbourne, 3168, VIC, Australia
| | - Andrea Reitsma
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Australian Regenerative Medicine Institute, Monash University (MU), Melbourne, 3168, VIC, Australia
| | | | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Glen M Boyle
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - Carly J Pierce
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - Stuart W Littler
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia
| | - David A Winkler
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Monash Institute of Pharmaceutical Sciences, Parkville, 3052, MU, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - Cielo Pasay
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia.,Australian Centre for International and Tropical Health, UQ, Australia
| | - Peter G Parsons
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | | | - Maree T Smith
- Centre for Integrated Preclinical Drug Development, UQ, Australia
| | | | - Susan K Nilsson
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.,Australian Regenerative Medicine Institute, Monash University (MU), Melbourne, 3168, VIC, Australia
| | - John Tsanaktsidis
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.
| | - G Paul Savage
- CISRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC, Australia.
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD, Australia.
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13
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Li X, Clatworthy EB, Masters AF, Maschmeyer T. Molecular Cobalt Clusters as Precursors of Distinct Active Species in Electrochemical, Photochemical, and Photoelectrochemical Water Oxidation Reactions in Phosphate Electrolytes. Chemistry 2015; 21:16578-84. [PMID: 26404053 DOI: 10.1002/chem.201502428] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Indexed: 11/09/2022]
Abstract
Three cobalt model molecular compounds, Co-cubane ([Co4 (µ3 -O)4 (µ-OAc)4 py4 ]), Co-trimer ([Co3 (μ3 -O)(µ-OAc)6 py3 ]PF6 ), and Co-dimer ([Co2 (μ-OH)2 (µ-OAc)(OAc)2 py4 ]PF6 ), are investigated as water oxidation reaction (WOR) catalysts, using electrochemical, photochemical, and photoelectrochemical methodologies in phosphate electrolyte. The actual species contributing to the catalytic activity observed in the WOR are derived from the transformation of these cobalt compounds. The catalytic activity observed is highly dependent on the initial compound structure and on the particular WOR methodology used. Co-cubane shows no activity in the electrochemical WOR and negligible activity in the photochemical WOR, but is active in the photoelectrochemical WOR, in which it behaves as a precursor to catalytically active species. Co-dimer also shows no activity in the electrochemical WOR, but behaves as a precursor to catalytically active species in both the photochemical and photoelectrochemical WOR experiments. Co-trimer behaves as a precursor to catalytically active species in all three of the WOR methodologies.
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Affiliation(s)
- Xiaobo Li
- Laboratory of Advanced Catalysis for Sustainability, School of Chemistry, University of Sydney, Sydney NSW, 2006 (Australia), Fax: (+61) 2-9351-3329
| | - Edwin B Clatworthy
- Laboratory of Advanced Catalysis for Sustainability, School of Chemistry, University of Sydney, Sydney NSW, 2006 (Australia), Fax: (+61) 2-9351-3329
| | - Anthony F Masters
- Laboratory of Advanced Catalysis for Sustainability, School of Chemistry, University of Sydney, Sydney NSW, 2006 (Australia), Fax: (+61) 2-9351-3329
| | - Thomas Maschmeyer
- Laboratory of Advanced Catalysis for Sustainability, School of Chemistry, University of Sydney, Sydney NSW, 2006 (Australia), Fax: (+61) 2-9351-3329.
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Biegasiewicz KF, Ingalsbe ML, St. Denis JD, Gleason JL, Ho J, Coote ML, Savage GP, Priefer R. Evaluation of a chiral cubane-based Schiff base ligand in asymmetric catalysis reactions. Beilstein J Org Chem 2012; 8:1814-8. [PMID: 23209516 PMCID: PMC3511016 DOI: 10.3762/bjoc.8.207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 09/19/2012] [Indexed: 11/27/2022] Open
Abstract
Recently, a novel chiral cubane-based Schiff base ligand was reported to yield modest enantioselectivity in the Henry reaction. To further explore the utility of this ligand in other asymmetric organic transformations, we evaluated its stereoselectivity in cyclopropanation and Michael addition reactions. Although there was no increase in stereocontrol, upon computational evaluation using both M06L and B3LYP calculations, it was revealed that a pseudo six-membered ring exists, through H-bonding of a cubyl hydrogen to the copper core. This decreases the steric bulk above the copper center and limits the asymmetric control with this ligand.
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Affiliation(s)
- Kyle F Biegasiewicz
- Department of Chemistry, Biochemistry, and Physics, Niagara University, NY 14109, USA
| | - Michelle L Ingalsbe
- Department of Chemistry, Biochemistry, and Physics, Niagara University, NY 14109, USA
| | | | - James L Gleason
- Department of Chemistry, McGill University, Montreal, QC, H3A 2K6, Canada
| | - Junming Ho
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Michelle L Coote
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - G Paul Savage
- CSIRO Materials Science and Engineering, Clayton South MDC 3169, Australia
| | - Ronny Priefer
- Department of Chemistry, Biochemistry, and Physics, Niagara University, NY 14109, USA
- College of Pharmacy, Western New England University, Springfield, MA 01119, USA
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