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Bakardjiev M, Holub J, Růžičková Z, Růžička A, Fanfrlík J, Štíbr B, McKee ML, Hnyk D. Transformation of various multicenter bondings within bicapped-square antiprismatic motifs: Z-rearrangement. Dalton Trans 2021; 50:12098-12106. [PMID: 33656022 DOI: 10.1039/d0dt04225k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reported herein are mutual rearrangements in the whole series of seven bicapped-square antiprismatic closo-C2B8H10 by means of high-quality computations that disprove the earlier postulated dsd (diamond-square-diamond) scheme for these isomerizations. The experimentally existing closo-1,2-C2B8H10 was able to be converted to 1,6-, and 1,10-isomers by pyrolysis, and the dsd (diamond-square-diamond) mechanism was offered as an explanation of these processes. However, these computations disprove the postulated dsd scheme for these isomerizations that take place in the ten-vertex closo series. Experimentally observed thermal rearrangements, both in the parent and substituted closo-1,2-C2B8H10, closo-1-CB9H10-, and closo-B10H102-, indirectly support these refined computations. All these processes are based on the new concept of the so-called Z-mechanism, being consistent with a transition state of a boat shape with an open hexagonal belt that results from the initial breakage of three bonds. Such bond breakings and the consequent bond formations bring to mind the shape of the letter Z. In effect, the pattern of multicenter bonding shifts from reactant through a transition state to product. The molecular rearrangements that are available experimentally favour either the axial or equatorial isomers, and this ratio depends on temperature and the type of cluster and its substitution.
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Affiliation(s)
- Mario Bakardjiev
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, CZ - 250 68, Husinec-Řež, Czech Republic.
| | - Josef Holub
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, CZ - 250 68, Husinec-Řež, Czech Republic.
| | - Zdeňka Růžičková
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
| | - Jindřich Fanfrlík
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ - 166 10, Prague 6, Czech Republic
| | - Bohumil Štíbr
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, CZ - 250 68, Husinec-Řež, Czech Republic.
| | - Michael L McKee
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, 36849, USA.
| | - Drahomír Hnyk
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, CZ - 250 68, Husinec-Řež, Czech Republic.
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2
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Vrána J, Holub J, Samsonov MA, Růžičková Z, Cvačka J, McKee ML, Fanfrlík J, Hnyk D, Růžička A. Access to cationic polyhedral carboranes via dynamic cage surgery with N-heterocyclic carbenes. Nat Commun 2021; 12:4971. [PMID: 34404809 PMCID: PMC8371172 DOI: 10.1038/s41467-021-25277-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/02/2021] [Indexed: 12/03/2022] Open
Abstract
Polyhedral boranes and heteroboranes appear almost exclusively as neutral or anionic species, while the cationic ones are protonated at exoskeletal heteroatoms or they are instable. Here we report the reactivity of 10-vertex closo-dicarbadecaboranes with one or two equivalents of N-heterocyclic carbene to 10-vertex nido mono- and/or bis-carbene adducts, respectively. These complexes easily undergo a reaction with HCl to give cages of stable and water soluble 10-vertex nido-type cations with protonation in the form of a BHB bridge or 10-vertex closo-type cations containing one carbene ligand when originating from closo-1,10-dicarbadecaborane. The reaction of a 10-vertex nido mono-carbene adduct with phosphorus trichloride gives nido-11-vertex 2-phospha-7,8-dicarbaundecaborane, which undergoes an oxidation of the phosphorus atom to P = O, while the product of a bis-carbene adduct reaction is best described as a distorted C2B6H8 fragment bridged by the (BH)2PCl2+ moiety. In comparison to their neutral or anionic counterparts, examples of cationic boron clusters remain scarce. Here, the authors prepare a variety of cationic polyhedral boranes by reacting closo-10-vertex carboranes with N-heterocyclic carbenes; the resulting open-cage cationic nido- arachno- or closo- derivatives are water soluble, which may enable unprecedented applications.
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Affiliation(s)
- Jan Vrána
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic
| | - Josef Holub
- Institute of Inorganic Chemistry, Czech Academy of Sciences, Řež, Czech Republic
| | - Maksim A Samsonov
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic
| | - Zdeňka Růžičková
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Michael L McKee
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, USA
| | - Jindřich Fanfrlík
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Drahomír Hnyk
- Institute of Inorganic Chemistry, Czech Academy of Sciences, Řež, Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic.
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Reactions of Experimentally Known Closo-C2B8H10 with Bases. A Computational Study. CRYSTALS 2020. [DOI: 10.3390/cryst10100896] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
On the basis of the direct transformations of closo-1,2-C2B8H10 with OH(−) and NH3 to arachno-1,6,9-OC2B8H13(−) and arachno-1,6,9-NC2B8H13, respectively, which were experimentally observed, the DFT computational protocol was used to examine the corresponding reaction pathways. This work is thus a computational attempt to describe the formations of 11-vertex arachno clusters that are formally derived from the hypothetical closo-B13H13(2−). Moreover, such a protocol successfully described the formation of arachno-4,5-C2B6H11(−) as the very final product of the first reaction. Analogous experimental transformations of closo-1,6-C2B8H10 and closo-1,10-C2B8H10, although attempted, were not successful. However, their transformations were explored through computations.
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Dziedzic RM, Axtell JC, Rheingold AL, Spokoyny AM. Off-Cycle Processes in Pd-Catalyzed Cross-Coupling of Carboranes. Org Process Res Dev 2019; 23:1638-1645. [PMID: 33776400 DOI: 10.1021/acs.oprd.9b00257] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Off-cycle processes in catalytic reactions can dramatically influence the outcome of the chemical transformation and affect its yield, selectivity, rate, and product distribution. While the generation of off-cycle intermediates can complicate reaction coordinate analyses or hamper catalytic efficiency, the generation of such species may also open new routes to unique chemical products. Recently, we reported the Pd-mediated functionalization of carboranes with a range of O-, N-, and C-based nucleophiles. By utilizing a Pd-based catalytic system supported by a biaryl phosphine ligand developed by Buchwald and co-workers, we discovered an off-cycle isomerization process ("cage-walking") that generates four regioisomeric products from a single halogenated boron cluster isomer. Here we describe how several off-cycle processes affect the regioisomer yield and distribution during Pd-catalyzed tandem cage-walking/cross-coupling. In particular, tuning the transmetallation step in the catalytic cycle allowed us to incorporate the cage-walking process into Pd-catalyzed cross-coupling of sterically unencumbered substrates, including cyanide. This work demonstrates the feasibility of using tandem cage-walking/cross-coupling as a unique low-temperature method for producing regioisomers of mono-substituted carboranes.
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Affiliation(s)
- Rafal M Dziedzic
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, United States
| | - Jonathan C Axtell
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, United States
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States
| | - Alexander M Spokoyny
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, United States.,California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095, United States
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Bakardjiev M, Tok OL, Růžička A, Růžičková Z, Holub J, Hnyk D, Fanfrlík J, Štíbr B. Quantitative syntheses of permethylated closo-1,10-R 2C 2B 8Me 8 (R = H, Me) carboranes. Egg-shaped hydrocarbons on the Frontier between inorganic and organic chemistry. RSC Adv 2018; 8:38238-38244. [PMID: 35559069 PMCID: PMC9090134 DOI: 10.1039/c8ra06640j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/31/2018] [Indexed: 11/25/2022] Open
Abstract
Electrophilic methylation of the closo-1,10-R2C2B8H8 (1) (R = H or Me) dicarbaboranes at higher temperatures or thermal rearrangement of the 1,6-R2C2B8Me8 (3) compounds at 400-500 °C generated the B-permethylated derivatives closo-1,10-R2C2B8Me8 (2) in quantitative (>95%) yields. The compounds exhibit extreme air stability as a consequence of a rigid, egg shaped hydrocarbon structures incorporating inner 1,10-C2B8 carborane core.
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Affiliation(s)
- Mario Bakardjiev
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic Husinec-Řež 1001 Czech Republic
| | - Oleg L Tok
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic Husinec-Řež 1001 Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice Studentská 573 532 10 Pardubice Czech Republic
| | - Zdeňka Růžičková
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice Studentská 573 532 10 Pardubice Czech Republic
| | - Josef Holub
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic Husinec-Řež 1001 Czech Republic
| | - Drahomír Hnyk
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic Husinec-Řež 1001 Czech Republic
| | - Jindřich Fanfrlík
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Flemingovo nám. 2, 166 10 Prague 6 Czech Republic
| | - Bohumil Štíbr
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic Husinec-Řež 1001 Czech Republic
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Bakardjiev M, Tok OL, RůŽička A, RůŽičková Z, Holub J, Hnyk D, Špalt Z, Fanfrlík J, Štíbr B. Methyl camouflage in the ten-vertex closo-dicarbaborane(10) series. Isolation of closo-1,6-R 2C 2B 8Me 8 (R = H and Me) and their monosubstituted analogues. Dalton Trans 2018; 47:11070-11076. [PMID: 30033463 DOI: 10.1039/c8dt02586j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reported are procedures leading to the first types of methyl camouflaged dicarbadecaboranes with fewer than eleven vertices. The compounds contain the closo-1,6-C2B8 scaffolding inside the egg-shaped hepta - decamethyl sheath, which imparts unusually high air and solvolytic stability to all of these compounds.
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Affiliation(s)
- Mario Bakardjiev
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Husinec-ŘeŽ 1001, Czech Republic
| | - Oleg L Tok
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Husinec-ŘeŽ 1001, Czech Republic
| | - Aleš RůŽička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
| | - Zdeňka RůŽičková
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
| | - Josef Holub
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Husinec-ŘeŽ 1001, Czech Republic
| | - Drahomír Hnyk
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Husinec-ŘeŽ 1001, Czech Republic
| | - Zbyněk Špalt
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Husinec-ŘeŽ 1001, Czech Republic
| | - Jindřich Fanfrlík
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Bohumil Štíbr
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Husinec-ŘeŽ 1001, Czech Republic
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Nishino K, Hashimoto K, Tanaka K, Morisaki Y, Chujo Y. Comparison of luminescent properties of helicene-like bibenzothiophenes with o-carborane and 5,6-dicarba-nido-decaborane. Sci China Chem 2018. [DOI: 10.1007/s11426-018-9258-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Zhang Y, Zhang ZX, Wang Y, Li H, Bai FQ, Zhang HX. The effect of the embedded o-carborane ligand on the photophysical properties of a cyclometalated Pt(ii) complex: a theoretical investigation. Inorg Chem Front 2018. [DOI: 10.1039/c8qi00071a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The embedded o-carborane ligands will have an impact on the photophysical properties and quantum efficiency of these highly efficient blue phosphorescent materials.
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Affiliation(s)
- Yu Zhang
- Laboratory of Theoretical and Computational Chemistry
- International Joint Research Laboratory of Nano-Micro Architecture Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
| | - Zhi-Xiang Zhang
- Laboratory of Theoretical and Computational Chemistry
- International Joint Research Laboratory of Nano-Micro Architecture Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
| | - Yu Wang
- Laboratory of Theoretical and Computational Chemistry
- International Joint Research Laboratory of Nano-Micro Architecture Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
| | - Hui Li
- Laboratory of Theoretical and Computational Chemistry
- International Joint Research Laboratory of Nano-Micro Architecture Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
| | - Fu-Quan Bai
- Laboratory of Theoretical and Computational Chemistry
- International Joint Research Laboratory of Nano-Micro Architecture Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
| | - Hong-Xing Zhang
- Laboratory of Theoretical and Computational Chemistry
- International Joint Research Laboratory of Nano-Micro Architecture Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
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10
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Bakardjiev M, Růžička A, Růžičková Z, Holub J, Tok OL, Štíbr B. Electrophilic Halogenation of closo-1,2-C 2B 8H 10. Inorg Chem 2017; 56:5971-5975. [DOI: 10.1021/acs.inorgchem.7b00627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mario Bakardjiev
- Institute of Inorganic
Chemistry, Academy of Sciences of the Czech Republic, 250 68 Řež, Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical
Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
| | - Zdeňka Růžičková
- Department of General and Inorganic Chemistry, Faculty of Chemical
Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
| | - Josef Holub
- Institute of Inorganic
Chemistry, Academy of Sciences of the Czech Republic, 250 68 Řež, Czech Republic
| | - Oleg L. Tok
- Institute of Inorganic
Chemistry, Academy of Sciences of the Czech Republic, 250 68 Řež, Czech Republic
| | - Bohumil Štíbr
- Institute of Inorganic
Chemistry, Academy of Sciences of the Czech Republic, 250 68 Řež, Czech Republic
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Tok OL, Bakardjiev M, Štíbr B, Hnyk D, Holub J, Padělková Z, Růžička A. Click Dehydrogenation of Carbon-Substituted nido-5,6-C2B8H12 Carboranes: A General Route to closo-1,2-C2B8H10 Derivatives. Inorg Chem 2016; 55:8839-43. [PMID: 27551885 DOI: 10.1021/acs.inorgchem.6b01386] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Triethylamine-catalyzed dehydrogenation of carbon-disubstituted dicarbaboranes 5,6-R2-nido-5,6-C2B8H10 [1, where R = H (1a), Me (1b), and Ph (1c)] in refluxing acetonitrile leads to a high-yield (up to 85-95%) formation of a series of dicarbaboranes 1,2-R2-closo-1,2-C2B8H8 (2). The monosubstituted 6-R-nido-5,6-C2B8H11 (3) analogues [where R = Ph (3a), naph (1-naphthyl; 3b), Bu (3c)] afforded 1-R-1,2-closo C2B8H9 (4) isomers [where R = Ph (4a), naph (4b), n-Bu (4c)] as the main products; compounds 4a and 4c were accompanied by 2-R-1,2-C2B8H9 (5) isomers (total yields up to 90%), with the 4/5 molar ratio being strongly dependent on the nature of R (4:1 and 1:1, respectively). All of these cage-closure reactions are supposed to proceed via the stage of the corresponding Et3NH(+) salts of nido anions [5,6-R2-5,6-C2B8H9](-) (1(-)) and [6-R-5,6-C2B8H10](-) (3(-)), which lose H2 and Et3N upon heating (dehydrodeamination). The cage-closure mechanisms leading to closo isomers 2, 4, and 5 have been substantiated by B3LYP/6-31+G* calculations of the reaction profile for a simple 1a(-) → 2a + H(-) conversion. All of the compounds isolated have been characterized by multinuclear ((11)B, (1)H, and (13)C) NMR spectroscopy, mass spectrometry, and elemental analyses, and the structure of 1-Ph-closo-1,2-C2B8H9 (4a) was established by an X-ray diffraction study.
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Affiliation(s)
- Oleg L Tok
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic , 25068 Řež, Czech Republic
| | - Mario Bakardjiev
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic , 25068 Řež, Czech Republic
| | - Bohumil Štíbr
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic , 25068 Řež, Czech Republic
| | - Drahomír Hnyk
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic , 25068 Řež, Czech Republic
| | - Josef Holub
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic , 25068 Řež, Czech Republic
| | - Zdenka Padělková
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice , Studentská 573, 53210 Pardubice, Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice , Studentská 573, 53210 Pardubice, Czech Republic
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Bakardjiev M, Štíbr B, Holub J, Tok OL, Švec P, Růžičková Z, Růžička A. Sequential Camouflage of the arachno-6,9-C 2B 8H 14 Cage by Substituents. Inorg Chem 2016; 55:7068-74. [DOI: 10.1021/acs.inorgchem.6b00964] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Mario Bakardjiev
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, 25068 Řež, Czech Republic
| | - Bohumil Štíbr
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, 25068 Řež, Czech Republic
| | - Josef Holub
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, 25068 Řež, Czech Republic
| | - Oleg L. Tok
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, 25068 Řež, Czech Republic
| | - Petr Švec
- Department of General and Inorganic Chemistry,
Faculty of Chemical Technology, University of Pardubice, Studentská
573, 53210 Pardubice, Czech Republic
| | - Zdeňka Růžičková
- Department of General and Inorganic Chemistry,
Faculty of Chemical Technology, University of Pardubice, Studentská
573, 53210 Pardubice, Czech Republic
| | - Aleš Růžička
- Department of General and Inorganic Chemistry,
Faculty of Chemical Technology, University of Pardubice, Studentská
573, 53210 Pardubice, Czech Republic
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