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Poater J, Escayola S, Poater A, Teixidor F, Ottosson H, Viñas C, Solà M. Single─Not Double─3D-Aromaticity in an Oxidized Closo Icosahedral Dodecaiodo-Dodecaborate Cluster. J Am Chem Soc 2023; 145:22527-22538. [PMID: 37728951 PMCID: PMC10591335 DOI: 10.1021/jacs.3c07335] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Indexed: 09/22/2023]
Abstract
3D-aromatic molecules with (distorted) tetrahedral, octahedral, or spherical structures are much less common than typical 2D-aromatic species or even 2D-aromatic-in-3D systems. Closo boranes, [BnHn]2- (5 ≤ n ≤ 14) and carboranes are examples of compounds that are singly 3D-aromatic, and we now explore if there are species that are doubly 3D-aromatic. The most widely known example of a species with double 2D-aromaticity is the hexaiodobenzene dication, [C6I6]2+. This species shows π-aromaticity in the benzene ring and σ-aromaticity in the outer ring formed by the iodine substituents. Inspired by the hexaiodobenzene dication example, in this work, we explore the potential for double 3D-aromaticity in [B12I12]0/2+. Our results based on magnetic and electronic descriptors of aromaticity together with 11B{1H} NMR experimental spectra of boron-iodinated o-carboranes suggest that these two oxidized forms of a closo icosahedral dodecaiodo-dodecaborate cluster, [B12I12] and [B12I12]2+, behave as doubly 3D-aromatic compounds. However, an evaluation of the energetic contribution of the potential double 3D-aromaticity through homodesmotic reactions shows that delocalization in the I12 shell, in contrast to the 10σ-electron I62+ ring in the hexaiodobenzene dication, does not contribute to any stabilization of the system. Therefore, the [B12I12]0/2+ species cannot be considered as doubly 3D-aromatic.
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Affiliation(s)
- Jordi Poater
- Departament
de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
- ICREA, Pg. Lluís
Companys 23, 08010 Barcelona, Spain
| | - Sílvia Escayola
- Departament
de Química, Institut de Química
Computacional i Catàlisi, Universitat de Girona, C/Maria Aurèlia Capmany,
69, 17003 Girona, Catalonia Spain
- Donostia
International Physics Center (DIPC), 20018 Donostia, Euskadi Spain
| | - Albert Poater
- Departament
de Química, Institut de Química
Computacional i Catàlisi, Universitat de Girona, C/Maria Aurèlia Capmany,
69, 17003 Girona, Catalonia Spain
| | - Francesc Teixidor
- Institut
de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones
Científicas, Campus Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Henrik Ottosson
- Department
of Chemistry - Ångström Laboratory, Uppsala University, 751
20 Uppsala, Sweden
| | - Clara Viñas
- Institut
de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones
Científicas, Campus Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Miquel Solà
- Departament
de Química, Institut de Química
Computacional i Catàlisi, Universitat de Girona, C/Maria Aurèlia Capmany,
69, 17003 Girona, Catalonia Spain
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2
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Shernyukov AV, Salnikov GE, Rudakov DA, Genaev AM. Noncatalytic Bromination of Icosahedral Dicarboranes: The Key Role of Anionic Bromine Clusters Facilitating Br Atom Insertion into the B-H σ-Bond. Inorg Chem 2021; 60:3106-3116. [PMID: 33595316 DOI: 10.1021/acs.inorgchem.0c03392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism of the noncatalytic bromination of carboranes was studied experimentally and theoretically. We found that the reactions of o- and m-carboranes 1 and 2 with elemental bromine are first order in the substrate but unusually high (approximately fifth) order in bromine. The calculated energy barriers of these reactions decrease sharply as more bromine molecules are added to the quantum-chemical system. A considerable primary deuterium kinetic isotope effect for the bromination of 2 indicates that the rate-limiting stage is B-H bond breakage. According to quantum-chemical reaction path calculations, the bond breakage proceeds after the intrusion of a bromine atom into the B-H σ-bond. The 9-Br and 9-OH substituents in carborane 1 strongly retard the bromination of the corresponding derivatives. The bromination mechanism of 9-OH-1 is complex and includes neutral, deprotonated, and protonated forms of the carborane. The high experimental kinetic reaction order in bromine, together with quantum chemical modeling, points to a specific mechanism of bromination facilitated by anionic bromine clusters which significantly stabilize the transition state.
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Affiliation(s)
- Andrey V Shernyukov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - George E Salnikov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - Dmitry A Rudakov
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
| | - Alexander M Genaev
- N.N. Vorozhtsov Institute of Organic Chemistry, Pr. Ak. Lavrentieva 9, Novosibirsk 630090, Russia
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Alpha shift correlation (ASC) method. Sensitivity of 11B NMR shifts to halogen substitution in the ten-vertex nido and arachno series of boron clusters. Linear behavior of NMR effects. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.11.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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Štíbr B, Tok OL, Holub J. Quantitative Assessment of Substitution NMR Effects in the Model Series of o-Carborane Derivatives: α-Shift Correlation Method. Inorg Chem 2017; 56:8334-8340. [PMID: 28654251 DOI: 10.1021/acs.inorgchem.7b01023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The principles of a new α-shift correlation (ASC) NMR method are demonstrated on a model series of substituted derivatives of o-carborane for which reliable NMR data are available. This graphical method revealed an acceptable linear correlation between α(11B) or α(13C) shifts and those induced by substituents in unsubstituted (u) positions of the carborane cluster. The linearity holds for all nuclei involved in skeletal bonding: Δδ(N)u = g × α (where N = 11B, 13C, and 1H). The factor g (slope of the correlation line × 102) becomes an important measure of sensitivity of a given cage position to substituent changes. The β, γ, and δ = A (= antipodal) shifts can be therefore derived from the α-shift, are linearly proportional, and reflect additive character in double substitution. The ASC method appears to be an important tool for quantitative assessment of substituent NMR effects in all exo-substituted boron-cluster systems.
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Affiliation(s)
- Bohumil Štíbr
- 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
| | - Josef Holub
- Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic , 250 68 Řež, Czech Republic
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Štíbr B. 11B-NMR shielding effects in theclosoborane series: sensitivity of shifts and their additivity. NEW J CHEM 2017. [DOI: 10.1039/c7nj02689g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NMR shielding effects for [Xm-closo-BnHn−m]2−anions exhibit a simple linear behaviour in all positions of the borane cluster.
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Affiliation(s)
- B. Štíbr
- Institute of Inorganic Chemistry
- Academy of Sciences of The Czech Republic
- The Czech Republic
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6
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Poly-iodinated closo 1,2-C 2 B 10 and nido [7,8-C 2 B 9 ] − carborane frameworks: Synthesis and consequences. J Organomet Chem 2015. [DOI: 10.1016/j.jorganchem.2015.05.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Hnyk D, Jayasree EG. Cationiccloso-carboranes 2. Do computed11B and13C NMR chemical shifts support their experimental availability? J Comput Chem 2012; 34:656-61. [DOI: 10.1002/jcc.23176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/30/2012] [Accepted: 09/07/2012] [Indexed: 11/11/2022]
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Puga A, Teixidor F, Sillanpää R, Kivekäs R, Arca M, Barberà G, Viñas C. From Mono- to Poly-Substituted Frameworks: A Way of Tuning the Acidic Character of CcH ino-Carborane Derivatives. Chemistry 2009; 15:9755-63. [DOI: 10.1002/chem.200900925] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ringstrand B, Bateman D, Shoemaker RK, Janoušek Z. Improved synthesis of [closo-1-CB9H10]– anion and new C-substituted derivatives. ACTA ACUST UNITED AC 2009. [DOI: 10.1135/cccc2008151] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The Brellochs method was utilized to gain access to the [closo-1-CB9H10]– anion (1). Previous work describing the details of the synthesis of 1 via the [closo-2-CB9H10]– anion (2) was brief and insufficient. Therefore, we report an optimized procedure for the synthesis of 1, the preparation of the unknown C-halogenated series using N-halosuccinimides and bis(benzenesulfonyl)fluoroamine, and the unknown C-methylated product using CH3I. NMR properties and regularities within the series were also investigated.
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Núñez R, Tutusaus O, Teixidor F, Viñas C, Sillanpää R, Kivekäs R. Highly Stable Neutral and Positively Charged Dicarbollide Sandwich Complexes. Chemistry 2005; 11:5637-47. [PMID: 16035001 DOI: 10.1002/chem.200500288] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Novel sandwich metallacarboranes commo-[3,3'-Ni(8-SMe2-1,2-C2B9H10)2] (1), commo-[3,3'-Co(8-SMe2-1,2-C2B9H10)2]+ (2+), commo-[3,3'-Ru(8-SMe2-1,2-C2B9H10)2] (4) and commo-[3,3'-Fe(8-SMe2-1,2-C2B9H10)2] (5) have been prepared by reaction of [10-SMe2-7,8-nido-C2B9H10]- with NiCl2 x 6 H2O, CoCl2, [RuCl2(dmso)4] and [FeCl2(dppe)], respectively. Reduction of 2+ with metallic Zn leads to the neutral and isolable complex commo-[3,3'-Co(8-SMe2-1,2-C2B9H10)2] (3). Theoretical calculations using the ZINDO/1 semiempirical method show three energy minima for complexes 1-3 and 5 that agree with the presence of three different rotamers in solution at low temperature, while four relative energy minima have been found for 4. The calculated rotational energy barriers for complexes 1-5 have been found in the range 5.2+/-0.2 and 11.5+/-0.2 kcal mol(-1). These values are in agreement with the experimental data calculated for complexes 2+ and 5. Only one rotamer is found in the X-ray crystal structure of complexes 1-3, while two are observed for 4. Neutral complexes 1, 3 and 4 exhibit a gauche conformation, whereas a cisoid conformation is found for the 2+ ion. Rotamers evident from X-ray diffraction studies are in agreement with the global energy minimum calculated by the ZINDO/1 method. The electrochemical studies conducted on 1, 3, 4 and 5 support the proposal that the charge-compensated ligand [10-SMe2-7,8-nido-C2B9H10]- stabilises lower oxidation states in metals than the dianionic [7,8-nido-C2B9H11]2- and even the [C5H5]- ligands.
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Affiliation(s)
- Rosario Núñez
- Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas, Campus de U.A.B., Bellaterra, 08193 Barcelona, Spain
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11
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Janoušek Z, Hilton CL, Schreiber PJ, Michl J. C-Halogenation of the closo-[CB11H12]- Anion. ACTA ACUST UNITED AC 2002. [DOI: 10.1135/cccc20021025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A synthesis is described of the four C-halogenated 1-X-CB11H11- anions (X = I, Br, Cl, F) using N-halosuccinimides and N-fluorobis(benzenesulfonyl)amine as halogenating agents. The procedure yields only the desired product next to unreacted starting material. Regularities in the 11B and 13C NMR chemical shifts of singly halogenated icosahedral carboranes are summarized.
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Viñas C, Barberà G, Oliva JM, Teixidor F, Welch AJ, Rosair GM. Are halocarboranes suitable for substitution reactions? The case for 3-I-1,2-closo-C(2)B(10)H(11): molecular orbital calculations, aryldehalogenation reactions, (11)B NMR interpretation of closo-carboranes, and molecular structures of 1-Ph-3-Br-1,2-closo-C(2)B(10)H(10) and 3-Ph-1,2-closo-C(2)B(10)H(11). Inorg Chem 2001; 40:6555-62. [PMID: 11735463 DOI: 10.1021/ic010493o] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper, the chemistry of 3-X-1,2-closo-C(2)B(10)H(11) (X = halogen) derivatives is extended. Molecular orbital and (11)B and (13)C NMR calculations on these species are presented. A qualitative interpretation of the (11)B NMR spectra of closo o-carborane derivatives is also provided. The synthesis of 3-X-1-R-o-carborane (X = I, Br and R = Me, Ph) derivatives is reported, and aryldehalogenation at the B3 position is reported for the first time. The molecular and crystal structures of 1-phenyl-3-bromo-1,2-dicarba-closo-dodecaborane and 3-phenyl-1,2-dicarba-closo-dodecaborane are described.
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Affiliation(s)
- C Viñas
- Institut de Ciència de Materials de Barcelona (CSIC),Campus U.A.B., E-08193 Bellaterra, Spain.
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Oliva J, Viñas C. Electronic structure and assignment of experimental 11 B nuclei NMR signals in the ortho -carborane 1,2-(SH) 2 -1,2-C 2 B 10 H 10 by ab initio calculations. J Mol Struct 2000. [DOI: 10.1016/s0022-2860(00)00646-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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14
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McKee ML, Wang ZX, Schleyer PVR. Ab Initio Study of theHyperclosoBoron Hydrides BnHnand BnHn-. Exceptional Stability of Neutral B13H13. J Am Chem Soc 2000. [DOI: 10.1021/ja994490a] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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NMR as a tool for elucidation of structures and estimation of electron distribution in boranes and their derivatives. Inorganica Chim Acta 1999. [DOI: 10.1016/s0020-1693(99)00055-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Affiliation(s)
- Michael L. McKee
- Contribution from the Department of Chemistry, Auburn University, Auburn, Alabama 36849
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17
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Deck KJ, Brenton P, Fehlner TP. Substitution on Metallaboranes at Boron. Syntheses of closo-1-X-[2,3,4-(η5-C5Me5)3(μ-H)2Co3B2H], X = Cl and OH, and closo-1,5-Cl2-[2,3,4-(η5-C5Me5)3(μ-H)2Co3B2] from closo-[2,3,4-(η5-C5Me5)3(μ-H)2Co3B2H2]. Inorg Chem 1997. [DOI: 10.1021/ic961184e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kathryn J. Deck
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Paula Brenton
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Thomas P. Fehlner
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
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Synthesis and characterisation of metal complexes of ether carbaboranes. Molecular structures of d6 ML3, d8 ML2 and d10 ML complexes of mono- and di-ether C2B9 carbaborane ligands, showing the progressive importance of secondary M…O bonding. J Organomet Chem 1994. [DOI: 10.1016/0022-328x(94)88203-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Heřmánek S, Fusek J, Štíbr B, Plešek J, Jelínek T. Elucidation of structures of nido-y-CB8H12 and B9H−12 by two-dimensional 11B-11B NMR spectroscopy. Polyhedron 1986. [DOI: 10.1016/s0277-5387(00)84871-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Plešek J, Heřmánek S, Štíbr B. Electron transfer phenomena in isolated icosahedral borane units. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/0022-5088(79)90096-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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