1
|
Rodríguez-Kessler PL, Muñoz-Castro A. Intercluster B-H and B-B aggregation in iso- and trans-[B 20H 18] 2-. Spherical aromaticity in borane dimers. Dalton Trans 2024; 53:13960-13967. [PMID: 39101449 DOI: 10.1039/d4dt01699h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
The formation of molecular-based functional materials is a key step towards the development of technologies at the nanoscale. Recently, it has been shown that after oxidation of closo-[B10H10]2- anions, an induced aggregation of two cluster units is achieved, retaining their parent B10 backbones as persistent building blocks. Such characterization provides an interesting scenario to further understand relevant factors leading to aggregation in a minimal structure involving two units. Here, we explore the interaction between closo-[B10H10]2- units in two isomers, namely, iso- and trans-[B20H18]2-, involving different intercluster contacts based on B-B and B-H interactions, respectively. Our results show that the inherent spherical aromatic characteristics of the parent closo-[B10H10]2- cluster are persistent in both iso- and trans-[B20H18]2- isomers as an interplay between the spherical aromatic properties from both B10 motifs, leading to an overlap of the shielding regions from shielding cone properties, ascribed as a dual spherical-spherical aromatic cluster. From 11B-NMR features, it came out that trans-[B20H18]2- involves larger differences in comparison to closo-[B10H10]2-, owing to the variation of the B10-B10 backbone provided by the intercluster B-interaction, thus resulting in a more effective aggregation connecting such building units, towards boron-based cluster materials.
Collapse
Affiliation(s)
- Peter L Rodríguez-Kessler
- Centro de Investigaciones en Óptica A.C., Loma del Bosque 115, Col. Lomas del Campestre, León, Guanajuato, 37150, Mexico
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
| |
Collapse
|
2
|
Rodríguez-Kessler PL, Muñoz-Castro A. [Ag(Sn 9-Sn 9)] 5- and [(η 4-Sn 9)Ag(η 1-Sn 9)] 7-, as aggregates of spherical aromatic building blocks. Persistence of aromaticity upon cluster gathering. Phys Chem Chem Phys 2024; 26:8419-8425. [PMID: 38407459 DOI: 10.1039/d3cp05394f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Formation of cluster-based materials requires a fundamental understanding of the resulting cluster aggregation processes. The Sn94- Zintl-ion structure can be viewed as a building block featuring a spherical aromatic species, leading to a cluster gathering upon oxidative coupling and/or mediated by transition metals. Here, we evaluate the spherical aromatic properties of [Sn9-Sn9]6-, [Ag(Sn9-Sn9)]5- and [(η4-Sn9)Ag(η1-Sn9)]7-, as aggregates of two Sn9 building units held together via oxidative coupling and mediated by a Ag(I) transition metal center. Our results from magnetic criteria of aromaticity show that the inherent spherical aromatic characteristics of the parent Sn94- cluster are persistent in the overall aggregate where the enabled shielding cones ascribed to each Sn9 unit are able to interplay between them, leading to an overlap of the shielding regions. Hence, the two approaches for bringing cluster units together are able to retain the inherent spherical aromatic features for each Sn9 unit, leading to a cluster-based dimer where the parent properties remain. Thus, further cluster-based materials can be envisaged from aggregation upon oxidative coupling and/or mediated by transition metals, where the constituent building blocks retain their initial features, useful to guide the formation of more complex cluster-based aggregates.
Collapse
Affiliation(s)
- Peter L Rodríguez-Kessler
- Centro de Investigaciones en Óptica A.C., Loma del Bosque 115, Col. Lomas del Campestre, León, Guanajuato, 37150, Mexico.
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
| |
Collapse
|
3
|
Orozco-Ic M, Soriano-Agueda L, Escayola S, Sundholm D, Merino G, Matito E. Understanding Aromaticity in [5]Helicene-Bridged Cyclophanes: A Comprehensive Study. J Org Chem 2024; 89:2459-2466. [PMID: 38236016 DOI: 10.1021/acs.joc.3c02485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
This study explores the aromaticity of doubly [5]helicene-bridged (1,4)cyclophane and triply [5]helicene-bridged (1,3,5)cyclophane via calculations of the magnetic response and of electronic aromaticity indices. The primary objective is to assess the π-electron delocalization to determine whether they sustain global ring currents associated with π aromaticity. The molecules show local ring currents in the presence of an external magnetic field. The ring currents flow diatropically in the stacked six-membered rings and in the helicene arms. However, these π currents are not interconnected due to the discontinuity of the π delocalization at the C-C single bonds connecting the central six-membered rings to the helicene arms. Electronic indices suggest that the helicene-arm systems have significantly smaller electron delocalization than benzene. The reduction in the delocalization does not compromise their ability to exhibit ring currents in the presence of an external magnetic field. The analysis provides further evidence that the magnetic criteria yield a different degree of aromaticity for the helicene arms than obtained in the calculation of the electronic aromaticity indices. However, both approaches confirm that the studied molecules are not globally aromatic.
Collapse
Affiliation(s)
- Mesías Orozco-Ic
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
| | - Luis Soriano-Agueda
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
| | - Sílvia Escayola
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, Girona, 17003 Catalonia, Spain
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, A. I. Virtasen aukio 1, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Gabriel Merino
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida, Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310 Mérida, Yuc., México
| | - Eduard Matito
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
| |
Collapse
|
4
|
Lingas R, Charistos ND, Muñoz-Castro A. Charge delocalization and aromaticity of doubly reduced double-walled carbon nanohoops. Phys Chem Chem Phys 2023. [PMID: 37448229 DOI: 10.1039/d3cp01994b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/15/2023]
Abstract
Cycloparaphenylenes (CPPs) exhibit selective host capabilities, featuring the ability to incorporate smaller CPPs to form double-walled host-guest complexes. Moreover, CPPs can also be stabilized by global aromaticity under twofold oxidation or reduction, involving electronic conjugation along with the overall structural backbone. Herein we explore the structural modifications, bonding, electron delocalization and magnetic properties of doubly reduced double-walled CPP complexes with DFT methods, in the isolated and aggregate [n + 5]CPP⊃[n]CPP2- (n = 5-8) species. Our results show that the hosts undergo structural, bonding and delocalization deformations towards quinoidal configurations and exhibit global long-ranged shielding cones similar to global aromatic free dianionic CPPs, accounting for charge delocalization on the outer nanohoops, whereas the guests preserve local aromatic benzenoid configurations, resulting in global and local aromatic circuits within the host-guest aggregate. This observation suggests that in multi-layered related species electronic delocalization will be retained at the outer structural surface. The aromaticity of the hosts is manifested in the strong upfield shifts of the guests 1H-NMR signals. Hence, CPP complexes can be extended to doubly reduced species stabilized by global host aromaticity expanding our understanding of doubled-walled nanotubes at the nanoscale regime.
Collapse
Affiliation(s)
- Rafael Lingas
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54 124, Greece.
| | - Nickolas D Charistos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54 124, Greece.
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
| |
Collapse
|
5
|
Lingas R, Charistos ND, Muñoz-Castro A. Local and global aromaticity under rotation: analysis of two- and three-dimensional representative carbon nanostructures. Phys Chem Chem Phys 2023; 25:14285-14293. [PMID: 37183443 DOI: 10.1039/d3cp00569k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Nanoscaled 2D and 3D carbon structures with closed curved π-surfaces are of relevance in the development of desirable building units for materials science. Such species are able to sustain local and global aromatic circuits involving isolated regions or the overall structural backbone, respectively. Here we account for local and global aromaticity under rotation of representative two- and three-dimensional species involving para-connected and fused edge-sharing phenyl rings ([8]CPP, [10]CPP, CNB), and C60 fullerene at different charge states. Our results denote that nanoscaled 2D global aromatics mimic the behaviour of the most prototypical aromatic 6π-circuit, given by benzene, where the shielding cone properties vary along the rotation motion. In contrast, 3D spherical aromatics remain almost invariant under rotation, given the distinctive characteristics of such species, differing from 2D global aromatics. Dissection of orbital contributions reveals that π-orbitals are determinants for shifting from non-aromatic to spherical aromatic species. Under rotation, the variation of the anisotropic effect inherent to such nanoscaled structures is accounted for, which is relevant to rationalize variation in NMR signal shifts upon the formation of host-guest aggregates.
Collapse
Affiliation(s)
- Rafael Lingas
- Aristotle University of Thessaloniki, Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Thessaloniki, 54 124, Greece.
| | - Nickolas D Charistos
- Aristotle University of Thessaloniki, Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Thessaloniki, 54 124, Greece.
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
| |
Collapse
|
6
|
Olea Ulloa C, Muñoz-Castro A. Infinitene as two fused helicoidal trails of fused rings: evaluation of the magnetic behavior of [12]infinitene and anionic species displaying global aromaticity and antiaromaticity. Phys Chem Chem Phys 2023; 25:8190-8197. [PMID: 36880673 DOI: 10.1039/d2cp06039f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The unique formation of an infinity-shaped carbon backbone made exclusively from fused benzene rings has recently been achieved. The structure of [12]infinitene can be viewed as two fused [6]helicene structures with a central crossover section, depicting a global aromatic behavior along with the overall structure, with deshielding regions along both helicoidal axes. In addition, the 13C-NMR characteristics are discussed. The formation of a cumulative region involving the shielding regions from the aromatic rings is depicted along with the overall aesthetically pleasant structural backbone, which is enhanced at the crossover section. For the evaluated dianionic counterpart, the structure shows a deshielding region above the fused-ring trail and a helicoidal shielding region, ascribed to a global antiaromatic counterpart. The aromaticity is recovered and enhanced at the tetranionic state. Thus, the neutral and tetranionic states are able to build up a long-ranged shielding region, given by the global aromatic behavior, with an enhanced shielding region at the center of the crossover section displaying π-π stacked rings.
Collapse
Affiliation(s)
- Carolina Olea Ulloa
- Carrera de Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Pedro de Valdivia 425, Providencia, Santiago, Chile
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
| |
Collapse
|
7
|
Macleod-Carey D, Muñoz-Castro A. Switch from local to global aromatic character in Möbius carbon nanobelts upon dioxidation. Evaluation of magnetic behavior in neutral and charged species. Phys Chem Chem Phys 2023; 25:4467-4471. [PMID: 36722854 DOI: 10.1039/d2cp05326h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Here we show that recent Möbius carbon nanobelts (MCNBs) can be switched from a local to a global aromatic behavior upon dioxidation. Hence, large aromatic structures can be achieved by the choice of the charge states, giving rise to shielding cone characteristics extended within the overall structure at the nanoscale regime, pushing the limit of aromatic circuits to 198 π-electrons.
Collapse
Affiliation(s)
- Desmond Macleod-Carey
- Laboratorio de Química Inorgánica y Materiales Moleculares, Facultad de Ingenieria, Universidad Autonoma de Chile, Llano Subercaceaux 2801, San Miguel, Santiago, Chile
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
| |
Collapse
|
8
|
Orozco-Ic M, Charistos ND, Muñoz-Castro A, Islas R, Sundholm D, Merino G. Core-electron contributions to the molecular magnetic response. Phys Chem Chem Phys 2022; 24:12158-12166. [PMID: 35543541 DOI: 10.1039/d1cp05713h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Orbital contributions to the magnetic response depend on the method used to compute them. Here, we show that dissecting nuclear magnetic shielding tensors using natural localized molecular orbitals (NLMOs) leads to anomalous core contributions. The arbitrariness of the assignment might significantly affect the interpretation of the magnetic response of nonplanar molecules such as C60 or [14]helicene and the assessment of their aromatic character. We solve this problem by computing the core- and σ-components of the induced magnetic field (and NICS) and the magnetically induced current density by removing the valence electrons (RVE). We estimate the core contributions to the magnetic response by performing calculations on the corresponding highly charged molecules, such as C6H630+ for benzene, using gauge-including atomic orbitals and canonical molecular orbitals (CMOs). The orbital contributions to nuclear magnetic shielding tensors are usually estimated by employing a natural chemical shielding (NCS) analysis in NLMO or CMO bases. The RVE approach shows that the core contribution to the magnetic response is small and localized at the nuclei, contrary to what NCS calculations suggest. This may lead to a completely incorrect interpretation of the magnetic σ-orbital response of nonplanar structures, which may play a major role in the overall magnetic shielding of the system. The RVE approach is thus a simple and inexpensive way to determine the magnetic response of the core- and σ-electrons.
Collapse
Affiliation(s)
- Mesías Orozco-Ic
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland.
| | - Nickolas D Charistos
- Aristotle University of Thessaloniki, Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Thessaloniki, 54 124, Greece
| | - Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares, Facultad de Ingeniería, Universidad Autonoma de Chile, El Llano Subercaseaux 2801, Santiago, Chile
| | - Rafael Islas
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. República 275, 8370146, Santiago, Chile
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland.
| | - Gabriel Merino
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310, Mérida, Yuc., Mexico.
| |
Collapse
|
9
|
On the Aromaticity and 13C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C6(CH3)6]2+: A {C5(CH3)5}−–{CCH3}3+ Aggregate. CHEMISTRY 2021. [DOI: 10.3390/chemistry3040097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The experimentally characterized hexamethylbenzene dication C6(CH3)62+ shows a pentagonal-pyramidal structure involving a carbon-capped five-membered ring. The structural characterization of this hypercoordination (or hypervalency) gives rise if the aromatic behavior remains in the resulting pentagon ring. Here, we investigated the induced magnetic field of C6(CH3)62+ to gain a deeper understanding of the resulting non-classical structural situation in a representative pentagonal-pyramidal structure. Our results support the view of a C5(CH3)5−/CCH33+ structure, depicting a π-aromatic pentamethylcyclopentadienyl anion with a 6π-electron kernel, with a capped carbon which does not decrease the characteristic shielding cone property of the aromatic ring. Hence, carbon-capped rings are suggested to retain the aromatic behavior from the former aromatic ring. We expect that the analysis of both the overall magnetic response and NMR chemical shifts may be informative to unravel the characteristic patterns in the formation of hypervalent carbon atoms involving non-classical chemical environments.
Collapse
|
10
|
Tkachenko NV, Popov IA, Kulichenko M, Fedik N, Sun Z, Muñoz‐Castro A, Boldyrev AI. Bridging Aromatic/Antiaromatic Units: Recent Advances in Aromaticity and Antiaromaticity in Main‐Group and Transition‐Metal Clusters from Bonding and Magnetic Analyses. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Nikolay V. Tkachenko
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill 84322-0300 Logan UT USA
| | - Ivan A. Popov
- Theoretical Division Los Alamos National Laboratory 87545 Los Alamos NM USA
| | - Maksim Kulichenko
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill 84322-0300 Logan UT USA
| | - Nikita Fedik
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill 84322-0300 Logan UT USA
| | - Zhong‐Ming Sun
- Tianjin Key Lab of Rare Earth Materials and Applications State Key Laboratory of Elemento-Organic Chemistry School of Materials Science and Engineering Nankai University 300350 Tianjin China
| | - Alvaro Muñoz‐Castro
- Grupo de Química Inorgánica y Materiales Moleculares Facultad de Ingeniería Universidad Autonoma de Chile El Llano Subercaseaux 2801 Santiago Chile
| | - Alexander I. Boldyrev
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill 84322-0300 Logan UT USA
| |
Collapse
|
11
|
Muñoz-Castro A. Aromaticity in Phenyl Decorated closo-Monocarboranes. Planar-Spherical Aggregates Involving 7-12-Vertex Cages. J Phys Chem A 2021; 125:4861-4866. [PMID: 34048262 DOI: 10.1021/acs.jpca.1c02934] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The characterized phenyl decorated closo-monocarboranes with variable sizes from 7- to 12-vertex cages, [Ph-closo-CBnHn]-, n = 6-11, allow us to address the role of the varying size and shape of the carborane cage in dual planar-spherical aromatic species. Our results show the formation of adjacent shielding cone characteristics enabled from both planar and spherical aromatic fragments, despite the different structures of the closo-monocarboranes. Under a field perpendicular to the phenyl ring, both shielding cones are enabled, which overlap at long-range regions, in contrast to other orientations leading to a short-range response from the planar aromatic fragment. Thus, a two- or one-aromatic circuit is enabled selectively within the same molecular unit, by controlling the orientation of the external field. Along with the series, a variable extension of the shielding cone from the carborane cage is observed, which is larger for the -CB11H11 case, decreasing toward -CB6H6, denoting a similar extension from both the planar and spherical aromatic regions at the [4-Ph-closo-4-CB8H8]- (4) counterpart. The analysis of such multiple aromatic structures shows that, despite the different sizes and shapes of the closo cages, a similar aromatic behavior remains. In addition, the anisotropy of the induced magnetic field is given graphically, denoting a larger anisotropy for the planar aromatic moiety owing to its two-dimensional structure, which is suggested to discriminate between planar and spherical aromatic fragments within the same molecule.
Collapse
Affiliation(s)
- Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares, Facultad de Ingeniería, Universidad Autonoma de Chile, El Llano Subercaseaux 2801 Santiago, Chile
| |
Collapse
|
12
|
Lingas R, Charistos ND, Muñoz-Castro A. Aromaticity of ortho and meta 8-Cycloparaphenylene and Their Dications: Induced Magnetic Field Analysis with Localized and Delocalized Orbitals in Strained Nanohoops. Chemphyschem 2021; 22:741-751. [PMID: 33620136 DOI: 10.1002/cphc.202100057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/21/2021] [Indexed: 11/06/2022]
Abstract
Dications of cycloparaphenyles ([n]CPPs) are known to exhibit in-plane global aromaticity, contained in a nanobelt structure. Recently synthesized ortho and meta isomers of [n]CPPs break the radial symmetry of π structure incorporating perpendicular oriented π orbitals. Herein we set to explore the aromaticity of neutral and dicationic ortho and meta isomers of [8]CPP by dissecting the induced magnetic field to contributions of the twofold radial/perpendicular π system using delocalized canonical molecular orbitals (CMO), and introducing the natural localized molecular orbitals (NLMO) analysis with DFT methods. The dications sustain a reduced global aromatic character of the radial π system under a perpendicular orientation of the external field which declines from ortho to meta isomer and reinforces local aromaticity of ortho ring while it destroys aromaticity of meta ring. Aromaticity variations are determined by symmetry governed rotational excitations of frontier π orbitals. The parallel orientation reveals a substantial reduction of local aromaticity verified with NICSπ analysis and electron delocalization indices.
Collapse
Affiliation(s)
- Rafael Lingas
- Department of Chemistry Laboratory of Quantum and Computational Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54 124, Greece
| | - Nickolas D Charistos
- Department of Chemistry Laboratory of Quantum and Computational Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54 124, Greece
| | - Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares Facultad de Ingeniería, Universidad Autónoma de Chile, El Llano Subercaseaux, 2801, Santiago, Chile
| |
Collapse
|
13
|
Escayola S, Poater A, Muñoz-Castro A, Solà M. An unprecedented π-electronic circuit involving an odd number of carbon atoms in a grossly warped non-planar nanographene. Chem Commun (Camb) 2021; 57:3087-3090. [DOI: 10.1039/d1cc00593f] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The formation of π-aromatic circuits along a grossly warped nanographene, C80H30, containing five- and seven-membered rings inserted into a six-membered mesh, reveals global π-circuits at the edge of the backbone.
Collapse
Affiliation(s)
- Sílvia Escayola
- Institute of Computational Chemistry and Catalysis and Department of Chemistry
- University of Girona
- 17003 Girona
- Spain
- Donostia International Physics Center (DIPC)
| | - Albert Poater
- Institute of Computational Chemistry and Catalysis and Department of Chemistry
- University of Girona
- 17003 Girona
- Spain
| | - Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares
- Facultad de Ingeniería
- Universidad Autónoma de Chile
- El Llano Subercaseaux 2801
- Chile
| | - Miquel Solà
- Institute of Computational Chemistry and Catalysis and Department of Chemistry
- University of Girona
- 17003 Girona
- Spain
| |
Collapse
|
14
|
Interplay Between Planar and Spherical Aromaticity: Shielding Cone Behavior in Dual Planar‐Planar, Planar‐Spherical and Spherical‐Spherical Aromatics. Chemphyschem 2020; 21:1384-1387. [DOI: 10.1002/cphc.202000322] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/13/2020] [Indexed: 12/31/2022]
|
15
|
Li A, Wang Y, Downing DO, Chen F, Zavalij P, Muñoz‐Castro A, Eichhorn BW. Endohedral Plumbaspherenes of the Group 9 Metals: Synthesis, Structure and Properties of the [M@Pb
12
]
3−
(M=Co, Rh, Ir) Ions. Chemistry 2020; 26:5824-5833. [DOI: 10.1002/chem.201905451] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Ai‐Min Li
- Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA
| | - Yi Wang
- Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA
| | - Domonique O. Downing
- Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA
| | - Fu Chen
- Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA
| | - Peter Zavalij
- Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA
| | - Alvaro Muñoz‐Castro
- Grupo de Química Inorgánica y Materiales Moleculares Facultad de Ingeniería Universidad Autonoma de Chile El Llano Subercaseaux 2801 Santiago Chile
| | - Bryan W. Eichhorn
- Department of Chemistry and Biochemistry University of Maryland College Park MD 20742 USA
| |
Collapse
|
16
|
Kulichenko M, Fedik N, Boldyrev A, Muñoz‐Castro A. Expansion of Magnetic Aromaticity Criteria to Multilayer Structures: Magnetic Response and Spherical Aromaticity of Matryoshka‐Like Cluster [Sn@Cu
12
@Sn
20
]
12−. Chemistry 2020; 26:2263-2268. [DOI: 10.1002/chem.201905088] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 12/17/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Maksim Kulichenko
- Department of Chemistry and Biochemistry Utah State University Logan UT 84322-0300 USA
| | - Nikita Fedik
- Department of Chemistry and Biochemistry Utah State University Logan UT 84322-0300 USA
| | - Alexander Boldyrev
- Department of Chemistry and Biochemistry Utah State University Logan UT 84322-0300 USA
| | - Alvaro Muñoz‐Castro
- Grupo de Química Inorgánica y Materiales Moleculares Facultad de Ingeniería Universidad Autonoma de Chile El Llano Subercaseaux 2801 Santiago Chile
| |
Collapse
|
17
|
Muñoz-Castro A, King RB. Th@C 86, Th@C 82, Th@C 80, and Th@C 76: role of thorium encapsulation in determining spherical aromatic and bonding properties on medium-sized endohedral metallofullerenes. Phys Chem Chem Phys 2020; 22:23920-23928. [PMID: 33073794 DOI: 10.1039/d0cp03784b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thorium encapsulated metallofullerenes (Th-EMFs) with external C76, C80, C82, and C86 cages have been synthesized, with the 13C-NMR spectrum recorded for Th@C82. Here, we explore computationally the chemical bonding, NMR and spherical aromaticity of Th@C82 and related thorium-encapsulated metallofullerenes. Our results show that these Th-EMFs are new examples of spherical aromatic structures, representing interesting low-symmetry exceptions to the Hirsch 2(N + 1)2 rule of spherical aromaticity. Their electronic structures are based on π-electron counts of 80, 84, 86, and 90, respectively, with a shell structure ranging from S2P6D10F14G18H22I8 to S2P6D10F14G18H22I18, where the partially filled I-shell remains as a frontier orbital. Their behavior is comparable to that of the spherical aromatic alkali-C606- phases, which in addition to the favorable endohedral Th-fullerene bonding account for their particular abundance exhibiting the ability to sustain a long-range shielding cone as a result of the favorable metal-cage bonding. This rationalization of such species as neutral spherical aromatic EMFs suggests the possibility of an extensive series of aromatic fullerenes with nuclearity larger than C60 buckminsterfullerene as stable building blocks towards nanostructured metal-organic materials.
Collapse
Affiliation(s)
- Alvaro Muñoz-Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares, Universidad Autonoma de Chile, Llano Subercaseaux 2801, San Miguel, Santiago, Chile.
| | - R Bruce King
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
| |
Collapse
|
18
|
Orozco‐Ic M, Barroso J, Charistos ND, Muñoz‐Castro A, Merino G. Consequences of Curvature on Induced Magnetic Field: The Case of Helicenes. Chemistry 2019; 26:326-330. [DOI: 10.1002/chem.201904390] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Mesías Orozco‐Ic
- Departamento de Física Aplicada Centro de Investigación y, de Estudios Avanzados, Unidad Mérida Mérida Yucatán México
| | - Jorge Barroso
- Departamento de Física Aplicada Centro de Investigación y, de Estudios Avanzados, Unidad Mérida Mérida Yucatán México
| | - Nickolas D. Charistos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry Aristotle University of Thessaloniki Thessaloniki 54 124 Greece
| | - Alvaro Muñoz‐Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares Facultad de Ingeniería Universidad Autónoma de Chile Santiago Chile
| | - Gabriel Merino
- Departamento de Física Aplicada Centro de Investigación y, de Estudios Avanzados, Unidad Mérida Mérida Yucatán México
| |
Collapse
|
19
|
Attia AAA, Brânzanic AMV, Muñoz-Castro A, Lupan A, King RB. Cationic gold clusters with eight valence electrons: possible spherical aromatic systems with Sigma holes. Phys Chem Chem Phys 2019; 21:17779-17785. [PMID: 31372619 DOI: 10.1039/c9cp03440d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The energetically preferred structures of the gold clusters Au9+, Au113+, and Au124+ with eight skeletal electrons have been studied by density functional theory for comparison with the 8-electron Au102+ cluster shown previously to have a highly favored Td tetracapped octahedral structure. The low-energy structures for the Au9+ and Au113+ clusters are found to be similar relatively spherical polyhedra. Such systems can be considered to exhibit spherical aromaticity in accord with their filled 1S21P6 shells, their diatropic NICS(0) values ranging from -21.4 to -44.3 ppm, and their shielding cone surfaces. However, the preferred spherical polyhedra for Au9+ and Au113+ are not the same as the closo deltahedra found in the BnHn2- borane dianions. Instead they have smaller internal cavities formed by capping faces of smaller deltahedra or by formation of internal Au-Au bonds. The lowest energy Au124+ structures are not similar nearly spherical polyhedral structures. Instead they are derived from planar gold subclusters by adding more gold atoms to form tetrahedral Au4 bubbles. The planar origin of the low-energy Au124+ structures relates to the energetic preference for neutral Au<14 clusters for planar structures or nearly planar structures containing small polyhedral bubbles. The presence of σ-holes has been identified on the surfaces of the complete series of the Aun(n-8)+ (n = 9 to 12) clusters. The strength of their electrostatic interactions is predicted to increase upon increasing cluster size.
Collapse
Affiliation(s)
- Amr A A Attia
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania.
| | | | | | | | | |
Collapse
|
20
|
Kupka T, Gajda Ł, Stobiński L, Kołodziej Ł, Mnich A, Buczek A, Broda MA. Local aromaticity mapping in the vicinity of planar and nonplanar molecules. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:359-372. [PMID: 31034627 DOI: 10.1002/mrc.4880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
We report on nucleus-independent magnetic shielding (NICS) scans over the centers of six- and five-membered rings in selected metal phthalocyanines (MPc) and fullerene C60 for more accurate characterization of local aromaticity in these compounds. Detailed tests were conducted on model aromatic molecules including benzene, pyrrole, indole, isoindole, and carbazole and subsequently applied to H2 Pc, ZnPc, Al(OH)Pc, and CuPc. Similar behavior of three selected magnetic probes, Bq, 3 He, and 7 Li+ , approaching perpendicularly the ring centers, was observed. For better visualization of shielding zone over the centers of aromatic rings, we introduced a simple mathematical procedure: the first and second derivatives of scan curves with respect to magnetic probe position enabled their additional examination. It allowed an easier localization of curve minimum and discrimination between areas in space varying by the magnetic field magnitude and to illustrate local aromaticity of two different kinds of rings in MPc with better resolution. Our results supported earlier reports on very low aromaticity indexes of pyrrole ring incorporated into MPc and significant aromaticity of the central macrocycle. No direct dependence between harmonic oscillator model of aromaticity and NICS was observed. Instead, a correlation between position of scan curve minimum and its magnitude were observed. In addition, the NICS values and 3 He chemical shifts in the middle of neutral C60 and C606- anion agreed well with the reported experimental NMR values for He@C60 and He@C606- .
Collapse
Affiliation(s)
- Teobald Kupka
- Faculty of Chemistry, University of Opole, Opole, Poland
| | - Łukasz Gajda
- Faculty of Chemistry, University of Opole, Opole, Poland
| | - Leszek Stobiński
- Faculty of Process and Chemical Engineering, Warsaw University of Technology, 1, Waryńskiego Street, 00-645, Warsaw, Poland
- nanoMAT Ltd., Waryńskiego 1 (FL. 4, RM. 401), 00-645, Warsaw, Poland
| | | | - Adrianna Mnich
- Faculty of Chemistry, University of Opole, Opole, Poland
| | - Aneta Buczek
- Faculty of Chemistry, University of Opole, Opole, Poland
| | | |
Collapse
|
21
|
Fedik N, Boldyrev AI, Muñoz-Castro A. Aromatic character of [Au13]5+ and [MAu12]4+/6+ (M = Pd, Pt) cores in ligand protected gold nanoclusters – interplay between spherical and planar σ-aromatics. Phys Chem Chem Phys 2019; 21:25215-25219. [DOI: 10.1039/c9cp04477a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ligand-protected superatoms are able to behave as both spherical and planar aromatic species, providing a strong link between spherical and planar σ-aromatics, which can be controlled selectively by tuning their redox charge states.
Collapse
Affiliation(s)
- Nikita Fedik
- Department of Chemistry and Biochemistry
- Utah State University
- Logan
- USA
| | | | - Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares
- Facultad de Ingenieria
- Universidad Autonoma de Chile
- Santiago
- Chile
| |
Collapse
|
22
|
Muñoz-Castro A. Local and global aromaticity in a molecular carbon nanobelt: insights from magnetic response properties in neutral and charged species. Phys Chem Chem Phys 2018; 20:3433-3437. [DOI: 10.1039/c7cp08323h] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The generation of local and global aromaticity in nanobelt structures can be modified according to different charge states.
Collapse
Affiliation(s)
- A. Muñoz-Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares
- Facultad de Ingeniería
- Universidad Autonoma de Chile
- Santiago
- Chile
| |
Collapse
|
23
|
Muñoz-Castro A, King RB. Formation of Spherical Aromatic Endohedral Metallic Fullerenes. Evaluation of Magnetic Properties of M@C 28 (M = Ti, Zr, and Hf) from DFT calculations. Inorg Chem 2017; 56:15251-15258. [PMID: 29166009 DOI: 10.1021/acs.inorgchem.7b02611] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The small C28 cage has been shown experimentally to encapsulate titanium, zirconium, and hafnium (M), among other elements. Here, we explore computationally its magnetic response properties accounting for both global and local shielding tensors. Our results exhibit a continuous shielding region for M@C28 for an orientation-averaged applied field thereby differing from that observed for the hollow C28 structure. Moreover, under a specific orientation of the applied field a long-ranged shielding cone is obtained supporting the spherical aromatic behavior expected by the 2(N + 1)2 Hirsch rule for M@C28, standing for its particular abundance. The comparison between the hollow and endohedral C28 fullerenes exhibits a characteristic long-range behavior at the outside region of the structure. The particular shape of the local chemical shift anisotropy tensor at a representative carbon atom exhibits inherent patterns as a consequence of the spherical aromatic behavior. This shows the capabilities from NMR experiments to account for the nonaromatic → aromatic variation. We envisage that the current approach will be beneficial in comparative studies of aromatic and electronic structure properties, to gain a deeper understanding of the geometrical and electronic structure situation in other endohedral species beyond that available from the information provided by routine NMR measurements.
Collapse
Affiliation(s)
- Alvaro Muñoz-Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares, Universidad Autonoma de Chile , Llano Subercaseaux 2801, San Miguel, Santiago, Chile.,Relativistic Molecular Physics Group, Universidad Andres Bello , Republica 275, Santiago, Chile
| | - R Bruce King
- Department of Chemistry, University of Georgia , Athens, Georgia 30602, United States
| |
Collapse
|
24
|
Charistos ND, Papadopoulos AG, Nikopoulos TA, Muñoz-Castro A, Sigalas MP. Canonical orbital contributions to the magnetic fields induced by global and local diatropic and paratropic ring currents. J Comput Chem 2017; 38:2594-2604. [DOI: 10.1002/jcc.24917] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Nickolas D. Charistos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry; Aristotle University of Thessaloniki; Thessaloniki 54 124 Greece
| | - Anastasios G. Papadopoulos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry; Aristotle University of Thessaloniki; Thessaloniki 54 124 Greece
| | - Thomas A. Nikopoulos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry; Aristotle University of Thessaloniki; Thessaloniki 54 124 Greece
| | - Alvaro Muñoz-Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares; Universidad Autonoma de Chile; El Llano Subercaseaux Santiago 2801 Chile
- Doctorado en FisicoQuimica Molecular; Universidad Andres Bello, Av. Republica 275; Santiago Chile
| | - Michael P. Sigalas
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry; Aristotle University of Thessaloniki; Thessaloniki 54 124 Greece
| |
Collapse
|