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Savastano M, López de la Torre MD, Pagliai M, Poggi G, Ridi F, Bazzicalupi C, Melguizo M, Bianchi A. Crystal engineering of high explosives through lone pair-π interactions: Insights for improving thermal safety. iScience 2023; 26:107330. [PMID: 37636051 PMCID: PMC10448033 DOI: 10.1016/j.isci.2023.107330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 06/27/2023] [Accepted: 07/05/2023] [Indexed: 08/29/2023] Open
Abstract
In this high-risk/high-reward study, we prepared complexes of a high explosive anion (picrate) with potentially explosive s-tetrazine-based ligands with the sole purpose of advancing the understanding of one of the weakest supramolecular forces: the lone pair-π interaction. This is a proof-of-concept study showing how lone pair-π contacts can be effectively used in crystal engineering, even of high explosives, and how the supramolecular architecture of the resulting crystalline phases influences their experimental thermokinetic properties. Herein we present XRD structures of 4 novel detonating compounds, all showcasing lone pair-π interactions, their thermal characterization (DSC, TGA), including the correlation of experimental thermokinetic parameters with crystal packing, and in silico explosion properties. This last aspect is relevant for improving the safety of high-energy materials.
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Affiliation(s)
- Matteo Savastano
- Department of Human Sciences and Quality of Life Promotion, University San Raffaele Roma, Via di Val Cannuta 247, 00166 Rome, Italy
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | | | - Marco Pagliai
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Giovanna Poggi
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
- CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - Francesca Ridi
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
- CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - Carla Bazzicalupi
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Manuel Melguizo
- Department of Inorganic and Organic Chemistry, University of Jaén, 23071 Jaén, Spain
| | - Antonio Bianchi
- Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
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Martínez-Camarena Á, Savastano M, Blasco S, Delgado-Pinar E, Giorgi C, Bianchi A, García-España E, Bazzicalupi C. Assembly of Polyiodide Networks with Cu(II) Complexes of Pyridinol-Based Tetraaza Macrocycles. Inorg Chem 2021; 61:368-383. [PMID: 34933551 PMCID: PMC8753606 DOI: 10.1021/acs.inorgchem.1c02967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Polyiodide networks
are currently of great practical interest for
the preparation of new electronic materials. The participation of
metals in the formation of these networks is believed to improve their
mechanical performance and thermal stability. Here we report the results
on the construction of polyiodide networks obtained using Cu(II) complexes
of a series of pyridinol-based tetraazacyclophanes as countercations.
The assembly of these crystalline polyiodides takes place from aqueous
solutions on the basis of similar structural elements, the [CuL]2+ and [Cu(H–1L)]+ (L = L2, L2-Me, L2-Me3) complex cations, so that the peculiarities induced by the
increase of N-methylation of ligands, the structural variable of ligands,
can be highlighted. First, solution equilibria involving ligands and
complexes were analyzed (potentiometry, NMR, UV–vis, ITC).
Then, the appropriate conditions could be selected to prepare polyiodides
based on the above complex cations. Single-crystal XRD analysis showed
that the coordination of pyridinol units to two metal ions is a prime
feature of these ligands, leading to polymeric coordination chains
of general formula {[Cu(H–1L)]}nn+ (L = L2-Me, L2-Me3). In the presence of the I–/I2 couple, the polymerization tendency
stops with the formation of [(CuL)(CuH–1L)]3+ (L = L2-Me, L2-Me3) dimers which are surrounded by polyiodide networks. Moreover,
coordination of the pyridinol group to two metal ions transforms the
surface charge of the ring from negative to markedly positive, generating
a suitable environment for the assembly of polyiodide anions, while
N-methylation shifts the directional control of the assembly from
H-bonds to I···I interactions. In fact, an extended
concatenation of iodine atoms occurs around the complex dimeric cations,
the supramolecular I···I interactions become shorter
and shorter, fading into stronger forces dominated by the orbital
overlap, which is promising for effective electronic materials. Polyiodides with high iodine density
are generated by Cu(II)
complexes of pyridinol-based tetraazacyclophanes. Direct coordination
of iodine atoms to Cu(II), anion−π interactions with
electron-poor aromatic surfaces, and shift of the directional control
of assembly from H-bonds to I···I interactions, governed
by N-methylation, are the main elements leading to enhanced iodine
chaining and strengthening of I···I contacts.
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Affiliation(s)
- Álvaro Martínez-Camarena
- ICMol, Department of Inorganic Chemistry, University of Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Matteo Savastano
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Salvador Blasco
- ICMol, Department of Inorganic Chemistry, University of Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Estefanía Delgado-Pinar
- ICMol, Department of Inorganic Chemistry, University of Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.,Department of Chemistry, CQC, University of Coimbra, P3004-535 Coimbra, Portugal
| | - Claudia Giorgi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Antonio Bianchi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Enrique García-España
- ICMol, Department of Inorganic Chemistry, University of Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Carla Bazzicalupi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
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Synthesis, Structure and Hirshfeld Surface Analysis of a New Iron Complex [Fe(N4Py)(tcnspr)] (tcnspr). J Inorg Organomet Polym Mater 2021. [DOI: 10.1007/s10904-021-01898-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Stabilisation of Exotic Tribromide (Br 3-) Anions via Supramolecular Interaction with A Tosylated Macrocyclic Pyridinophane. A Serendipitous Case. Molecules 2020; 25:molecules25143155. [PMID: 32664239 PMCID: PMC7396983 DOI: 10.3390/molecules25143155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 12/22/2022] Open
Abstract
Tetraaza-macrocyclic pyridinophane L-Ts, decorated with a p-toluenesulfonyl (tosyl; Ts) group, appear to be a useful tool to provide evidence on how the interplay of various supramolecular forces can help stabilise exotic anionic species such as tribromide (Br3−) anions. Indeed, crystals of (H2L-Ts)(Br3)1.5(NO3)0.5 unexpectedly grew from an acidic (HNO3) aqueous solution of L-Ts in the presence of Br− anions. The crystal structure of this compound was determined by single crystal XRD analysis. Hydrogen bonds, salt-bridges, anion-π, π-π stacking, and van der Waals interactions contribute to stabilising the crystal lattice. The observation of two independent Br3− anions stuck over the π-electron densities of pyridine and tosyl ligand groups, one of them being sandwiched between two pyridine rings, corroborates the significance of anion-π interactions for N-containing heterocycles. We show herein the possibility of detecting anion-π contacts from fingerprint plots generated by Hirshfeld surface analysis, demonstrating the effective usage of this structural investigation technique to further dissect individual contributions of stabilising supramolecular forces.
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Genesis of Complex Polyiodide Networks: Insights on the Blue Box/I−/I2 Ternary System. CRYSTALS 2020. [DOI: 10.3390/cryst10050387] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Stoddart’s blue box (BB) (cyclobis(paraquat-p-phenylene))/iodide binary system was recently demonstrated to give rise to porous three-dimensional networks which can hardly be classified as common XOF-type materials (X = M, C, S, i.e., metal, covalent, or supramolecular organic frameworks), leading to the definition of permutable organized frameworks (POFs). The ternary BB/iodide/iodine system was reported to generate pentaiodide-based structures constituted by the most complex interlocked polyiodides so far isolated (up to an infinite supramolecular pseudopolyrotaxane with a poly[3]catenane axle). The missing link, i.e., the XRD structure of the BB/triiodide complex, is herein reported: structural similarities and novel Raman evidence, opening perspectives in the genesis of solid-state BB-based complex polyiodide networks from solution.
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Martínez-Camarena Á, Savastano M, Llinares JM, Verdejo B, Bianchi A, García-España E, Bazzicalupi C. Stabilization of polyiodide networks with Cu(ii) complexes of small methylated polyazacyclophanes: shifting directional control from H-bonds to I⋯I interactions. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00912a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Modulation of hydrogen bonds and iodine–iodine interactions, both covalent and supramolecular, unlocks novel possibilities for the construction of transition metal-polyiodide hybrid networks.
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Affiliation(s)
| | - Matteo Savastano
- Department of Chemistry “Ugo Schiff”
- University of Florence
- 50019 Sesto Fiorentino
- Italy
| | - José M. Llinares
- ICMol
- Department of Organic Chemistry
- University of Valencia
- Paterna
- Spain
| | - Begoña Verdejo
- ICMol
- Department of Inorganic Chemistry
- University of Valencia
- Paterna
- Spain
| | - Antonio Bianchi
- Department of Chemistry “Ugo Schiff”
- University of Florence
- 50019 Sesto Fiorentino
- Italy
| | | | - Carla Bazzicalupi
- Department of Chemistry “Ugo Schiff”
- University of Florence
- 50019 Sesto Fiorentino
- Italy
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Savastano M, García-Gallarín C, López de la Torre MD, Bazzicalupi C, Bianchi A, Melguizo M. Anion-π and lone pair-π interactions with s-tetrazine-based ligands. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.06.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Savastano M, García-Gallarín C, Giorgi C, Gratteri P, López de la Torre MD, Bazzicalupi C, Bianchi A, Melguizo M. Solid State and Solution Study on the Formation of Inorganic Anion Complexes with a Series of Tetrazine-Based Ligands. Molecules 2019; 24:E2247. [PMID: 31208109 PMCID: PMC6631435 DOI: 10.3390/molecules24122247] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/18/2022] Open
Abstract
Four molecules (L1-L4) constituted by an s-tetrazine ring appended with two identical aliphatic chains of increasing length bearing terminal morpholine groups were studied as anion receptors in water. The basicity properties of these molecules were also investigated. Speciation of the anion complexes formed in solution and determination of their stability constants were performed by means of potentiometric (pH-metric) titrations, while further information was obtained by NMR and isothermal titration calorimetry (ITC) measurements. The crystal structures of two neutral ligands (L3, L4) and of their H2L3(ClO4)2∙2H2O, H2L4(ClO4)2∙2H2O, H2L3(PF6)2, and H2L3(PF6)2∙2H2O anion complexes were determined by single crystal X-ray diffraction. The formation of anion-π interactions is the leitmotiv of these complexes, both in solution and in the solid state, although hydrogen bonding and/or formation of salt-bridges can contribute to their stability. Evidence of the ability of these ligands to form anion-π interactions is given by the observation that even the neutral (not-protonated) molecules bind anions in water to form complexes of significant stability, including elusive OH- anions.
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Affiliation(s)
- Matteo Savastano
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Italy.
| | | | - Claudia Giorgi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Italy.
| | - Paola Gratteri
- Department of NEUROFARBA-Pharmaceutical and Nutraceutical Section, and Laboratory of Molecular Modeling Cheminformatics & QSAR, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy.
| | | | - Carla Bazzicalupi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Italy.
| | - Antonio Bianchi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Italy.
| | - Manuel Melguizo
- Department of Inorganic and Organic Chemistry, University of Jaén, 23071 Jaén, Spain.
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Savastano M, Bazzicalupi C, García-Gallarín C, López de la Torre MD, Bianchi A, Melguizo M. Supramolecular forces and their interplay in stabilizing complexes of organic anions: tuning binding selectivity in water. Org Chem Front 2019. [DOI: 10.1039/c8qo01152d] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interplay of different supramolecular forces in stabilizing organic anion complexes with s-tetrazine-based ligands in aqueous solution: a microscopic description.
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Affiliation(s)
- Matteo Savastano
- Department of Chemistry “Ugo Schiff”
- University of Florence
- 50019 Sesto Fiorentino
- Italy
- CSGI
| | - Carla Bazzicalupi
- Department of Chemistry “Ugo Schiff”
- University of Florence
- 50019 Sesto Fiorentino
- Italy
| | | | | | - Antonio Bianchi
- Department of Chemistry “Ugo Schiff”
- University of Florence
- 50019 Sesto Fiorentino
- Italy
| | - Manuel Melguizo
- Department of Inorganic and Organic Chemistry
- University of Jaén
- 23071 Jaén
- Spain
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