All-nitrogen spiropentadiene-N5.
Xiao Tian1, Xiao-Xu Bo1, Yi-Hong Ding1
1Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China.
The Journal of Chemical Physics
|November 7, 2021
Summary
Researchers explored a novel all-nitrogen spiropentadiene molecule, a high-energy isomer of the pentanitrogen cation. This unique spirocyclic structure shows significant sigma delocalization, warranting further spectroscopic investigation.
Area of Science:
- High-energy nitrogen chemistry
- Computational chemistry
- Materials science
Background:
- The pentanitrogen cation (N5+) family is known to contain only one experimentally verified isomer, a V-shaped structure.
- Exploring novel nitrogen allotropes is crucial for developing advanced materials and energetic compounds.
Purpose of the Study:
- To investigate the theoretical possibility and properties of a new all-nitrogen spirocyclic molecule, spiropentadiene.
- To assess its potential as a novel high-energy density material.
Main Methods:
- High-level computational chemistry methods were employed to model the structure and energy of the proposed molecule.
- Analysis of sigma delocalization was performed to understand bonding characteristics.
Main Results:
- A novel all-nitrogen spiropentadiene isomer (02) was computationally identified.
- This isomer is predicted to be energetically accessible, approximately 100 kcal/mol above the known V-shaped N5+.
- Significant sigma delocalization was observed in the proposed spiropentadiene structure.
Conclusions:
- The all-nitrogen spiropentadiene (02) is a promising candidate for a new class of spirocyclic nitrogen molecules.
- Its unique electronic structure and high energy content warrant further experimental and spectroscopic investigation.
- This discovery opens new avenues for research into high-nitrogen energetic materials.
Related Concept Videos
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
6.2K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
6.2K
01:16Other Nuclides: 31P, 19F, 15N NMR
490
Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a...
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a...
490
01:17Spin–Spin Coupling: One-Bond Coupling
1.1K
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
1.1K
01:202° Amines to N-Nitrosamines: Reaction with NaNO2
4.7K
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
4.7K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.2K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.2K
01:15Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
595
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
595