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5 pages, 490 KiB

Open AccessProceeding Paper

Hexa-Substituted Hybrid C₆₀ Derivatives with Norbornadiene Fragments: Synthesis and Structure

by Arslan R. Akhmetov, Zarema R. Sadretdinova, Arthur R. Tulyabaev and Leonard M. Khalilov

Chem. Proc. 2023, 14(1), 67; https://doi.org/10.3390/ecsoc-27-16104 - 15 Nov 2023

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New hybrid fullerene C₆₀ derivatives with five norbornadiene fragments, at a distance from the fullerene core of several methylene groups, were synthesized for the first time. Subsequent photoirradiation of these derivatives leads to only partial (up to 20%) opening of double bonds in norbornadiene fragments to form quadricyclane substituents. It is assumed that the resulting fullerene C₆₀ derivatives can serve as a basis to create high-energy materials. Full article

(This article belongs to the Proceedings of 27th International Electronic Conference on Synthetic Organic Chemistry)

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9 pages, 2670 KiB

Open AccessCommunication

Accelerating the Design of High-Energy-Density Hydrocarbon Fuels by Learning from the Data

by Linyuan Wen, Shiqun Shan, Weipeng Lai, Jinwen Shi, Mingtao Li, Yingzhe Liu, Maochang Liu and Zhaohui Zhou

Molecules 2023, 28(21), 7361; https://doi.org/10.3390/molecules28217361 - 31 Oct 2023

Cited by 1 | Viewed by 2331

Abstract

In the ZINC20 database, with the aid of maximum substructure searches, common substructures were obtained from molecules with high-strain-energy and combustion heat values, and further provided domain knowledge on how to design high-energy-density hydrocarbon (HEDH) fuels. Notably, quadricyclane and syntin could be topologically assembled through these substructures, and the corresponding assembled schemes guided the design of 20 fuel molecules (ZD-1 to ZD-20). The fuel properties of the molecules were evaluated by using group-contribution methods and density functional theory (DFT) calculations, where ZD-6 stood out due to the high volumetric net heat of combustion, high specific impulse, low melting point, and acceptable flash point. Based on the neural network model for evaluating the synthetic complexity (SCScore), the estimated value of ZD-6 was close to that of syntin, indicating that the synthetic complexity of ZD-6 was comparable to that of syntin. This work not only provides ZD-6 as a potential HEDH fuel, but also illustrates the superiority of learning design strategies from the data in increasing the understanding of structure and performance relationships and accelerating the development of novel HEDH fuels. Full article

(This article belongs to the Special Issue Molecular Design and Theoretical Investigation of Energetic Materials)

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15 pages, 2590 KiB

Open AccessArticle

A Norbornadiene-Based Molecular System for the Storage of Solar–Thermal Energy in an Aqueous Solution: Study of the Heat-Release Process Triggered by a Co(II)-Complex

by Franco Castro, Jorge S. Gancheff, Juan C. Ramos, Gustavo Seoane, Carla Bazzicalupi, Antonio Bianchi, Francesca Ridi and Matteo Savastano

Molecules 2023, 28(21), 7270; https://doi.org/10.3390/molecules28217270 - 25 Oct 2023

Cited by 4 | Viewed by 3645

Abstract

It is urgent yet challenging to develop new environmentally friendly and cost-effective sources of energy. Molecular solar thermal (MOST) systems for energy capture and storage are a promising option. With this in mind, we have prepared a new water-soluble (pH > 6) norbornadiene derivative (HNBD1) whose MOST properties are reported here. HNBD1 shows a better matching to the solar spectrum compared to unmodified norbornadiene, with an onset absorbance of λ_onset = 364 nm. The corresponding quadricyclane photoisomer (HQC1) is quantitatively generated through the light irradiation of HNBD1. In an alkaline aqueous solution, the MOST system consists of the NBD1⁻/QC1⁻ pair of deprotonated species. QC1⁻ is very stable toward thermal back-conversion to NBD1⁻; it is absolutely stable at 298 K for three months and shows a marked resistance to temperature increase (half-life t_½ = 587 h at 371 K). Yet, it rapidly (t_½ = 11 min) releases the stored energy in the presence of the Co(II) porphyrin catalyst Co-TPPC (ΔH_storage = 65(2) kJ∙mol⁻¹). Under the explored conditions, Co-TPPC maintains its catalytic activity for at least 200 turnovers. These results are very promising for the creation of MOST systems that work in water, a very interesting solvent for environmental sustainability, and offer a strong incentive to continue research towards this goal. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)

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5 pages, 395 KiB

Open AccessProceeding Paper

Covalent Binding of C₆₀ Fullerene to Quadricyclanes A Synthetic Avenue to Hexamethanofullerenes with Promising Antitumor Activity

by Arslan Akhmetov, Zarema Sadretdinova, Lilya U. Dzhemileva, Airat Tuktarov and Usein Dzhemilev

Chem. Proc. 2022, 8(1), 95; https://doi.org/10.3390/ecsoc-25-11649 - 13 Nov 2021

Viewed by 977

Abstract

The Bingel–Hirsch reaction was used to synthesize two new hexamethanofullerenes containing six quadricyclane fragments. Preliminary experiments have established that the synthesized compounds have a high antitumor effect in combination with cisplatin on human T-lymphoblastic leukemia cells (Jurkat cells). Full article

(This article belongs to the Proceedings of The 25th International Electronic Conference on Synthetic Organic Chemistry)

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12 pages, 1397 KiB

Open AccessFeature PaperArticle

A Procedure for Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, with Application to 66 Molecules ^†

by Paul R. Rablen

Chemistry 2020, 2(2), 347-360; https://doi.org/10.3390/chemistry2020022 - 30 Apr 2020

Cited by 29 | Viewed by 5803

Abstract

A method is presented for the direct computation of hydrocarbon strain energies using computational group equivalents. Parameters are provided at several high levels of electronic structure theory: W1BD, G-4, CBS-APNO, CBS-QB3, and M062X/6-31+G(2df,p). As an illustration of the procedure, strain energies are computed [...] Read more.

(This article belongs to the Special Issue Radically Different—A Themed Issue in Honor of Professor Bernd Giese on the Occasion of His 80th Birthday)

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14 pages, 2424 KiB

Open AccessArticle

Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes

by Mads Mansø, Lorette Fernandez, Zhihang Wang, Kasper Moth-Poulsen and Mogens Brøndsted Nielsen

Molecules 2020, 25(2), 322; https://doi.org/10.3390/molecules25020322 - 13 Jan 2020

Cited by 23 | Viewed by 5652

Abstract

The photochromic norbornadiene/quadricyclane (NBD/QC) couple has found interest as a molecular solar thermal energy (MOST) system for storage of solar energy. To increase the energy difference between the two isomers, we present here the synthesis of a selection of benzo-fused NBD derivatives that contain an aromatic unit, benzene, naphthalene or phenanthrene, fused to one of the NBD double bonds, while the carbon atoms of the other double bond are functionalized with donor and acceptor groups. The synthesis protocols involve functionalization of benzo-fused NBDs with bromo/chloro substituents followed by a subjection of these intermediates to a cyanation reaction (introducing a cyano acceptor group) followed by a Sonogashira coupling (introducing an arylethynyl donor group, -C≡CC₆H₄NMe₂ or -C≡CC₆H₄OMe). While the derivatives have good absorption properties in the visible region (redshifted relative to parent system) in the context of MOST applications, they lack the ability to undergo NBD-to-QC photoisomerization, even in the presence of a photosensitizer. It seems that loss of aromaticity of the fused aromatics is too significant to allow photoisomerization to occur. The concept of destroying aromaticity of a neighboring moiety as a way to enhance the energy density of the NBD/QC couple thus needs further structural modifications, in the quest for optimum MOST systems. Full article

(This article belongs to the Special Issue New Studies of Conjugated Compounds)

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