Dicationic Boron Derivatives of Schlenk’s and Thiele’s Hydrocarbon

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

In recent years, neutral NHC-stabilized boryl radicals have been investigated as reactive species in various organic transformations. However, cationic boron significantly less explored. addition, boron-centered open-shell with S > 1/2 emerged attractive synthetic targets. this study, we provide a route to an radical cation salt of the weakly coordinating [Al(ORF)4]- (RF = C(CF3)3) anion. The procedure was extended dicationic diboron derivatives Schlenk's and Thiele's hydrocarbons meta- para-phenylene coupling units between spin centers. While most known isolable biradicals singlet ground-state thermally accessible triplet state, version hydrocarbon occupies spin-state, shown by combined electron paramagnetic resonance spectroscopy density functional theory studies. Furthermore, initial reactivity studies dications elemental sulfur diphenyldiselenide are presented.

Language: Английский

---

Redox- and Charge-State Dependent Trends in 5, 6, and 7-Membered Boron Heterocycles: A Neutral Ligand Coordination Chemistry Approach to Boracyclic Cations, Anions, and Radicals

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(10), P. 1510 - 1522

Published: May 6, 2024

ConspectusBoron heterocycles represent an important subset of heteroatom-incorporated rings, attracting attention from organic, inorganic, and materials chemists. The empty pz orbital at the boron center makes them stand out as quintessential Lewis acidic molecules, also serving a means to modulate electronic structure photophysical properties in facile manner. As boracycles are ripe for extensive functionalization, they used catalysis, chemical biology, science, continue be explored synthons conjugated reagents. Neutral boron(III)-incorporated polycyclic molecules some most studied types boracycles, understanding their redox transformations is applications relying on electron transfer charge transport. While relevant species can often electrochemically observed, it remains challenging isolate characterize where and/or skeleton have been chemically reduced.We describe our recent work isolating 5-, 6-, 7-membered boracyclic radicals, anions, cations, focusing stabilization strategies, ligand-mediated bonding situations, reactivity. We present versatile neutral ligand coordination chemistry approach that permits transformation potent electrophiles powerful nucleophilic facilitate diverse bond activation chemistry. Although there wide range suitable stabilizing ligands, we employed both diamino-N-heterocyclic carbenes (NHCs) cyclic(alkyl)(amino) (CAACs), which led with tunable structures aromaticity trends. highlight successful isolation borafluorene radicals demonstrate reversible behavior, undergoing oxidation cation or reduction anion. anion synthon has prepare boryl main-group transition-metal bonds, luminescent oxabora-spirocycles, borafluorenate-crown ethers, CO-releasing via carbon dioxide activation. expanded 6-membered characterized bis(NHC-supported 9-boraphenanthrene)s corresponding bis(CAAC-stabilized 9-boraphenanthrene) biradical. detail interconvertible multiredox states boraphenalene, boraphenalenyl radical, anion, mimic charge-states all-hydrocarbon analogue. Reactivity studies displayed unusual reactivity multiple sites periphery tricyclic scaffold. Reduced borepins, containing heterocycles, isolated. stepwise one-pot synthesis combining halo-borepin precursor, CAAC, KC8 afford monomeric borepin anions. π-system was extended contain two rings fused pentacyclic scaffold, permitted diborepin biradicals dibora-quinone core.Our goal provide guide explaining current structure–function trends strategies redox-active boron-incorporated initiate rational design use these compounds across vast space.

Language: Английский

---

Crystalline Boron‐Centered Analogues of Müller's Hydrocarbon

Chinese Journal of Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: June 16, 2024

Comprehensive Summary Müller's hydrocarbon is a well‐known open‐shell singlet diradicaloid, yet its structural determination and redox property remain elusive due to extremely high reactivity. Herein, we report the successful synthesis full characterizations of first neutral boron‐centered analogue ( 4 ) hydrocarbon, along with dianionic 5 2− featuring three isolable states. In presence two equivalents N‐heterocyclic carbene (NHC), reduction 4,4”‐bis(triisopropylphenylbromoboryl)terphenyl 3 potassium graphite afforded NHC‐stabilized boryl diradicaloid near‐pure diradical character y 0 = 0.93). Stepwise reductions 4,4”‐bis(dimesitylboryl)terphenyl in THF yielded monoradical anion ·− dianion , respectively, accompanied by decreasing aromaticity within conjugated spacer. Experimental studies theoretical analyses revealed that both exhibit large spin distributions at boron atoms, ground states, small singlet‐triplet energy gaps.

Language: Английский

---

Crystalline Radical Anion of a Diboratriazole and Its Conversion to a Neutral Radical Driven by a Carbene

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(30), P. 20945 - 20950

Published: July 21, 2024

One-electron reduction of diboratriazole

Language: Английский

---

Pentacyclic fused diborepinium ions with carbene- and carbone-mediated deep-blue to red emission

Chemical Science, Journal Year: 2024, Volume and Issue: 15(35), P. 14358 - 14370

Published: Jan. 1, 2024

Designing molecules that can undergo late-stage modifications resulting in specific optical properties is useful for developing structure-function trends materials, which ultimately advance optoelectronic applications. Herein, we report a series of fused diborepinium ions stabilized by carbene and carbone ligands (diamino-N-heterocyclic carbenes, cyclic(alkyl)(amino) carbodicarbenes, carbodiphosphoranes), including detailed bonding analysis. These are the first structurally confirmed examples diborepin dications detail how distortions core pentacyclic system impact aromaticity, stability, their light-emitting properties. Using same scaffold, coordinating were used to dramatically shift emission profile, exhibit colors ranging from blue red (358-643 nm). Notably, these access expanded regions visible spectrum compared known borepins, with quantum yields up 60%. Carbones determined be superior stabilizing ligands, improved stability solution solid states. Density functional theory was provide insight into as well transitions result observed photophysical

Language: Английский

---

Ligand-Tuned Open- and Closed-Shell Diborepins

Synfacts, Journal Year: 2024, Volume and Issue: 20(07), P. 0692 - 0692

Published: June 14, 2024

Key words diborepins - open-shell singlet bora-quinone biradical

Language: Английский

---