Refine
Has Fulltext
- yes (105)
Is part of the Bibliography
- yes (105)
Year of publication
Document Type
- Journal article (75)
- Preprint (30)
Language
- English (105) (remove)
Keywords
- boron (46)
- diborenes (15)
- Boron (11)
- carbenes (9)
- inorganic chemistry (8)
- density functional calculations (6)
- diborynes (6)
- aromaticity (5)
- heterocycles (5)
- N-heterocyclic carbenes (4)
- borylene (4)
- diborane (4)
- diboranes (4)
- diborene (4)
- luminescence (4)
- radical (4)
- structure elucidation (4)
- Bor (3)
- Diborane (3)
- Multiple bonds (3)
- bond activation (3)
- boranes (3)
- borylation (3)
- borylenes (3)
- fluorescence (3)
- hydroboration (3)
- low-valent compounds (3)
- multiple bonds (3)
- radicals (3)
- singlet oxygen (3)
- small-molecule activation (3)
- Anorganische Chemie (2)
- Aromaticity (2)
- BN compounds (2)
- Biradicals (2)
- Borylene (2)
- Cycloaddition (2)
- DFT (2)
- DFT calculations (2)
- EDA-NOCV (2)
- Heterocycles (2)
- Main-group chemistry (2)
- bonding (2)
- carbene ligands (2)
- chemical bonding (2)
- computational chemistry (2)
- conjugation (2)
- crystal structure (2)
- cycloaddition (2)
- diazadiborinines (2)
- diboration (2)
- diradicals (2)
- hydrogenation (2)
- low-valent main group chemistry (2)
- main group elements (2)
- main-group chemistry (2)
- multiple bonding (2)
- one-electron oxidation (2)
- oxidative addition (2)
- platinum (2)
- polycycles (2)
- redox (2)
- ring expansion (2)
- single-crystal X-ray study (2)
- transition metal complex (2)
- two-photon absorption (2)
- 1,2-additions (1)
- 1,2-azaborinine (1)
- 1,4-Diborabenzene (1)
- ACID (1)
- Acene (1)
- Arylborylene Complexes (1)
- B,N-heterocycles (1)
- B,N-heterocylcles (1)
- B-B bond (1)
- B-B bond activation (1)
- Beryllium (1)
- Bindungsaktivierung (1)
- Biradikale (1)
- Boranes (1)
- Borylation (1)
- B−H activation (1)
- C-H activation (1)
- CH activation (1)
- CO activation (1)
- CO2 fixation (1)
- Carbene (1)
- Chemie (1)
- DFT mechanism (1)
- DNA/RNA binding (1)
- DNA/RNA sensors (1)
- Diboranes (1)
- Diborene (1)
- Diboryne (1)
- Dihydroboranes (1)
- EPR spectroscopy (1)
- Heterocyclen (1)
- Heterocyclische Verbindungen (1)
- Hydroarylation (1)
- K-region (1)
- Kristallographie (1)
- Lewis acidity (1)
- Lewis acids (1)
- Lewis adducts (1)
- Lewis-base adducts (1)
- Metallocene (1)
- Metallocenes (1)
- Multiple bonding (1)
- N ligands (1)
- N-functionalization (1)
- N-heterocyclic olefins (1)
- NHCs (1)
- NIR OLED (1)
- NMR spectroscopy (1)
- OLEDs (1)
- Organoboron chemistry (1)
- Palladium-catalyzed silaboration (1)
- Parent Piano-Stool Complex (1)
- Pnictogen reduction (1)
- R factor = 0.018 (1)
- R factor = 0.027 (1)
- Ruthenium (1)
- Selen (1)
- Selenium (1)
- T = 100 K (1)
- T = 174 K (1)
- Tellur (1)
- Tellurium (1)
- Tetrafluorodiborane (1)
- Titanium (1)
- Transition metals (1)
- Wade’s rules (1)
- X-ray crystallography (1)
- \(\pi\) interactions (1)
- ab initio calculations (1)
- acenes (1)
- acetone (1)
- alkenes (1)
- alkylideneborane (1)
- alkynes (1)
- amine borane dehydrocoupling (1)
- anionic dimetalloborylene complexes (1)
- antiaromaticity (1)
- azaborinines (1)
- azaborole (1)
- azadiboretidines (1)
- azobenzenes (1)
- beryllium (1)
- binary species (1)
- bioimaging (1)
- biradicals (1)
- bismuth (1)
- bond Activation (1)
- bond dissociation energies (1)
- bond theory (1)
- borafluorenes (1)
- boraselenone (1)
- borohydrides (1)
- boroles (1)
- boron chains (1)
- boron tetraiodide (1)
- boron-bound hydrogen (1)
- boronate (1)
- boronic acid (1)
- boronium cations (1)
- boryl anion (1)
- borylene complexes (1)
- carbene (1)
- carbene donor (1)
- carbocations (1)
- carbon dioxide (1)
- carborane (1)
- catalysis (1)
- catenation (1)
- cationic species (1)
- cations (1)
- cell imaging (1)
- chain structures (1)
- chalcogens (1)
- charge transfer (1)
- chelates (1)
- chemistry (1)
- chirality (1)
- chromism (1)
- chromophores (1)
- circularly polarized luminescence (1)
- complexes (1)
- conjugated oligomers (1)
- crystal-structure (1)
- crystallographic analyses (1)
- crystallography (1)
- cumulene (1)
- cyclic (alkyl)(amino)carbene (1)
- cyclic alkyl(amino)carbene (1)
- cyclization (1)
- cyclopenten-4-yl cation (1)
- data-to-parameter ratio = 22.3 (1)
- data-to-parameter ratio = 23.6. (1)
- decarbonylation (1)
- dehydrocoupling (1)
- density functional theory (1)
- density-functional calculations (1)
- design (1)
- desymmetrization (1)
- diboraindanes (1)
- diborane(6) (1)
- diboron (1)
- diboryne (1)
- dicoordinate borylene (1)
- dilaboration (1)
- donor-acceptor systems (1)
- dual fluorescence (1)
- electrochemistry (1)
- electrolytes (1)
- electron donors (1)
- electron storage (1)
- electron-precise diborates (1)
- electrophiles (1)
- electrophilic substitution (1)
- enamines (1)
- equilibrium (1)
- erovalent diboron compounds (1)
- fluorescent probes (1)
- furan (1)
- fused thiazaboroles (1)
- group 13 (1)
- group 8 metals (1)
- half-sandwich complexes (1)
- halides (1)
- halogens (1)
- helicene (1)
- helicenes (1)
- heterodinuclear compound (1)
- homochiral dimer (1)
- hybrid materials (1)
- hydroamination (1)
- hydroarylation (1)
- hydrogen (1)
- hyperconjugation (1)
- imide ligands (1)
- iminoboranes (1)
- insertion (1)
- intersystem crossing (1)
- iodine (1)
- isoelectronic analogues (1)
- isomer (1)
- isomerization (1)
- isomers (1)
- ketenes (1)
- ligand exchange (1)
- ligands (1)
- low-valent main-group species (1)
- luminescent (1)
- mean σ(C–C) = 0.004 Å (1)
- mechanism (1)
- metal borylene complexes (1)
- metal-free (1)
- metallaboranes (1)
- metallacycles (1)
- metathesis (1)
- methyl exchange (1)
- methyl viologen (1)
- molecular-structure (1)
- naphthyridine (1)
- near-IR chromophores (1)
- nitrogen heterocycles (1)
- nitrogen ligands (1)
- nitrogen trichloride (1)
- nucleic acid (1)
- nucleophile (1)
- nucleophilic addition (1)
- nucleophilic substitution (1)
- oligomerization (1)
- organic chemistry (1)
- organometallic chemistry (1)
- orylation (1)
- oxidation (1)
- palladium (1)
- pericyclic reaction (1)
- phosphorus (1)
- phosphorus heterocycles (1)
- photoelectron spectroscopy (1)
- photoisomerization (1)
- photolysis (1)
- photophysical prosperties (1)
- phthalocyanines (1)
- pi-conjugation (1)
- pincer ligand (1)
- polycyclic aromatic hydrocarbon (1)
- polycyclic aromatic hydrocarbons (1)
- potassium reagent (1)
- push-pull stabilization (1)
- pyrenes (1)
- pyridinium (1)
- reaction mechanism (1)
- reaction mechanisms (1)
- reactive intermediates (1)
- rearrangement (1)
- rearrangements (1)
- redox processes (1)
- redox reactions (1)
- reduction (1)
- reductive coupling (1)
- ring-expansion reactions (1)
- ruthenium (1)
- s-block metals (1)
- salt metathesis (1)
- sigma boranes (1)
- silaboration (1)
- silylenes (1)
- small HOMO-LUMO gap (1)
- solid-state NMR (1)
- solid-state sturcture (1)
- spectroscopy (1)
- spin distribution (1)
- spiroborates (1)
- steric effects (1)
- strained molecules (1)
- structural analysis (1)
- supramolecular assembly (1)
- synchrotron radiation (1)
- synthesis (1)
- synthetic methods (1)
- terminal alkynes (1)
- tetramers (1)
- tetrametallaborides (1)
- tetraorganoborate salt (1)
- theranostics (1)
- thermal rearrangement (1)
- thiophene (1)
- threecoordinate boron (1)
- titanium (1)
- transfer hydrogenation (1)
- transition metal (1)
- transition metals (1)
- triarylamine (1)
- triarylborane (1)
- triarylboranes (1)
- triboranes (1)
- trimetallaborides (1)
- triple bonds (1)
- viologens (1)
- wR factor = 0.038 (1)
- wR factor = 0.069 (1)
- weak intermolecular coordination (1)
- π aromaticity (1)
- π-extension (1)
Institute
Sonstige beteiligte Institutionen
A practical and direct method was developed for the production of versatile alkyl boronate esters via transition metal-free borylation of primary and secondary alkyl sulfones. The key to the success of the strategy is the use of bis(neopentyl glycolato) diboron (B\(_{2}\)neop\(_{2}\)), with a stoichiometric amount of base as a promoter. The practicality and industrial potential of this protocol are highlighted by its wide functional group tolerance, the late-stage modification of complex compounds, no need for further transesterification, and operational simplicity. Radical clock, radical trap experiments, and EPR studies were conducted which show that the borylation process involves radical intermediates.
Boroles are attracting broad interest for their myriad and diverse applications, including in synthesis, small molecule activation and functional materials. Their properties and reactivity are closely linked to the cyclic conjugated diene system, which has been shown to participate in cycloaddition reactions, such as the Diels-Alder reaction with alkynes. The reaction steps leading to boranorbornadienes, borepins and tricyclic boracyclohexenes from the thermal reaction of boroles with alkynes are seemingly well understood as judged from the literature. Herein, we question the long-established mechanistic picture of pericyclic rearrangements by demonstrating that seven-membered borepins (i. e., heptaphenylborepin and two derivatives substituted with a thienyl and chloride substituent on boron) exist in a dynamic equilibrium with the corresponding bicyclic boranorbornadienes, the direct Diels-Alder products, but are not isolable products from the reactions. Heating gradually converts the isomeric mixtures into fluorescent tricyclic boracyclohexenes, the most stable isomers in the series. Results from mechanistic DFT calculations reveal that the tricyclic compounds derive from the boranorbornadienes and not the borepins, which were previously believed to be intermediates in purely pericyclic processes.
A series of highly substituted 1,2-azaborinines, including a phenylene-bridged bis-1,2-azaborinine, was synthesized from the reaction of 1,2-azaborete rhodium complexes with variously substituted alkynes. 1-Rhoda-3,2-azaborole complexes, which are accessible by phosphine addition to the corresponding 1,2-azaborete complexes, were also found to be suitable precursors for the synthesis of 1,2-azaborinines and readily reacted with alkynyl-substituted 1,2-azaborinines to generate new regioisomers of bi-1,2-azaborinines, which feature directly connected aromatic rings. Their molecular structures, which can be viewed as boron-nitrogen isosteres of biphenyls, show nearly perpendicular 1,2-azaborinine rings. The new method using rhodacycles instead of 1,2-azaborete complexes as precursors is shown to be more effective, allowing the synthesis of a wider range of 1,2-azaborinines.
Cyclic alkyl(amino)carbene-stabilized (cyano)hydroboryl anions were synthesized by deprotonation of (cyano)dihydroborane precursors. While they display boron-centered nucleophilic reactivity towards organohalides, generating fully unsymmetrically substituted cyano(hydro)organoboranes, they show cyano-nitrogen-centered nucleophilic reactivity towards haloboranes, resulting in the formation of hitherto unknown linear 2-aza-1,4-diborabutatrienes.
Boron's unique position in the Periodic Table, that is, at the apex of the line separating metals and nonmetals, makes it highly versatile in chemical reactions and applications. Contemporary demand for renewable and clean energy as well as energy‐efficient products has seen boron playing key roles in energy‐related research, such as 1) activating and synthesizing energy‐rich small molecules, 2) storing chemical and electrical energy, and 3) converting electrical energy into light. These applications are fundamentally associated with boron's unique characteristics, such as its electron‐deficiency and the availability of an unoccupied p orbital, which allow the formation of a myriad of compounds with a wide range of chemical and physical properties. For example, boron's ability to achieve a full octet of electrons with four covalent bonds and a negative charge has led to the synthesis of a wide variety of borate anions of high chemical and electrochemical stability—in particular, weakly coordinating anions. This Review summarizes recent advances in the study of boron compounds for energy‐related processes and applications.
A one-pot synthesis of a CAAC-stabilized, unsymmetrical, cyclic diborene was achieved via consecutive two-electron reduction steps from an adduct of CAAC and B\(_2\)Br\(_4\)(SMe\(_2\))\(_2\). Theoretical studies revealed that this diborene has a considerably smaller HOMO–LUMO gap than those of reported NHC- and phosphine-supported diborenes. Complexation of the diborene with [AuCl(PCy\(_3\))] afforded two diborene–Au\(^I\) π complexes, while reaction with DurBH\(_2\), P\(_4\) and a terminal acetylene led to the cleavage of B−H, P−P, and C−C π bonds, respectively. Thermal rearrangement of the diborene gave an electron-rich cyclic alkylideneborane, which readily coordinated to Ag\(^I\) via its B=C double bond.
The Fischer carbene synthesis, involving the conversion of a transition metal (TM)-bound CO ligand to a carbene ligand of the form [=C(OR’)R] (R, R’ = organyl groups), is one of the seminal reactions in the history of organometallic chemistry. Carbonyl complexes of p-block elements, of the form [E(CO)n] (E = main-group fragment), are much less abundant than their TM cousins; this scarcity and the general instability of low-valent p-block species means that replicating the historical reactions of TM carbonyls is often very difficult. Here we present a step-for-step replica of the Fischer carbene synthesis at a borylene carbonyl involving nucleophilic attack at the carbonyl carbon followed by electrophilic quenching at the resultant acylate oxygen atom. These reactions provide borylene acylates and alkoxy-/silyloxy-substituted alkylideneboranes, main-group analogues of the archetypal transition metal acylate and Fischer carbene families, respectively. When either the incoming electrophile or the boron center has a modest steric profile, the electrophile instead attacks at the boron atom, leading to carbene-stabilized acylboranes – boron analogues of the well-known transition metal acyl complexes. These results constitute faithful main-group replicas of a number of historical organometallic processes and pave the way to further advances in the field of main-group metallomimetics.
Twisted boron-based biradicals featuring unsaturated C\(_2\)R\(_2\) (R=Et, Me) bridges and stabilization by cyclic (alkyl)(amino)carbenes (CAACs) were recently prepared. These species show remarkable geometrical and electronic differences with respect to their unbridged counterparts. Herein, a thorough computational investigation on the origin of their distinct electrostructural properties is performed. It is shown that steric effects are mostly responsible for the preference for twisted over planar structures. The ground-state multiplicity of the twisted structure is modulated by the σ framework of the bridge, and different R groups lead to distinct multiplicities. In line with the experimental data, a planar structure driven by delocalization effects is observed as global minimum for R=H. The synthetic elusiveness of C\(_2\)R\(_2\)-bridged systems featuring N-heterocyclic carbenes (NHCs) was also investigated. These results could contribute to the engineering of novel main group biradicals.
A cyclic alkyl(amino)carbene‐stabilized 1,4‐diborabenzene (DBB) ligand enables the isolation of 18‐electron two‐legged parent piano‐stool Fe\(^{0}\) and Ru\(^{0}\) complexes, [(η\(^{6}\)‐DBB)M(CO)\(_{2}\)], the ruthenium complex being the first of its kind to be structurally characterized. [(η\(^{6}\)‐DBB)Fe(CO)\(_{2}\)] reacts with E\(_{4}\) (E=P, As) to yield mixed DBB‐cyclo‐E\(_{4}\) sandwich complexes with planar E\(_{4}\)\(^{2-}\) ligands. Computational analyses confirm the strong electron‐donating capacity of the DBB ligand and show that the E\(_{4}\) ligand is bound by four equivalent Fe−P σ bonds.
The reactions of carbodiimides with the iron arylborylene complex [Fe=BDur(CO)\(_{3}\)(PMe\(_{3}\))] (Dur=2,3,5,6-Me\(_{4}\)C\(_{6}\)H) and the iron bis(borylene) complex [Fe{=BDur}{=BN(SiMe\(_{3}\))\(_{2}\)}(CO)\(_{3}\)] yield a wide variety of temperature-dependent products, including known FeBNC and novel FeBNB metallacycles, complexes of N-heterocyclic boracarbene and spiro-boracarbene ligands and a unique 1,3,2,4-diazadiborolyl pianostool complex, characterized by NMR spectroscopy and X-ray crystallography. The product distributions can be rationalized by considering sequences of cycloaddition, metathesis, insertion, and C−H activation pathways mainly governed by sterics.