Refine
Has Fulltext
- yes (75)
Is part of the Bibliography
- yes (75)
Year of publication
Document Type
- Journal article (75) (remove)
Language
- English (75) (remove)
Keywords
- boron (26)
- inorganic chemistry (8)
- Boron (7)
- diborenes (7)
- aromaticity (5)
- density functional calculations (5)
- carbenes (4)
- diborynes (4)
- heterocycles (4)
- luminescence (4)
- radical (4)
- structure elucidation (4)
- boranes (3)
- diborane (3)
- fluorescence (3)
- radicals (3)
- singlet oxygen (3)
- Anorganische Chemie (2)
- BN compounds (2)
- Bor (2)
- DFT (2)
- EDA-NOCV (2)
- Heterocycles (2)
- Multiple bonds (2)
- N-heterocyclic carbenes (2)
- bonding (2)
- borylene (2)
- borylenes (2)
- carbene ligands (2)
- chemical bonding (2)
- computational chemistry (2)
- crystal structure (2)
- diazadiborinines (2)
- hydroboration (2)
- main group elements (2)
- multiple bonds (2)
- one-electron oxidation (2)
- oxidative addition (2)
- platinum (2)
- polycycles (2)
- redox (2)
- single-crystal X-ray study (2)
- small-molecule activation (2)
- two-photon absorption (2)
- 1,2-azaborinine (1)
- 1,4-Diborabenzene (1)
- ACID (1)
- Acene (1)
- Aromaticity (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)
- Biradicals (1)
- Biradikale (1)
- Borylation (1)
- Borylene (1)
- B−H activation (1)
- Carbene (1)
- Chemie (1)
- Cycloaddition (1)
- DNA/RNA binding (1)
- DNA/RNA sensors (1)
- Diborane (1)
- Diboryne (1)
- Dihydroboranes (1)
- EPR spectroscopy (1)
- Heterocyclen (1)
- Heterocyclische Verbindungen (1)
- Hydroarylation (1)
- K-region (1)
- Kristallographie (1)
- Lewis acidity (1)
- Lewis adducts (1)
- Main-group chemistry (1)
- N ligands (1)
- N-functionalization (1)
- N-heterocyclic olefins (1)
- NHCs (1)
- NIR OLED (1)
- OLEDs (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)
- Titanium (1)
- Wade’s rules (1)
- X-ray crystallography (1)
- \(\pi\) interactions (1)
- ab initio calculations (1)
- acenes (1)
- acetone (1)
- alkenes (1)
- alkylideneborane (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 activation (1)
- bond dissociation energies (1)
- bond theory (1)
- borafluorenes (1)
- boraselenone (1)
- borohydrides (1)
- boroles (1)
- boron tetraiodide (1)
- boron-bound hydrogen (1)
- boronate (1)
- boronic acid (1)
- boryl anion (1)
- borylation (1)
- borylene complexes (1)
- carbene (1)
- carbene donor (1)
- carbocations (1)
- carborane (1)
- catenation (1)
- cationic species (1)
- cations (1)
- cell imaging (1)
- charge transfer (1)
- chemistry (1)
- chirality (1)
- chromism (1)
- chromophores (1)
- circularly polarized luminescence (1)
- complexes (1)
- conjugated oligomers (1)
- conjugation (1)
- crystal-structure (1)
- crystallographic analyses (1)
- cumulene (1)
- cyclic alkyl(amino)carbene (1)
- cyclization (1)
- cycloaddition (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)
- diboranes (1)
- diboration (1)
- diborene (1)
- dicoordinate borylene (1)
- dilaboration (1)
- diradicals (1)
- donor-acceptor systems (1)
- dual fluorescence (1)
- electrochemistry (1)
- electrolytes (1)
- electron storage (1)
- electron-precise diborates (1)
- electrophilic substitution (1)
- enamines (1)
- equilibrium (1)
- fluorescent probes (1)
- furan (1)
- fused thiazaboroles (1)
- group 13 (1)
- group 8 metals (1)
- halides (1)
- halogens (1)
- helicene (1)
- helicenes (1)
- heterodinuclear compound (1)
- homochiral dimer (1)
- hybrid materials (1)
- hydroamination (1)
- hydrogen (1)
- hydrogenation (1)
- hyperconjugation (1)
- imide ligands (1)
- iminoboranes (1)
- intersystem crossing (1)
- isoelectronic analogues (1)
- isomer (1)
- isomerization (1)
- ketenes (1)
- ligands (1)
- luminescent (1)
- main-group chemistry (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)
- 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)
- 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)
- rearrangements (1)
- redox processes (1)
- reduction (1)
- ring expansion (1)
- ring-expansion reactions (1)
- ruthenium (1)
- s-block metals (1)
- salt metathesis (1)
- sigma boranes (1)
- silaboration (1)
- solid-state NMR (1)
- solid-state sturcture (1)
- spin distribution (1)
- spiroborates (1)
- steric effects (1)
- supramolecular assembly (1)
- synchrotron radiation (1)
- terminal alkynes (1)
- tetramers (1)
- tetrametallaborides (1)
- tetraorganoborate salt (1)
- theranostics (1)
- thermal rearrangement (1)
- thiophene (1)
- threecoordinate boron (1)
- titanium (1)
- transition metal (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
A series of methylene-bridged bis(triarylboranes) has been synthesized via two complementary routes using metal-free catalytic Si/B exchange condensation under mild conditions. The title compounds comprise two borane moieties that show effective internal π-conjugation involving the respective boron centers and the adjacent hetaryl groups. Conjugation between both borane units, however, is disrupted by the aliphatic linker. Cyclic voltammetry revealed minimal electronic communication between the boron centers, as evidenced by two closely spaced reduction processes. The UV-vis spectra showed bathochromic shifted absorption bands compared to related monoboranes, which is attributed to the methylene bridge. A further red-shift results upon introduction of methyl or SiMe\(_3\) groups at the terminal thiophene rings.
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.
We investigate NCl\(_{3}\) and the NCl\(_{2}\) radical by photoelectron-photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms-TPES) of NCl\(_{3}\) is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl\(_{3}\) and its ms-TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N−Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined.
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.
A number of novel alkynyl-functionalized diarylbis(dimethylamino)diboranes(4) are prepared by salt metathesis, and the appended alkynyl groups are subjected to hydroboration. Their reactions with monohydroboranes lead to discrete boryl-appended diborane(4) species, while dihydroboranes induce their catenation to oligomeric species, the first known examples of well-characterized macromolecular species with B−B bonds. The oligomeric species were found to comprise up to ten repeat units and are soluble in common organic solvents. Some of the oligomeric species have good air stability and all were characterized by NMR and vibrational spectroscopy and size-exclusion chromatography techniques.
The parent borylene (CAAC)(Me\(_{3}\)P)BH, 1 (CAAC=cyclic alkyl(amino)carbene), acts both as a Lewis base and one-electron reducing agent towards group 13 trichlorides (ECl\(_{3}\), E=B, Al, Ga, In), yielding the adducts 1-ECl\(_{3}\) and increasing proportions of the radical cation [1]\(^{•+}\) for the heavier group 13 analogues. With boron trihalides (BX\(_{3}\), X=F, Cl, Br, I) 1 undergoes sequential adduct formation and halide abstraction reactions to yield borylboronium cations and shows an increasing tendency towards redox processes for the heavier halides. Calculations confirm that 1 acts as a strong Lewis base towards EX3 and show a marked increase in the B−E bond dissociation energies down both group 13 and the halide group.
A 1,8-naphthyridine diphosphine (NDP) reacts with boron-containing Lewis acids to generate complexes featuring a number of different naphthyridine bonding modes. When exposed to diborane B\(_{2}\)Br\(_{4}\), NDP underwent self-deprotonation to afford [NDP-B\(_{2}\)Br\(_{3}\)]Br, an unsymmetrical diborane comprised of four fused rings. The reaction of two equivalents of monoborane BBr\(_{3}\) and NDP in a non-polar solvent provided the simple phosphine-borane adduct [NDP(BBr\(_{3}\))\(_{2}\)], which then underwent intramolecular halide abstraction to furnish the salt [NDP-BBr\(_{2}\)][BBr\(_{4}\)], featuring a different coordination mode from that of [NDP-B\(_{2}\)Br\(_{3}\)]Br. Direct deprotonation of NDP by KHMDS or PhCH2K generates mono- and dipotassium reagents, respectively. The monopotassium reagent reacts with one or half an equivalent of B\(_{2}\)(NMe\(_{2}\))\(_{2}\)Cl\(_{2}\) to afford NDP-based diboranes with three or four amino substituents.
The synthesis, photophysical, and electrochemical properties of selectively mono-, bis- and tris-dimethylamino- and trimethylammonium-substituted bis-triarylborane bithiophene chromophores are presented along with the water solubility and singlet oxygen sensitizing efficiency of the cationic compounds Cat\(^{1+}\), Cat\(^{2+}\), Cat(i)\(^{2+}\), and Cat\(^{3+}\). Comparison with the mono-triarylboranes reveals the large influence of the bridging unit on the properties of the bis-triarylboranes, especially those of the cationic compounds. Based on these preliminary investigations, the interactions of Cat\(^{1+}\), Cat\(^{2+}\), Cat(i)\(^{2+}\), and Cat\(^{3+}\) with DNA, RNA, and DNApore were investigated in buffered solutions. The same compounds were investigated for their ability to enter and localize within organelles of human lung carcinoma (A549) and normal lung (WI38) cells showing that not only the number of charges but also their distribution over the chromophore influences interactions and staining properties.
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.
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.