Refine
Has Fulltext
- yes (34)
Is part of the Bibliography
- yes (34)
Document Type
- Journal article (18)
- Preprint (16)
Keywords
- boron (12)
- diborenes (7)
- carbenes (6)
- Boron (4)
- diborene (3)
- Aromaticity (2)
- Biradicals (2)
- Cycloaddition (2)
- Diborane (2)
- EDA-NOCV (2)
- Multiple bonds (2)
- aromaticity (2)
- bond activation (2)
- bonding (2)
- borylene (2)
- borylenes (2)
- diborynes (2)
- hydrogenation (2)
- inorganic chemistry (2)
- main-group chemistry (2)
- structure elucidation (2)
- 1,2-azaborinine (1)
- 1,3,2,4-Diazadiboretidin-2-yl-Ligand (1)
- 1,4-Diborabenzene (1)
- A-Frame-Komplex (1)
- B-N-Kupplung (1)
- Beryllium (1)
- Biradikale (1)
- Bor-Carbonylkomplexe (1)
- Boranes (1)
- Borylene (1)
- Butatrien-Analogon (1)
- C-H activation (1)
- CO activation (1)
- DFT (1)
- DFT mechanism (1)
- Diboranes (1)
- Diboren (1)
- Diborene (1)
- Dichtefunktionalrechnungen (1)
- Hydroborierung (1)
- Isosterie (1)
- Kation (1)
- Lewis adducts (1)
- Lewis-base adducts (1)
- Main-group chemistry (1)
- Multiple bonding (1)
- N-functionalization (1)
- N-heterocyclic carbenes (1)
- NMR spectroscopy (1)
- Organoboron chemistry (1)
- Parent Piano-Stool Complex (1)
- Photoisomerisierung (1)
- Pnictogen reduction (1)
- Reduktionen (1)
- Tetrafluorodiborane (1)
- Transition metals (1)
- Triboran (1)
- Umlagerungen (1)
- X-ray crystallography (1)
- acetone (1)
- alkynes (1)
- amine borane dehydrocoupling (1)
- bond dissociation energies (1)
- boraselenone (1)
- boron-bound hydrogen (1)
- boryl anion (1)
- borylation (1)
- borylene complexes (1)
- carbene donor (1)
- cations (1)
- chalcogens (1)
- conjugation (1)
- crystallographic analyses (1)
- crystallography (1)
- cumulene (1)
- cyclic (alkyl)(amino)carbene (1)
- cyclic alkyl(amino)carbene (1)
- cycloaddition (1)
- density-functional calculations (1)
- desymmetrization (1)
- diborane(6) (1)
- diboranes (1)
- diboryne (1)
- dicoordinate borylene (1)
- electron donors (1)
- erovalent diboron compounds (1)
- fused thiazaboroles (1)
- group 13 (1)
- group 8 metals (1)
- heterocycles (1)
- hydroarylation (1)
- hydroboration (1)
- iminoboranes (1)
- insertion (1)
- ligand exchange (1)
- low-valent main group chemistry (1)
- metathesis (1)
- nucleophile (1)
- nucleophilic addition (1)
- nucleophilic substitution (1)
- one-electron oxidation (1)
- oxidative addition (1)
- photoisomerization (1)
- platinum (1)
- push-pull stabilization (1)
- radical (1)
- reaction mechanism (1)
- reaction mechanisms (1)
- reactive intermediates (1)
- rearrangements (1)
- redox processes (1)
- reduction (1)
- reductive coupling (1)
- ring expansion (1)
- salt metathesis (1)
- small HOMO-LUMO gap (1)
- small-molecule activation (1)
- spectroscopy (1)
- structural analysis (1)
- transfer hydrogenation (1)
- transition metal complex (1)
- transition metals (1)
- triboranes (1)
Institute
Sonstige beteiligte Institutionen
EU-Project number / Contract (GA) number
- 669054 (22)
Room temperature hydrogenation of an SIDep-stabilized diboryne (SIDep = 1,3-bis(diethylphenyl)-4,5-dihydroimidazol-2-ylidene) and a CAAC-supported diboracumulene (CAAC = 1-(2,6- diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) provided the first selective route to the corresponding 1,2-dihydrodiborenes. DFT calculations showed an overall exothermic (ΔG = 19.4 kcal mol\(^{-1}\) two-step asynchronous H\(_2\) addition mechanism proceeding via a bridging hydride.
Whereas the reduction of N-heterocyclic carbene (NHC)-stabilised cymantrenyldibromoboranes, (NHC)BBr\(_2\)Cym, in benzene results in formation of the corresponding diborenes (NHC)\(_2\)B\(_2\)Cym\(_2\), a change of solvent to THF yields a borylene of the form (NHC)\(_2\)BCym, stabilised through its boratafulvene resonance form.
The reductive coupling of an NHC-stabilized aryldibromoborane yields a mixture of trans- and cis-diborenes in which the aryl groups are coplanar with the diborene core. Under dilute reduction conditions two diastereomers of a borirane-borane intermediate are isolated, which upon further reduction give rise to the aforementioned diborene mixture. DFT calculations suggest a mechanism proceeding via nucleophilic attack of a dicoordinate borylene intermediate on the aryl ring and subsequent intramolecular B-B bond formation.
Die Reaktion zwischen Aryl‐ und Amino(dihydro)boranen und Dibora[2]ferrocenophan 1 führt zur Bildung von 1,3‐trans‐Dihydrotriboranen durch formale Hydrierung und Insertion eines Borylens in die B=B Doppelbindung. Die Aryltriboran‐Derivate unterliegen einer reversiblen Photoisomerisierung zugunsten eines cis‐1,2‐μ‐H‐3‐Hydrotriborans, während eine Hydridabstraktion zu kationischen Triboranen führt, welche die ersten doppelt basenstabilisierten B\(_3\)H\(_4\)\(^+\)‐Analoga darstellen.
The reaction of aryl‐ and amino(dihydro)boranes with dibora[2]ferrocenophane 1 leads to the formation 1,3‐trans ‐dihydrotriboranes by formal hydrogenation and insertion of a borylene unit into the B=B bond. The aryltriborane derivatives undergo reversible photoisomerization to the cis ‐1,2‐μ‐H‐3‐hydrotriboranes, while hydride abstraction affords cationic triboranes, which represent the first doubly base‐stabilized B3H4\(^+\) analogues.
The addition of alkynes to a staturated N-heterocyclic carbene (NHC)-supported diboryne results in spontaneous cycloaddition, with complete B≡B and C≡C triple bond cleavage, NHC ring- expansion and activation of a variety of C-H bonds, leading to the formation of complex mixtures of fused B,N-heterocycles.
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.
A series of 22 new bis(phosphine), bis(carbene) and bis(isonitrile) tetrahalodiborane adducts has been synthesized, either by direct adduct formation with highly sensitive B2X4 precursors (X = Cl, Br, I) or by ligand exchange at stable B2X4(SMe2)2 precursors (X = Cl, Br) with labile dimethylsulfide ligands. The isolated compounds have been fully characterized using NMR spectroscopic, (C,H,N)- elemental and, for 20 of these compounds, X-ray crystallographic analysis, revealing an unexpected variation in the bonding motifs. Besides the classical B2X4L2 diborane(6) adducts, some of the more sterically demanding carbene ligands induce a halide displacement leading to the first halide-bridged monocationic diboron species, [B2X3L2]A (A = BCl4, Br, I). Furthermore, low-temperature 1:1 reactions of B2Cl4 with sterically demanding N-heterocyclic carbenes led to the formation of kinetically unstable mono-adducts, one of which was structurally characterized. A comparison of the NMR and structural data of new and literature-known bis-adducts shows several trends pertaining to the nature of the halides and the stereoelectronic properties of the Lewis bases employed.
The transfer hydrogenation of NHC-supported diborenes with dimethylamine borane proceeds with high selectivity for the trans-1,2-dihydrodiboranes(6). DFT calculations suggest a stepwise proton-first-hydride-second reaction mechanism via an intermediate μ-hydrodiboronium dimethylaminoborate ion pair.
B≡N and B≡B triple bonds induce C-H activation of acetone to yield a (2-propenyloxy)aminoborane and an unsymmetrical 1-(2- propenyloxy)-2-hydrodiborene, respectively. DFT calculations showed that, despite their stark electronic differences, both the B≡N and B≡B triple bonds activate acetone via a similar coordination-deprotonation mechansim. In contrast, the reaction of acetone with a cAAC-supported diboracumulene yielded a unique 1,2,3-oxadiborole, which according to DFT calculations also proceeds via an unsymmetrical diborene, followed by intramolecular hydride migration and a second C-H activation of the enolate ligand.