2118-02-7Relevant academic research and scientific papers
Bis(pentafluorophenyl)borinic acid: A cyclic trimer in the solid state and a monomer, with hindered rotation around the B-OH bond, in solution
Beringhelli, Tiziana,D'Alfonso, Giuseppe,Donghi, Daniela,Maggioni, Daniela,Mercandelli, Pierluigi,Sironi, Angelo
, p. 1588 - 1590 (2003)
The title molecule in the solid state exists as a cyclic trimer, with B-O(H)-B bridges and a cyclo-hexane-like structure (C2 twist-boat conformation); dissolution in toluene-d8 affords the B(C6F5)2OH monomer, in which the low-temperature 19F NMR data reveal restricted rotation of the OH substituent around the Ar2B-OH bond (Ea = 39 kJ mol-1), as a result of the partial double-bond character of this interaction.
Bonding in Barium Boryloxides, Siloxides, Phenoxides and Silazides: A Comparison with the Lighter Alkaline Earths
Carpentier, Jean-Fran?ois,Cordier, Marie,Dorcet, Vincent,Hammoud, Joanna,Kahlal, Samia,Le Coz, Erwann,Roisnel, Thierry,Saillard, Jean-Yves,Sarazin, Yann
supporting information, p. 11966 - 11982 (2021/07/16)
Barium complexes ligated by bulky boryloxides [OBR2]? (where R=CH(SiMe3)2, 2,4,6-iPr3-C6H2 or 2,4,6-(CF3)3-C6H2), siloxide
The preparation of pentafluorophenyldihaloboranes from pentafluorophenylmercurials C6F5HgR and BX3: the dramatic dependence of the reaction direction on the ligand R
Bardin, Vadim V.,Adonin, Nicolay Yu.
, p. 1523 - 1531 (2019/07/22)
Abstract: In search of convenient preparations of C6F5BX2 (X = Cl, Br), reactions of C6F5HgR (R = C6F5, C6H5, C2H5, Br and Cl) with BX3 were studied. Under the action of BCl3 the order of the C–Hg bond cleavage is C6F5Hg–C6H5 > C6F5–HgC2H5 > C6F5–HgC6F5 >> C6F5–HgCl. With more reactive BBr3 the sequence is C6F5Hg–C6H5 > C6F5–HgC2H5 ~ C6F5Hg–C2H5 > C6F5–HgC6F5 ≥ C6F5–HgBr. During the study we found the simple way to alkyldibromoboranes which is presented by the preparation of C2H5BBr2 from C2H5HgBr and BBr3. It is the second example of synthesis of alkylmercury derivative in an addition to the earlier reported formation of cyclopropylmercurials from di(cyclopropyl)mercury and BX3. Graphic abstract: [Figure not available: see fulltext.].
Sequential C?H Borylation and N-Demethylation of 1,1′-Biphenylamines: Alternative Route to Polycyclic BN-Heteroarenes
Zhang, Jianbo,Jung, Hoimin,Kim, Dongwook,Park, Sehoon,Chang, Sukbok
, p. 7361 - 7365 (2019/04/30)
Described herein is an unprecedented access to BN-polyaromatic compounds from 1,1′-biphenylamines by sequential borane-mediated C(sp2)?H borylation and intramolecular N-demethylation. The conveniently in situ generated Piers’ borane from a borinic acid reacts with a series of N,N-dimethyl-1,1′-biphenyl-2-amines in the presence of PhSiH3 to afford six-membered amine-borane adducts bearing a C(sp2)?B bond at the C2′-position. These species undergo an intramolecular N-demethylation with a B(C6F5)3 catalyst to provide BN-isosteres of polyaromatics. According to computational studies, a stepwise ionic pathway is suggested. Photophysical characters of the resultant BN-heteroarenes shown them to be distinctive from those of all-carbon analogues.
Polymer Meets Frustrated Lewis Pair: Second-Generation CO2-Responsive Nanosystem for Sustainable CO2 Conversion
Chen, Liang,Liu, Renjie,Yan, Qiang
supporting information, p. 9336 - 9340 (2018/07/25)
Frustrated Lewis pairs (FLP), a couple comprising a sterically encumbered Lewis acid and Lewis base, can offer latent reactivity for activating inert gas molecules. However, their use as a platform for fabricating gas-responsive materials has not yet developed. Merging the FLP concept with polymers, we report a new generation CO2-responsive system, differing from the first-generation ones based on an acid–base equilibrium mechanism. Two complementary Lewis acidic and basic block copolymers, installing bulky borane- and phosphine-containing blocks, were built as the macromolecular FLP. They can bind CO2 to drive micellar formation, in which CO2 as a cross-linker bridges the block chains. This dative bonding endows the assembly with ultrafast response (2 can function as nanocatalysts for recyclable C1 catalysis, opening a new direction of sustainable CO2 conversion.
Selective C?O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ
Zhang, Jianbo,Park, Sehoon,Chang, Sukbok
, p. 13757 - 13761 (2017/10/09)
Described herein is the selective reduction of sugars with hydrosilanes catalyzed by using Piers’ borane [(C6F5)2BH] generated in situ. The hydrosilylative C?O bond cleavage of silyl-protected mono- and disaccharides in the presence of a (C6F5)2BH catalyst, generated in situ from (C6F5)2BOH, takes place with excellent chemo- and regioselectivities to provide a range of polyols. A study of the substituent effects of sugars on the catalytic activity and selectivity revealed that the steric environment around the anomeric carbon (C1) is crucial.
Heterolytic dihydrogen activation by B(C6F5) 3 and carbonyl compounds
Lindqvist, Markus,Sarnela, Nina,Sumerin, Victor,Chernichenko, Konstantin,Leskelae, Markku,Repo, Timo
, p. 4310 - 4312 (2012/06/16)
Aromatic carbonyl compounds in combination with B(C6F 5)3 are able to activate H2 heterolytically. The reactivity of the carbonyl-B(C6F5)3 adduct is initiated by its thermal dissociation into components. After H2 addition, aromatic carbonyl compounds convert into aryl-substituted methanes or alcohols.
Separating electrophilicity and lewis acidity: The synthesis, characterization, and electrochemistry of the electron deficient tris (aryl)boranes B(C6F5)3-n(C6Cl 5)n (n = 1-3)
Ashley, Andrew E.,Herrington, Thomas J.,Wildgoose, Gregory G.,Zaher, Hasna,Thompson, Amber L.,Rees, Nicholas H.,Kraemer, Tobias,Oehare, Dermot
body text, p. 14727 - 14740 (2011/11/04)
A new family of electron-deficient tris(aryl)boranes, B(C6F 5)3-n(C6Cl5)n (n = 1-3), has been synthesized, permitting an investigation into the steric and electronic effects resulting from the gradual replacement of C6F5 with C6Cl5 ligands. B(C6F5) 2(C6Cl5) (3) is accessed via C 6Cl5BBr2, itself prepared from donor-free Zn(C6Cl5)2 and BBr3. Reaction of C6Cl5Li with BCl3 in a Et2O/hexane slurry selectively produced B(C6Cl5)2Cl, which undergoes B-Cl exchange with CuC6F5 to afford B(C 6F5)(C6Cl5)2 (5). While 3 forms a complex with H2O, which can be rapidly removed under vacuum or in the presence of molecular sieves, B(C6Cl5) 3 (6) is completely stable to refluxing toluene/H2O for several days. Compounds 3, 5, and 6 have been structurally characterized using single crystal X-ray diffraction and represent the first structure determinations for compounds featuring B-C6Cl5 bonds; each exhibits a trigonal planar geometry about B, despite having different ligand sets. The spectroscopic characterization using 11B, 19F, and 13C NMR indicates that the boron center becomes more electron-deficient as n increases. Optimized structures of B(C6F 5)3-n(C6Cl5)n (n = 0-3) using density functional theory (B3LYP/TZVP) are all fully consistent with the experimental structural data. Computed 11B shielding constants also replicate the experimental trend almost quantitatively, and the computed natural charges on the boron center increase in the order n = 0 (0.81) 6F5 for C6Cl5. The direct solution cyclic voltammetry of B(C6F5)3 has been obtained for the first time and electrochemical measurements upon the entire series B(C6F5)3-n(C6Cl 5)n (n = 0-3) corroborate the spectroscopic data, revealing C6Cl5 to be a more electron-withdrawing group than C6F5, with a ca. +200 mV shift observed in the reduction potential per C6F5 group replaced. Conversely, use of the Guttmann-Beckett and Childs' methods to determine Lewis acidity on B(C6F5)3, 3, and 5 showed this property to diminish with increasing C6Cl5 content, which is attributed to the steric effects of the bulky C6Cl5 substituents. This conflict is ascribed to the minimal structural reorganization in the radical anions upon reduction during cyclic voltammetric experiments. Reduction of 6 using Na(s) in THF results in a vivid blue paramagnetic solution of Na+ [6]?-; the EPR signal of Na+[6]?- is centered at g = 2.002 with a( 11B) 10G. Measurements of the exponential decay of the EPR signal (298 K) reveal [6]?- to be considerably more stable than its perfluoro analogue.
Isobutene polymerization using chelating diboranes: Polymerization in aqueous suspension and hydrocarbon solution
Lewis, Stewart P.,Chai, Jianfang,Collins, Scott,Sciarone, Timo J. J.,Henderson, Lee D.,Fan, Cheng,Parvez, Masood,Piers, Warren E.
, p. 249 - 263 (2009/05/30)
The use of the chelating diboranes o-C6F4[B(C 6F5)2]2 (1) and o-C 6F4(9-BC12F8)2 (2: 9-BC12F8 = 1,2,3,4,5,6,7,8-octafluoro-9-borafluorene) for the polymerization of isobutene (IB) in aqueous suspension or in hydrocarbon solution was studied. Polymerizations in aqueous suspension provided polymer of moderate MW and at variable conversion and were dependent on temperature, mode of diborane addition, the presence of surfactant, and the acidity of and nature of the anion present in the aqueous phase. The T dependence of MW over the T range -80 to -20 °C was studied in aqueous suspension, and higher MW polymer was formed at lower T. The hydrolysis and methanolysis of diboranes 1 and 2 was studied by NMR spectroscopy. Reactions of diborane 1 with excess MeOH or water afford solutions containing oxonium acids [o-C6F4{B(C 6F5)2}2(μ-OR)][(ROH) nH] (7: R = H, n > 2; 3: R = Me, n = 3). When diborane 1 is present in excess over water or MeOH, degradation of the diborane is observed. In this case the products are o-C6F4{B(C6F 5)2}H (5) and (C6F5)2BOH 7 or (C6F5)2BOMe 4, respectively. In the case of diborole 2, o-C6F4(9-BC12F 8)B(2-C12F8-2"-H)(μ-OH) · 7H2O (17) and o-C6F4(9-BC12F 8)B(2-C12F8-2"-H)(μ-OMe) (11) were isolated from reactions of 2 with water and MeOH, respectively, and were characterized by X-ray crystallography. None of these degradation products effect IB polymerization in aqueous suspension. As a model for initiation of polymerization, the reaction of diborole 2 with 1,1-diphenylethylene (DPE) was studied. Addition of MeOH at low T results in efficient formation of the ion-pair [Ph2CMe][o-C6F4(9-BC 12F8)2(μ-OMe)] via protonation of DPE. Polymerizations in hydrocarbon media were exothermic and rapid and gave quantitative yields of polymer even at very low concentrations of diborane 1. The T dependence of MW was studied in hydrocarbon solution and showed non-Arrhenius behavior. This was explained by competitive chain transfer to monomer at elevated T and chain transfer to molecular water at lower T.
Polyfluoroorganoboron-oxygen compounds. 4 [1] lithium pentafluorophenyltrimethoxyborate, Li[C6F5B(OMe) 3], reactions with selected electrophiles and nucleophiles
Adonin, Nicolay Yu.,Bardin, Vadim V.,Floerke, Ulrich,Frohn, Hermann-Josef
, p. 2638 - 2646 (2008/10/09)
Li[C6F5B(OMe)3] (1a) reacted with the electrophiles CD3C(O)CD3, CH3OD, CD 3CN, CH3CN, HOC2H4OH, Br 2, and I2 to give C6F5X (X = D, H, Br, I). The treatment of 1a with Me3SiCl or BF3 in CH 2Cl2 and CCl3F or pentene resulted in C 6F5B(OMe)2 or C6F5BF 2, respectively. The attempted metathesis of 1a with KF or [Bu 4N]Br in CH2Cl2 led to a mixture of M[(C 6F5)2B(OMe)2] (2b,c, main product) and M[C6F5B(OMe)3] (1b,c, minor product) (M = [Bu4N], K). Even in the presence of diethyl ether, THF, DME, or TMEDA salt 1a underwent dismutation to the diarylborate salt [Li(L) n][(C6F5)2B(OMe)2] (L = Et2O, THF, DME, TMEDA) and [Li(L)n][B(OMe)4]. In subsequent reactions with aqueous K[HF2] or [Bu 4N][HF2] M[(C6F5) 2B(OMe)2] (M = K, [Bu4N], [Li(L)n]) yielded K[(C6F5)2BF2] (4c) or [Bu4N][(C6F5)2BF2] (4b). The molecular structure of [Li·TMEDA][(C6F5) 2B(OMe)2] from single crystals showed significant cation-oxygen interactions.
