Stable Borane Adducts of Alcoholates and Carboxylates

Kather, Ralf; Lork, Enno; Vogt, Matthias; Beckmann, Jens

doi:10.1002/zaac.201700058

Cited by 9 publications

(4 citation statements)

References 64 publications

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“…For the doped donor or acceptor hosts, the NMR spectra all exhibit dual-peak features with the lower-field peaks at δ = 40.56 ppm assigned to the resonance of noncoordinated B atoms in BCF and the upper-field peaks originating from the four-coordinate boron upon interacting with the hosts . Considering the shielding effect that the electron cloud density outside the B nucleus can increase, − this result affirms the role of BCF as an electrophilic Lewis acid in our concerned doping systems. Of surprise, more significant shifts in the four-coordinate boron peaks are observed in the doped IT-4F or PBDB-T (over 40 ppm) compared to that in PBDB-TF with BCF.…”

Section: Resultssupporting

confidence: 70%

“…Of surprise, more significant shifts in the four-coordinate boron peaks are observed in the doped IT-4F or PBDB-T (over 40 ppm) compared to that in PBDB-TF with BCF. The less significant NMR peak shift in the doped PBDB-TF seems unconventional and differentiates from previous studies (over 40 ppm shifts in the 11 B peaks are often witnessed in the BCF-doped polymers). ,− Actually, the degree of NMR peak shifts has been correlated to the bond strength between BCF and hosts . In our case, the reduced peak shift implies a weak bonding strength between PBDB-TF and BCF, which may be explained by the enlarged steric hindrance around the electron-rich functional groups in the polymer host of PBDB-TF .…”

Section: Resultscontrasting

confidence: 42%

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Control of Nanomorphology in Fullerene-Free Organic Solar Cells by Lewis Acid Doping with Enhanced Photovoltaic Efficiency

Zhang

et al. 2019

ACS Appl. Mater. Interfaces

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Generating desired efficiency enhancements in organic solar cells (OSCs) by charge-transfer doping requires to obtain modified optoelectronic properties while retaining the favorable nanomorphology. We report a thermally assisted doping based on Lewis acid tris(pentafluorophenyl)-borane (BCF) as a p-dopant for two groups of OSCs comprising the PBDB-TF and PBDB-T donors and a nonfullerene acceptor IT-4F. We found that the face-on molecular packing in the PBDB-TF:IT-4F blend or neat PBDB-TF donor films is favorably modified with the formation of frustrated Lewis pairs (FLPs) in the donor, which is in contrast to the hampered π–π stacking in the doped PBDB-T film. The different impacts of BCF dopants on the morphology lead to contrasting photovoltaic behaviors where the PBDB-TF-based devices receive enhanced power conversion efficiencies (PCEs) in the presence of BCF, while reduction of efficiencies is observed in the PBDB-T device. In the best doping conditions with the proposed hot-film deposition, we achieve a boosted PCE of 14.1% in PBDB-TF:IT-4F solar cells at low BCF concentrations. Based on the same fluorinated donor, the described BCF doping also applies to NF-solar cells based on the NF-acceptor Y6, leading to an increase in the PCE to 16.0%. Our results suggest that controlling the degree of FLP formation in the donor component with the addition of BCF is key to obtaining desired improvements on nanomorphology and relevant photophysical properties in OSCs.

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Section: Resultssupporting

confidence: 70%

Section: Resultscontrasting

confidence: 42%

Control of Nanomorphology in Fullerene-Free Organic Solar Cells by Lewis Acid Doping with Enhanced Photovoltaic Efficiency

Zhang

et al. 2019

ACS Appl. Mater. Interfaces

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“…The exchange of the two OAc F groups was further supported by a 19 F– 19 F EXSY experiment performed at −60 °C (Figure b). In the 13 C NMR spectrum, two resonances corresponding to the two CO of the OAc F groups were observed; one at δ 159.6, in line with that observed for [(Ac F O)B(C 6 F 5 ) 3 ] − borates, and one at δ 165.4, slightly deshielded compared to that of (P,C)Au(OAc F ) 2 1- i Pr at ca. δ 161, in line with the higher electron deficiency of the Au(III) center, and consistent with the 5–15 ppm deshielding found in the literature for other d/p-block elements when going from κ 1 to κ 2 -coordinated OAc F ligands .…”

Section: Resultssupporting

confidence: 75%

Mechanism of Alkyne Hydroarylation Catalyzed by (P,C)-Cyclometalated Au(III) Complexes

et al. 2022

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Over the last 5−10 years, gold(III) catalysis has developed rapidly. It often shows complementary if not unique features compared to gold(I) catalysis. While recent work has enabled major synthetic progress in terms of scope and efficiency, very little is yet known about the mechanism of Au(III)-catalyzed transformations and the relevant key intermediates have rarely been authenticated. Here, we report a detailed experimental/computational mechanistic study of the recently reported intermolecular hydroarylation of alkynes catalyzed by (P,C)-cyclometalated Au(III) complexes. The cationic (P,C)Au(OAc F ) + complex (OAc F = OCOCF 3 ) was authenticated by mass spectrometry (MS) in the gas phase and multi-nuclear NMR spectroscopy in solution at low temperatures. According to density functional theory (DFT) calculations, the OAc F moiety is κ 2 -coordinated to gold in the ground state, but the corresponding κ 1 -forms featuring a vacant coordination site sit only slightly higher in energy. Side-on coordination of the alkyne to Au(III) then promotes nucleophilic addition of the arene. The energy profiles for the reaction between trimethoxybenzene (TMB) and diphenylacetylene (DPA) were computed by DFT. The activation barrier is significantly lower for the outer-sphere pathway than for the alternative inner-sphere mechanism involving C−H activation of the arene followed by migratory insertion. The π-complex of DPA was characterized by MS. An unprecedented σ-arene Au(III) complex with TMB was also authenticated both in the gas phase and in solution. The cationic complexes [(P,C)Au(OAc F )] + and [(P,C)Au(OAc F )(σ-TMB)] + stand as active species and off-cycle resting state during catalysis, respectively. This study provides a rational basis for the further development of Au(III) catalysis based on π-activation.

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“…The magnesium compound, [Tism Pr i Benz ]MgOC(H)OB(C 6 F 5 ) 3 , is also obtained upon addition of B(C 6 F 5 ) 3 to the formate derivative, [Tism Pr i Benz ]Mg(O 2 CH), and structural characterization by X-ray diffraction demonstrates that the formate moiety bridges the magnesium and boron centers (Figure ). , …”

mentioning

confidence: 99%

Zinc and Magnesium Catalysts for the Hydrosilylation of Carbon Dioxide

2017

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The terminal zinc and magnesium hydride compounds, [κ-Tism]ZnH and [Tism]MgH, which feature the tris[(1-isopropylbenzimidazol-2-yl)dimethylsilyl]methyl ligand, react with B(CF) to afford the ion pairs, {[Tism]M}[HB(CF)] (M = Zn, Mg), which are rare examples of these metals in trigonal monopyramidal coordination environments. Significantly, in combination with B(CF), {[Tism]M}-[HB(CF)] generates catalytic systems for the hydrosilylation of CO by RSiH to afford sequentially the bis(silyl)acetal, HC(OSiR), and CH (RSiH = PhSiH, EtSiH, and PhSiH). In contrast to many other catalysts for these transformations, both the zinc and magnesium catalytic systems are active at room temperature, and the latter provides the first example of catalytic hydrosilylation of CO involving a magnesium compound. Also of note, the selectivity of the catalytic systems may be controlled by the nature of the silane, with PhSiH favoring CH, and PhSiH favoring the bis(silyl)acetal, HC(OSiPh).

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Stable Borane Adducts of Alcoholates and Carboxylates

Cited by 9 publications

References 64 publications

Control of Nanomorphology in Fullerene-Free Organic Solar Cells by Lewis Acid Doping with Enhanced Photovoltaic Efficiency

Control of Nanomorphology in Fullerene-Free Organic Solar Cells by Lewis Acid Doping with Enhanced Photovoltaic Efficiency

Mechanism of Alkyne Hydroarylation Catalyzed by (P,C)-Cyclometalated Au(III) Complexes

Zinc and Magnesium Catalysts for the Hydrosilylation of Carbon Dioxide

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