The Influence of C(sp<sup>3</sup>)H–Selenium Interactions on the <sup>77</sup>Se NMR Quantification of the π‐Accepting Properties of Carbenes

Junor, Glen P.; Lorkowski, Jan; Weinstein, Cory M.; Jazzar, Rodolphe; Pietraszuk, Cezary; Bertrand, Guy

doi:10.1002/ange.202010744

Cited by 29 publications

(12 citation statements)

References 77 publications

(30 reference statements)

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“…Initially, one might predict that their electronic properties should be similar, however the steric differences between the IAd and ICy ligands may cause variation in their electronic properties. This disparity observation has been further supported by Bertrand et al in their recent work involving a family of cyclic alkly(amino) carbenes (CAAC)-selenium adducts [24]. The findings from experimental and computational works demonstrated the existence of non-classical hydrogen bonding (NCHB), arising from a negative hyperconjugation interaction between the lone pair of selenium (H-bond acceptor) and the σ* C-H orbital of C(sp 3 )-H (H-bond donor), as shown in Figure 6.…”

Section: Resultsmentioning

confidence: 64%

Influence of Fluorine Substituents on the Electronic Properties of Selenium-N-Heterocyclic Carbene Compounds

Jamil

Endot

2020

Molecules

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N-heterocyclic carbenes (NHCs) are common ancillary ligands in organometallic compounds that are used to alter the electronic and steric properties of a metal centre. To date, various NHCs have been synthesised with different electronic properties, which can be done by modifying the backbone or changing the nitrogen substituents group. This study describes a systematic modification of NHCs by the inclusion of fluorine substituents and examines the use of selenium-NHC compounds to measure the π-accepting ability of these fluorinated NHC ligands. Evaluation of the 77Se NMR chemical shifts of the selenium adducts reveals that fluorinated NHCs have higher chemical shifts than the non-fluorinated counterparts, IMes and IPh. Higher 77Se NMR chemical shifts values indicate a stronger π-accepting ability of the NHC ligands. The findings of this study suggest that the presence of fluorine atoms has increased the π-accepting ability of the corresponding NHC ligands. This work supports the advantage of the 77Se NMR chemical shifts of selenium-NHC compounds for assessing the influence of fluorine substituents on NHC ligands.

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Section: Resultsmentioning

confidence: 64%

Influence of Fluorine Substituents on the Electronic Properties of Selenium-N-Heterocyclic Carbene Compounds

Jamil

Endot

2020

Molecules

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“…[29b] The developed synthetic protocol for NHC-phosphinidenes of the general formula (NHC)PR (Scheme 2) paired with the observation of (NHC)PPh cleavage by treatment of (iPr 2 Im)PPh (1) with elemental selenium and tellurium to yield (iPr 2 Im)Se ( 13) and (iPr 2 Im)Te ( 14) (Scheme 4) is particularly useful to determine the electronic properties of NHCs by 31 P and 77 Se NMR spectroscopy as demonstrated by Bertrand and Ghadwal recently. [12,30] Several transition metal complexes of NHC-phosphinidenes have been reported so far in the literature. Larocque and Lavoie provided an early example in 2014 and reported the reaction of a first-generation ruthenium benzylidene Grubbs complex with (Mes 2 Im)PPh.…”

Section: Resultsmentioning

confidence: 99%

“…1 H NMR (500.1 MHz, CDCl 3 , 298 K): δ = 1.39 (d, 12H, 3 J HH = 6.9 Hz, iPr-CH 3 ), 5. 30 Synthesis of (iPr 2 Im)Te ( 14): A suspension of (iPr 2 Im)PPh (1) (100 mg, 384 μmol) and amorphous tellurium (75.0 mg, 588 μmol) in 5 mL toluene was heated for 24 h at 85°C. The resulting solution was filtered and all volatiles of the filtrate were removed in vacuo.…”

Section: Synthesis Of (Ipr 2 Im)se (13)mentioning

confidence: 99%

A General Synthetic Route to NHC‐Phosphinidenes: NHC‐mediated Dehydrogenation of Primary Phosphines

Radius

Horrer

Philipp

et al. 2021

Zeitschrift anorg allge chemie

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The dehydrocoupling of primary phosphines with N-heterocyclic carbenes (NHCs) to yield NHC-phosphinidenes is reported. The reaction of two equivalents of the NHCs Me 2 Im (1,3dimethylimidazolin-2-ylidene), Me 4 Im (1,3,4,5-tetramethylimidazolin-2-ylidene), iPr 2 Im (1,3-di-iso-propylimidazolin-2ylidene) and Mes 2 Im (2,4,6-trimethylphenylimidazolin-2-ylidene) with PhPH 2 and MesPH 2 led to the NHC stabilized phosphinidenes (NHC)PAr: (iPr 2 Im)PPh ( 1), (Mes 2 Im)PPh ( 2), (Me 4 Im)PPh ( 3), (Mes 2 Im)PMes ( 4), (Me 2 Im)PMes ( 5), (Me 4 Im)PMes ( 6) and (iPr 2 Im)PMes ( 7). The reaction of tBuPH 2 with two equivalents of the NHCs afforded the corresponding NHC stabilized parent phosphinidenes (NHC)PH: (iPr 2 Im)PH ( 8), (Mes 2 Im)PH ( 9) and (Me 4 Im)PH (10). Reaction of 1 with oxygen and sulfur led to isolation of iPr 2 Im-P(O) 2 Ph (11) and iPr 2 Im-P(S) 2 Ph (12), whereas the reaction with elemental selenium and tellurium gave (NHC) PPh cleavage with formation of (iPr 2 Im)Se ( 13), iPr 2 ImTe (14) and different cyclo-oligophosphines. Furthermore, the complexes [{(iPr 2 Im)PPh}W(CO) 5 ] (15), [Co(CO) 2 (NO){(iPr 2 Im)PPh}] (16) and [(η 5 -C 5 Me 5 )Co(η 2 -C 2 H 4 ){(iPr 2 Im)PPh}] (17) have been prepared starting from 1 and a suitable transition metal complex precursor. The complexes 16 and 17 decompose in solution upon heating to ca. 80°C to yield the NHC complexes [Co(iPr 2 Im)(CO) 2 (NO)] and [(η 5 -C 5 Me 5 )Co(iPr 2 Im)(η 2 -C 2 H 4 )] with formation of cyclo-oligophosphines. The reaction of 1 with [Ni(COD) 2 ] afforded the diphosphene complex [Ni(iPr 2 Im) 2 (trans-PhP = PPh)] 18.

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“…H47 to H51 are all vinylic/aromatic protons of the furan ring, this is evident in their chemical shift values (ranging from 6.5ppm to 8.9ppm). They experience further deshielded properties when they are localized around the highly electronegative oxygen atoms [50].…”

Section: Nuclear Magnetic Resonance (Nmr) Spectroscopymentioning

confidence: 99%

“…We carried out UV-Vis spectroscopic calculations of FTPF using Gaussian09W in gas, DMF, hexane and THF solvents in order to investigate the effect of these solvents on maximum wavelength (λmax) of the electronic absorption transitions. The 1 H-NMR and 13 C-NMR calculations were performed to determine the chemical shifts values for hydrogen and carbon atoms in the FTPF monomer unit [49,50].…”

Section: Spectroscopic and Geometrical Propertiesmentioning

confidence: 99%

Understanding the Electronic Interactions, Vertical Excitation Analysis, and the Photovoltaic Properties of 5-(2-ethylhexyl)-1,3-di(furan-2-yl)-4H-thieno[3,4-c]pyrrole-4,6-dione

Enudi

Louis

Ogunwale

et al. 2021

Preprint

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Organic photovoltaic (OPV) are a promising new class of photovoltaic as they offer several advantageous features including large surface area to volume ratio, low cost, lightweight properties, and durability. The limitation of OPV that prevented their adoption for use in the past was their low power conversion efficiency (PCE) but that drawback has been solved by the development of the donor-acceptor-donor (D-A-D) system with high conversion efficiencies. Herein, 5-(2-ethylhexyl)-1,3-di (furan-2-yl)-4H-thieno [3,4-c]pyrrole-4,6(5H)-dione (FTPF), a donor-acceptor-donor monomer was investigated for its optoelectronic, excited state, and photovoltaic properties using a density functional theory (DFT) and time-dependent density function theory (TD-DFT) at the B3LYP/6-31+G(d,p) theoretical method. The spectral analysis (FT-IR, UV-vis, and NMR), electronic molecular properties, natural bonding orbitals (MOs and NBOs) analyses, and excitation were studied at this level in gas, hexane, DMF, and THF. The UV-Vis spectrum showed that FTPF exhibited mono-absorption in non-polar gas and hexane, but dual absorptions in polar solvents (DMF and THF) having maximum wavelength (λmax) at 351, 359, 371 and 373 nm in gas, hexane, THF, and DMF respectively, showing a major red shift as solvent became polar. The hole-electron excitation studies of the first five singlet states: S0→S1/S2/S3/S4/S5 in gas and DMF phases showed that S0→S1 is a delocalized π→π* Rydberg excitations originating from the D-A-D C=C π bonds, S0→S2 is π→π* local excitation, while S0→S3 in water occurred as an n→π* from the carbonyl and azolide groups of the acceptor unit, but n→π* charge transfer (CT) in DMF. The S0→S5 in water and S0→S4 are n→π* LE type excitations, while S0→S5 in DMF conformed to a delocalized π→π* excitation extended over the D-A-D conjugated backbone. FTPF provided efficient electron injection in all studied solvent; showing that FTPF is a sure-bet for opto-electronic application.

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The Influence of C(sp³)H–Selenium Interactions on the ⁷⁷Se NMR Quantification of the π‐Accepting Properties of Carbenes

Cited by 29 publications

References 77 publications

Influence of Fluorine Substituents on the Electronic Properties of Selenium-N-Heterocyclic Carbene Compounds

Influence of Fluorine Substituents on the Electronic Properties of Selenium-N-Heterocyclic Carbene Compounds

A General Synthetic Route to NHC‐Phosphinidenes: NHC‐mediated Dehydrogenation of Primary Phosphines

Understanding the Electronic Interactions, Vertical Excitation Analysis, and the Photovoltaic Properties of 5-(2-ethylhexyl)-1,3-di(furan-2-yl)-4H-thieno[3,4-c]pyrrole-4,6-dione

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The Influence of C(sp3)H–Selenium Interactions on the 77Se NMR Quantification of the π‐Accepting Properties of Carbenes

Cited by 29 publications

References 77 publications

Influence of Fluorine Substituents on the Electronic Properties of Selenium-N-Heterocyclic Carbene Compounds

Influence of Fluorine Substituents on the Electronic Properties of Selenium-N-Heterocyclic Carbene Compounds

A General Synthetic Route to NHC‐Phosphinidenes: NHC‐mediated Dehydrogenation of Primary Phosphines

Understanding the Electronic Interactions, Vertical Excitation Analysis, and the Photovoltaic Properties of 5-(2-ethylhexyl)-1,3-di(furan-2-yl)-4H-thieno[3,4-c]pyrrole-4,6-dione

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The Influence of C(sp³)H–Selenium Interactions on the ⁷⁷Se NMR Quantification of the π‐Accepting Properties of Carbenes