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Impact of position of electron withdrawing cyano groups on nonlinear optical properties of centrosymmetric donor‐π‐acceptor system

“…Our compounds differ from these molecules in having additional dimethylamine substituents at the terminal phenyl rings and, in case of Ref. [ ], in having methoxy groups in the central phenyl ring instead of hexyl groups; such structural modifications, be them applied separately or in combination, lead to an overall red‐shift in absorption and emission of our compounds compared to a 2PV precursor . Moreover, the difference in the optical properties caused by a CN‐attachment in α‐ or β‐position has been found to correlate with the distorsion of the central phenylene ring against the CN‐vinylene planes that is much more peripheral phenyl rings than those in α‐dscn and β‐dscn homologues .…”

“…With θ 1 (S 1 ) = 1.6°, β‐dscn adopts a significantly more planar conformation (Table ), albeit perfect planarity is precluded due to a torsion θ 2 = 4.5° of the CN‐vinylene plane with respect to the outer phenyl ring. The pronounced twist in the S 0 geometry promotes torsional‐induced nonradiative deactivation channels which, in the case of α‐dscn, cannot be avoided by emission from a planar, quinoidal mesomeric structure in S 1 and, thus, gives rise to a very small fluorescence quantum yield . The Stokes shift, taken as the energy difference between the absorption and emission spectrum, is with 0.56 eV (in toluene) notably larger for α‐dscn than for β‐dscn (0.37 eV in toluene) for any given solvent (Table ); this is an indication that the intramolecular relaxation energy is larger in α‐dscn than for β‐dscn.…”

“…In contrast, the absorption and the emission spectra of its counterpart α‐dscn are not visibly structured (Figure ). Thus, the structural reorganization on going from the first excited to the ground state is strongly influenced by the CN position: While a structured spectrum indicates backbone planarization in going from S 0 to S 1 for the case of β‐dscn, such a planarization is expected to be sterically hindered in α‐dscn …”

Impact of position of electron withdrawing cyano groups on nonlinear optical properties of centrosymmetric donor‐π‐acceptor system

“…Our compounds differ from these molecules in having additional dimethylamine substituents at the terminal phenyl rings and, in case of Ref. [ ], in having methoxy groups in the central phenyl ring instead of hexyl groups; such structural modifications, be them applied separately or in combination, lead to an overall red‐shift in absorption and emission of our compounds compared to a 2PV precursor . Moreover, the difference in the optical properties caused by a CN‐attachment in α‐ or β‐position has been found to correlate with the distorsion of the central phenylene ring against the CN‐vinylene planes that is much more peripheral phenyl rings than those in α‐dscn and β‐dscn homologues .…”

“…With θ 1 (S 1 ) = 1.6°, β‐dscn adopts a significantly more planar conformation (Table ), albeit perfect planarity is precluded due to a torsion θ 2 = 4.5° of the CN‐vinylene plane with respect to the outer phenyl ring. The pronounced twist in the S 0 geometry promotes torsional‐induced nonradiative deactivation channels which, in the case of α‐dscn, cannot be avoided by emission from a planar, quinoidal mesomeric structure in S 1 and, thus, gives rise to a very small fluorescence quantum yield . The Stokes shift, taken as the energy difference between the absorption and emission spectrum, is with 0.56 eV (in toluene) notably larger for α‐dscn than for β‐dscn (0.37 eV in toluene) for any given solvent (Table ); this is an indication that the intramolecular relaxation energy is larger in α‐dscn than for β‐dscn.…”

“…In contrast, the absorption and the emission spectra of its counterpart α‐dscn are not visibly structured (Figure ). Thus, the structural reorganization on going from the first excited to the ground state is strongly influenced by the CN position: While a structured spectrum indicates backbone planarization in going from S 0 to S 1 for the case of β‐dscn, such a planarization is expected to be sterically hindered in α‐dscn …”

Poly(benzyl ether) dendrimers with strongly fluorescent distyrylbenzene cores as the fluorophores for peroxyoxalate chemiluminescence: insulating effect of dendritic structures on fluorescent sites

“…1 H NMR (400 MHz) and 13 C NMR (100 MHz) spectra were recorded in CDCl 3 as the solvent, and chemical shifts (δ) were given in ppm relative to tetramethylsilane (TMS) as the internal standard. Matrix-assisted laser desporption inonization time-of-flight mass spectral (MALDI-TOF-MS) measurements were taken on using dithranol (1,8,9-anthracentriol) as a matrix.…”

Revisiting the Ullman's Radical Chemistry for Phthalocyanine Derivatives

“…The synthesis of phthalonitrile 2 wasc arried out on the basis of Leznoff's procedure [20] with substantial modifications (Scheme S1 in the Supporting Information). [23] 2,2-Dimethylpropan-1,3-diol, av icinal diol that could be used without furtherp urification, was preferred to ethylene glycold ue to its ease of handling (Scheme S1). The conversion of it to 2 was achieved by the Rosenmund-von Braun reactionu nder microwave irradiation in N-methyl-2-pyrrolidone (NMP) which makes possible to obtain ac leanerp roduct with ab etter yield in a shortert ime.…”

Impact of position of electron withdrawing cyano groups on nonlinear optical properties of centrosymmetric donor‐π‐acceptor system

“…Our compounds differ from these molecules in having additional dimethylamine substituents at the terminal phenyl rings and, in case of Ref. [ ], in having methoxy groups in the central phenyl ring instead of hexyl groups; such structural modifications, be them applied separately or in combination, lead to an overall red‐shift in absorption and emission of our compounds compared to a 2PV precursor . Moreover, the difference in the optical properties caused by a CN‐attachment in α‐ or β‐position has been found to correlate with the distorsion of the central phenylene ring against the CN‐vinylene planes that is much more peripheral phenyl rings than those in α‐dscn and β‐dscn homologues .…”

“…With θ 1 (S 1 ) = 1.6°, β‐dscn adopts a significantly more planar conformation (Table ), albeit perfect planarity is precluded due to a torsion θ 2 = 4.5° of the CN‐vinylene plane with respect to the outer phenyl ring. The pronounced twist in the S 0 geometry promotes torsional‐induced nonradiative deactivation channels which, in the case of α‐dscn, cannot be avoided by emission from a planar, quinoidal mesomeric structure in S 1 and, thus, gives rise to a very small fluorescence quantum yield . The Stokes shift, taken as the energy difference between the absorption and emission spectrum, is with 0.56 eV (in toluene) notably larger for α‐dscn than for β‐dscn (0.37 eV in toluene) for any given solvent (Table ); this is an indication that the intramolecular relaxation energy is larger in α‐dscn than for β‐dscn.…”

“…In contrast, the absorption and the emission spectra of its counterpart α‐dscn are not visibly structured (Figure ). Thus, the structural reorganization on going from the first excited to the ground state is strongly influenced by the CN position: While a structured spectrum indicates backbone planarization in going from S 0 to S 1 for the case of β‐dscn, such a planarization is expected to be sterically hindered in α‐dscn …”

Poly(benzyl ether) dendrimers with strongly fluorescent distyrylbenzene cores as the fluorophores for peroxyoxalate chemiluminescence: insulating effect of dendritic structures on fluorescent sites

“…1 H NMR (400 MHz) and 13 C NMR (100 MHz) spectra were recorded in CDCl 3 as the solvent, and chemical shifts (δ) were given in ppm relative to tetramethylsilane (TMS) as the internal standard. Matrix-assisted laser desporption inonization time-of-flight mass spectral (MALDI-TOF-MS) measurements were taken on using dithranol (1,8,9-anthracentriol) as a matrix.…”

Revisiting the Ullman's Radical Chemistry for Phthalocyanine Derivatives

“…The synthesis of phthalonitrile 2 wasc arried out on the basis of Leznoff's procedure [20] with substantial modifications (Scheme S1 in the Supporting Information). [23] 2,2-Dimethylpropan-1,3-diol, av icinal diol that could be used without furtherp urification, was preferred to ethylene glycold ue to its ease of handling (Scheme S1). The conversion of it to 2 was achieved by the Rosenmund-von Braun reactionu nder microwave irradiation in N-methyl-2-pyrrolidone (NMP) which makes possible to obtain ac leanerp roduct with ab etter yield in a shortert ime.…”

Impact of position of electron withdrawing cyano groups on nonlinear optical properties of centrosymmetric donor‐π‐acceptor system

“…Our compounds differ from these molecules in having additional dimethylamine substituents at the terminal phenyl rings and, in case of Ref. [ ], in having methoxy groups in the central phenyl ring instead of hexyl groups; such structural modifications, be them applied separately or in combination, lead to an overall red‐shift in absorption and emission of our compounds compared to a 2PV precursor . Moreover, the difference in the optical properties caused by a CN‐attachment in α‐ or β‐position has been found to correlate with the distorsion of the central phenylene ring against the CN‐vinylene planes that is much more peripheral phenyl rings than those in α‐dscn and β‐dscn homologues .…”

“…With θ 1 (S 1 ) = 1.6°, β‐dscn adopts a significantly more planar conformation (Table ), albeit perfect planarity is precluded due to a torsion θ 2 = 4.5° of the CN‐vinylene plane with respect to the outer phenyl ring. The pronounced twist in the S 0 geometry promotes torsional‐induced nonradiative deactivation channels which, in the case of α‐dscn, cannot be avoided by emission from a planar, quinoidal mesomeric structure in S 1 and, thus, gives rise to a very small fluorescence quantum yield . The Stokes shift, taken as the energy difference between the absorption and emission spectrum, is with 0.56 eV (in toluene) notably larger for α‐dscn than for β‐dscn (0.37 eV in toluene) for any given solvent (Table ); this is an indication that the intramolecular relaxation energy is larger in α‐dscn than for β‐dscn.…”

“…In contrast, the absorption and the emission spectra of its counterpart α‐dscn are not visibly structured (Figure ). Thus, the structural reorganization on going from the first excited to the ground state is strongly influenced by the CN position: While a structured spectrum indicates backbone planarization in going from S 0 to S 1 for the case of β‐dscn, such a planarization is expected to be sterically hindered in α‐dscn …”

Poly(benzyl ether) dendrimers with strongly fluorescent distyrylbenzene cores as the fluorophores for peroxyoxalate chemiluminescence: insulating effect of dendritic structures on fluorescent sites

“…1 H NMR (400 MHz) and 13 C NMR (100 MHz) spectra were recorded in CDCl 3 as the solvent, and chemical shifts (δ) were given in ppm relative to tetramethylsilane (TMS) as the internal standard. Matrix-assisted laser desporption inonization time-of-flight mass spectral (MALDI-TOF-MS) measurements were taken on using dithranol (1,8,9-anthracentriol) as a matrix.…”

Revisiting the Ullman's Radical Chemistry for Phthalocyanine Derivatives

“…The synthesis of phthalonitrile 2 wasc arried out on the basis of Leznoff's procedure [20] with substantial modifications (Scheme S1 in the Supporting Information). [23] 2,2-Dimethylpropan-1,3-diol, av icinal diol that could be used without furtherp urification, was preferred to ethylene glycold ue to its ease of handling (Scheme S1). The conversion of it to 2 was achieved by the Rosenmund-von Braun reactionu nder microwave irradiation in N-methyl-2-pyrrolidone (NMP) which makes possible to obtain ac leanerp roduct with ab etter yield in a shortert ime.…”