Chromophore Structure, Second Harmonic Generation, and Orientational Order in Zirconium Phosphonate/Phosphate Self-Assembled Multilayers
摘要:
Two new phosphonate-terminated polar azo dyes, one that is substantially rigid (1) and the other with a large molecular hyperpolarizability (2), were designed and incorporated into zirconium-based surface multilayers. Second harmonic generation (SHG) was observed from the multilayers as a function of incident and polarization angles and compared with that from the previously reported aminophenylazophenylphosphonic acid chromophore 3. The new dyes are analogous to moieties commonly used in electric field-poled polymers, allowing comparisons between the polymers and the multilayers. Apparent order parameters (cos(3) theta) are >0.2 for 1 and approximate to 0.16 for 2. Because of local field effects, the value for 1 is probably a lower limit. Use of other dyes that are both rigid and highly polar led to H-aggregation. Insertion of a nonpolar chromophore layer among the polar layers had no effect on SHG. The syntheses involved several novel reactions, involving the preparation of an unsymmetrically substituted diphenylpiperazine, an anilinoalkyl phosphonate, and the deprotected phosphonic acids themselves.
Chromophore Structure, Second Harmonic Generation, and Orientational Order in Zirconium Phosphonate/Phosphate Self-Assembled Multilayers
摘要:
Two new phosphonate-terminated polar azo dyes, one that is substantially rigid (1) and the other with a large molecular hyperpolarizability (2), were designed and incorporated into zirconium-based surface multilayers. Second harmonic generation (SHG) was observed from the multilayers as a function of incident and polarization angles and compared with that from the previously reported aminophenylazophenylphosphonic acid chromophore 3. The new dyes are analogous to moieties commonly used in electric field-poled polymers, allowing comparisons between the polymers and the multilayers. Apparent order parameters (cos(3) theta) are >0.2 for 1 and approximate to 0.16 for 2. Because of local field effects, the value for 1 is probably a lower limit. Use of other dyes that are both rigid and highly polar led to H-aggregation. Insertion of a nonpolar chromophore layer among the polar layers had no effect on SHG. The syntheses involved several novel reactions, involving the preparation of an unsymmetrically substituted diphenylpiperazine, an anilinoalkyl phosphonate, and the deprotected phosphonic acids themselves.
Synthesis of some new distyrylbenzene derivatives using immobilized Pd on an NHC-functionalized MIL-101(Cr) catalyst: photophysical property evaluation, DFT and TD-DFT calculations
[Pd-NHC-MIL-101(Cr)] was investigated in the synthesis of distyrylbenzenederivatives using the Heck reaction. The Pd-NHC-MIL-101(Cr) catalyst showed high efficiency in the synthesis of these π-conjugated materials and products were obtained in high yields with low Pd-contamination based on ICP analysis. The photophysical behaviors for some of the synthesized distyrylbenzenederivatives were evaluated. The DFT and
Combination of formamide and cyanuric chloride afforded a new combined “CN” source which is highly stable and safe and can be used in organic cyanation transformation reactions instead of common cyanide sources. This study unfolds the efficient Pd‐catalyzedcyanation of aryl halides using TCT‐formamide reagent as a new combined “CN” source.
Immobilized Pd on a NHC functionalized metal–organic framework MIL‐101(Cr): an efficient heterogeneous catalyst in Suzuki−Miyaura coupling reaction in water
A novel Pd−NHC functionalized metal–organicframework (MOF) based on MIL‐101(Cr) was synthesized and used as an efficientheterogeneouscatalyst in the C‐C bond formation reactions. Using this heterogeneous Pd catalyst system, the Suzuki−Miyaura coupling reaction was accomplished well in water, and coupling products were obtained in good to excellent yields in short reaction time. The Pd−NHC−MIL‐101(Cr)
Chromophore Structure, Second Harmonic Generation, and Orientational Order in Zirconium Phosphonate/Phosphate Self-Assembled Multilayers
作者:H. E. Katz、W. L. Wilson、G. Scheller
DOI:10.1021/ja00094a019
日期:1994.7
Two new phosphonate-terminated polar azo dyes, one that is substantially rigid (1) and the other with a large molecular hyperpolarizability (2), were designed and incorporated into zirconium-based surface multilayers. Second harmonic generation (SHG) was observed from the multilayers as a function of incident and polarization angles and compared with that from the previously reported aminophenylazophenylphosphonic acid chromophore 3. The new dyes are analogous to moieties commonly used in electric field-poled polymers, allowing comparisons between the polymers and the multilayers. Apparent order parameters (cos(3) theta) are >0.2 for 1 and approximate to 0.16 for 2. Because of local field effects, the value for 1 is probably a lower limit. Use of other dyes that are both rigid and highly polar led to H-aggregation. Insertion of a nonpolar chromophore layer among the polar layers had no effect on SHG. The syntheses involved several novel reactions, involving the preparation of an unsymmetrically substituted diphenylpiperazine, an anilinoalkyl phosphonate, and the deprotected phosphonic acids themselves.