已经合成了一个新的两亲物家族,它们源自具有不寻常拓扑结构的刚性二羧酸头基单元。这些分子在水溶液中的聚集已经通过 1 H NMR 和染料溶解方法进行了检查。两种聚集模式似乎在这组两亲分子中起作用,一种由头部决定,另一种由柔性尾部决定。当尾部很短或不存在时,前一种模式占优势,当尾部含有六个或更多非极性原子时,后者占优势。后一种模式看似是典型的胶束化过程,但前者的合作性较差
The synthesis of polyenes with 3 or 5 conjugated double bonds bearing alkylanthryl and alkylpyridinium terminal groups is described. Alkyl chains of suitable length were introduced in both the anthracene and/or pyridine moiety to reduce the solubility in water thus improving the ability to form Langmuir-Blodgett films.
Calorimetric and quantum chemical studies of some photodimers of anthracenes
作者:Stefan Grimme、Sigrid D. Peyerimhoff、Henri Bouas-Laurent、Jean-Pierre Desvergne、Hans-Dieter Becker、Stefan M. Sarge、Herbert Dreeskamp
DOI:10.1039/a900965e
日期:——
By differential scanning calorimetry (DSC) the reaction enthalpies of the thermal splitting of the following photochemically produced dimers of meso-substituted anthracenes in fluid solutions were determined: the head-to-tail (ht) dimers of 9-decylanthracene (DEA) and 9-decyloxyanthracene (DOA) in hydrocarbon solvents, and the head-to-head (hh) dimer of 9-methoxyanthracene (MOA) and the mixed hh dimer of 9-methoxyanthracene and 9-methoxy-10-methylanthracene (MMOA) in chlorinated solvents. The molar reaction enthalpy (in kJ mol-1) is found to be lower for the ht dimers (-28 kJ mol-1, DEA and -29 kJ mol-1, DOA) than for the hh dimers (-43 kJ mol-1, MOA and -44 kJ mol-1, MMOA) with an estimated precision of ±3 kJ mol-1 each. Quantum mechanical computations give energy differences for the thermal splitting of dianthracene and the two dimers of 9-methoxyanthracene in reasonable agreement with the reaction enthalpies observed. An analysis of the change in bond energies caused by the dimerization reveals that the relative stability of the dimer is mainly caused by a large increase in bond strength of the lateral benzene rings on dimerization.
Synthesis and characterization of anthracene-clustering dendrimers: observation of fluorescence resonance energy transfer in the multichromophoric system
A series of anthracene-clustering dendrimers bearing various aliphatic substituents at the terminal positions were synthesized using a direct coupling strategy. A remarkable effect of the side chains was imparted to chemical properties of the dendrimers such as drastically increased solubility. Although the multibranched anthracene arrays in the dendritic architectures exhibited no cooperativity in terms of the absorption feature and behaved as single chromophoric systems, investigations focusing on fluorescence properties revealed that a type of cooperativity was present as expressed in the reduced quantum yields of fluorescence. An alternative approach utilizing time-resolved fluorescence decay measurements clearly demonstrated that the most reasonable mechanism of the cooperative action should involve two discernible channels of intramolecular fluorescence resonance energy transfer (FRET) occurring from one chromophore to the others within and across junctions of the branching units. (C) 2004 Elsevier Ltd. All rights reserved.
Synthesis and aggregation properties of a new family of amphiphiles with an unusual headgroup topology
作者:Thomas M. Stein、Samuel H. Gellman
DOI:10.1021/ja00036a048
日期:1992.5
family of amphiphiles, derived from a rigid dicarboxylic acid headgroup unit of unusual topology, has been synthesized. The aggregation of these molecules in aqueous solution has been examined by 1 H NMR and dye solubilization methods. Two modes of aggregation appear to be operative within this group of amphiphiles, one determined by the headgroup and the other determined by the flexible tail. The
已经合成了一个新的两亲物家族,它们源自具有不寻常拓扑结构的刚性二羧酸头基单元。这些分子在水溶液中的聚集已经通过 1 H NMR 和染料溶解方法进行了检查。两种聚集模式似乎在这组两亲分子中起作用,一种由头部决定,另一种由柔性尾部决定。当尾部很短或不存在时,前一种模式占优势,当尾部含有六个或更多非极性原子时,后者占优势。后一种模式看似是典型的胶束化过程,但前者的合作性较差
Spectroelectrochemical Investigations of the Spreading of 4-Pentadecyl Pyridine onto the Au(111) Electrode
The adsorption of 4-pentadecyl-pyridine (C15-4-Py) onto the Au(111) electrode was investigated with the help of electrochemical and spectroscopic techniques. Electrochemical studies demonstrated that a film of C15-4-Py spreadsonto the metal surface at potentials close to the potential of zero charge (pzc) and desorbs from the electrode surface at potentials which are sufficiently negative. The character