Two-Dimensional Crystallization of Phthalocyanine Pigments at the Air/Water Interface

Abstract

Two-dimensional crystallization of highly planar phthalocyanine (Pc) pigments underneath the headgroups of a lipid Langmuir monolayer was observed and characterized by synchrotron X-ray diffraction at grazing angles of incidence (GID). The crystallization was achieved through spontaneous adsorption of positively charged, water-soluble Pc's to a spread dihexadecyl phosphate (DHDP) monolayer at the air/water interface. Analysis of the GID and rod profiles show that the lipid, pigment, and counterions form a complex in which the pigment plane is tilted with respect to the liquid surface; this is consistent with previous independent X-ray reflectivity investigations. In addition, the two-dimensional crystalline order of DHDP monolayers on pure H 2 O has been determined and an analysis of its structure both before and after complexation is presented.

Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

“…The rod scan analysis (using Eqs. 4.1 and 4.2) yields an average chain-length ∼ 20 Å, and a tilted angle with respect to the surface normal < 5 • , consistent with the reflectivity and previous reports [83]. in Fig.…”

“…In this study, monolayers materials DHDP and DMPA (also has PO − 4 head group) were both spread at salt (e.g., CsI and BaI 2 ) solution/gas interfaces [47,78,83], providing the uniformly charged surfaces. All X-ray fluorescence were conducted at the untilted phase of monolayers, implying that the molecular area is fixed at 41±1Å…”

Effect of Transition Metal Cations on Assembly of Highly Ordered 2D Multiporphyrin Arrays on Liquid and Solid Substrates

“…Плавный рост π на начальном участке (участок низких поверхностных давлений изо-термы, выпуклость которого обращена к оси х) свиде-тельствует о легкости изменения ориентации молекул с "face-on" типа на "edge-on" и их сборке в агрегаты с увеличивающимся углом наклона плоскостей молекул относительно поверхности субфазы и/или образовани-ем смещённых агрегатов J-типа (slipped cofacial J-type aggregates). [32][33] Энергетическая выгода образования агрегатов для обеих типов структур, содержащих ещё не включенные в координационную сетку тектоны, обеспечивается π-π взаимодействиями макроциклов. Следовательно, в силу кинетических или стерических причин, определенная доля периферийных пиридиль-ных групп лиганда остается свободной, т.е.…”

Phase separation in mixed monolayers of arachidic acid and a phthalocyanine of zinc

“…The study of mixed films of dissimilar components [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] is of practical interest due to the fact that a great number of compounds of technological interest need a film former. Phthalocyanines (Pc), porphyrins (P), metallo-porphyrins (MP) and metallophthalocyanines (MPc) are an example.…”