title: Two-dimensional "nano-ring and nano-crystal" morphologies in Langmuir monolayer of phthalocyaninato nickel complexes.
abstract: Three 1,8,15,22-tetrasubstituted phthalocyaninato nickel complexes Ni[Pc(alpha-OR)(4)] [H(2)Pc(alpha-OC(5)H(11))(4) = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(7)H(15))(4) = 1,8,15,22-tetrakis(2,4-dimethyl-3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(10)H(7))(4) = 1,8,15,22-tetrakis(2-naphthyloxy)phthalocyanine] (1-3) have been prepared by treating the corresponding metal-free phthalocyanines H(2)Pc(alpha-OR)(4) with Ni(acac)(2)2H(2)O in refluxing n-pentanol. Structures of the Langmuir monolayers of these compounds at different temperature have been investigated. Compound 1 formed nano-ring structures with the outer diameter of 70-150 nm and inner diameter of 50 nm at 25.0 degrees C while 2 and 3 formed round particles. This difference can be ascribed to the different substituents at alpha position. The morphologies of the aggregates of 1 in monolayers have been found to change with temperature. Decreasing in temperature induced the formation of regular quadrate crystals. UV-vis absorption spectra revealed strong intermolecular interactions in the nano-ring aggregates. Polarized UV-vis absorption spectra suggest a titled orientation with respect to the surface of substrate for phthalocyanine macrocycles in the nano-ring aggregates.
authors.affiliation: Contribution from the Key Lab for Colloid and Interface Chemistry of Education Ministry, Department of Chemistry, Shandong University, Jinan 250100, China.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Liu
authors.forename: Hongguo
authors.initials: H
authors.lastname: Liu
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Bian
authors.forename: Xueying
authors.initials: X
authors.lastname: Wang
authors.forename: Yanli
authors.initials: Y
authors.lastname: Chen
authors.forename: Jianzhuang
authors.initials: J
authors.lastname: Jiang
authors.forename: Xiyou
authors.initials: X
authors.lastname: Li