Highly selective thioalcohol modified phthalocyanine sensors for Ag(i) and Pd(ii) based on target induced J- and H-type aggregations: synthesis, electrochemistry and peripheral metal ion binding studies

Abstract

We have described highly selective 1(4),8(11),15(18),22(25)-(1-hydroxyhexan-3-ylthio)-phthalocyanine sensors, M{Pc[α-SCH(C(3)H(7))(C(2)H(5)OH)](4)} (MPc(α-HHT)(4), where M = Zn(II) (2), Cu(II) (3) or Co(II) (4) and HHT: -SCH(C(3)H(7))(C(2)H(5)OH)). The formation of S-M-S {S = sulfur; M = Ag(I) or Pd(II)} bonds on the periphery in the case of Ag(I) and Pd(II) metal ions induces H- or J-aggregation, respectively, which results in significant changes in the absorption of the B- and, in particular, the Q-band. The binding ratios of Ag(I) to the periphery of 2 and 3 were found to be ca. 2:1 and 3:2, respectively. On the other hand, the binding ratios of Pd(II) to the periphery of the same compounds were found to be 3:1 and 4:1. The fluorescence of 2 exhibited distinct changes in response to treatment with Ag(I) and Pd(II) ions in solution. The fluorescence spectra emission intensity of 2 was quenched upon titration with Ag(I) and Pd(II) and a new emission maximum was observed upon titration with Pd(II). FTIR, (1)H-NMR, (13)C-NMR, UV-vis, MALDI-TOF MS and elemental analysis data were used to characterize the novel compounds. Transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FE-SEM) were also used as complementary techniques to investigate the morphology and to image the interfacial aggregates of 2. The redox behaviours of the complexes were examined by voltammetry and in situ spectroelectrochemistry on Pt in a nonaqueous medium.

High-performance optical limiters based on stable phthalocyanine J-type dimers

“…Their specific structures cause unusual spectral properties. Unlike the monomers [10], in the UV/Vis spectra of dimers ( Fig. 3) an additional band, which is red-shifted relative to the basic Q-band, is revealed.…”

Metal ion sensing soluble α or β tetrasubstituted gallium and indium phthalocyanines: Synthesis, characterization, photochemistry and aggregation behaviors

“…The peripheral and/or nonperipheral substituted phthalocyanines could be form two types of aggregations which affect on electronic and optical properties. One type is face-to-face H-aggregation [19] and other type is side-to-side J-aggregation [20]. Generally, phthalocyanine aggregation results in a decrease in intensity of the Q-band corresponding to the monomeric species, simultaneously a new, broader and blueshifted or red-shifted band is seen to increase in intensity.…”

“…This shift to lower wavelengths indicates to H-type aggregation among the phthalocyanine molecules. In rare cases, red-shifted bands have been observed corresponding to J-type aggregation of the phthalocyanine molecules [20].…”

Water soluble quarternizable gallium and indium phthalocyanines bearing quinoline 5-sulfonic acid: Synthesis, aggregation, photophysical and electrochemical studies

“…Nevertheless, their solubility can be made better by adding suitable organic groups to phthalocyanine ring in common organic solvents [20][21][22]. In addition, tendency to aggregation can be reduced with attaching suitable substituent [23]. These kinds of attractive approachs to increase water solubility, reduce aggregation so that its excited state lifetimes start to enhance and develop its cellular uptake in aqueous media [24] are of extremely importance in PTD studies.…”

“…Moreover, the complete understanding of essential features of the MPcs with or without redox-active metal center is necessary to investigate the redox behaviour of MPcs which is nearly with regard to put into practice technologically, such as electrocatalysis [21][22][23] and electrochromism [32].…”