Strong aggregation properties of novel naphthalocyanines

Tai, Seiji; Hayashi, Naoaki

doi:10.1039/p29910001275

Cited by 40 publications

(29 citation statements)

References 27 publications

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“…In order to evaluate the dimerization constant and monomer and dimer spectra, the upper limit of the working concentration range was determined by the highest concentration at which experimental values could be best reproduced with the calculated parameters (38) assuming that no higher aggregates that dimers were present. This range lay below Neither significant wavelength shifts nor relevant modifications in shape were observed; this particular behavior had already been found for some Pc and naphthalocyanines either in homogeneous (13,39,40) or micellar (41) media and greatly contrasts with that observed for the vast majority of compounds in the family (42).…”

Section: Monomer-dimer Equilibriummentioning

confidence: 63%

Photophysical and Aggregation Studies of t‐Butyl‐Substituted Zn Phthalocyanines

Fernández

Awruch

Dicelio

1996

Photochem & Photobiology

108

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Three potential photosensitizers for photodynamic therapy: tetra-t-butyl phthalocyaninato Zn(II), tetrakis-(1,ldimethyl-2-phthalimido)ethylphthalocyaninato Zn(II), and tetrakis-(l,l-dimethyl-2-amino)ethylphthalocyaninato Zn(II), have been studied in homogeneous organic media. Dimerization constants and monomer and dimer spectra have been determined. Fluorescence, triplet and singlet oxygen quantum yields were measured and the photophysical characterization of the triplet state was performed for the three dyes. These parameters were evaluated in connection with aggregation results.

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Section: Monomer-dimer Equilibriummentioning

confidence: 63%

Photophysical and Aggregation Studies of t‐Butyl‐Substituted Zn Phthalocyanines

Fernández

Awruch

Dicelio

1996

Photochem & Photobiology

108

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“…Interestingly, it is found that the size distribution of PLL-NPs is roughly constant (~ 100 nm) over the whole doping range (1-10 %), while small particles (~ 30 nm) 4 emerge from the initial large Si-NPs (~ 80 nm) with the increase of ZnPc. With the consideration that the shape of Q band of Si-NPs is consistent with that of face-to-face or H-aggregates of phthalocyanines, 29 the small particles are reasonable to be ascribed to pure ZnPc aggregates. That means Si-NPs only form blank particles with additional ZnPc aggregates, and PLL-NPs successfully encapsulate ZnPc molecules.…”

Section: Synthesis Of Znpc-loaded Ps-dts Npsmentioning

confidence: 96%

Synthesis and optimization of ZnPc-loaded biocompatible nanoparticles for efficient photodynamic therapy

et al. 2016

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Zinc (II) phthalocyanine (ZnPc) is a promising photosensitizer for PDT but suffers from aggregation in physiologic aqueous environment. In this paper, a type of biocompatible polymeric nanoparticles (NPs) was prepared to encapsulate ZnPc molecules. Mostly because of the planar structure, ZnPc molecules were difficult to be encapsulated into the polymeric NPs unless further coated with a thick poly-L-lysine (PLL) layer. The PLL shell endowed the NPs good biocompatibility, efficient cellular uptake, and potential bioconjugation. The degree of aggregation (DOA) of ZnPc molecules in PLL-NPs was thoroughly investigated based on self-defined relative DOA, and a loading capacity of 4 wt % was deduced as the turning point for the aggravating of aggregation. Similarly, the optimal loading capacity of ZnPc was determined to be 4 % according to 1 O 2 generation rate, demonstrating the feasibility of DOA approach. Polymers with large rigid units (PVK and PFO) were also utilized to relieve the aggregation of ZnPc in NPs. Taking advantage of the optimized ZnPc-loaded NPs, high PDT efficacy was demonstrated on HepG2 cells and in tumor-bearing mice as well. The high in vitro and in vivo PDT efficacy and biocompatibility are both demonstrated. Aside from affording a type of efficient biocompatible nanophotosensitzes, this work is also instructive to the design of other types of ZnPc-based nanocarriers, in which aggregation should be well considered.

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“…Since the Q band is sensitive to the environment of the Pc or Nc molecule, a broad Q band spectrum for stacked film ensures a healthy SnNc film growth over VONc [9,10]. Meanwhile the weak improvement for mixed deposition might be due to the adjacent stacking of both materials producing some amount of segregation and thereby formation of dimeric species [11]. This effect is also reflected in the B-band (300-400 nm) for annealed mixed deposited sample showing a blueshift (330 nm) compared to all other samples (345 nm) indicative of a shift in the relative positions of valance and conduction bands.…”

Section: Optical Characterizationmentioning

confidence: 98%

“…But for mixed deposited sample, due to the formation of dimeric species the strong intermolecular interactions adds relaxation pathways, shorten the excited state lifetime, and thereby reduce the effective non-linear absorption. If the naphthalocyanines used are with axial ligands, this aggregation effect can be effectively suppressed [11]. Saturable absorbers find applications in Q-Switching and mode-locking, which are techniques employed to obtain short and ultrafast laser pulses of nanosecond and picosecond durations respectively.…”

Section: Optical Characterizationmentioning

confidence: 99%