144586-89-0Relevant articles and documents
β-Octamethoxy-Substituted 22π and 26π Stretched Porphycenes: Synthesis, Characterization, Photodynamics, and Nonlinear Optical Studies
Rana, Anup,Lee, Sangsu,Kim, Dongho,Panda, Pradeepta K.
supporting information, p. 12129 - 12135 (2015/08/18)
Three meso-expanded tetrapyrrolic aromatic macrocycles, including 22π and 26π acetylene-cumulene bridged stretched octamethoxyporphycenes and octamethoxy[22]porphyrin-(2.2.2.2), are reported, for the first time, by modification of previously reported synthetic methods. This strategy led to an enhancement in the overall yield of their corresponding octaethyl analogues. The methoxy-substituted expanded porphycenes display slightly blueshifted absorption relative to their ethyl analogues, along with very weak fluorescence, probably due to efficient intramolecular charge transfer (ICT). Additionally, the two-photon absorption (TPA) cross sections of these macrocycles were evaluated; these are strongly related to core expansion of the porphyrin aromaticity through increased meso-bridging carbon atoms as well as conformational flexibility and substitution effects at the macrocyclic periphery. In particular, the octamethoxy stretched porphycenes display strong TPA compared with the octaethyl analogues due to the dominant ICT character of methoxy groups with a maximum TPA cross section of 830 GM at 1700 nm observed for 26π-octamethoxyacetylene-cumuleneporphycene.
Photophysics and photochemistry of 22π and 26π acetylene-cumulene porphyrinoids
M?rtire, Daniel O.,Jux, Norbert,Aramendía, Pedro F.,Martín Negri,Lex, Johann,Braslavsky, Silvia E.,Schaffner, Kurt,Vogel, Emanuel
, p. 9969 - 9978 (2007/10/02)
The aromatic 26π acetylene-cumulene porphyrinoid 8 has been synthesized by a reaction sequence involving reductive carbonyl coupling of the dialdehyde 12 utilizing low-valent titanium in the crucial step. Like its lower 22π homologs 6 and 7, the new tetrapyrrolic macrocycle 8 is centrosymmetric in the crystal and has a practically planar ring framework. The photophysical and photochemical properties of 6-8 have been studied and compared to those of the related 18π porphycene 5. The absorption spectrum of 8 has the most red-shifted and intensified visible bands (εmax = 119600 at 889 nm in dichloromethane) of this particular series of (4n + 2)π porphyrinoids. None of the compounds exhibit any photoreactivity. The photophysical properties were determined by a combination of techniques, including steady-state thermal lensing, flash photolysis, laser-induced optoacoustic spectroscopy (LIOAS), and steady-state and time-resolved NIR spectroscopy. The 22π and 26π porphyrinoids do not phosphoresce. The triplet energy (ET) of 7 was therefore measured by way of reversible energy transfer to oxygen yielding singlet molecular oxygen, O2(1Δg), indirect detection by LIOAS of the increase in triplet yield induced by O2(3Σg-)-enhanced S → T intersystem crossing afforded the ET of 6, and an upper limit of ET could be obtained by energy-transfer experiments from O2(1Δg) to 8. The quantum yields of fluorescence, triplet formation, and the ET values dropped significantly on going from 5 to 6-8 (all measurements at room temperature). The triplet energies of 6, 7, and 8 are all below the energy of O2(1Δg). Compound 7, with the highest ET of the three, produces O2(1Δg) with a quantum yield of φΔ = 0.06 through a reversible energy-transfer mechanism. Although this value is about six times smaller than φΔ of 5, the phototherapeutic activities of both 5 and 7 toward tumors in mice are comparable. The φΔ values for 6 and 8 are lower than 10-3?; hence, these porphyrinoids do not function as photodynamic sensitizers.
Acetylene-cumulene porphycene compounds for photodynamic therapy
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, (2008/06/13)
Dihydro- and tetrahydro-acetylene-cumulene porphycene compounds having the structure shown below STR1 are useful as photogynamic therapy agents.
