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Allyloxyporphyrin-functionalized multiwalled carbon nanotubes (MWCNT-TPP) were synthesized by radical polymerization and characterized by FTIR, UV/Vis absorption, and X-ray photoelectron spectroscopy; elemental analysis; TEM; and thermogravimetric analysis. Z-scan studies revealed that this nanohybrid exhibits enhanced nonlinear optical (NLO) properties compared to a control sample consisting of a covalently unattached physical blend of MWCNTs and porphyrin, as well as to the separate MWCNTs and porphyrin. At the wavelengths used, the mechanism of enhanced optical limiting likely involves reverse saturable absorption, nonlinear scattering, and photoinduced electron/energy transfer between the MWCNTs and the porphyrin. The role of electron/energy transfer in the NLO performance of MWCNT-TPP was investigated by Raman and fluorescence spectroscopy. [ABSTRACT FROM AUTHOR]

Two multi-walled carbon nanotube (MWCNT)-based nanohybrids, MWCNT-ZnTPP and MWCNT-TPP (TPP=5-[4-{2-(4-formylphenoxy)- ethyloxy}phenyl]-10,15,20-triphenylporphyrin, ZnTPP=5-[4-{(4-formylphenyl)ethynyl}phenyl]-10,15,20-triphenylporphinatozinc(II)), were prepared directly from pristine MWCNTs through 1,3-dipolar cycloaddition reactions. Covalent attachment of the porphyrins to the surfaces of the MWCNTs was confirmed by Fourier transform infrared spectroscopy, ultraviolet/visible absorption, fluorescence, Raman, and X-ray photoelectron spectroscopy, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin moieties to the surface of the MWCNTs significantly improves the solubility and ease of processing of these MWCNT-porphyrin composite materials. Z-scan studies reveal that these MWCNT-porphyrin nanohybrids exhibit enhanced nonlinear optical properties under both nanosecond and picosecond laser pulses at λ=532 nm in comparison with free MWCNTs and the free porphyrin chromophores, whereas superior optical limiting performance was displayed by MWCNT-porphyrin composite materials rather than MWCNTs/ZnTPP and MWCNTs/TPP blends, which is consistent with a remarkable accumulation effect as a result of the covalent linkage between the porphyrin and the MWCNTs. [ABSTRACT FROM AUTHOR]

Porphyrin‐functionalized multi‐walled carbon nanotubes (MWCNTs) have been prepared through 1,3‐dipolar cycloaddition reactions. Covalent attachment of porphyrins to the MWCNTs' surfaces affords composite materials with excellent solubility and facile processing. These MWCNT–porphyrin nanohybrids exhibit strong optical limiting of both nanosecond and picosecond laser pulses at 532 nm, attributed to a combination of nonlinear scattering, reverse saturable absorption, and photoinduced energy transfer. For more information, see the Full Paper by C. Zhang et al. on page 14159 ff. [ABSTRACT FROM AUTHOR]

Review: 66 refs. [ABSTRACT FROM AUTHOR]

In the title compound, C24H22Br2N2S, the dihedral angles between the central pyrimidine ring and the pendant bromo-benzene rings are 11.02 (11) and 13.20 (12)°. The butyl side chain adopts a gauche conformation [C-C-C-C = -67.4 (4)°]. In the crystal, weak aromatic π-π stacking is observed between the pyrimidine ring and one of the benzene rings [centroid-centroid separation = 3.6718 (17) Å].