Regioisomer‐Free C_4h β‐Tetrakis(tert‐butyl)metallo‐phthalocyanines: Regioselective Synthesis and Spectral Investigations

Abstract

Metal β-tetrakis(tert-butyl)phthalocyanines are the most commonly used phthalocyanines due to their high solubility, stability, and accessibility. They are commonly used as a mixture of four regioisomers, which arise due to the tert-butyl substituent on the β-position, and to the best of our knowledge, their regioselective synthesis has yet to be reported. Herein, the C4h-selective synthesis of β-tetrakis(tert-butyl)metallophthalocyanines is disclosed. Using tetramerization of α-trialkylsilyl phthalonitriles with metal salts following acid-mediated desilylation, the desired metallophthalocyanines were obtained in good yields. Upon investigation of regioisomer-free zinc β-tetrakis(tert-butyl)phthalocyanine using spectroscopy, the C4h single isomer described here was found to be distinct in the solid state to zinc β-tetrakis(tert-butyl)phthalocyanine obtained by a conventional method.

Synthesis of Phthalocyanines with a Pentafluorosulfanyl Substituent at Peripheral Positions

“…However, SF 5 ‐phthalonitriles 4 b and 4 c failed to be cyclized under these conditions. This is presumably due to the steric hindrance and strong electronegativity of the SF 5 group on the neighboring cyano moiety. Finally, desired α‐SF 5 ‐substituted Pc 3 b and α,β‐SF 5 ‐substituted 3 c were obtained under harsh conditions, that is, without solvent at higher reaction temperatures (180–200 °C), in 28 % and 7.8 % yield, respectively, as a mixture of regioisomers.…”

Temperature-dependent changes in the molecular orientation and visible color of phthalocyanine films

“…[29][30][31] According to previous studies, intense visible-to-NIR bands of Pcs are effective for determining their molecular orientation on thin lm by polarized optical waveguide spectroscopy. 32,33 Optical waveguide spectra of the thin lm of 1 obtained using non-polarized, spolarized, and p-polarized light at various temperatures are shown in Fig. 7.…”

Liquid state $^{15}$N NMR studies of $^{15}$N isotope labeled phthalocyanines

“…Tetra-tert-butyl substituted phthalocyanine derivatives have been studied intensively in the literature. 13 Most of the synthetic work was described starting from dinitril derivatives, but there are also some starting from anhydride derivative using urea as the nitrogen source. 14 The MALDI-TOF spectra of synthesized complexes gave molecular ion peaks for 6, 7, and 8, at m/z 808.415, 803.228, and 747.079, respectively.…”

“…10 In Pc chemistry, 15 N labeled unsubstituted copper(II) Pc is reported and the isotopic shifts of the IR and Raman bands are studied experimentally and theoretically. 11 Unsubstituted 15 N labeled metal-free Pc has been reported and the proton transfer mechanism has been investigated in solid state using high resolution 15 N and 13 C CPMAS NMR spectroscopy. 12 To the best of our knowledge, for the soluble Pcs liquid state 15 N NMR has not been reported to date.…”