Helical Self‐Assembly of Optically Active Phthalocyanine Derivatives: Effect of ZnO Coordination Bond on Morphology and Handedness of Nanostructures

Abstract

Two optically active phthalocyanine derivatives with eight peripheral chiral (S)-4'-(2-methylbutoxy)biphenyl moieties on the β-position of the phthalocyanine ring are synthesized. The circular dichroism (CD) spectra show signals in the Q absorption region for both compounds 1 and 2 in chloroform solution, indicating the effective chiral-information transfer from the peripheral chiral (S)-4'-(2-methylbutoxy)biphenyl side chains to the phthalocyanine chromophore at the molecular level. Their self-assembling properties are further investigated by using electronic absorption and Fourier transform infrared spectroscopy, transmission electronic microscopy, scanning electronic microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Experimental results reveal the effect of the metal-coordination bond on molecular packing models in these nanostructures, which in turn results in the self-assembled nanostructures with different morphologies, from nanosheets for 1 to helical nanofibers for 2. In addition, good semiconducting properties of the nanostructures fabricated from phthalocyanine derivatives 1 and 2 are revealed by current-voltage measurements.

Recent Progress in Optically-Active Phthalocyanines and Their Related Azamacrocycles

“…A similar reaction between (S)-4-hydroxy-4 ′ -(2methylbutoxy)biphenyl and 4,5-dichloro-1,2-dicyanobenzene in the presence of K 2 CO 3 in DMF produced 1,2-dicyano-4,5-bis[(S)-4 ′ -(2-methylbutyoxy)biphenyl]benzene, which was then tetramerized similarly, to yield octa-substituted H 2 -and ZnPcs at β-positions, i.e., 14((S)-H 2 Pc-A) and 14((S)-ZnPc-A) (Zhang et al, 2013). 14((S)-H 2 Pc-B) and 14((S)-CuPc-B) were similarly prepared using a phthalonitrile having a long alkyl chain at the 4,5-positions, which was synthesized in four steps starting from catechol (Tian et al, 2013b).…”

Helical Self‐Assembly of Optically Active Glycoconjugated Phthalocyanine J‐Aggregates

“…The substance class of phthalocyanines includes only a few examples where supramolecular chiral aggregates had been detected in solution. However, in some cases it has been shown that Pcs with chiral substituents are able to form the desired helical aggregates . The driving force for such chiral aggregates can be viewed as a combination of ‐ ‐ and metal‐ligand interactions as was mentioned above.…”

“…Therefore, it is important to understand the influence of the aggregation of such molecules in this context. Substitution at the periphery of the phthalocyanine core by chiral groups like sugars leads to an asymmetry of the chromophore of the respective Pc and can be measured by circular dichroism (CD) spectroscopy . On one hand, CD‐spectroscopy can identify chirality transfer from the substituent to the chromophore which occurs on the molecular scale and results in sharp negative or positive peaks in the CD spectrum .…”

Self-assembled core–shell nanospheres and dendritic nanostructure of novel tetra-(3-phenyprop-2-allyloxy) phthalocyanine in different solvents

“…Because of their excellent chemical and thermal stability, phthalocyanine compounds have been used in various potential applications such as chemical sensors, 3 electrocatalyst, data storage systems, nonlinear optics, liquid crystals 4 and photosensitizers for photodynamic therapy. 16 Recently, Zhu and coworkers 17 have reported the design and synthesis of two phthalocyanine compounds with optical activity. [6][7][8][9] Molecular materials and machines, based on supramolecular self-assembly, perform some special functions such as electrical conductivity, chemical sensing, 10 and mechanical movement.…”

“…[12][13][14][15] In general, great progress has been made in the self-assembly of phthalocyanines that forms various morphology nanostructures. 16 Recently, Zhu and coworkers 17 have reported the design and synthesis of two phthalocyanine compounds with optical activity. And their selfassembly properties was comparatively investigated.…”