Homologous series of liquid-crystalline metal free and copper octa-<i>n</i>-alkoxyphthalocyanines

Pol, J.F. van der; Neeleman, E.; Zwikker, Jan W.; Nolte, Roeland J. M.; Drenth, W.; Aerts, J.; Visser, R. J. J.; Picken, Stephen J.

doi:10.1080/02678298908034177

Cited by 169 publications

(87 citation statements)

References 49 publications

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“…Molecular modelling calculations suggest that the mutual steric interactions of the adjacent methylene linking groups of Pc series 1 encourage the peripheral alkyl chains to lie out of the plane of the Pc ring, whereas the relatively small alkoxy linking groups of Pc Series 2 allows the side chains to sit comfortably in the plane of the macrocycle. [13] This conformational difference is consistent with the lower clearing temperatures (> 50 8C) for Pc series 1 relative to those of series 2 (Table 1 and Figure 3) and has been held responsible for the tilted arrangement of the phthalocyanines within the columnar stack of the mesophases formed by Pc series 1.…”

Section: Discussionsupporting

confidence: 76%

“…It is notable that the change in enthalpy for the transition from crystal to mesophase is only a few kJ mol À1 for Pc series 6, whereas for Pc series 2 the crystal to columnar mesoA C H T U N G T R E N N U N G phase transition is associated with a much larger enthalpy change (70-100 kJ mol À1 ) consistent with the melting of highly ordered alkyl chains. [13] Further structural characterisation of the highly disordered crystals formed by Pc series 6 is required.…”

Section: Discussionmentioning

confidence: 99%

“…By placing long alkyl (Pc series 1) [11,12] or alkoxy (Pc series 2) [11,13] side chains on the peripheral positions (2,3,9,10,16,17,23,24) of the phthalocyanine ring the solubility is enhanced and leads to liquid-crystalline behaviour in which the aromatic rings assemble into columnar stacks. Derivatives with long alkyl side chains attached to the nonpe-A C H T U N G T R E N N U N G ripheral sites (1,4,8,11,15,18,22,25) also form columnar liquid crystals (Pc series 3).…”

Section: Introductionmentioning

confidence: 99%

“…The thermal transition temperatures (in 8C) for members of phthalocyanine series 1-6 as measured by using polarising microscopy and differential thermal calorimetry. [a,b] Series 1 [12] Series 2 [13] Series 3 [14] Series 4 [16] Series 5 www.chemeurj.org sociated with the thin axis of the crystal. However, some information on packing within the crystal of the Pc series 6-A C H T U N G T R E N N U N G (C 5 -C 10 ) is obtained from analysis of the diagnostic Q-band of the UV-visible absorption spectra obtained from spincoated films (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

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The Self‐Ordering Properties of Novel Phthalocyanines with Out‐of‐Plane Alkyl Substituents

McKeown

Helliwell

Hassan

et al. 2006

Chemistry A European J

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Two novel homologous series of phthalocyanines were prepared from 2,2‐dialkylindane and 2,2‐dialkyl‐1,3‐benzodioxole precursors. It was anticipated that attaching alkyl chains to five‐membered rings, fused to the peripheral sites of the phthalocyanine ring, would result in the adoption of an out‐of‐plane configuration and thereby discourage cofacial aggregation, to provide an analogy with picket‐fence porphyrins. This strategy proved partially successful. Some members of the series of phthalocyanines derived from 2,2‐dialkyl‐1,3‐benzodioxoles, in which the alkyl chains are linked to the phthalocyanine via a cyclic ketal, form spin‐coated thin films in which the phthalocyanine cores are perfectly isolated. This behaviour is associated with the formation of a disordered crystal that appears as a mesophase in the thermal profile of these materials. However, the phthalocyanines derived from 2,2‐dialkylindanes display a columnar mesophase over a wide temperature range, with some liquid crystalline derivatives at ambient temperature. A single‐crystal X‐ray diffraction structure of the octahexyl derivative of this series shows how the columnar assembly accommodates the out‐of‐plane alkyl chains by tilting the macrocyclic plane of the phthalocyanine components with respect to the axis of the column. This study helps to emphasise the importance of both the steric and electronic effects of substituents on the packing behaviour of phthalocyanines in the condensed phase, and especially the role of electron‐donating oxygen atoms directly attached to the ring.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Self‐Ordering Properties of Novel Phthalocyanines with Out‐of‐Plane Alkyl Substituents

McKeown

Helliwell

Hassan

et al. 2006

Chemistry A European J

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confidence: 99%

Thermal and optical behaviour of octa-alkoxy substituted phthalocyaninatovanadyl complexes

Sleven¹,

Cardinaels²,

Binnemans³

et al. 2002

Liquid Crystals

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This paper deals with the synthesis of vanadyl phthalocyanines substituted with eight alkoxy chains in the peripheral (2,3, 9, 10,16, 17, 23, 24 ) positions. The alkoxy chain length was varied, and octa-octyloxy (C8H17O), octa-dodecyloxy (C12H25O) and octa-hexadecyloxy (C16H33O) substituted vanadyl phthalocyanine complexes were prepared. Studies by polarizing optical microscopy and small angle X-ray di V raction (XRD) revealed that all the complexes are liquid crystalline and that these metallomesogens exhibit a columnar phase. The symmetry of the 2D lattice is rectangular, with a c 2 mm space group, as determined by the indexation of the XRD re ections; hence a rectangular columnar phase (Colr ) was assigned. A double periodicity, although weak, along the axis of the columns was found, which indicates some degree of pairing or dimerization. A tentative explanation based on an antiferroelectric stacking is given. Transition enthalpies were determined by di V erential scanning calorimetry. The compounds start to decompose above 250 ß C before reaching the clearing temperatures. A signi cant bathochromic shift of the Q-band in the UV/Vis spectra of the vanadyl complexes compared with the metal-free ligands and other metallophthalocyanines (M = Co II , Ni II , Cu II , ZnII ) was also observed.

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Charge Transport in Mesomorphic Phthalocyanines Studied by Pulse-Radiolysis Time-Resolved Microwave Conductivity

Warman

Schouten

1996

Appl. Organometal. Chem.

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The pulse‐radiolysis time‐resolved microwave conductivity (PR‐TRMC) technique has been used to obtain information on the transport of charge within columnarly stacked, peripherally octaalkoxy‐substituted phthalocyanines. Data are presented on the one‐dimensional, intracolumnar charge mobility and on the timescale of quasi‐two‐dimensional intercolumnar electron tunnelling. Particular attention is paid to materials that are liquid‐crystalline at room temperature, because of their potential technological importance in optoelectric charge transport layers and molecular semiconductor devices. The relevance of the data to channeled charge transport in aligned thin layers is discussed.

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Homologous series of liquid-crystalline metal free and copper octa-n-alkoxyphthalocyanines

Cited by 169 publications

References 49 publications

The Self‐Ordering Properties of Novel Phthalocyanines with Out‐of‐Plane Alkyl Substituents

The Self‐Ordering Properties of Novel Phthalocyanines with Out‐of‐Plane Alkyl Substituents

Thermal and optical behaviour of octa-alkoxy substituted phthalocyaninatovanadyl complexes

Charge Transport in Mesomorphic Phthalocyanines Studied by Pulse-Radiolysis Time-Resolved Microwave Conductivity

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