Magnetomesogens: Bis(1,3-di(4′-decoxyphenyl)propane-1,3-dionato)oxovanadium (IV)

Styring, Peter; Tantrawong, Sukrit; Beattie, David R.; Goodby, John W.

doi:10.1080/02678299108036445

Cited by 16 publications

(2 citation statements)

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“…The complex with ten side chains displays a linear chain structure in the crystal phase and possibly a weak linear chain structure in the D,, phase. The fact that other researchers have found similar vanadyl 1,3-diketonate complexes to be mesomorphic with four side chains is surprising [ 6 ] . Our future reports will deal with additional mesophase characterization of IV and structural variations on this system, as well as polarization studies.…”

Section: Discussionmentioning

confidence: 94%

“…This modification seemed likely to provide improved phase behaviour since during the course of our investigations it was reported that a related vanadyl 1,3-diketonate complex with four side chains was mesomorphic [6]. Additionally, we considered that the unusual behaviour of I (n = 8,lO) may be in part due to the bulky nature of these complexes which could result in kinetic problems in the directional ordering of the V=O group.…”

Section: Vanadyl 13-diketonate Complexes With Four Side Chainsmentioning

confidence: 85%

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The development of polar discotic metallomesogens Vanadyl 1,3-diketonate complexes

1993

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The dependence of mesomorphism of 1,3-diketonate vanadium-oxo (vanadyl) complexes on the number of side chains was investigated. These complexes have a large dipole normal to the disc plane and are under investigation in an effort to generate discotic phases with polar order. Relatively complex phase behaviour is observed when the vanadyl 1,3-diketonate complexes are appended with four phenyl groups with two octyloxy or decyloxy side chains each for a total ofeight side chains. These complexities are most likely related to the order/disorder associated with the polar vanadyl group. Vanadyl 1,3-diketonate complexes with four side chains were prepared by replacement of two of the phenyl groups with methyl or trifluoromethyl groups, and these complexes displayed only crystal phases. Complexes with two trialkyloxy phenyls and two dialkyloxy phenyls were synthesized and found to display a very stable D,, phase. The presence of additional alkyloxy groups was found also to promote a linear chain structure,in the crystal phase. IntroductionNew liquid crystals with polar mesogens are of interest as a means of generating materials which can interact strongly with electric fields. Polar mesogens may also be used to produce new materials with ferroelectric behaviour, given that bulk dipolar order can be established. In the quest for new achiral ferroelectric liquid crystals, columnar phases of pyramid shaped macrocyclic organic mesogens have been investigated [l]. The pyramid shape of the mesogen in these systems promotes a headto-tail organization and hence can create polar order within a given column. There have been a number of elegant studies on these organic pyramidal liquid crystals [l], but ferroelectric behaviour has not been demonstrated. This fact is probably due to small dipoles and large activation energies for redirecting the dipoles, since recent theoretical studies indicate that ferroelectric phases should exist [2].As a result of these difficulties associated with prospective ferroelectric organic discotic systems, we have been focusing on inorganic vanadium-oxo (vanadyl) complexes. The vanadyl group is attractive since it often exhibits a square pyrimidal structure and has a large directional dipole associated with the V=O bond [3]. In addition, work in this laboratory has recently shown that liquid crystalline vanadyl complexes can arrange in a linear chain structure (i.e. --V=O--V=O--), thereby creating local polar order between mesogens [4]. We report herein our results on a series of discotic 1,3-diketonate vanadyl complexes for which we explore the effects of the number of side chains on the mesomorphic behaviour.

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Section: Discussionmentioning

confidence: 94%

Section: Vanadyl 13-diketonate Complexes With Four Side Chainsmentioning

confidence: 85%