Lowering Melting Points in Asymmetrically Substituted Salen-copper(II) Complexes Exhibiting Mesomorphic Behavior. Structure of the Mesogen Cu(5-hexyloxySalen)

Abstract

In comparison with their symmetrical analogues, unsymmetrically substituted Cu−Salen complexes show mesophases with lowered melting points. For terminally substituted complexes, symmetrical ones (R1 = R2) have only an SA phase, while for unsymmetrical alkoxy substitution a monotropic SE phase occurs and the melting temperature decreases with no loss in mesophase stability. Lateral substitution, when it is symmetrical (R3 = R4), lowers mesophase stability but not melting temperature, and when it is unsymmetrical, it greatly lowers both mesophase stability and melting temperature compared with the parent compound. Substitution at the imine carbon (R5, R6) also lowers chemical stability (decomposition) of the compounds. The structure of the 5-hexyloxy complex (R1 = R2 = OC6H13, R3 = R4 = R5 = H) shows the pre-mesophasic arrangement likely adopted after melting.

Department(s)

Chemistry

Sponsor(s)

Great Britain. Engineering and Physical Sciences Research Council

Keywords and Phrases

Melting points

International Standard Serial Number (ISSN)

0020-1669

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2002 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Mar 2002

Link to Full Text

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