Unsuspected mesomorphism in 'tail-free' cyclopalladated 3,5-disubstituted-2-(2'-pyridyl)pyrroles

摘要

The first cyclopalladation of 3,5-disubstituted-2-(2'-pyridyl)pyrroles leads to columnar metallomesogens of non-conventional molecular shape.rnIn the large area of cyclopalladated complexes, which involves several fields of application, pyridylpyrroles (PyrPy) have been somewhat neglected, though the presence of a very acid NH bond should make these ligands very attractive for coordinating a wide variety of metals. The few reports concerning 2,2'-PyrPy complexes completely lack cyclopalladated examples and this absence prompted us to explore the chemistry of this class of ligands towards the Pd(ii) centre in the formation of versatile new molecular materials. Thus, we have synthesized two 3,5-disubstituted-2-(2'-pyridyl)pyrroles and we have investigated their cyclopalladating ability and the reactivity of the resulting dinuclear bridged complexes towards β-diketones as ancillary ligands, in analogy with more classical cyclopalladating ligands. Moreover, the use of aliphatic and fluoroaliphatic groups on both the PyrPy and the ancillary ligands has encouraged us to investigate further the solid state organization of the new crystalline molecular materials, knowing that perfluorinated ligands can be used in the control of the solid-state architectures of both molecular organic and inorganic solids and of their film-forming ability.