Ferroelectric liquid crystal behavior in platinum orthometallated complexes
Abstract
Di-μ-chloro-bis[(η3-2-methylallyl)platinum] reacts with chiral NC6H4OR2-p [HL*; with R1, R2, or both equal to either (R)- or (S)-1-methylheptyl], to yield the C,N-cyclometallated platinum(II) compounds [Pt2(μ-Cl)2(L*)2] (2). Treatment of 2 with Tl[(p-H21C10OC6H4CO)2CH] produces mononuclear orthoplatinated complexes (3) incorporating a β-diketonate. Both complexes 2 and 3 are mesomorphic materials that display smectic A (SmA) and chiral smectic C (SmC*) phases. Their mesogenic properties are compared with those of their palladium analogues, reported previously. The platinum complexes show somewhat more stable mesophases. A study of the ferroelectric properties of compounds 2 and 3 has been performed.