Interpenetrating digold(i) diacetylide macrocycles

Abstract

The cyclic dialkynyldigold(I) complexes [1,2-C₂H₄(O-3-C₆H₄OCH₂CCAu)₂(μ-LL)] were prepared by reaction under basic conditions of the dialkyne 1,2-C₂H₄(O-3-C₆H₄OCH₂CCH)₂ with [AuCl(SMe₂)] and the corresponding diphosphine ligands LL = Ph₂P(CH₂)_nPPh₂ (n = 1–6), trans-Ph₂PCHCHPPh₂ and Ph₂PCCPPh₂. The new organometallic macrocycles have ring sizes ranging from 23 to 28 atoms, and the complexes with LL = Ph₂P(CH₂)₄PPh₂ and trans-Ph₂PCHCHPPh₂ have been structurally characterized. In both cases, the digold(I) macrocycles assemble into dimers in the solid state through Au⋯Au aurophilic bonding, with a phenyl group of each macrocycle occupying the cavity of the other. However, this extensive interpenetration occurs without the catenation observed in some similar complexes. The complexes give room temperature emissions above 400 nm in solution and the solid state, and a red shift of approximately 50 nm between emission maxima in the solution and the solid state spectra is suggested to be an indication of the strong interpenetration in the solid state.