Gold(I) and Platinum(II) Tetracenes and Tetracenyldiacetylides: Structural and Fluorescence Color Changes Induced by σ-Metalation

σ-Metalation of tetracene can change the emission color of and introduce new structural dimensionality to the organic chromophore. Two synthetic entries to σ-metallotetracenes have been explored, leading to emissive mononuclear (Ph 3 PAu I )-tetracene ( 1 ) and cis -[Br(Et 3 P) 2 Pt II ]-tetracene ( 2 ) and binuclear (R 3 PAu I ) 2 -tetracenyldiacetylide (R = Ph ( 4 ), Me ( 5 )) and trans -[I(Et 3 P) 2 Pt II ] 2 -tetracenyldiacetylide ( 6 ). Metalation can lower the emission energy of tetracene up to 0.53 eV. The X(Et 3 P) 2 Pt II group (X = Br, I) has stronger perturbations on the tetracenyl ring than the R 3 PAu I group. σ-Metalation also leads to different crystal packing of the complexes and thus arrangements of the tetracenyl rings. Aurophilic attraction operates in 5, leading to self-assembly of the molecules into a novel honeycomb structure composed of helical Au I chains. In contrast to the other complexes, the crystal of 5 is not emissive, possibly due to efficient exciton delocalization.