New heterobimetallic Au(i)-Pt(ii) polyynes achieving a good trade-off between transparency and optical power limiting performance

Two series of new heterobimetallic Au(i)-Pt(ii) polyynes have been easily synthesized by cross-coupling under mild conditions. The absorption profiles of these two series of Au(i)-Pt(ii) polyynes are quite similar. However, the Au(i)-Pt(ii) polyynes with a 1,4-bis(diphenylphosphino)benzene ligand show stronger triplet (T₁) emission and superior optical power limiting (OPL) performance than the corresponding Au(i)-Pt(ii) polyynes with a 1,3-bis(diphenylphosphino)propane ligand. Hence, the 1,4-bis(diphenylphosphino)benzene ligand is more effective than the 1,3-bis(diphenylphosphino)propane ligand for optimizing the transparency and OPL ability of OPL materials. When compared with the corresponding homometallic Pt(ii) polyynes, these heterobimetallic Au(i)-Pt(ii) polyynes display a blue shift in their absorption spectra, showing better transparency in the visible-light region. Besides, these heterobimetallic Au(i)-Pt(ii) polyynes show stronger OPL ability than their corresponding homometallic Pt(ii) polyynes as well as the state-of-the-art OPL material C₆₀, demonstrating their enormous application potential in the nonlinear optics field. In brief, the introduction of Au(i) precursors with tetrahedral diphosphine ligands into the backbone of Pt(ii) polyynes can simultaneously achieve enhanced transparency and high OPL ability for OPL materials, providing a new strategy to optimize OPL materials.