One-Dimensional Heterobimetallic Au/Ag Coordination Polymer Showing a Selective, Reversible, and Visible Vapor-Chromic Photoluminescent Response toward Methanol.

A heterobimetallic coordination polymer [Au 4 (dppmt) 4 (AgCl) 2 ] n ( 1 ) incorporating an in situ generated P-S ligand (dppmtH) was synthesized from the solvothermal reaction of Au(tht)Cl, AgCl, and dpppyatc in CH 3 CN/CH 2 Cl 2 (dppmtH = (diphenylphosphino)methanethiol, tht = tetrahydrothiophene, dpppyatc = N , N -bis((diphenylphosphaneyl)methyl)- N -(pyridin-2-yl)-amino-thiocarbamide). The structure of 1 contains a one-dimensional helical Au-Au chain in which the unique [Au 4 Ag 2 S 2 ] cluster units are connected by [Au 2 (dppmt) 2 ] dimers. Upon excitation at 343 nm, 1 exhibited cyan (495 nm) phosphorescent emission at quantum yield (QY) = 22.3% and τ = 0.78 μs (λ ex = 375 nm). Coordination polymer 1 exhibited a rapid, selective, reversible, and visible vapor-chromic response on exposure to methanol (MeOH) vapor with its emission shifting to a more intense green (530 nm, λ ex = 388 nm) with QY = 46.8% and τ = 1.24 μs (λ ex = 375 nm). A polymethylmethacrylate film containing 1 served as a reversible chemical sensor for the sensitive detection of MeOH in air.