Ce/Au(CN)2--Based Coordination Polymers Containing and Lacking Aurophilic Interactions

New members of the Ln[Au(CN)(2)](3)3H(2)O and [nBu(4)N](2)[Ln(NO3)(4)Au(CN)(2)] series Ln = Ce (CeAu3 and CeAu respectively) are reported herein where their synthesis, structure and photoluminescence properties are discussed. The first is a 3-D coordination polymer with aurophilic interactions of 3.35 angstrom and the latter is a 1-D coordination polymer that lacks them. At 293 K both CeAu3 and CeAu display characteristic Ce-III-based emission at (max) = 393 nm (5d(2)F(J)), however in CeAu3 Au-I-based emission ((max) = 410, (MLCT)-M-1) dominates the spectrum. At 77 K however, the dominant emission is Au-I-based with characteristic emissions of (max) = 430 nm ((MLCT)-M-1) and 490 nm ((MLCT)-M-3). The key difference in the luminescence of these two materials can be rationalized in terms of their respective structures, through either the aurophilic network and lack thereof and/or the rigidity offered in the 3-D structure of CeAu3.