Pseudohalide Ions as Ligands to Tune Architecture and Luminescence of Polymetallic CU(I) Assemblies.

The reaction of preassembled Cu(I) bimetallic units {Cu2 (dppm)2 } and {Cu2 (dppa)2 } (dppm: bis(diphenylphosphino)methane and dppa: bis(diphenylphosphino)amine) with pseudohalide linkers (azido, dicyanamide, and tricyanomethanide) allows for the quantitative and selective preparation of three discrete tetrametallic metallacycles of formula [Cu4 (μ2 -dppm)4 (N3 )2 ](PF6 )2 , [Cu4 (μ2 -dppm)4 (N(CN)2 )2 ](PF6 )2 , and [Cu4 (μ2 -dppm)4 (C(CN)3 )4 ]. To explore further the impact of the linker on the architecture and dimensionality of the molecular edifice, the study was extended to more sophisticated tetradentate cyanocarbanion ligands (tcnsMe- : 2-(methylthio)-1,1,3,3-propanetetracarbonitrile and tcnsEt- : 2-(ethylthio)-1,1,3,3-propanetetracarbonitrile). Three ladder-like one-dimensional coordination polymers and an octametallic metallacycle have been obtained. The careful comparison of the metric and geometrical intramolecular and intermolecular parameters observed in this series of seven derivatives allows for rationalization of their molecular architectures. The subtle balance between the length and steric hindrance of the ligand and the formation of noncovalent interaction networks greatly influences the topology and dimensionality of the resulting assemblies and will be discussed hereafter. The photophysical properties of these seven polymetallic Cu(I) compounds have also been also studied.