Heteronuclear Gold(I)-Copper(I) Complexes with Thia- and Mixed Thia-Aza Macrocyclic Ligands: Synthesis, Structures and Optical Properties

The reactivity of the heterometallic polynuclear complexes [{Au(R)2}2Cu2(MeCN)2]n (R=C6F5, C6Cl5) with the thioether crowns 1,4,7-trithiacyclononane (L1, [12]aneS3), 1,4,8,11-tetrathiacyclododecane (L2, [14]aneS4), 1,4,7,10,13,16,19,22-octathiacyclotetracosane (L3, [24]aneS8), and the quinoline functionalized pendant arm derivatives of the 12-membered mixed-donor macrocycles 1-aza-,4,7,10-trithiacyclododecane ([12]aneNS3) and 1,7-diaza-4,10-dithiacyclododecane ([12]aneN2S2), L4 and L5, respectively, was investigated in THF solution. While with L4 and L5 only ionic compounds of general formulation [Cu(L)][Au(R)2] were isolated and structurally characterized (none of them featuring Au & sdot;& sdot;& sdot;Cu interactions), with L1-L3, beside similar ionic compounds, some heteronuclear complexes of general formulation [{Au(R)2}{Cu(L)}] and featuring Au & sdot;& sdot;& sdot;Cu interactions were also obtained. All of them display rather unusual non-classical C-H & sdot;& sdot;& sdot;Au hydrogen interactions. The complexes display in the solid state different optical properties related to their structures, which have been studied experimentally and theoretically via TD-DFT calculations. In particular, all compounds of the type [{Au(R)2}{Cu(L)}] featuring Au & sdot;& sdot;& sdot;Cu metallophilic interactions display luminescence in the solid state both at room temperature (RT) and at 77 K. On the contrary, ionic compounds of general formulation [Cu(L)][Au(R)2], except [Cu(L4)][Au(C6F5)2], are not luminescent. Heterometallic polynuclear complexes [{Au(R)2}2Cu2(MeCN)2]n (R=C6F5, C6Cl5) were reacted in THF solution with thioether crowns ligands featuring a different number of S-donor atoms and ring size cavity, and with the quinoline functionalized pendant arm derivatives of tetradentate 12-membered N/S mixed-donor macrocycles. With the latter only ionic compounds of general formula [Cu(L)][Au(R)2] (L=macrocyclic ligand) were isolated and structurally characterized and none of them featured an Au & sdot;& sdot;& sdot;Cu metallophilic interaction. The optical properties of all complexes were studied experimentally and theoretically via TD-DFT calculations.image