The vapochromic behaviors of {Ag2L2[Au(C6F5)2]2}n (L = Et2O (1), Me2CO (2), THF (3), CH3CN (4)) were studied. {Ag2L2[Au(C6F5)2]2}n (L = Et2O (1)) was synthesized by the reaction of [Bu4N][Au(C6F5)2] with AgOClO3 in 1:1 molar ratio in CH2Cl2/Et2O (1:2). 1 was used as starting material with THF to form {Ag2L2[Au(C6F5)2]2}n (L = THF (3)). 3 crystallizes in the monoclinic space group C2/c and consists of tetranuclear units linked together via aurophilic contacts resulting in the formation of a 1D polymer that runs parallel to the crystallographic z axis. The gold(I) atoms are linearly coordinated to two pentafluorophenyl groups and display additional Au...Ag close contacts within the tetranuclear units with distances of 2.7582(3) and 2.7709(3) A. Each silver(I) center is bonded to the two oxygen atoms of the THF molecules with a Ag-O bond distance of 2.307(3) A. TGA analysis showed that 1 loses two molecules of the coordinated solvent per molecular unit (1st one: 75-100 degrees, second one: 150-175 degrees C), whereas 2, 3, and 4 lose both volatile organic compounds (VOCs) and fluorinated ligands in a less well defined manner. Each complex loses both the fluorinated ligands and the VOCs by a temperature of about 325 degrees C to give a 1:1 gold/silver product. X-ray powder diffraction studies confirm that the reaction of vapors of VOCs with 1 in the solid state produce complete substitution of the ether molecules by the new VOC. The VOCs are replaced in the order CH3CN > Me2CO > THF > Et2O, with the ether being the easiest to replace. {Ag2(Et2O)2[Au(C6F5)2]2}n and {Ag2(THF)2[Au(C6F5)2]2} n both luminesce at room temperature and at 77 K in the solid state. Emission maxima are independent of the excitation wavelength used below about 500 nm. Emission maxima are obtained at 585 nm (ether) and 544 nm (THF) at room temperature and at 605 nm (ether) and 567 nm (THF) at 77 K.

By reaction of the Lewis base NBu4[Au(3,5-C6F3Cl2)2] and AgCF3COO in the presence of NBu4CF3COO the heterometallic compound (NBu4)2[Au(3,5-C6F3Cl22Ag4(CF3COO)5] (2) is obtained. The structure displays an unprecendented square pyramidal AuAg4 arrangement built up through four AuAg closed-shell interactions and two Au-C-Ag 3c-2e- bridges.

[AuAg3(C6F5)(CF3CO2)3(CH2PPh3)]n (2) was prepared by reaction of [Au(C6F5)(CH2PPh3)] (1) and [Ag(CF3CO2)] (1:3). The crystal structures of complexes 1 and 2 were determined by X-ray diffraction, and the latter shows a polymeric 2D arrangement built by Au...Ag, Ag...Ag, and Ag...O contacts. The metallophilic interactions observed in 2 in the solid state seem to be preserved in concentrated THF solutions, as suggested by EXAFS, pulsed-gradient spin-echo NMR, and photophysical studies, which showed that the structural motif [AuAg3(C6F5)(CF3CO2)3(CH2PPh3)] is maintained under such conditions. Time-dependent DFT calculations agree with the experimental photophysical energies and suggest a metal-to-ligand charge-transfer phosphorescence process. Ab initio calculations give an estimated interaction energy of around 60 kJ mol(-1) for each Au...Ag interaction.

Reaction of [Ag(CF3CO2)] with tetrahydrothiophene (tht) (2:1) in dichloromethane leads to the synthesis of [Ag4(CF3CO2)4(tht)2] (1), which further reacts with mesitylgold(I) ([Au(mes)]) (1:1) to afford [AuAg4(mes)(CF3CO2)4(tht)] n (3). Treatment of [Au(mes)] with [Ag(RCO2)] (R = CF3, CF2CF3) and tht (molar ratio 1:4:1 or 1:4:3) leads to the new Au/Ag systems [AuAg4(mes)(RCO2)4(tht) x ] n (x = 1, R = CF3 (3), CF2CF3 (4); x = 3, R = CF3 (5), CF2CF3 (6)). The crystal structures of 3, 4, and 6 have been established by X-ray diffraction, all of them displaying Au···Ag interactions supported by mesityl ligands that bridge three metal centers in an unprecedented situation in transition metal chemistry. Additional Au−S−Ag and Ag−O−Ag (3 and 4) or Ag−S−Ag (6) bonds result in two-dimensional polymers that contain both Au···Ag and Ag···Ag contacts. Treatment of 3 with water (1:2) in dichloromethane leads to {[AuAg4(mes)(CF3CO2)4(tht)(H2O)]·H2O·CH2Cl2} n (7), whose crystal structure shows the partial break of the cyclic [Ag2(μ-RCO2)2] dimer present in the structures of 3, 4, and 6, probably caused by the coordination of one molecule of water to one of the AgI centers. It also displays Au···Ag and Ag···Ag interactions, as well as Ag−C bonding interactions and additional Ag−O contacts, which result in a monodimensional polymer. The crystal structure of 1 has also been determined by X-ray diffraction.