Vapochromic behavior of {Ag2(Et2O) 2[Au(C6F5)2]2} n with volatile organic compounds

Resumen

The vapochromic behaviors of {Ag2L2[Au(C 6F5)2]2}n (L = Et 2O (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 CH 2Cl2/Et2O (1:2). 1 was used as starting material with THF to form {Ag2L2[Au(C6F 5)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) Å. 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) Å. TGA analysis showed that 1 loses two molecules of the coordinated solvent per molecular unit (1st one: 75-100°, second one: 150-175°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°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 > Me 2CO > THF > Et2O, with the ether being the easiest to replace. {Ag2(Et2O)2[Au(C6F 5)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. © 2008 American Chemical Society.