Coordination Chemistry of the Solvated AgI and AuI Ions in Liquid and Aqueous Ammonia, Trialkyl and Triphenyl Phosphite, and Tri-n-butylphosphine Solutions

Abstract

The coordination chemistry of solvated Ag(I) and Au(I) ions has been studied in some of the most strong electron-pair donor solvents, liquid and aqueous ammonia, and the P donor solvents triethyl, tri-n-butyl, and triphenyl phosphite and tri-n-butylphosphine. The solvated Ag(I) ions have been characterized in solution by means of extended X-ray absorption fine structure (EXAFS), Raman, and (107)Ag NMR spectroscopy and the solid solvates by means of thermogravimetry and EXAFS and Raman spectroscopy. The Ag(I) ion is two- and three-coordinated in aqueous and liquid ammonia solutions with mean Ag-N bond distances of 2.15(1) and 2.26(1) A, respectively. The crystal structure of [Ag(NH3)3]ClO4.0.47 NH3 (1) reveals a regular trigonal-coplanar coordination around the Ag(I) ion with Ag-N bond distances of 2.263(6) A and a Ag...Ag distance of 3.278(2) A separating the complexes. The decomposition products of 1 have been analyzed, and one of them, [Ag(NH3)2]ClO4, has been structurally characterized by means of EXAFS, showing [Ag(NH3)2] units connected into chains by double O bridges from perchlorate ions; the Ag...Ag distance is 3.01(1) A. The linear bisamminegold(I) complex, [Au(NH3)2]+, is predominant in both liquid and aqueous ammonia solutions, as well as in solid [Au(NH3)2]BF4, with Au-N bond distances of 2.022(5), 2.025(5), and 2.026(7) A, respectively. The solvated Ag(I) ions are three-coordinated, most probably in triangular fashion, in the P donor solvents with mean Ag-P bond distances of 2.48-2.53 A. The Au(I) ions are three-coordinated in triethyl phosphite and tri-n-butylphosphine solutions with mean Au-P bond distances of 2.37(1) and 2.40(1) A, respectively.