Synthesis and Thermal Stability of Silver Carboxylates: Crystal Structure of Silver Pivalate

摘要

Silver(I) carboxylates Ag(RCOO) (R = i-Pr, n-Pr, t-Bu, i-Bu) are synthesized by reactions between AgNO_3 and potassium carboxylates in aqueous solutions and characterized by elemental analysis and IR spectroscopy. The X-ray structure of Ag(t-BuCOO) is determined: space group P1-bar, a =5.810(3) A, b = 13.646(5) A, c = 16.700(5) A, #alpha# = 107.56(3) deg, #beta#=90.47(4) deg, #gamma# = 94.24(3) deg, and Z = 4. The structure consists of polymeric chains formed by silver pivalate dimers, each linked with the two neighbors by two extra Ag-O bonds. The intradimer Ag-O bond lengths are 2.17 and 2.20 A. In a nitrogen atmosphere at p = 1 atm, all of the Ag(RCOO) compounds decompose to Ag between 120 and 250 deg C. At a reduced pressure of 0.01 mmHg, they can be sublimed at 220 to 250 deg C. The thermal stability and volatility of Ag(RCOO) increases in the R order i-Pr < n-Pr approx t-Bu approx i-Bu.