Dynamic disorder in the high-temperature polymorph of bis[diamminesilver(I)] sulfate—reasons and consequences of simultaneous ammonia release from two different polymorphs

Bereczki, Laura and Fogaça, Lara Alexandre and Dürvanger, Zsolt and Harmat, Veronika and Kamarás, Katalin and Németh, Gergely and Barta Holló, Berta and Petruševski, Vladimir M. and Bódis, Eszter and Farkas, Attila and Szilágyi, Miklós Imre and Kótai, László (2021) Dynamic disorder in the high-temperature polymorph of bis[diamminesilver(I)] sulfate—reasons and consequences of simultaneous ammonia release from two different polymorphs. JOURNAL OF COORDINATION CHEMISTRY, 74. pp. 2144-2162. ISSN 0095-8972

Preview

Text JCC-AgAM2SO4-Bereczki-manuscript-prior-submission.pdf - Accepted Version Download (1MB) | Preview

Abstract

We prepared and characterized a high-t tetragonal polymorph of diamminesilver(I) sulfate (a = 8.6004(4) Å, c = 6.2123(6) Å) (compound 1-HT). The phase transformation of the low-temperature polymorph of diamminesilver(I) sulfate (compound 1-LT) into the high-temperature polymorph (compound 1-HT) partly coincides with the initial stage of the thermal decomposition of 1-LT. Selecting appropriate conditions, we separated the two processes and determined the standard heat of formation of the LT polymorph (ΔH298 = −1208.92 kJ/mol) and the enthalpy of polymorphic transformation (ΔHLT→HT = 13.18 kJ/mol). The high-temperature XRD results showed that the lattice constants of the LT polymorph (1-LT) extend in the direction of a, b, and compress in the direction of c in the 1-HT polymorph. According to high temperature SXRD data, the Ag–Ag distance (in the direction of c) shortens from 3.20 Å (1-LT) to 3.11 Å (1-HT), while the extension in the a,b direction weakens/disrupts the N-H…O-S hydrogen bonds and the coordinative Ag…O-S interactions. The IR and Raman spectroscopic data confirm the weakening/breaking of N-H…O-S hydrogen bonds. A vacuum-assisted thermal deammoniation experiment of 1-LT in the preparation of monoamminesilver(I) sulfate showed that the product is the mixture of silver(I) sulfate and the initial diamminesilver(I) sulfate complex.

Actions (login required)

Edit Item