Complex Formation Equilibria between Ag(I) and Thioureas in Propan-2-ol. (18th December 2013)

• Record Type: Journal Article
• Authors: De Marco, Domenico
• Other Names: Masoud M. S. Academic Editor.; Zhang J. Academic Editor.
• Is Part Of: ISRN inorganic chemistry. Volume 2013(2013)
• Publication Date: 2013-12-18
• Subjects: Chemistry, Inorganic -- Periodicals; 546
• DOI: 10.1155/2013/189394
• Languages: English
• ISSNs: 2314-470X

Abstract

Abstract : The complex formation equilibria between Ag(I) and thiourea (Tu), N methyl-Thiourea (MeTu), N, N′-dimethyl-Thiourea (Me2 Tu), N, N, N′, N′ Tetramethyl-Thiourea (Me4 Tu), N-ethyl-Thiourea (EtTu), N, N′ diethyl-Thiourea (Et2 Tu), and N, N′-Ethylen-Thiourea (EnTu) in propan-2-ol as solvent medium have been investigated by potentiometry within the temperature range 10°C–40°C and self-determined ionic medium by (AgNO3 ) concentration range6.36 · 10 - 6 – 3.83 · 10 - 5 m·dm −3 (no background electrolyte added). The experimental results can be interpreted with the stepwise formation of tris-coordinated complexesAgL n (n = 1 – 3 ; hereafter charge is omitted). The stability constants logβ n and the standard thermodynamic changes in enthalpy (Δ H n ° ) and entropy (Δ S n ° ) for overall complex formation reactionsA g I + n L = A g L n (n = 1 – 3 ) have been evaluated. The reactions are exothermic in nature and entropy disfavored for all the investigated ligands. The standard enthalpy and entropy changes for the stepwise reactionsA g L n - 1 + L = A g L n have been evaluated by difference Δ Δ H n ° = Δ H n ° - Δ H n - 1 ° and Δ Δ S n ° = Δ S n ° - Δ S n - 1 ° . The stepwise enthalpy are mutually linearly related to the corresponding entropy changes with isoequilibrium temperaturesT i s o = 285, 305, and 363 K forn = 1, 2, or 3 respectively.