Infrared Absorption Studies of Aqueous Complex Ions. II. Cyanide Complexes of Cu (I) in Aqueous Solution

Abstract

In the system CuCN–KCN–H2O, we have observed infrared absorption spectra of three distinct complex ions: Cu(CN)2−,ε=165±25 mole−1 liter cm−1 at 2125 cm−1;Cu(CN)3=,ε=1090±10 mole−1 liter cm−1 at 2094 cm−1;andCu(CN)4≡,ε=1657±15 mole−1 liter cm−1 at 2076 cm−1.At 29°C, the constants for the dissociation of Cu(CN)4≡ into Cu(CN)3=+CN— are: K4, 3c = 0.0076±0.0005 mole liter—1 [in terms of concentrations at 0.1—0.2f Cu(I)] and K4, 3a = 0.026 mole liter—1 (in terms of activities). Analogous values for the dissociation of Cu(CN)3= into Cu(CN)2—+CN— are K3, 2c = (2.44±0.36)×10—5 mole liter—1, and K3, 2a = 4.2×10—5. The above values are calculated from approximately 100 determinations. At 25°C, the corresponding values of these constants are approximately K4, 3c = 0.0057 and K3, 2c = 1.5×10—5. Using the activity constants determined in this paper and a value of 1×10—24 for the constant: [Cu+][CN—]2/[Cu(CN)2—] we derive the following values: [Cu+][CN—]3/[Cu(CN)3=] = 2.6×10—29 and [Cu+][CN—]4/[Cu(CN)4≡] = 5×10—31. The free energies of formation of the complex ions are thus: Cu(CN)2—, ΔFf0 = 58.5 kcal/mole; Cu(CN)3=, ΔFf0 = 91.8 kcal/mole; and Cu(CN)4≡, ΔFf0 = 129 kcal/mole.

Double Stranded Helical Organo-lead 3D-Supramolecular Coordination Polymer Containing Copper Cyanide and Phenanthroline Ligand as Antimicrobial Agent

“…On the other hand, the very informative parameter of the cyanide complexes is the cyanide stretching frequency. The t CN band of 1 locates at 2138 cm -1 which is higher than that of K 3-[Cu(CN) 4 ] (t CN = 2076 cm -1 ) [45] and lower than those of CuCN (2172 cm -1 ) [46] and [(nBu 4 N)Cu(CN) 2 ] (2190 cm -1 ) [47] which exhibits nonlinearly bridging cyanide groups, a result of the fact that the (NC-Cu-CN) fragment in the structure of 1is nonlinear. The case which is supported by X-ray results indicating bent CuCN groups (C3-Cu2-C9 = 127.07 o ).…”

Structure and Catalytic Activity of New Metal‐Organic Frameworks Based on Copper Cyanide and Quinoline Bases

“…The ν(CϵN) bands of 1 and 2 are located at 2121 and 2111 cm -1 , respectively, which are lower than the band of the extended linear -CuCN-CuCN-chains (2170 cm -1 ), [34,35] as a result of the fact that the binding of the donor quinolone ligands to the copper atoms weakens the CuCN bonds, thus lowering ν(CN). Also, for the same reason a downward frequency shift is observed for the ν(CuC/N) mode than that observed for CuCN or even for CuCN:NEt 3 (ν(CuC) = 531 cm -1 ).…”

Bimetallic multidimensional supramolecular coordination polymers containing triphenyltin cation and CuCN

“…Consulting the IR spectrum of II, Table 5, and that of I (vide supra) indicates that they contain the Ph 3 Sn and CuCN fragments. In consequence of bridging the tetrahedral Cu(CN) 4 building blocks by the Ph 3 Sn units via an essential covalent CueC^N/Sn bond, one can realize the presence of n C^N band (2111 cm À1 ) at higher wavenumbers than the band of the genuine salt of the corresponding [Cu (CN) 4 ] 3À anion (2076 cm À1 ) [18], which contains non-bridged cyanide groups. In addition, the stretching frequencies much higher than those of the genuine salts; K 3 4 ], have been assigned to linear bridging between metal centers, while frequencies near those of the salts are associated with terminal or non-linear bridging CN groups [8,19,20].…”