186646-58-2Relevant academic research and scientific papers
Reversible C60 Binding to Dendrimer-Containing Ir(CO)Cl(PPh2R)2 Complexes
Catalano, Vincent J.,Parodi, Nicholas
, p. 537 - 541 (2008/10/09)
The phosphine compounds PPh2(G-1) and PPh2(G-2), where G-1 is 3,5-bis(benzyloxy)benzyl and G-2 is 3,5-bis((3,5-bis(benzyloxy)oxy)benzyl, were synthesized. The complexes, trans-Ir(CO)Cl(PPh2(G-1))2,1, and trans-Ir(CO)Cl(PPh2(G-2))2, 2, show reversible binding with C60. Thermodynamic data on the reversible binding were obtained in chlorobenzene by line width analysis of the 31P{1H} NMR spectra. The activation parameters ΔG265? (kcal mol-1), ΔH? (kcal mol-1), and ΔS? (cal mol-1 K-1) were calculated as 1.3, 18, and 20 for 1·C60 and 1.3, 24, and 42 for 2·C60. The thermodynamic quantities ΔG265° (kcal mol-1), ΔH° (kcal mol-1), and ΔS° (cal mol-1 K-1) were determined to be -2.8, -25, and -105 for 1·C60 and -3.0, -18, and -57 for 2·C60. The rates of reaction with O2 for 1 and 2 were measured and are comparable to that for trans-Ir(CO)Cl(PPh3)2 under similar conditions. The compound PdI2(PPh2(G-1))2, 3, does not show reversible binding with C60. Crystal structures were obtained for 1 (a = 10.218(1) A, b = 12.731(3) A, c = 13.116(2) A, a = 112.05(1)°, β = 108.30(1)°, γ = 102.22(1)°, V= 1392.2(4) A3) and 3 (a = 10.243(2) A, b = 12.689(2) A, c = 13.146(2) A, α = 112.33(1)°, β = 108.96(1)°, γ = 101.23(1)°, V= 1392.4(4) A3).
