206193-69-3Relevant academic research and scientific papers
Self-association of new mixed-ligand diimine-N-acyl-N′,N′-dialkyl thioureate complexes of platinum(II) in acetonitrile solution
Koch, Klaus R.,Sacht, Cheryl,Lawrence, Claire
, p. 689 - 695 (2007/10/03)
The complexes [Pt(bipy)L]PF6 and [Pt(phen)L]PF6 (HL = N-acyl-N′,N′-di-n-butylthiourea) showed pronounced self-association in CD3CN solution at 25 °C according to an equilibrium 2[Pt(diimine)-(L-S,O)]+ ? [{Pt(diimine)(L-S,O)}2]2+ for which association constants, KD, have been estimated from the concentration dependence of the 1H NMR shifts of these complexes. The values of KD range from 1.8 to 114 M-1 depending on the structure of the diimine as well as the nature of the N-acyl group; the values of the 1,10-phenanthroline complexes are generally larger than those for the corresponding 2,2′-bipyridine analogues. In general, N-1-naphthoyl-N′,N′-dibutylthiourea complexes self-associate to a lesser extent than the corresponding N-benzoyl analogues. From the temperature dependence of the KD values, the thermodynamic parameters ΔG, ΔH and ΔS have been estimated. An average Δ(ΔG) increment of 2.4 ± 0.4 kJ mol-1 per aromatic ring of the diimine moiety co-ordinated to the complexes is consistent with energies generally associated with π-π stacking and cation π interactions observed for other systems.
