127540-83-4Relevant academic research and scientific papers
Mechanistic aspects of the cyclometalation of quinoline-8-carboxaldehyde with platinum(II)
Anklin, Clemens G.,Pregosin, Paul S.,Wombacher, Franz J.,Rüegg, Hubert J.
, p. 1953 - 1958 (2008/10/08)
Rates of reaction at 61°C in CDCl3 for the cyclometalation of quinoline-8-carboxaldehyde (1) with trans-PtCl2(1)L (L = PEt3, PBun3, PPh3, PTol3, AsEt3, AsPri3, AsTol3) are reported. Starting from trans-PtCl2(1)(PEt3), there is a kinetic isotope effect kH/kD = 1.4. Modification of the Pt(II) complex to trans-PtBr2(1)L enhances the rate by a factor of ca. 70. The use of sym-trans-[Pt(μ-Cl)(SnCl3)(PTol3)]2 and 2 equiv of 1 affords facile cyclometalation at room temperature within the mixing time. The direct generation of cationic complexes via cis-PtCl2L2 plus Ag(CF3SO3) followed by addition of 1 is also shown to lead to facile cyclometalation. All of these reactions are discussed in terms of the importance of cationic metal compounds. Synthetically, the most efficient cyclometalation of 1 can be accomplished by using [Pt(μ-Cl)(η3-CH2C(CH3)CH 2)]2. 1H and 31P NMR data are given for selected examples.
