Reactivity of Quinoline-8-carbaldehyde toward Platina-β-diketone and Acetyl(amine)platinum(II) Complexes. Formation of Acyl(hydroxyalkyl)platinum(IV)

Abstract

The reaction of the platina-β-diketone [Pt2{(COMe)2H}2(μ-Cl)2] (1) with quinoline-8-carbaldehyde (C9H6NCHO) in MeOH/H2O (Pt/C9H6NCHO = 1/2) leads to the cleavage of the chloride bridges in 1 with acetaldehyde displacement and to the formation of the acetylacyl(hydroxyalkyl)platinum(IV) complex [Pt(COMe)Cl(C9H6NCO-κN,κC)(C9H6NCHOH-κN,κC)] (3) as a single diastereomer (OC-6-46). Water-assisted activation of the OC–H bond of one aldehyde and H transfer to the oxygen atom of the second aldehyde occurs. In the presence of sodium methoxide, dehydrochlorination of the platinum starting material affords the dinuclear [Pt2(C9H6NCO-κN,κC)2(μ-COMe)2] (4) with acetyl bridges in a head-to-tail fashion. Pyridine or tetrahydrofuran fail to cleave the acetyl bridges, which are readily cleaved by triphenylphosphane to afford the mononuclear [Pt(C9H6NCO-κN,κC)(COMe)(PPh3)] (5) with the two acyl groups in cis positions. The reaction of the diacetylbis(amine)platinum(II) complexes [Pt(COMe)2(NH2R)2] (R = CH2Ph (2a), Et (2b)) with quinoline-8-carbaldehyde produced the Schiff base products [Pt(COMe)2(C9H6NCHNR-κN,κN′)] (R = CH2Ph (6a), Et (6b)). The complexes have been fully characterized, and X-ray diffraction structures of 3 and 4 are reported.

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…1170, Scheme 97) with 8-formylquinoline(1171) led to the ligand exchange/carbonyl addition/C-H activation product 1172 upon reaction with methanol[1141]. Reaction with sodium methoxide however led to the C-H oxidative addition product 1173, which could also form via the reaction of complex 1172 with sodium methoxide.…”