Synthesis, structure and characterization of adenine-based aminocarbene complexes of platinum(II)

• Adenines were found to attack the hydroxycarbene C atom of platina-β-diketones.
• Adenine-based aminocarbene complexes of platinum are prepared and characterized.
• A substantial pπ–pπ bonding character in the aminocarbene–platinum units was found.
• DFT calculations give insight into the course of aminocarbene Pt complex formation.

The reaction of the dinuclear platina-β-diketone [Pt2{(COMe)2H}2(μ-Cl)2] (1) with two equivalents of adenine and its methylated derivatives N6-R,9-R′Ade–H resulted in adenine-based aminocarbene platinum(II) complexes [Pt(COMe)Cl{CMe(N6-R,9-R′Ade–H)-κC,κN}] (R/R′ = Me/Me, 2; H/Me, 3; H/H, 4) whose identities were confirmed by NMR and IR spectroscopies as well as by high-resolution mass spectrometric investigations. Single-crystal X-ray diffraction analyses of complexes 2 and 4·THF revealed relatively short Pt–C and N–C bonds in the aminocarbene–platinum units, which is in accord with a substantial double bond character of these bonds. The electronic structure of these complexes will be further confirmed by DFT calculations as also the course of reaction.

Reactions of the dinuclear platina-β-diketone 1 with adenine and its methylated derivatives resulted in formation of adenine-based aminocarbene platinum(II) complexes 2–4 (R, R′ = H, Me). These reactions belong to the few ones where a nucleophile (here the N6 atoms of adenines) attacks the hydroxycarbene C atom of platina-β-diketones.Figure optionsDownload as PowerPoint slide