Complexes Containing a Phenol–Platinum(II) Hydrogen Bond: Synthons for Supramolecular Self‐Assembly and Precursors for Hydridoplatinum(IV) Complexes

The cycloneophylplatinum(II) complexes [Pt(CH2CMe2C6H4)(κ2‐NN′‐2‐C5H4NCH2‐NH‐R], R = 2‐C6H4OH, 1; R = 3‐C6H4OH, 2; R = 4‐C6H4OH, 3, and [Pt(CH2CMe2C6H4)(κ2‐NN′‐2‐C5H4NCH=N‐2‐C6H4OH)], 4, are reported. The structures of 1 and 4 each contain an intramolecular OH··Pt hydrogen bond, while complex 3 contains an intermolecular OH··Pt hydrogen bond and forms a new type of supramolecular polymer. In contrast, the complex [PtCl2(κ2‐NN′‐2‐C5H4NCH=N‐2‐C6H4OH)], 5, forms a dimer through intermolecular OH··ClPt hydrogen bonding. Reaction of complex 4 with HCl or HBr occurs by oxidative addition to give hydridoplatinum(IV) complexes [PtHX(CH2CMe2C6H4)(κ2‐NN′‐2‐C5H4NCH=N‐2‐C6H4OH)], 6, X = Cl; 7, X = Br. The sequential formation of isomers of these compounds is interpreted in terms of a proposed reaction mechanism. Electron‐rich organoplatinum complexes can form intramolecular or intermolecular OH··Pt hydrogen bonds, but formation of hydroplatinum(IV) complexes requires a strong acid such as HCl.