Reactions of aquapentachloroplatinic acid, (H3O)[PtCl5(H2O)]·2(18C6)·6H2O (1) (18C6 = 18‐crown‐6), and H2[PtCl6]·6H2O (2) with heterocyclic N, N donors (2, 2′‐bipyridine, bpy; 4, 4′‐di‐tert‐butyl‐2, 2′‐bipyridine, tBu2bpy; 1, 10‐phenanthroline, phen; 4, 7‐diphenyl‐1, 10‐phenanthroline, Ph2phen; 2, 2′‐bipyrimidine, bpym) afforded with ligand substitution platinum(IV) complexes [PtCl4(N∩N)] (N∩N = bpy, 3a; tBu2bpy, 3b; Ph2phen, 5; bpym, 7) and/or with protonation of N, N donor yielding (R2phenH)2[PtCl6] (R = H, 4a; Ph, 4b) and (bpymH)+ (8). With UV irradiation Ph2phen and bpym reacted with reduction yielding platinum(II) complexes [PtCl2(N∩N)] (N∩N = Ph2phen, 6; bpym, 9). Identities of all complexes were established by microanalysis as well as by NMR (1H, 13C, 195Pt) and IR spectroscopic investigations. Molecular structures of [PtCl4(bpym)]·MeOH (7) and [PtCl2(Ph2phen)] (6) were determined by X‐ray diffraction analyses. Differences in reactivity of bpy/bpym and phen ligands are discussed in terms of calculated structures of complexes [PtCl5(N∩N)]— with monodentately bound N, N ligands (N∩N = bpy, 10a; phen, 10b; bpym, 10c).
