Quantum Chemical Studies of <i>cis</i> -[M(NH ₃ ) ₂ Cl ₂ ] (M = Co ^I , Rh ^I , Ir ^I , Ni ^II , Pd ^II , Pt ^II , Cu ^III , Ag ^III , an

To gain molecular-level insights into cisplatin and its metal analogs, we performed a comprehensive investigation of the geometric and electronic structures of cis-[M(NH3)2Cl2] (M = CoI, RhI, IrI, NiII, PdII, PtII, CuIII, AgIII, and AuIII), along with their bonding characteristics and hydrolysis behaviors. All complexes adopt a planar, four-coordinate geometry, with the dx2‐y2 orbital predominantly involved in ligand interactions. EDA-NOCV analyses indicate that the total interaction energy increasing from Group 9 to 11 with σ-interactions dominates the metal–ligand bonding. cis-[M(NH3)2Cl2] with M = CoI, RhI, and IrI were found to be unstable, exhibiting a tendency to form five-coordinated species. In contrast, cis-[M(NH3)2Cl2] complexes (M = NiII, PdII, PtII, CuIII, AgIII, and AuIII) undergo ligand exchange reactions via penta-coordinate trigonal-bipyramidal-like transition states. Their monoaquated derivatives all demonstrated high reactivity toward guanine. Considering their hydrolysis behaviors, cis-[AuIII(NH3)2Cl2]+ emerges as a potential candidate for antitumor applications.