The behavior of palladium diacetate cyclic trimer [Pd(OAc)(2)](3) (1) upon its dissolution in methanol and wet chloroform was studied by H-1 and C-13 NMR including 2D-HSQC and 2D-DOSY techniques. Upon dissolution, trimer 1 reacts with methanol and is completely transformed first into the methoxo complex Pd-3(mu-OMe)(OAc)(5) (2), which already at -18 degrees C undergoes a slow exchange of second bridging acetate ligand between the same palladium atoms to form the symmetric dimethoxo complex Pd-3(mu-OMe)(2)(OAc)(4), the maximum relative concentration of which reaches 20-30 mol % of initial loading trimer 1. Along with the dimethoxo complex, both soluble and insoluble polynuclear palladium clusters are gradually formed at -18 degrees C, and their total amount reaches up to 60% of the starting Pd2+ loading. The increase of temperature to 27 degrees C results in the reduction of palladium(II) to Pd metal by methanol, which is oxidized and transformed into formaldehyde hemiacetal and methyl formate. Upon dissolution in wet chloroform, trimer 1 is reversibly hydrolyzed to the hydroxo complex Pd-3 (mu-OH)(OAc)(5) (10) in ratio 1/10 approximate to 3/1. The temperature decrease and addition of acetic acid shift the equilibrium in this system toward trimer 1, and addition of water shifts it in the opposite direction. Addition of methanol to the equilibrium mixture of 1 and 10 results in the fast exchange of bridging acetate in trimer 1 by the mu-OMe group. Substitution of the mu-OH ligand by mu-OMe in 10 occurs in parallel but more slowly. Complex 2 formed in both cases is more stable in chloroform than in methanol.