[en] Arene ruthenium(II) schiff-base complexes of formulations [(η⁶-p-cymene)Ru(O₂CCH=CR¹R²)(O-2-C₆H₄CH=NC₆H₄-p-Me)](1a-c) and [(η⁶-p-cymene)Ru(O₂CCH=CR¹R²)(C₅H₄N-2-CH=NC₆H₄-p-Me)](ClO₄) (2a,b) (R¹=H, R²=Ph (a), R¹=R²=Me (b), R¹=H, R²=Me (c) have been prepared by reacting the chloro adducts with the silver salts of the α,β-unsaturated carboxylic acids in methanol or tetrahydrofuran and characterised by analytical and spectroscopic methods. The molecular structure of [(η⁶-p-cymene)Ru(O₂CCH=CMe₂)(O-2-C₆H₄CH=NC₆H₄-p-Me).H₂O (lb.H₂O) has been determined by x-ray crystallography. The crystal belongs to the monoclinic space group P2₁/n with the following cell dimensions for the C₂₉H₃₅NO₄Ru (M = 562.65): a 8.509 (5) A, b = 21.123 (4) A, c = 14.824 (4) A, β = 93.88 (3)^o. V = 2658(2) A³, Z = 4. D c = 1.406 g cm^-3, μ(Mo-Kα) = 6.24 cm^-l, λ(Mo-Kα) = 0.7107A, T = 293 K, R₁ = 0.0478 (wR₂ = 0.1111) for 3056 reflections with I > 2σ (I) and 316 parameters. The complexes 1 and 2 have ruthenium(II) centre bonded to an η⁶-p-cymene group, a unidentate carboxylate and a bidentate chelating schiff-base ligand. The carboxylate ligand is involved in hydrogen-bonding interaction with the lattice water molecule. (author)