Novel carbonyl complexes of ruthenium with α-substituted oxime derivatives of terpenes

The reactions of Ru 3 (CO) 12 with 1R,4S,6S -4-dimethylamino-4,7,7-trimethylbicyclo[4.1.0]heptane-3-one oxime (dimethylaminocaraneoxime) ( I ), 1R,4S,6S -4-methylamino-4,7,7-trimethylbicyclo[4.1.0]heptane-3-one oxime (methylaminocarane oxime) ( II ), and 1R,2R,5R -2-benzylthio-2,6,6-trimethylbicyclo[3.1.1]heptane-3-one oxime (benzylthiopinaneoxime) ( III ) were studied. The binuclear complex Ru 2 (CO) 4 {μ-η 3 (O,N,X)-L} 2 was formed as the main product in every reaction, when Ru 3 (CO) 12 was heated with terpenoid to 80°C. In the above complex, two terpene ligands are coordinated in the form of ‘head-to tail’ bridge by the oxime groups at a binuclear metal fragment Ru-Ru. The heteroatom of the second functional group of every bridging ligand (nitrogen of amino group in I and II, sulfur of the thio group in III) is additionally coordinated to the ruthenium atom to give the chelate five-membered ring. Also the reactions of terpenoids I, II, III with Ru 3 (CO) 12 were performed at room temperature using Me 3 NO. In this case, as in the thermal reactions, the main product was the binuclear complex. However, in the reactions of Ru 3 (CO) 12 with I and II , the trinuclear clusters were isolated that readily transformed to binuclear complexes in a solution. The complexes synthesized can exist as two diasteromers due to their chiral metal core. However, in all the cases, only one diastereomer was isolated, which indicates stereospecific nature of the above reactions. The compounds obtained were characterized by IR, 1 H-, 13 C{ 1 H}-, COSY, and HXCOBI-NMR spectroscopy, the specific optical rotation angles were measured. For the binuclear complexes with ligands I, III and for trinuclear cluster with ligand II , single crystals were obtained and studied by X-ray diffraction.