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Organometallic ruthenium complex of quinolone antibacterial agent ofloxacin [(η6-p-cymene)RuCl(O,O-oflo)]·2.8H2O (1·2.8H2O) was isolated and its crystal structure was determined. In this »piano-stool« complex, quinolone is bidentately coordinated to the metal through the ring carbonyl and one of the carboxylic oxygen atoms. Interactions of the title complex with DNA were studied by spectroscopic methods (electronic, fluorescence, CD) and atomic force microscopy (AFM). It was established that the electrostatic attraction between the ruthenium complex and DNA in a solution is important for the binding since interactions were observed only in a solution with low ionic strengths. An induced CD (ICD) signal was observed in the solution of DNA and title complex which proves the interaction between ruthenium and macromolecule. Competitive binding between cisplatin and 1 to DNA revealed that cisplatin prevents binding of 1. Our experiments revealed that binding of the title complex to DNA occurs also if guanine N7 is protonated. AFM has shown that title complex provokes DNA shrinkage. Preliminary biological tests have also been performed.

The organoaluminum-mediated alkylation of tailor-made rare-earth metal carboxylate complexes was studied, and implications of the degree of Ln alkylation and organoaluminum-chloride-mediated cation formation for 1,3-diene polymerization were investigated. Highly substituted rare-earth metal benzoate complexes {Ln(O 2 CC 6 H 2 Me 3 -2,4,6) 3 } n (Ln ) Y, La, Nd), {Ln(O 2 CC 6 H 2 iPr 3 -2,4,6) 3 } n (Ln ) Y, La, Nd, Gd, Lu), {Ln(O 2 CC 6 H 2 tBu 3 -2,4,6) 3 (THF)} n (Ln ) Y, La), {Ln(O 2 CC 6 H 3 Ph 2 -2,6) 3 (THF)} n (Ln ) Y, La), and {Ln(O 2 CC 6 H 3 Mes 2 -2,6) 3 (THF)} n (Ln ) Y, La) were obtained quantitatively according to the silylamide route from Ln[N(SiMe 3 ) 2 ] 3 and alkyl(aryl)-substituted benzoic acids. Such oligomeric carboxylate complexes are insoluble in aliphatic and aromatic solvents, but could be crystallized from donor solvents such as THF, DMSO, and pyridine. X-ray crystallographic analyses indicated the formation of monomeric [Nd(O 2 CC 6 H 2 Me 3 -2,4,6) 3 (DMSO) 3 ] and dimeric [La(O 2 CC 6 H 2 Me 3 -2,4,6) 2 (µ-O 2 CC 6 H 2 Me 3 -2,4,6)-(DMSO) 2 ] 2 depending on the metal ion size. Depending on the steric demand of the benzoate ligands, mono-and bis(tetraalkylaluminate) complexes [Me 2 Al(O 2 CC 6 H 2 iPr 3 -2,4,6) 2 ] 2 Ln[(µ-Me) 2 AlMe 2 ] and {Ln(O 2 CC 6 H 2 tBu 3 -2,4,6)[(µ-Me) 2 AlMe 2 ] 2 } 2 , respectively, could be identified as major product components from the reaction with excess AlR 3 (R ) Me, Et), by means of 1 H NMR spectroscopy and X-ray structure analysis. When activated with Et 2 AlCl, the resulting binary Ziegler-type catalysts efficiently polymerized isoprene (>99% cis-1,4), the polymerization performance depending on the metal center (Nd > Gd > La) and the degree of alkylation ("Ln(AlMe 4 ) 2 " > "Ln(AlMe 4 )"). Equimolar reaction of [Me 2 Al(O 2 -CC 6 H 2 iPr 3 -2,4,6) 2 ] 2 Ln[(µ-Me) 2 AlMe 2 ] with R 2 AlCl (R ) Me, Et) quantitatively produced [Me 2 Al(O 2 -CC 6 H 2 iPr 3 -2,4,6)] 2 , proposing "Me 2 LnCl" as the polymerization-initiating species. Homoleptic Ln(AlMe 4 ) 3 was spotted as a crucial reaction intermediate and was used for the high-yield synthesis of the various alkylated carboxylate complexes according to a novel "tetraalkylaluminate" route.