Polyketones are synthesised by a transition‐metal‐catalysed copolymerisation of olefins and carbon monoxide. Nickel complexes with N,O‐chelating ligands turned out to be promising catalysts in that field. In this work a series of new N,O ligands with an electronically delocalised β‐enaminone backbone were synthesised and fully characterised. The ligand design was inspired by the ligand found in the most efficient nickel catalyst for polyketone synthesis and developed to a highly modular LEGO®‐like arsenal of reactions to versatile substituted β‐enaminone ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Seven novel imidazole and thiazole derivatives of diphos-type ligands are presented. They are of the general structure R2P(CH2)(2)PR2, where R is imidazol-2-yl (1), 1-methylimidazol-2-yl (2), 1-methyl-benzimidazol-2-yl (3), 1-methylimidazol-5-yl (4), 2-isopropylimidazol-4(5)-yl (5), thiazol-2-yl (6), benzothiazol-2-yl (7), thiazol-4-yl (8) or thiazol-5-yl (9). Syntheses involved direct metallation or halogenmetal exchange reactions. Their solubility, especially in aqueous solution, is strongly dependent on the nature of the substituents as is their partition coefficient log D. The crystal structures of compounds 2, 3, 7a and 9 as well as the structure of the rhodium complex (2)(2) , Corinna Wetzel [a] , Melanie Bongartz [a] , Anna-Louisa Noffke [a] and Bernhard Spingler

The tetranuclear ruthenium arene compound [(cym)4Ru4(2)Cl6]Cl2 (3) (cym = 6-p-cymene, 2 = 1,2-bis(di-N-methylimidazol-2-ylphosphino)ethane) was prepared and characterised by one-and twodimensional NMR techniques. Its cytotoxicity against four different cell lines was determined and, with an approximate IC50 of >100 M 3 can be regarded as non-toxic. Its partition coefficient in n-octanol/water (log D7.4) was also determined. The structures of complex 3 as well as of the related compound [(cym)2Ru2(4)Cl2]Cl2 (5) (4 = 1,2-bis(di-N-methylimidazol-2-ylphosphino)ethane dioxide) were determined by single crystal structure analysis. Upon oxidation in protic solvents, ligand 2 shows P-C bond cleavage reactions to yield P,P-bis(N-methylimidazol-2-yl)ethylene diphosphinic acid (6). [ ‡] X-ray structure analysis. KeywordsImidazolylphosphanes, Phosphane Ligands, PN Ligands, Ruthenium AbstractThe tetranuclear ruthenium arene compound [(cym) 4 Ru 4 (2)Cl 6 ]Cl 2 (3) (cym = η