Keywords: Carbon monoxide / Carbonyl ligands / Polymer conjugates / Manganese / EPR effect / Cytotoxicity CO-releasing molecules (CORMs) were coordinated to polymeric carrier systems for passive transport to tumour tissue or sites of inflammation, as described by the enhanced permeability and retention (EPR) effect. The developed conjugates consist of an organometallic fac-Mn(CO) 3 fragment, which is bound to a methacrylate or methacrylamide polymer backbone by bis(pyridylmethyl)amine-type ligands. The resulting Mn(CO) 3 -polymer conjugates were investigated as photoinducible CO-releasing molecules (photoCORMs). Furthermore, three model complexes [LMn(CO) 3 ]O 2 SCF 3

The synthesis of a new mixed amino−amido N-heterocyclic carbene (type A) starting from anthranilic acid is presented. A new straightforward synthetic approach to related diaminocarbenes of type B is also described. Both NHCs react with group 6 elements to form heteroureas and coordinate to L 2 ClM fragments (M = Rh, Ir; L 2 = COD, (CO) 2 ). IR spectroscopic analysis of the carbonyl complexes reveals that the diamino-NHC is a better donor ligand (TEP: 2054 cm −1 ) compared to the amino− amido NHC (TEP: 2060 cm −1 ). In line with this behavior, a carbene dimerization to give the corresponding olefin is observed only for derivatives of type A. X-ray structure determinations are reported for two Rh complexes of ligand A and its cationic precursor.

Derivatives of cationic six-membered N-heterocyclic carbene G with a quinazolinium scaffold are easily obtained by abstraction of an alcoholate group from related neutral precursors which are easily accessible. On the basis of this route, chalcogene adducts and metal complexes of G, which is a benzo-anellated pyrimidiniumylidene, could be prepared. Evaluation of the ligand properties by IR and 77 Se NMR spectroscopy indicate that cationic carbene G is a much more powerful π-acceptor (δ( 77 Se): 768 ppm) and a significantly weaker overall donor (TEP: 2073 cm −1 ) than related neutral carbene 4 (361 ppm, 2054 cm −1 ). DFT calculations provide a rationale for these experimental observations. AuCl complexes of both carbenes were used as catalysts for the cyclization of a propargylamide to a methyleneoxazoline. The complex containing the cationic carbene featured a much higher activity.