Thermodynamics of Complex Formation: Part I-Environmental & Non-environmental Effects on Stabilities of Complexes of 2-Phenylacetohydroxamic Acid with Cu(II), Ni(II) , Co(II), Mn(II) Zu(II) & Cd (II)

246-24

Rh-Catalyzed, Regioselective, C-H Bond Functionalization: Access to Quinoline-Branched Amines and Dimers

Rh-catalyzed, chelation-induced, C-5 regioselective C-H functionalization of 8-amidoquinolines with a range of N-Boc aminals is reported for the first time. The addition of in situ generated imines to C(sp)-H bonds afforded branched amines in good to excellent yields. Moreover, this transformation features good functional group compatibility, broad substrate scope, and mild reaction conditions and is suitable for gram-scale synthesis. In addition, an unprecedented, chelation-induced, site-selective, remote dimerization of quinolines led to the formation of dimer frameworks in moderate yields under Rh-catalyzed conditions

Is there a direct chloride cofactor requirement in the oxygen-evolving reactions of photosystem II?

The dark incubation at room temperature of photosystem II (PS II) membrane fragments in a chloride-free medium at pH 6.3 slowly leads to large chloride-restorable and non-restorable O evolution activity losses with time as compared with control samples incubated in the presence of 10 mM NaCl. The chloride requirement in O evolution generated under these conditions reveals a complex interplay among various experimental parameters, including the source of the plant material, the times of incubation, the sample concentration, the chloride concentration, as well as those treatments which are believed to specifically displace chloride from PS II such as alkaline pH pretreatment and NaSO addition. The results indicate that secondary, structural changes within the PS II complex are an important factor in determining the influence of chloride on the O evolution activity and raise the question whether or not chloride ions actually play a direct cofactor role in the water-oxidizing reactions leading to O evolution