Dual Brønsted/Lewis acid catalysis involving environmentally benign, readily accessible protic acid and iron promotes site-selective tert-alkylation of arenes using di-tert-butylperoxide and tertiary alcohols.
The syntheses, characterisation and biological activities (IC 50 ; DNA binding) of four mononuclear Pt oxazoline complexes are reported. These materials are the compounds cis-[PtCl) and all four are shown to have slightly lower cytotoxicities in vitro when compared to cisplatin against the A2780 ovarian cancer cell line. These new materials all appear to be bio-active via the formation of DNA adducts. Complexes 1 and 2 have been further characterised in the solid-state by X-ray diffraction methods.
A synthetic and structural (X-ray) investigation into the bonding modes of benzoxazole (box) and 2-methylbenzoxazole (Mebox) ligands with halide precursors of Zn and Pd has been undertaken to clarify earlier discrepancies concerning the nature of the bonding mode(s) of the two azoles. In four structurally characterised examples, all contain the title ligands in a κ(1)N bonding motif. Calculations at the density functional level (DFT) of theory (B3LYP) confirm the ground state stability of this class of coordination for several hypothetical Pd and Zn (gas phase) compounds. The attempt to obtain suitable crystalline material of PdCl(2)(box)(2) (i.e., 5) leads to substantial complex degradation. One minor product of this process has been identified (X-ray) as the diarylformamidinato complex C(26)H(22)N(4)O(4)Pd, presumably formed via a complex combination of the decomposition products of both free box and 5.
The synthesis and characterisation of a small library of Co and Cu derivatives (29 examples) incorporating the (Z)-1-R 1 -2-(4',4'-R 2 -2'-oxazolin-2'-yl)-eth-1-en-1-ate (L: R 1 = alkyl or aryl; R 2 = H or Me) skeleton is described. This work includes six new derivatives of "Tohda's Ligands". In the case where R 2 = H, solid-state stable Co(II) materials of formula Co(κ 2 -N,O-L)2 could, in some cases, be obtained following base-induced deprotonation of L+H and treatment with hydrated CoX2 salts. These complexes display redox induced solution decomposition behaviour giving Co(κ 2 -N,O-L)3 as one isolable product. Stable Cu(II) complexes could only be obtained in the case of for R 1 = Ph and R 2 = H. In the case of R 2 = Me, distorted tetrahedral Co(II) compounds (also Co(κ 2 -N,O-L)2) are obtained as above (twelve examples). Square planar derivatives of Cu(II), of similar stoichiometry, are likewise isolated (eleven new examples). In contrast to the R 2 = H reactions, all of these latter materials were found to be air-stable in solution or the solid phase. In total, 18 complexes have been characterised by single crystal X-ray diffraction. Molecular modelling (PM6(tm) and DFT) are also used to elucidate the molecular properties of selected complexes. Only a single Co complex (R 1 = t-butyl and R 2 = Me) of the library displays reversible one-electron redox properties.
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