Palladium(II) complexes of quinolinylaminophosphonates: synthesis, structural characterization, antitumor and antimicrobial activity

Three types of palladium(II) halide complexes of quinolinylaminophosphonates have been synthesized and studied. Diethyl and dibutyl [alpha-anilino-(quinolin-2-ylmethyl)]phosphonates (L1, 12) act as N,N-chelate ligands through the quinoline and aniline nitrogens giving complexes cis-[Pd(L1/12)X-2] (X Cl, Br) (1-4). Their 3-substituted analogues [alpha-anilino-(quinolin-3-ylmethyl)]phosphonates (L3, L4) form dihalidopalladium complexes trans-[Pd(L3/L4)(2)X-2] (5-8), with trans N-bonded ligand molecules only through the quinoline nitrogen. Dialkyl [alpha-(quinolin-3-ylamino)-N-benzyl]phosphonates (L5, L6) give tetrahalidodipalladium complexes [Pd-2(L5/L6)(3)X-4] (9-12), containing one bridging and two terminal ligand molecules. The bridging molecule is bonded to the both palladium atoms, one through the quinoline and the other through the aminoquinoline nitrogen, whereas terminal ligand molecules are coordinated each only to one palladium via the quinoline nitrogen. Each palladium ion is also bonded to two halide ions in a trans square-planar fashion. The new complexes were identified and characterized by elemental analyses and by IR, UV-visible, H-1, C-13 and P-31 nuclear magnetic resonance and ESI-mass spectroscopic studies. The crystal structures of complexes 1-4 and 6 were determined by X-ray structure analysis. The antitumor activity of complexes in vitro was investigated on several human tumor cell lines and the highest activity with cell growth inhibitory effects in the low micromolar range was observed for dipalladium complexes 11 and 12 derived from dibutyl ester L6. The antimicrobial properties in vitro of ligands and their complexes were studied using a wide spectrum of bacterial and fungal strains. No specific activity was noted. Only ligands L3 and L4 and tetrahalidodipalladium complexes 9 and 11 show poor activities against some Gram positive bacteria

The crystal and molecular structure of copper(I) trifluoromethanesulphonate cyclohexene complex

The first crystal structure of a copper(I) trifluoromethanesulphonate (cyclo)olefin complex, viz. copper(I) triflate-cyclohexene, CuOSO2CF3 · C6H10, is presented. The compound crystallises in the space group P with a 10.288(1), b 10.412(1), c 11.059(1) Å, α 65.81(1), β 81.25(1), γ 70.45(1)° and Z = 4. The structure has been solved by Patterson and Fourier methods and refined to a final R = 0.062. The compound consists of tetrameric units which are interconnected by Cu---O---Cu bridges to give an infinite chain. The tetramer has Si symmetry. Both Cu ions are four-coordinated with a geometry that is intermediate between trigonal pyramidal and tetrahedral. The copper ions in the tetramer are joined together by oxygen—sulphur—oxygen bridges of the triflate anion

Substrate‐Selective Catalysis

Substrate selectivity is an important output function for the validation of different enzyme models, catalytic cavity compounds, and reaction mechanisms as demonstrated in this review. In contrast to stereo-, regio-, and chemoselective catalysis, the field of substrate-selective catalysis is under-researched and has to date generated only a few, but important, industrial applications. This review points out the broad spectrum of different reaction types that have been investigated in substrate-selective catalysis. The present review is the first one covering substrate-selective catalysis and deals with reactions in which the substrates involved have the same reacting functionality and the catalysts is used in catalytic or in stoichiometric amounts. The review covers real substrate-selective catalysis, thus only including cases in which substrate-selective catalysis has been observed in competition between substrates