Cu(II) bis(oxamato) end-grafted poly(amidoamine) dendrimers.

Successive treatment of the diethyl ester of 3,4-bis(oxamate)phenylene benzoic acid (3,4-bopbH2Et2OH; ) with [Bu4N]OH and MCl2·nH2O (M = Cu, Ni; n = 2, 6) gave, upon extraction into CH2Cl2, binuclear complexes [Bu4N]4[{M(3,4-bopbO)}2CH2] (, M = Cu, Ni) as novel symmetric methylene diesters. In contrast, subsequent addition of [Bu4N]OH and anhydrous NiCl2 to afforded the very hygroscopic [Bu4N]3[Ni(3,4-bopbO)] () instead. In order to verify reaction conditions to achieve the corresponding carboxamides to - as a crucial step for the synthesis of higher generation dendrimers - was shown to react with RNH2 (R = Me (), Pr ()) to [RNH3][tdqc] (R = Me (), Pr (); tdqc = 1,2,3,4-tetrahydro-2,3-dioxo-6-quinoxaline carboxylate) by rearrangement reactions. Alternatively, if was converted first to 3,4-bopbH2EtF () and treated next with PrNH2, the corresponding carboxamide 3,4-bopbH2Et2NPrH () could be obtained in high yields. The reaction of with [Bu4N]OH and MCl2·nH2O (M = Cu, Ni; n = 2, 6) gave conveniently mononuclear [Bu4N]2[M(3,4-bopbNPrH)] (, M = Cu, Ni). After thus optimizing reaction conditions, for the synthesis of higher-branched bis(oxamato) type complexes the (polyamido)amines (en(II)H2), (den(III)H3), (den(V)H5) and (den(X)H10), possessing two, three, five or ten terminal amino groups, were reacted with appropriate equiv. of to give the corresponding carboxamides en(II)(3,4-bopbH2Et2)2 (), den(III)(3,4-bopbH2Et2)3 (), den(V)(3,4-bopbH2Et2)5 () and den(X)(3,4-bopbH2Et2)10 (). Compounds were converted to the corresponding Cu(II)-containing complexes , which were treated with the corresponding equiv. of [Cu(pmdta)][BF4]2 to afford . Complexes of the series and possess two, three, five or ten end-grafted mononuclear {Cu(3,4-bopb)}(2-) and trinuclear {Cu3(3,4-bopb)(pmdta)2}(2+) complex fragments, respectively. The identities of were established by NMR spectroscopy and ESI-MS measurements. For and , ESI-MS, UV/Vis and ESR studies were applied to confirm the identities of these species. The magnetic properties of the {Cu3(3,4-bopb)(pmdta)2}(2+) end-grafted poly(amidoamine) dendrimers were studied by susceptibility measurements vs. temperature to give J values between -112 () and -118 cm(-1) (), which are typically observed for discrete trinuclear Cu(II)-containing bis(oxamato) type complexes.

Facile synthesis of Ag@Pd satellites-Fe3O4 core nanocomposites as efficient and reusable hydrogenation catalysts.

Well-dispersed Ag@Pd supported on magnetite nanoparticles have been obtained through a simple colloidal impregnation method. The as-synthesised nanocomposite exhibits greatly enhanced catalytic reactivity and reusability towards 4-nitrophenol hydrogenation.

Phosphite copper(I) trifluoroacetates [((RO)3P)mCuO2CCF3] (m = 1, 2, 3): synthesis, solid state structures and their potential use as CVD precursors.

Metal-organics [((RO)(3)P)(m)CuO(2)CCF(3)] (R = CH(3): 11a, m = 1; 11b, m = 2; 11c, m = 3. R = CH(2)CH(3): 12a, m = 1; 12b, m = 2; 12c, m = 3. R = CH(2)CF(3): 13a, m = 1; 13b, m = 2; 13c, m = 3) are either accessible by the reaction of [((RO)(3)P)(m)CuCl] (R = CH(3): 5a, m = 1; 5b, m = 2; 5c, m = 3. R = CH(2)CH(3): 6a, m = 1; 6b, m = 2; 6c, m = 3) with [KO(2)CCF(3)] (7), or treatment of [Cu(2)O] (8) with HO(2)CCF(3) (9) and P(OR)(3) (2, R = CH(3); 3, R = CH(2)CH(3); 4, R = CH(2)CF(3)). (31)P{(1)H} NMR spectra [((CH(3)O)(3)P)(m)CuO(2)CCF(3)] (m = 1, 1.5, 2, 2.5, 3, 3.5, and 4) have been studied at 25 and -80 °C showing phosphite ligand exchange in solution. The molecular structures of 11a and 13a-13c in the solid state are reported. Complexes 11a and 13a are tetramers featuring µ-η(2)(1κO:2κO')- and µ(3)-η(2)(1κO:2κO':3κO')-(11a) or µ(3)-η(2)(1κO:2κO':3κO')-bonded O(2)CCF(3) ligands (13a) with the Cu(I) ions being part of CuPO(2) and CuPO(3) units (11a), while in 13a solely a CuPO(3) moiety is present. Skeletal isomerism of 11a vs. 13a is discussed. Compound 13b is dimeric ({CuP(2)O(2)}(2)) with pseudo-tetrahedral Cu environments and µ-η(2)(1κO:2κO')O(2)CCF(3) functionalities. In monomeric 13c the O(2)CCF(3) ligand is η(1)(κO)-bonded to a tetra-coordinated Cu(i) ion. The thermal solid state properties of 11, 12 and 13 were studied by Thermo Gravimetry (TG). These complexes decompose by phosphite elimination, decarboxylation and dealkylation. Hot-wall Chemical Vapour Deposition (CVD) experiments were carried out at 380 °C using 11c as precursor for the deposition of copper onto pieces of TiN-coated oxidized silicon substrates. Copper layers of high purity were obtained with grain sizes between 200-1200 nm.