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{{A series of cationic gold(I) alpha-diimine complexes of the type {[}(NHC)Au(alpha-diimine)]X or {[}(PPh(3))Au(alpha-diimine)]X, where NHC = IPr

{The reactions of TCNE- and TCNQ-functionalized (TCNE: tetracyanoethylene and TCNQ: 7,7', 8,8'-tetra-cyanoquinodimethane) zwitterionic benzoquinonemonoimines with a Cu(I)-BIAN complex (BIAN = bis-(o, o'-bisisopropylphenyl)acenaphthenequinonediimine) have been investigated and found to follow a diversity of interesting patterns. The complexes {[}Cu(BIAN)(NCMe)(L2)]BF4 (2) and {[}Cu(BIAN)(L2)(2)]BF4 (4) were obtained by reacting {[}Cu(BIAN)(NCMe) 2] BF4 (1) with one and two equivalents of L2, respectively. Following similar procedures, the complexes {[}Cu(BIAN)(NCMe)(L3)] BF4 (6) and {[}Cu(BIAN)(L3)(2)]BF4 (7) were obtained by reaction of 1 with L3. The reaction of 2 with 0.5 equiv. of 4,4'-bipyridine afforded {[}\{Cu(BIAN)-(L2)\}(2)(mu-4,4'-bipyridine)](BF4)(2) (3). The complexes were characterized by multinuclear NMR, IR and UV-Vis spectroscopic techniques, mass spectrometry, cyclic voltammetry and elemental analysis. The molecular structures of complexes 3 center dot 4CH(2)Cl(2) and 4 center dot CH2Cl2 were determined by single crystal X-ray diffraction. An unexpected coordination polymer {[}Cu(L2(-))(2)](infinity) (5) was also structurally characterized, which contains Cu(II) centres chelated by two N, O-bound ligands resulting from the monodeprotonation of L2.}

{{A series of new cationic and neutral (Ar-BIAN) copper(I) complexes {[}in which Ar-BIAN = bis(aryl)acenaphthenequinonediimine] was synthesised and characterised by elemental analysis, 1D and 2D NMR spectroscopy and single-crystal Xray diffraction. The cationic complexes of the general formula {[}Cu(Ar-BIAN)L-2]BF4 {[}L-2 = (PPh3)(2) (1), dppe (2), dppf (3), (AsPh3)(2) (4); Ar = 4-iPrC(6)H(4) (a), 4-MeOC6H4 (b), 4-NO2C6H4 (c), 2-iPrC(6)H(4) (d), Ph2PCH2CH2PPh2 (dppe), (Ph2PC5H4)(2)Fe (dppf)] were synthesised by reaction of {[}Cu(EPh3)(4)]BF4 (E = P or As) and equimolar amounts of Ar-BIAN ligands, or by reaction of equimolar amounts of {[}Cu(NCMe)(4)]BF4, 4-iPrC(6)H(4)-BIAN (a) and diphosphanes dppe or dppf, in dichloromethane, whereas the neutral complexes of the types {[}CuX(Ar-BIAN)(EPh3)] {[}X = Cl

{{A series of Ar-BIAN-based copper(I) complexes (where Ar-BIAN = bis(aryl) acenaphthenequinonediimine) were synthesised and characterised by H-1 and C-13 NMR spectroscopies, FT-IR spectroscopy, MALDI-TOF-MS spectrometry, cyclic voltammetry and single crystal X-ray diffraction. The bis-chelated complexes of general formula {[}Cu(Ar-BIAN)(2)]BF4 (where Ar = C6H5 (1), 4-iPrC(6)H(4) (3), 2-iPrC(6)H(4) (4)) were prepared by reaction of {[}Cu(NCMe)(4)]BF4 with two equivalents of the corresponding Ar-BIAN ligands, in dichloromethane, while the mono-chelated complexes of the type {[}Cu(Ar-BIAN)L2]BF4 (where Ar = 2,6-iPr(2)C(6)H(3)

{Three fluorinated Mo-Cu-thiolate isomers,{[}Ph4Ph{[}S2MoS2Cu(n-SPhF)], {[}n-SPhF = 2-fluorothiophenol (la)], 3-fluorothiophenol (lb), and 4-fluorothiophenol (1c)] were synthesized and spectroscopically characterized. The F-19-NMR signal of the fluorine atom in the.benzene has different chemical shift for each isomer, which is highly influenced by the local environment that can be manipulated by different solvents and solutes. The fluorine-19 chemical shift is an advantageous NMR structural probe in alternative to H-1-NMR {[}B.K. Maiti, T. Aviles, M. Matzapetakis, I. Moura, S.R. Pauleta, JJ.G. Moura, Eur. J. Inorg. Chem. (2012) 4159.], that can be used to provide local information on the pocket of the metal cluster in the Orange Protein (ORP). (C) 2014 Elsevier B.V. All rights reserved.}

{The complex {[}Ph4P](2){[}Cu(bdt)(2)] (1(red)) was synthesized by the reaction of {[}Ph4P]2{[}S2MoS2CuCl] with H2bdt (bdt = benzene-1,2-dithiolate) in basic medium. 1(red) is highly susceptible toward dioxygen, affording the one electron oxidized diamagnetic compound {[}Ph4P]{[}Cu(bdt)(2)] (1(ox)). The interconversion between these two oxidation states can be switched by addition of O-2 or base (Et4NOH = tetraethylammonium hydroxide), as demonstrated by cyclic voltammetry and UV-visible and EPR spectroscopies. Thiomolybdates, in free or complex forms with copper ions, play an important role in the stability of 1(red) during its synthesis, since in its absence, 1(ox) is isolated. Both 1(red) and 1(ox) were structurally characterized by X-ray crystallography. EPR experiments showed that 1(red) is a Cu(II)-sulfur complex and revealed strong covalency on the copper-sulfur bonds. DFT calculations confirmed the spin density delocalization over the four sulfur atoms (76%) and copper (24%) atom, suggesting that 1(red) has a ``thiyl radical character{''}. Time dependent DFT calculations identified such ligand to ligand charge transfer transitions. Accordingly, 1(red) is better described by the two isoelectronic structures {[}Cu(I)(bdt(2), 4S(3-{*}))](2-) {[}Cu-II(bdt(2), 4S(4-))](2-). On thermodynamic grounds, oxidation of 1(red) (doublet state) leads to 1(ox) singlet state, {[}Cu-III(bd(t)2, 4S(4-))](1-).}

{Two synthetic strategies of tetrathiomolybdate-metal clusters with the potential to be used as NMR structural probes for the location of the metal cofactor in the orange protein (ORP) are described. The first strategy is based on the substitution reaction in which small organic ligands bind directly to the metal centre in a molybdenumcopper hetero-dinuclear cluster. Interaction between {[}PPh4]2{[}MoS4CuCl] and either aliphatic {[}beta-mercaptoethanol (b-me)] or aromatic {[}o-aminobenzenethiol (abt)] thiols in the presence of a strong base resulted in the formation of {[}Ph4P]2{[}S2MoS2Cu(b-me)] (1a) and {[}Et4N]2{[}S2MoS2Cu(abt)]center dot H2O center dot 0.25DMF (1b), which can be used to obtain intermolecular NOEs. The compound 1a readily hydrolyzed to {[}Ph4P]2{[}OSMoS2Cu(b-me)] (1ahydro) in contact with a protic solvent. The second strategy consisted of the incorporation of cadmium into tetrathiomolybdate ({[}MoS4]2), which gives rise to the trinuclear cluster compound {[}PPh4]2{[}(MoS4)2Cd] (2). All clusters were characterized spectroscopically and their structure determined by X-ray diffraction. The NMR spectroscopic data are consistent with the formation of a complex with a 1:1 ratio of \{MoS4Cu\} and thiol. The 113Cd NMR chemical shift of compound 2 is consistent with the cadmium having a tetrahedral geometry and coordinated by four sulfur ligands. The tetraphenylphosphonium cation in compound 1a was replaced by a tetramethylammonium countercation originating in the water-soluble compound {[}Me4N-1a]. Solubility in aqueous buffers is a requirement for incorporating this cluster into apo-ORP. These compounds will be used to identify the exact location of the ORP heterometallic cluster using NMR methodologies.}

The reactivity of arylisocyanates in supercritical carbon dioxide (scCO(2)) was studied using the easily available complexes CpCo(CO)(2), CpCoPPh3Me2 and Ni(cod)(2) as catalysts. A study of the solubility of the catalysts in scCO(2) was undertaken in all cases. The complex CpCo(CO)(2) is very soluble, 1.7 x 10(-1) mol kg(-1), while CpCoPPh3Me2 has a lower solubility, 7.2 x 10(-3) mol kg(-1), and Ni(cod)(2) is insoluble in scCO(2). For comparison purposes, the reactions were performed in parallel in scCO(2), using toluene as a solvent and just with the neat liquid arylisocyanate. Reactions in scCO(2) either do not take place at all, when CpCo(CO), is used as catalyst, or occur with low yields affording the trimer of the corresponding arylisocyanate when CpCoPPh3Me2 or Ni(cod)(2) act as catalysts. No incorporation of CO2 into the organic substrate was observed. Better conversions to triarylisocyanate were obtained when the reactions were performed by direct mixture of the liquid arylisocyanate ArNCO (Ar = Ph, p-CH3C6H4, p-CH3OC6H4) and the catalyst. Using toluene as a solvent, the yields of the trimers were lower than those obtained in neat arylisocyanate, and in some cases they were not formed at all. For instance in the reaction of CpCo(CO), and tolylisocyanate either under stoichiometric or catalytic conditions the trimer is not obtained, instead the compound H2R3N3C2O2 (R = CH3C6H4), was isolated in low yield. In the reaction of Ni(cod)(2)/PPh3 with phenylisocyanate, the trimer was formed but in low yield. The lower yields of the trimers observed when the reactions were performed in scCO(2) or in toluene, compared to that observed in neat arylisocyanates, indicates that the decrease in reactivity is due to a decrease in concentration. (C) 2001 Elsevier Science B.V. All rights reserved.

The SiMe3 group (TMS), introduced as a substituent at the cyclopentadienyl ligand, is found to magnify the solubility of the corresponding metal complexes in supercritical carbon dioxide (scCO(2)). This is verified from comparative solubility measurements of the species (eta(5)-Me-3 SiC5H4)MoO2 Cl, 1a, (eta(5)-Me3SiC5H4)(2)ZrCl2, 2a, and (eta(5)-Me3SiC5H4)Co(CO)I-2.0.5(I-2), 3a (newly synthesised), and of their unsubstituted precursors 1b-3b, respectively. In spite of the increased solubility, the chemical, structural and reactivity properties of the TMS derivatives are scarcely affected. Confirmation comes from a detailed study of the cobalt complex 3a that includes X-ray structural determination. The geometry is most similar to that of the precursor 3b while an apparently different Co-CO interaction is observed in the carboxylated analogue [(eta(5)-PhCH2CO2C5H4)Co(CO) I-2, 3c]. The problem is computationally tackled by using the DFT B3LYP method. The optimised geometries of the simplified models of 3a-3c are all very similar. In particular, the computed stretching frequency of the unique CO ligand is consistent with the insignificant influence of the TMS group while it suggests a reduced amount of metal back-donation in 3c. It is inferred that the TMS complexes 1a-3a, while having higher solubility in scCO2, maintain almost unaltered the electronic and chemical features of their parent compounds. In particular, the role of 1a-3a as catalysts, that is well documented for homogeneous solutions, remains unaltered in the very different scCO(2) environment. The assumption is experimentally validated for 1a by performing with the latter two classic catalytic processes. The first process is the oxidation of PPh3 that is achieved by using molecular oxygen as an oxidant. The second example concerns the epoxidation of cyclohexene achieved in presence of tert-butyl hydroperoxide (TBHP).