Kauf, Thomas, Vitor Rosa, Christophe Fliedel, Roberto Pattacini, Naina Deibel, Teresa Aviles, Biprajit Sarkar, and Pierre Braunstein. "
{Reactivity of TCNE and TCNQ derivatives of quinonoid zwitterions with Cu(I)}."
{DALTON TRANSACTIONS}. {44} (2015): {5441-5450}.
Abstract{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.}
Maiti, Biplab K., Luisa B. Maia, Kuntal Pal, Bholanath Pakhira, Teresa Aviles, Isabel Moura, Sofia R. Pauleta, Jose L. Nunez, Alberto C. Rizzi, Carlos D. Brondino, Sabyasachi Sarkar, and Jose J. G. Moura. "
{One Electron Reduced Square Planar Bis(benzene-1,2-dithiolato) Copper Dianionic Complex and Redox Switch by O-2/HO-}."
{INORGANIC CHEMISTRY}. {53} (2014): {12799-12808}.
Abstract{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-).}
Bruno Pedras, Vitor Rosa, Richard Welter, Carlos Lodeiro, and Teresa Aviles. "
{New quinoline alpha-diimine ligands as fluorescent probes for metal ions: Ultrasound-assisted and conventional synthetic methods}."
{INORGANICA CHIMICA ACTA}. {381} (2012): {143-149}.
Abstract{Three new emissive 8-aminoquinoline derived probes (1)-(3) and one dinuclear Zn(II) complex (4) were synthesized and fully characterized. Their absorption spectra show maxima at 310-336 nm, and fluorescence emission between 456 and 498 nm. Compound (1) was characterized by single crystal X-ray diffraction. The effect upon Zn(II) and Cu(II) coordination to compounds (1)-(3) was studied by monitoring the changes in absorption and fluorescence spectra, and complemented by calculation of metal-ligand stability constants. The results indicate that compound (3) is the one that presents the most favorable geometry for coordinating two metal cations, fact that is confirmed by the synthesis of the dinuclear complex (4), with similar molecular geometry. (C) 2011 Elsevier B.V. All rights reserved.}
Vitor Rosa, Christophe Fliedel, Alessio Ghisolfi, Roberto Pattacini, Teresa Aviles, and Pierre Braunstein. "
{Influence of a thioether function in short-bite diphosphine ligands on the nature of their silver complexes: structure of a trinuclear complex and of a coordination polymer}."
{DALTON TRANSACTIONS}. {42} (2013): {12109-12119}.
Abstract{New cationic Ag(I) complexes were prepared by reaction of AgBF4 with two thioether-functionalized bis-(diphenylphosphino) amine ligands, Ph2PN(p-ArSMe)PPh2 (L1) and Ph2PN(n-PrSMe)PPh2 (L2), and compared with those obtained from the unfunctionalized ligands Ph2PN(Ph)PPh2 (L3) and Ph2PN(n-Bu)PPh2 (L4), respectively. The complex {[}Ag-3(mu(3)-Cl)(2)(mu(2)-L1-P, P)(3)](BF4) (1 center dot BF4) contains a triangular array of Ag centres supported by three bridging L1 ligands and two triply-bridging chlorides. In contrast, ligand L2 led to the coordination polymer {[}\{Ag-2(mu(3)-L2,-P,P,S)(2)(MeCN)(2)\}\{Ag-2(mu(2)-L2-P,P)(2)(MeCN)(2) \}(BF4)(4)](n) (2) in which the tethered thioether group connects intermolecularly a Ag2 unit to the diphosphine bridging the other Ag2 unit. With L3 and L4, two similar complexes were obtained, {[}Ag-2(mu(2)-L3)(BF4)(2)] (3) and {[}Ag-2(mu(2)-L4)(BF4)(2)] (4), respectively, with bridging diphosphine ligands and a BF4 anion completing the coordination sphere of the metal. Complexes 1 center dot BF4 center dot CH2Cl2, 2 center dot THF, 3 center dot 3CH(2)Cl(2) and 4 have been fully characterized, including by single crystal X-ray diffraction.}
Romain, Charles, Vitor Rosa, Christophe Fliedel, Frederic Bier, Frederic Hild, Richard Welter, Samuel Dagorne, and Teresa Aviles. "
{Highly active zinc alkyl cations for the controlled and immortal ring-opening polymerization of epsilon-caprolactone}."
{DALTON TRANSACTIONS}. {41} (2012): {3377-3379}.
Abstract{Zinc alkyl cations supported by N,N-BIAN-type bidentate ligands were found to be highly active in the immortal ROP of epsilon-caprolactone to yield narrowly disperse and chain length-controlled poly(epsilon-caprolactone), whether in solution or bulk polymerization conditions.}