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M Elena Olmos

Publications and source records attributed to M Elena Olmos.

14 recordsLinked to original sources
PubMed2006

Synthesis, coordination to Au(I) and photophysical properties of a novel polyfluorinated benzothiazolephosphine ligand.

The reaction between Ph2PH and C6F5CNS leads to the formation of the polyfluorinated benzothiazolephosphine ligand Ph2P(CNS)(C6F4) 1. The mechanism of the reaction involves the addition of the phosphine to the isothiocyanate and subsequent intramolecular nucleophilic aromatic substitution. This new ligand reacts with gold(I) substrates producing complexes [AuCl{Ph2P(CNS)(C6F4)}] 2 and [Au(C6F5){Ph2P(CNS)(C6F4)}] 3. Both the ligand 1 and complexes 2 and 3 display phosphorescence with emissions arising from n(P) -->pi*(heterocyclic ring) excited state for 1 and pi-->pi*(heterocyclic ring) excited state for 2 and 3. DFT and TD-DFT calculations agree with these results.

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PubMed2006

From diphosphane to diphosphodiide gold(III) derivatives of 1,2-diphosphinobenzene.

Treatment of 1,2-diphosphinobenzene with [Au(C6F5)3(tht)] leads to the diphosphane derivative [{Au(C6F5)3}(1,2-PH2C6H4PH2)] (1), which further reacts with other pentafluorophenylgold(III) reagents in the presence of acetylacetonate as deprotonating agent to afford phosphane-phosphide complexes. The noncyclic PPN[{Au(C6F5)3}2(1,2-PHC6H4PH2)] (2; PPN = bis(triphenylphosphine)iminium) has been shown to be a useful starting material for the synthesis of higher nuclearity cyclic or noncyclic diphosphide or even diphosphodiide derivatives through similar reactions. The crystal structures of the trinuclear anionic NBu4[{Au(C6F5)3}(1,2-PHC6H4PH){Au(C6F5)2Cl}{mu-Au(C6F5)2}] (3) and the hexanuclear [{Au(C6F5)3}(1,2-PC6H4P){Au(C6F5)3}{mu-M(dppe)M}2] (M = Au (12), Ag (13)) have been established by X-ray diffraction methods, the last complexes having a bicyclic ring containing three intramolecular interactions between the M(I) centres.

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PubMed2005

Au(I)...Ag(I) metallophilic interactions between anionic units: theoretical studies on a AuAg4 square pyramidal arrangement.

We have studied theoretically the organometallic compound (NBu4)2[Au(3,5-C6F3Cl2)2Ag4(CF3CO2)5], whose dianionic part displays a AuAg4 square pyramidal arrangement based on closed-shell Au(I)...Ag(I) interactions between two monoanionic fragments. DFT/B3LYP, ab initio Hartree-Fock (HF), and second-order Møller Plesset perturbation theory (MP2) calculations have been carried out for simplified model systems. Model system [AuPh2]-...[Ag4(CO2H)5]- (C1) has been chosen from DFT results as an appropriate model for the study of the interactions. The four Au(I)...Ag(I) interactions and two additional C...Ag(I) interactions are observed when dispersion-type interactions are considered in the level of theory (MP2) displaying a metallophilic attraction between two anionic units. The study of model C2 (similar to C1 but with minimized C...Ag(I) interactions) permits the study of the Au(I)...Ag(I) interactions separately, which confirms the existence of stabilizing Au(I)...Ag(I) interactions around 13 kJ.mol(-1) each.

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PubMed2005

Phosphorescent excited state of [Au2[(Ph2Sb)2O]3]2+: Jahn-Teller distortion at only one gold(I) center.

Dinuclear three-coordinate Au(I) complex [Au2{(Ph2Sb)2O}3](ClO4)2 1 displays an interesting phosphorescent behavior in which a large Stokes' shift is observed. Ab initio calculations show that the main distortion for the first triplet excited state, which is responsible for the luminescence behavior of complex 1, is a Jahn-Teller distortion for only one of the Au(I) centers together with a gold-gold distance shortening. This behavior could be extrapolated to other phosphorescent dinuclear three-coordinate Au(I) complexes.

Antimony↗
PubMed2005

A family of Au-Tl loosely bound butterfly clusters.

By treatment of the polymeric species [AuTl(C6Cl5)2]n with ketones or with acetylacetone and 4,4'-bipyridine, the new tetranuclear complexes [Au2Tl2(C6Cl5)4] x L (L = PhMeC=O, acacH) or [Au2Tl2(C6Cl5)4(bipy)] x (acacH) have been prepared. Their crystal structures have been determined by X-ray diffraction methods and they all present a central Au2Tl2 core formed via one Tl...Tl and four Au...Tl unsupported interactions resulting in a loosely bound butterfly cluster. These complexes are strongly luminescent in both the solid state and solution showing an optical behavior in agreement with the maintenance of the Tl...Tl contact even in solution.

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PubMed2005

Unsupported gold(I)-copper(I) interactions through eta1 Au-[Au(C6F5)2]- coordination to Cu+ Lewis acid sites.

The reaction of the complex [Au2Ag2(C6F5)4)N[triple bond]CCH3)2]n (1) with 1 equiv of CuCl in the presence of 1 equiv of pyrimidine ligand leads to the formation of the heteronuclear Au(I)-Cu(I) organometallic polymer [Cu{Au(C6F5)2}(N[triple bond]CCH3)(mu2-C4H4N2)]n (2) through a transmetalation reaction. Complex 2 displays unprecedented unsupported Au(I)...Cu(I) interactions of [Au(C6F5)2]- units with the acid Cu(I) sites in a [Cu(N[triple bond]CCH3)(mu2-pyrimidine)]n+(n) polymeric chain. Complex 2 has a rich photophysics in solution and in the solid state.

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PubMed2004

A detailed study of the vapochromic Behavior of [Tl[Au(C6Cl5)2]]n.

The linear-chain polymer [Tl[Au(C(6)Cl(5))(2)]](n), 1, reacts in the solid state and in solution with different volatile organic compounds such as tetrahydrofuran, acetone, tetrahydrothiophene, 2-fluoropyridine, acetonitrile, acetylacetone, and pyridine. Solid-state exposure of 1 to vapors of the above VOCs produces a selective and reversible change in its color that is perceptible to the human eye and even deeper under UV irradiation, allowing 1 to function as a sensor for these VOCs. Heating the samples exposed to the VOCs for a few minutes at 100 degrees C regenerates the original material without degradation, even after several exposure/heating cycles. The reversibility is further confirmed by X-ray powder diffraction measurements of complex 1 before and after exposure to vapors and again after heating the samples. The products obtained by reactions of complex 1 with the above VOCs as ligands in solution contain extended linear chains of alternating gold and thallium centers with two molecules of the organic ligands attached to each thallium atom. The stoichiometry of these materials has been confirmed by single-crystal X-ray diffraction as [Tl(THF)(2)[Au(C(6)Cl(5))(2)]](n), 3, and [Tl(acacH)(2)[Au(C(6)Cl(5))(2)]](n), 5. Comparison of FT-IR, UV-vis, and luminescence spectra at room temperature and at 77 K of the solid samples of complexes 2-9 with the spectra of complex 1 after its exposure to VOCs suggests interaction occurs between the organic VOCs and thallium in each case. Thermogravimetric analyses data indicate that all the thallium centers in these derivatives of complex 1 are neither fully nor equally coordinatively saturated. The materials formed appear to be intermediates between complex 1 with no VOCs attached and complexes 3-9 which contain two organic ligands coordinated to each thallium. A crystal structure analyses of one of these intermediates, [Tl(THF)(0.5)[Au(C(6)Cl(5))(2)]](n), 1.0.5THF, confirms this. Density functional calculations are in accord with the observed experimental results. Analysis reveals a substantial participation of the metal atoms in transitions that give rise to the observed emissions. Crystallographic data are as follows. For 1.0.5THF: triclinic, P1, a = 8.9296(1) A, b = 11.2457(1) A, c = 21.2465(3) A, alpha = 96.7187(7) degrees, beta = 92.5886(6) degrees, gamma = 98.5911(8) degrees, V = 2090.87(4) A(3), and Z = 2. For 3: monoclinic, P2(1)/c, a = 26.4163(6) A, b = 12.1619(2) A, c = 28.0813(6) A, alpha = 90 degrees, beta = 161.9823(6) degrees, gamma = 90 degrees, V = 2790.51(10) A(3), and Z = 4. For 5: monoclinic, P2(1)/c, a = 9.8654(2) A, b = 29.8570(5) A, c = 11.6067(2) A, alpha = 90 degrees, beta = 114.5931(6) degrees, gamma = 90 degrees, V = 3108.64(10) A(3), and Z = 4.

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PubMed2004

Gold-thallium supramolecular arrays with 4,4'-bipyridine. Solvent induction of luminescent networks.

The reaction of [AuTl(C(6)Cl(5))(2)](n) with bipy at different molar ratios, solvents or crystallisation conditions affords a series of two- and three-dimensional luminescent complexes, [AuTl(C(6)Cl(5))(2)(bipy)(0.5)](n), [AuTl(C(6)Cl(5))(2)(bipy)](n), [[Tl(bipy)][Tl(bipy)(0.5)(THF)][Au(C(6)Cl(5))(2)](2)](n), [[Tl(bipy)][Tl(bipy)(0.5)(THF)][Au(C(6)Cl(5))(2)](2)xTHF](n) and [[AuTl(C(6)Cl(5))(2)(bipy)]x0.5toluene](n)(bipy = 4,4'-bipyridine; THF = tetrahydrofuran) all of them containing polymeric chains formed via unsupported Au...Tl interactions and bridging bipyridine ligands.

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PubMed2003

(Tl[Au(C(6)Cl(5))(2)])(n): A vapochromic complex.

The X-ray structure of (Tl[Au(C(6)Cl(5))(2)])(n), 1, consists of 1-D linear polymer chains parallel to the crystallographic z axis. The crystal structure of 1 has channels that run parallel to these chains with interatom distances in the range 3.231-4.076 A. There are holes in these channels with diameters as large as 10.471 A, which can accommodate a variety of solvents. Complex 1 displays reversible vapochromic emission and absorption spectral behavior when the solid is exposed to a variety of organic vapors such as acetone, acetonitrile, triethylamine, acetylacetone, tetrahydrothiophene, 2-fluoropyridine, tetrahydrofuran, and pyridine. Complex 1 is luminescent at room temperature and at 77 K in the solid state. UV excitation at 495 nm leads to an emission at 531 nm.

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PubMed2003

Theoretical and photoluminescence studies on the d10-s2 AuI-TlI interaction in extended unsupported chains.

The reactions of solutions of TlPF(6) and OPPh(3) in tetrahydrofuran or acetone with NBu(4)[AuR(2)] (R=C(6)Cl(5), C(6)F(5)) gave the new complexes [Au(C(6)Cl(5))(2)](2)[Tl(OPPh(3))][Tl(OPPh(3))(L)] (L=THF (1), acetone (2)) and the previously reported [Tl(OPPh(3))(2)][Au(C(6)F(5))(2)] (3). The crystal structures of complexes 1 and 2 display extended unsupported chains with short intermolecular interactions between alternating gold(I) and thallium(I) centres. Moreover, the Tl(I) centres show two different types of geometrical environments, such as pseudotetrahedral and distorted trigonal-bipyramidal, due to the presence of solvent molecules that act as ligands in the solid-state structure. Quasirelativistic and nonrelativistic ab initio calculations were performed to study the nature of the intermetallic Au(I)-Tl(I) interactions and are consistent with the presence of a high ionic contribution (80 %) and dispersion-type (van der Waals) interaction with a charge-transfer contribution (20 %) when relativistic effects are taken into account. All complexes are luminescent in the solid state at room temperature and at 77 K. Complexes 1 and 2 show site-selective excitation, probably due to the different environments around the Tl(I) centres. The DFT and time-dependent (TD)-DFT calculations are in agreement with the experimental excitation spectra for all complexes and confirm the site-selective excitation behaviour as a function of the Tl(I) geometrical environment.

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PubMed2002

Do aurophilic interactions compete against hydrogen bonds? Experimental evidence and rationalization based on ab initio calculations.

[M(C6F5)(N(H)=CPh2)] (M = Ag (1) and Au (2)) complexes have been synthesized and characterized by X-ray diffraction analysis. Complex 1 shows a ladder-type structure in which two [Ag(C6F5)(N(H)=CPh2)] units are linked by a Ag(I)-Ag(I) interaction in an antiparallel disposition. The dimeric units are associated through hydrogen bonds of the type N-H...F(ortho). On the other hand, gold(I) complex 2 displays discrete dimers also in an antiparallel conformation in which both Au(I)-Au(I) interactions and N-H.F(ortho) hydrogen bonds appear within the dimeric units. The features of these coexisting interactions have been theoretically studied by ab initio calculations based on four different model systems in order to analyze them separately. The interactions have been analyzed at HF and MP2 levels of theory showing that, in this case, even at larger distances. The Au(I)-Au(I) interaction is stronger than Ag(I)-Ag(I) and that N-H.F hydrogen bonding and Au(I)-Au(I) contacts have a similar strength in the same molecule, which permits a competition between these two structural motifs giving rise to different structural arrangements.

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PubMed2002

Synthesis, structure, and photophysical studies of luminescent two- and three-dimensional gold-thallium supramolecular arrays.

The reactions of tetrahydrofuran solutions of NBu(4)[AuR(2)] (R = C(6)F(5), C(6)Cl(5)) with TlPF(6) and 4,4'-bipyridine lead to the synthesis of the luminescent materials [Tl(bipy)](2)[Au(C(6)F(5))(2)](2) 1 and [Tl(bipy)][Tl(bipy)(0.5)(thf)][Au(C(6)Cl(5))(2)](2) 2 in high yield. The structures of these complexes, as analyzed by X-ray diffraction, consist of planar polymers formed by repetition of Tl-Au-Au-Tl (1) or Tl-Au-Tl'-Au (2) moieties linked through bidentate bridging bipy ligands. In complex 1 these layers are associated via Tl...F contacts between atoms of adjacent planes, whereas in complex 2 each two polymeric layers are linked through additional bridging bipy molecules. Both complexes are strongly luminescent at room temperature and at 77 K in the solid state, losing this characteristic in solution even at high concentrations. The luminescence is attributed to interactions between metal atoms which are strongly affected by their structural dispositions. DFT calculations are in accord with the observed experimental behavior, showing the nature of the orbitals involved in each transition. Detailed analyses reveal a substantial participation of the metals in the transition giving rise to the emission maxima, and also other more energetic bands in which the ligands are involved and which also give rise to these emissions. The obtained theoretical excitation spectra clearly match the experimental results.

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