TTF-triazine-dipyridylamine Ligands : synthesis coordination chemistry

Date du colloque : 02/2011</p

Multifunctional Electroactive Ligands

Date du colloque : 02/2013</p

Bimetallic neutral palladium (II) bis(dithiolene) complex: Unusual synthesis, structural and theoretical study

The unusual synthesis of the dimeric dithiolene complex [PPh3)Pd(ethylene-1,2-dithiolate)](2) (1), containing the simplest dithiolene ligand, has been achieved through the reaction between tetrathiafulvalene (TTF) and Pd(PPh3)(4). The complex shows a folded structure in the solid state, according to single crystal X-ray analysis performed on crystals grown from two different system solvents and conditions, with a central [Pd2S2] ring folded about the S center dot center dot center dot S hinge by 67.9 degrees. The optimized geometry at the DFT level is in excellent agreement with the experimental structure. Moreover, TD-DFT calculations allowed the assignment of the low energy band arising at 576 nm to the HOMO - LUMO transition, between frontier orbitals having mixed metal and dithiolene character. (C) 2012 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved

Conducting mixed-valence salt of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with the paramagnetic heteroleptic anion [CrIII(oxalate)2(2,2′-bipyridine)](-)

The synthesis and crystal structure of the first tetrathiafulvalene (TTF) based radical cation salt containing the heteroleptic paramagnetic anion [CrIII(2,2′-bipy)(C2O4)2]− are reported. In the salt formulated as α′-(BEDT-TTF)2[Cr(C2O4)2(2,2′-bipy)]·CHCl2CH2Cl according to the single-crystal X-ray structure, the BEDT-TTF (bis(ethylenedithio)tetrathiafulvalene) donors are in a mixed valence state and form two types of uniform chains within organic layers. Two overlap modes are observed in these chains, which are canted with respect to the stacking direction, leading to a peculiar α′ packing mode. The anions organize in supramolecular chains sustained by π–π interactions between the bipyridine units. The magnetic behavior of the compound follows a Curie–Weiss law, with a magnetic contribution arising from both cationic and anionic counterparts. Single-crystal electrical transport measurements are in agreement with a semiconductor behavior and have been correlated with extended Hückel tight-binding calculations

New heterometallic coordination polymers constructed from 3d–3d′ binuclear nodes

Heterobinuclear [CuIIMnII] and [CuIICoII] cationic complexes can efficiently act as nodes for designing coordination polymers. The crystal structures of two binuclear precursors, [LCuCo(NO3)2] (1) and [LCuMn(NO3)2] (2), have been solved (L2− is the dianion of the Schiff base resulting from the 2 : 1 condensation of 3-methoxysalicyladehyde with 1,3-propanediamine). The nitrato ligands, coordinated to CoII and, respectively, the MnII ions from the precursors, are easily replaced by exo-dentate ligands, resulting in 1-D coordination polymers: 1∞[L(H2O)CuCo(oxy-bbz)]·CH3CN·C2H5OH (3), 1∞[L(H2O)CuCo(2,5-dhtp)]·CH3CN (5) and ∞[L(H2O)CuMn(ox)]·3H2O (6) (oxy-bbz2− = the dianion of 4,4′-oxy-bis(benzoic) acid; 2,5-dhtp2− = the dianion of 2,5-dihydroxy-terephthalic acid; ox2− = the dianion of the oxalic acid). In the case of the [CuMn] node, the interaction with oxy-bbz2− affords a binuclear complex, [LCuMn(oxy-bbz)(H2O)2] (4)

Pyrene bisiminopyridine ligand and its zinc complex

The synthesis of a pyrene bisiminopyridine ligand L was successfully accomplished by condensation between 1-aminopyrene and 2,6-pyridinecarboxaldehyde. The complexation of L with zinc triflate afforded a neutral metal complex formulated as [Zn(H2O)LCF3SO3)2].2Et2O. In the complex, the ligand is coordinated to zinc(II) through its three nitrogen atoms which form a distorted octahedral environment together with three oxygen atoms, two from the triflate anions and one from aqua ligand. Both compounds have been characterized using NMR, elemental analysis, mass spectrometry, electronic absorption (UV-Vis) and infrared. Luminescence properties of these compounds show an emission maxima at 412 nm, indicating a pyrene monomer emission

Tetrathiafulvalene-Triazine-Dipyridylamines as Multifunctional Ligands for Electroactive Complexes: Synthesis, Structures, and Theoretical Study

The electroactive ligands (2,4-bis-tetrathiafulvalene[6-(dipyridin-2-ylamino)]-1,3,5-triazine) TTF2-tz-dpa (1) and (2-tetrathiafulvalene[4,6-bis-(dipyridin-2-ylamino)]-1,3,5-triazine) TTF-tz-dpa(2) (2) have been synthesized by palladium cross-coupling catalysis, and the single crystal X-ray structure for 1 was determined. In the solid state the TTF and triazine units are practically coplanar and short intermolecular S center dot center dot center dot S contacts are established. Two neutral and one tetracationic Zn(II) complexes, formulated as (TTF2-tz-dpa)ZnCl2 (3), [ZnCl2(TTF-tz-dpa(2))Zn(H2O)Cl-2] (4), and ([(H2O)(2)Zn(TTF-tz-dpa(2))](ClO4)(2)}(2) (5) have been crystallized and analyzed by single crystal X-ray analysis. A peculiar feature is the evidence for anion-pi interactions, as shown by the short Cl center dot center dot center dot triazine and O(perchlorate)center dot center dot center dot triazine distances of 3.52 and 3.00 angstrom, respectively. A complex set of intermolecular pi center dot center dot center dot pi, S center dot center dot center dot S and hydrogen bonding interactions sustain the supramolecular organizations of the complexes in the solid state. Electronic absorption spectra provide evidence for the intramolecular charge transfer from TTF to triazine, also supported by time-dependent density functional theory (TD DFT) calculations

Cyanomethylene-bis(phosphonate) as ditopical ligand: stepwise formation of a 2-D heterometallic Fe(III)-Ag(I) coordination network

A new heteroditopic ligand, cyanomethylene-bis(5,5-dimethyl-2-oxo-1,3,2 lambda(5)-dioxa-phosphorinane) 1 (bphosCN), has been reacted with Fe(ClO4)(3) to afford the mononuclear complex Fe(bphosCN)(3) 2 which crystallized in the cubic system, space group Pa (3) over bar. The iron center, chelated by the oxygen atoms of the ligand, shows an almost perfect octahedral geometry, with the CN groups disposed at 120 degrees each other. Further reaction with AgClO4 provided the heterometallic coordination polymer (infinity)(2) {[(Fe (bphosCN)(3))(3)Ag-3(H2O)(2)]center dot(ClO4)(3)} 3 as the unique crystalline polymorph, in the monoclinic space group P21/a. The targeted 2D honeycomb type structure has been achieved through an interplay between coordinative CN-Ag bonds and CN center dot center dot center dot H2O bonds. The magnetic measurements demonstrate the existence of isolated paramagnetic Fe(III) centers in both complexes