RESUMEN
New data on the thermodynamic properties of the melting and sublimation of a series of volatile iridium(i) complexes [Ir(cod)(L)] with cyclooctadiene-1,5 (cod) and ß-diketones (L = RC(O)CHC(O)R') have been obtained with differential scanning calorimetry and vapor pressure measurements. Combining experimental, empirical and theoretical methods, ways to estimate difference in heat capacities between gas and crystal phases have been suggested. An effect on the volatility in introducing the simplest alkyl, fluorinated alkyl and aryl terminal groups (R and R') into the chelate ligand has been explained in terms of a detailed crystal packing analysis supported by a quantum chemical calculation of crystal lattice energies. To reveal the influence of the coordination center, the thermal behavior of complexes was compared with that for the tris-chelates, [Ir(L)3]. The study broadens our understanding of relationships between the structure and thermal properties of volatile precursors, which is useful for further tuning effective compounds for metal-organic chemical vapor deposition purposes.
RESUMEN
Herein, first examples of supramolecular hybrid organic-inorganic cluster-porphyrin [CPn (n = 2, 6)] systems constructed via metal-ligand coordination have been reported. The pyridine end-decorated Mo(ii) halide cluster ((Bu4N)2[{Mo6I8}(OOC-C5H4N)6]), possessing remarkable photophysical properties, was chosen as the inorganic part and A2-type zinc porphyrin 5,15-bis[(p-tolyl)porphyrinato(2-)]zinc was selected as the organic part. The crystal structures of CP2 and CP6 hybrids have been characterised by single crystal X-ray diffraction. The CP2 complex is composed of two zinc porphyrins, coordinated to pyridyl moieties of the same cluster molecule, related by an inversion center. In the case of the CP6 complex, each cluster has three pairs of coordinated symmetrically equivalent zinc porphyrins. Also, the formation of supramolecular hybrid CPn (n = 2, 6) systems was unambiguously demonstrated in solution via NMR and UV-Vis spectroscopy titration and diffusion ordered NMR spectroscopy (DOSY).
RESUMEN
Cluster compounds based on a new {Re3Mo3Se8}n core were obtained and studied. The polymeric solid K6[Re3Mo3Se8(CN)4(CN)2/2] (1) containing 24 cluster valence electrons (CVE) was isolated as a result of high-temperature reaction. Water-soluble salts K5[Re3Mo3Se8(CN)6]·11H2O (2) and Cs5[Re3Mo3Se8(CN)6]·H2O (3) were prepared from compound 1. Crystal structures of the diamagnetic compounds 2 and 3 contain a cluster anion [Re3Mo3Se8(CN)6]5- with a 22-electronic core {Re3Mo3Se8}+. Metathesis reaction followed by recrystallization from CH3CN yielded paramagnetic salt (Ph4P)4[Re3Mo3Se8(CN)6]·2CH3CN (4) containing the {Re3Mo3Se8}2+ core with 21 CVE. Cyclic voltammetry of the solution of 4 displayed three quasi-reversible waves with E1/2 = -0.325, -0.818 and -1.410 V vs. Ag/AgCl electrode indicating the presence of [Re3Mo3Se8(CN)6]4-/5-/6-/7- transitions. Electronic structure calculations showed that both mer- and fac-isomers of [Re3Mo3Se8(CN)6]n- clusters undergo great distortion when the number of CVE decreases.
RESUMEN
A series of lanthanide(iii) complexes based on the new chiral ligand L, which contains 1,10-phenanthroline and (-)-menthol fragments, namely [LnL2(NO3)3] (Ln = Eu (1), Gd (2), Tb (3), Dy (4)), have been synthesized and structurally characterized. Complexes 1-4 are isostructural and crystallize in the non-centrosymmetric space group P41212. The mononuclear complexes comprise a 10-coordinate Ln3+ ion with two bidentate N,N-donor ligands (L) and three bidentate chelating nitrate groups. The magnetic properties of complexes 1-4 are determined mainly by the Ln3+ ions. In the case of complexes 3 and 4, significant anisotropy results in nonlinear field dependences of magnetization at low temperature. Complexes 1, 3 and 4 exhibit metal-centered red (Eu3+), green (Tb3+) and yellow (Dy3+) luminescence, respectively, whereas complex 2 displays blue ligand-based luminescence in the solid state at room temperature. The luminescence quantum yield for the solid samples increases in the order 4 < 2 ≈ 3 < 1. The europium(iii) complex shows long luminescence lifetimes (up to 1750 µs) and a very high quantum yield (φf = 0.87); these make this compound promising for application in sensing and optoelectronics.
RESUMEN
The sterically hindered title complex, [Fe(3)Te(2)(C(36)H(40)N(2))(CO)(7)], was obtained by substitution of two carbonyl groups in the [Fe(3)(µ(3)-Te)(2)(CO)(9)] cluster by the bulky redox-active N,N'-bis(2,6-diisopropylphenyl)acenaphthene-1,2-diimine (dpp-BIAN) ligand. The asymmetric unit contains two molecules of the same geometry. The C=N bond lengths in dpp-BIAN indicate a rather low level of electron transfer from the cluster core to the dpp-BIAN ligand.
