The coordination chemistry of Fe(2+), Co(2+) and Cu(+) ions was explored with the triphosphine and triphosphinite ligands PhSi{CH2PPh2}3 (1) and PhSi{OPPh2}3 (2), so as to evaluate the impact of the electronic properties of the tripodal phosphorus ligands on the structure and reactivity of the corresponding complexes. The synthesis and characterization of the complexes [Fe(κ(3)-PhSi{CH2PPh2}3)(MeCN)3][OTf]2 (3) (OTf = O3SCF3), [Fe(κ(3)-PhSi{OPPh2}3)(MeCN)3][OTf]2 (3'), [Co(κ(2)-PhSi{CH2PPh2}3)Cl2] (4), [Co(κ(3)-PhSi{OPPh2}3)Cl2] (4'), [Cu(κ(3)-PhSi{CH2PPh2}3)Br] (5) and [Cu(κ(3)-PhSi{OPPh2}3)I] (5') were carried out. The crystal structures of 3, 3', 4, 4', and of the solvates 5·3THF and 5'·THF are reported.
View Article and Find Full Text PDFThe disproportionation of formic acid to methanol was unveiled in 2013 using iridium catalysts. Although attractive, this transformation suffers from very low yields; methanol was produced in less than 2% yield, because the competitive dehydrogenation of formic acid (to CO2 and H2) is favored. We report herein the efficient and selective conversion of HCOOH to methanol in 50% yield, utilizing ruthenium(II) phosphine complexes under mild conditions.
View Article and Find Full Text PDFSelf-assembly of neodymium nitrate and 2,5-dihydroxyl-1,4-benzoquinone (DHBQ) leads to the formation of a metal organic framework (MOF) of formula [Nd2(DHBQ)3(H2O)6]·18H2O. X-ray diffraction studies show that its crystalline structure is that of a two-dimensional coordination polymer packed in parallel sheets, with organised clusters of water molecules lying between the sheets and bridging them via a dense H-bond network. However, instead of forming faceted crystals, this MOF assembles into unusually shaped cylindrical particles of micrometre size.
View Article and Find Full Text PDFThe crystal structures of [PtCl(2)(ttcn)], [PdCl(2)(ttcn)], [Pt(ethylenediamine)(ttcn)](PF(6))(2), and [Pd(ethylenediamine)(ttcn)](PF(6))(2) (ttcn = 1,4,7-trithiacyclononane) show short apical metal---S(ttcn) distances, qualitatively indicating an interaction. Luminescence spectroscopy was used to study these crystalline complexes at room temperature and variable hydrostatic pressure. The luminescence band maximum of [PdCl(2)(ttcn)] shows a pressure-induced blue shift of +6 cm(-1)/kbar, while the platinum(II) compounds show a red shift of approximately -20 cm(-1)/kbar.
View Article and Find Full Text PDFIn the solid-state, the approximately square planar cation in orange crystals of [Pt(NO(2)phen)(ttcn)](PF(6))(2) (NO(2)phen = 5-nitro-1,10-phenanthroline; ttcn = 1,4,7-trithiacyclononane) has a short apical Pt...
View Article and Find Full Text PDFWe report here on the synthesis and characterisation of a first iron(II) spin-crossover coordination polymer with the dca spacer ligand, having the formula [Fe(aqin)2(dca)]ClO4.MeOH (aqin=8-aminoquinoline, dca=dicyanamide), which displays a two-step complete spin transition. Variable-temperature magnetic susceptibility measurements and Mössbauer spectroscopy have revealed that the two relatively gradual steps are centred at 215 and 186 K and are separated by an inflection point at about 201 K, at which 50 % of the complex molecules undergo a spin transition.
View Article and Find Full Text PDFThe paper reports the synthesis and detailed characterization of two new Fe(II) compounds: [Fe(pyim)(2)(bpen)](ClO(4))(2).2C(2)H(5)OH (2) and [Fe(pyim)(2)(bpe)](ClO(4))(2).C(2)H(5)OH (3) (pyim = 2-(2-pyridyl)imidazole, bpen = 1,2-bis(4-pyridyl)ethane, and bpe = 1,2-bis(4-pyridyl)ethene).
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