The alkynylation of [Pt(bzq)(μ-Cl)]₂ (bzqH = benzo[h]quinoline) with excess of LiCCR in diethyl ether leads to novel (7,8-benzoquinolinate)bis(alkynyl)platinate(II) monoanionic species [Pt(bzq)(CCR)₂]⁻ (R = ^tBu 1, SiMe₃2, Ph 3, Tol 4, C₆H₄CF₃-4 5, C₅H₄N-2 6, C₆H₄–CCPh 7) which have been isolated as tetrabutylammoniun salts. The molecular X-ray structures of 3 and 6 reveal the presence of discrete anions with bond lengths and angles similar to those of related cyclometalated Pt compounds and no evidence of π–π or Pt–Pt stacking interactions. The influence of the R substituent on the photophysics of the complexes has been examined by UV-visible absorption, emission spectroscopy and cyclic voltammetry. Complexes 1–6 show a similar strong luminescence in both the solid state (structureless emission) and frozen solutions (well-resolved vibronic structures) while the emissions in solution at room temperature are red shifted (relative to the glass) and weak. For these complexes, on the basis of TD-DFT calculations which reproduce the experimental structure of anion 3, [Pt(bzq)(CCPh)₂]⁻, the emissions are proposed to arise from mixed [π CCR/Pt d/π (bzq) → π* bzq] transitions. In contrast, complex 7 which contains the extended p-phenylethynylphenylacetylide ligand, CCC₆H₄–CCPh, displays a structured emission both at 298 K and in glassy CH₂Cl₂ solutions. In this case the lack of a significant rigidochromism and DFT theoretical calculations support the involvement of a low-lying, metal perturbed acetylenic ³ππ* (CCC₆H₄–CCPh) excited state.

In this work, the effect of nickel doping on the structural and magnetic properties of Fe₃O₄ nanoparticles is analysed. Ni _x Fe_3–x O₄ nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCI₂·4H₂O and Ni(AcO)₂·4H₂O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe₃O₄ phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni²⁺ cations in the Fe²⁺ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe²⁺ cations by Ni²⁺ atoms in the octahedral sites of the spinel structure.