Center for Magnetic Resonance

E.Yu. Bulatov, T.G. Chulkova, I.A. Boyarskaya, V.V. Kondratiev, M. Haukka, V.Yu. Kukushkin

“Triple associates based on (oxime)Pt(II) species, 18-crown-6, and water: Synthesis, structural characterization, and DFT study”

J. Molec. Struct. 2014, 1068, 176-181

DOI: 10.1016/j.molstruc.2014.04.010

The associates 2(cis-[PtCl₂(acetoxime)₂])⋅18-crown-6⋅2H₂O (1), 2(cis-[PtBr₂(acetoxime)₂])⋅18-crown-6⋅2H₂O (2), and trans-[PtCl₂(acetaldoxime)₂]⋅(18-crown-6)⋅2H₂O (3) were synthesized by co-crystallization of free corresponding platinum species and 18-crown-6 from wet solvents and characterized by ¹H NMR and IR spectroscopies, high-resolution mass-spectrometry (ESI), TG/DTA, and X-ray crystallography. The (oxime)Pt(II) species are assembled with 18-crown-6 and water by hydrogen bonding between the hydroxylic hydrogen atoms of the oxime ligands and the oxygen atom of water and between the hydrogen atoms of water and the oxygen atoms of 18-crown-6. In 2(cis-[PtX₂(acetoxime)₂])⋅18-crown-6⋅2H₂O (where X = Cl (1), Br (2)), the molecule of the crown ether is located between the two cis-[PtX₂(acetoxime)₂] species. The associate trans-[PtCl₂(acetaldoxime)₂]⋅(18-crown-6)⋅2H₂O (3) crystallizes into a 1D array structure. Water molecules play the role of linkers between the (oxime)Pt(II) species and the crown ether molecules. The electronic structures and vibrational frequencies of the triple associates were studied by density functional theory (DFT/B3LYP).

I.O. Koshevoy, Y.-C. Chang, Y.-A. Chen, A.J. Karttunen, E.V. Grachova, S.P. Tunik, J.Janis, T.A. Pakkanen, P.-T. Chou

“Luminescent Gold(I) Alkynyl Clusters Stabilized by Flexible Diphosphine Ligands”

Organometallics, 2014, ASAP

DOI: 10.1021/om5002952

Treatment of the homoleptic decanuclear compounds (AuC₂R)₁₀ with the cationic gold diphosphine complexes [Au₂(PR′₂-X-PR′₂)₂]²⁺ results in high-yield formation of the new family of hexanuclear clusters [Au₆(C₂R)₄(PR′₂-X-PR′₂)₂]²⁺ (PR′₂-X-PR′₂ = PPh₂-(CH₂)n-PPh₂, n = 2 (1, R = diphenylmethanolyl), n = 3 (3, R = diphenylmethanolyl; 4, R = 1-cyclohexanolyl; 5, R = 2-borneolyl), 4 (6, R = 1-cyclohexanolyl); PR′₂-X-PR′₂ = PCy₂-(CH₂)₂-PCy₂ (2, R = diphenylmethanolyl); PR′₂-X-PR′₂ = 1,2-(PPh₂-O)-C₆H₄ (7, R = diphenylmethanolyl); PR′₂-X-PR′₂ = (R,R)-DIOP (8, R = diphenylmethanolyl)). In the case of PPh₂-(CH₂)₄-PPh₂ phosphine and −C₂C(OH)Ph₂ alkynyl ligands an octanuclear cluster of a different structural type, [Au₈(C₂C(OH)Ph₂)₆(PPh₂-(CH₂)₄-PPh₂)₂]²⁺ (9), was obtained. Complexes 1–3, 7, and 9 were studied by X-ray crystallography. NMR and ESI-MS spectroscopic investigations showed that all but two (2 and 9) compounds are fluxional in solution and demonstrate dissociative chemical equilibria between major and a few minor forms. All of these complexes are intensely emissive in the solid state at room temperature and demonstrate very high quantum yields from 0.61 to 1.0 with weak influence of the alkynyl substituents R′ and the diphosphine backbones on luminescence energies. Two crystalline forms of the cluster 2 (P2₁/n and P2₁ space groups) exhibit unexpectedly contrasting yellow and sky blue emission, maximized at 572 and 482 nm, respectively. Electronic structure calculations with density functional methods demonstrate that the transitions responsible for the highly effective phosphorescence are dominated by contributions from the Au and π-alkynyl orbitals.

A.A. Melekhova, D.V. Krupenya, V.V. Gurzhiy, A.S. Melnikov, P.Yu. Serdobintsev, S.I. Selivanov, S.P. Tunik

“Synthesis, characterization, luminescence and non-linear optical properties of diimine platinum(II) complexes with arylacetylene ligands”

J. Organomet. Chem., 2014, accepted

DOI: 10.1016/j.jorganchem.2014.04.002

A series of platinum(II) complexes (diimine)Pt(C≣CR)₂, where diimine is 2,2′-bipyridine (bpy) or 4,4′-bis(tert-butyl)-2,2′-bipyridine (dtbpy) and alkynyl ligand is biphenylacetylide or terphenylacetylide, were synthesized and their photophysical and non-linear optical properties were investigated. All compounds (1–3) were characterized using NMR spectroscopy, ESI mass-spectrometry and elemental analysis. X-Ray crystal structure of the complex containing 4,4′-bis(tert-butyl)-2,2′-bipyridine and terphenylacetylide ligands is reported. The electronic absorption and emission spectra of the complexes have been studied. Room temperature phosphorescence was observed for the complexes in solution with the luminescence quantum yield in the 7.5–11% range and excited state lifetimes in microsecond time domain. All complexes under study exhibit two-photon luminescence and their double quantum absorption cross-section was found to be in the 9–22 GM range.