Center for Magnetic Resonance

Mikhail A. Kinzhalov, Konstantin V. Luzyanin, Irina A. Boyarskaya, Galina L. Starova, Vadim P. Boyarskiy

“Synthetic and structural investigation of [PdBr₂(CNR)₂] (R = Cy, Xyl)”

Journal of Molecular Structure 2014, 1068, 222–227

DOI: 10.1016/j.molstruc.2014.04.025

Reaction of cis-dichloro-bis-(cyclohexylisocyanide)palladium(II) ([PdCl₂(CNCy)₂], (1) or cis-dichloro-bis-(2,6-dimethylphenyl-isocyanide)palladium(II) ([PdCl₂(CNXyl)₂], (2) with excess of potassium bromide in acetone furnished complexes trans-dibromo-bis-(cyclohexylisocyanide)palladium(II) ([PdBr₂(CNCy)₂], (3) or trans-dibromo-bis-(2,6-dimethylphenylisocyanide)palladium(II) ([PdBr₂(CNXyl)₂], (4), respectively. Both compounds were characterized by elemental analyses (C, H, N), high resolution ESI⁺-MS, IR, ¹H and ¹³C{¹H} NMR spectroscopies, and their crystals were analyzed by a single-crystal and powder X-ray diffraction methods. To rationalise the dependence of the structure of 1–4 on type of halogen ligands, the Gibbs free energies of corresponding cis- and trans-isomers of 1–4 were estimated at the DFT B3LYP level of theory.

Ludmila L. Rodina, Jury J. Medvedev, Olesia S. Galkina and Valerij A. Nikolaev

“Thermolysis of 4-Diazotetrahydrofuran-3-ones: Total Change of Reaction Course Compared to Photolysis”

European Journal of Organic Chemistry 2014, 14, 2993–3000

DOI: 10.1002/ejoc.201400161

Thermolysis of 2,2,5,5-tetrasubstituted 4-diazodihydrofuran-3-ones in protic (BnOH) and aprotic (DMSO) media, in contrast to photolysis, gives rise to the formation of 2,2,4,5-substituted 3(2H)-furanones as a result of 1,2-alkyl (aryl) shift. The thermal stability of diazodihydrofuranones in these processes is determined by the nature of the substituents at the C-5 atom of the heterocyclic structure: alkyl and electron-donating groups in the para-position of the aryl substituent notably reduce the persistence of diazodihydrofuranones, whereas aryl groups and electron-withdrawing substituents increase their stability considerably. Thermolysis of substituted 4-diazodihydrofuran-3-ones in DMSO solution is a first-order reaction that furnishes higher yields of furanones than thermolysis in BnOH. The reaction can serve as a preparative method for the synthesis of tetrasubstituted-3(2H)-furanones.

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.