Center for Magnetic Resonance

E.A. Valishina, M.F.C. Guedes da Silva, M.A. Kinzhalov, S.A. Timofeeva, T.M. Buslaeva, M. Haukka, A.J.L. Pombeiro, V.P. Boyarskiy, V.Yu. Kukushkin, K.V. Luzyanin

“Palladium-ADC complexes as efficient catalysts in copper-free and room temperature Sonogashira coupling”

J. Molec. Catalysis , 2014, 395, 162-171

DOI:10.1016/j.molcata.2014.08.018

The metal-mediated coupling between cis-[PdCl₂(CNR¹)₂] [R¹ = cyclohexyl (Cy) 1, t-Bu 2, 2,6-Me₂C₆H₃ (Xyl) 3, 2-Cl-6-MeC₆H₃ 4] and hydrazones H₂NN=CR²R³ [R², R³ = Ph 5; R², R³ = C₆H₄(OMe-4) 6; R²/R³ = 9-fluorenyl 7; R² = H, R³ = C6H4(OH-2) 8] provided carbene complexes cis-[PdCl₂{C(N(H)N=CR²R³)=N(H)R¹}(CNR¹)] (9–24) in good (80–85%) yields. Complexes 9–24 showed high activity [yields up to 99%, and turnover numbers (TONs) up to 3.7 × 10⁴] in the Sonogashira coupling of various aryl iodides with a range of substituted aromatic alkynes without the need of copper co-catalyst. The catalytic procedure runs at 80 °C for 1 h in EtOH using K₂CO₃ as a base. No formation of homocoupling or acetylene decomposition products was observed. Designed copper-free Sonogashira system can also run at room temperature giving target products with yields up to 87% and TONs up to 87.

I.I. Eliseev, P.V. Gushchin, Yi.-A. Chen, P.-T. Chou, M. Haukka, G.L. Starova, V.Yu. Kukushkin

“Phosphorescent Pt(II) Systems Featuring Both 2,2’-Dipyridylamine and 1,3,5-Triazapentadiene Ligands”

Eur. J. Inorg. Chem. 2014 , 4101-4108

DOI:10.1002/ejic.201402364

The treatment of cis-[Pt(dpa)(RCN)₂][SO₃CF₃]₂ {dpa = 2,2′-dipyridylamine, R = Me, Et, CH₂Ph, Ph; [2a–d](OTf)₂} (OTf = SO₃CF₃) with 2 equiv. of N,N′-diphenylguanidine [NH=C(NHPh)₂] in CH₂Cl₂ solutions at room temp. for 16 h gives [Pt(dpa){NH=C(R)NC(NHPh)=NPh}][SO₃CF₃] {[3a,b,d](OTf)} as the addition products and [Pt(dpa){NH=C(R)NHC(R)=NH}][SO₃CF₃]₂ {[4a,b](OTf)₂} as the tailoring products. The formulation of complexes [3a,b,d](OTf) and [4a,b](OTf)₂ was supported by satisfactory C, H, and N elemental analyses and agreeable high-resolution ESI-MS, IR, and ¹H (including ¹H–¹H COSY experiments) and ¹³C{¹H} NMR data. The structures of all of the platinum species were determined by single-crystal X-ray diffraction. The resultant complexes are nonemissive in solution, mainly because of the interaction between the empty d_z² orbital in a square-planar configuration and solvent molecules. However, in the solid state, complexes [3a,b,d](OTf) exhibit strong phosphorescence with quantum yields (peak wavelength) of 0.23 (490 nm), 0.27 (483 nm), and 0.20 (532 nm), respectively.