Avance 250 spectrometer

NMR spectra were registered on a Bruker Avance 250 spectrometer (250 MHz for ¹H, 63 MHz for ¹³C) (Bruker, Rivas-Vaciamadrid, Spain) and maintained by the Unidad de Resonancia Magnética Nuclear, UCM. Infrared spectra were obtained by preparing KBr disks for each compound and registering their spectra on a Perkin Elmer Paragon 1000 FT-IR spectrophotometer (Tres Cantos, Spain). Melting points were taken on a Reichert 723 hot stage microscope (Vienna, Austria). CHN combustion elemental analyses were performed by the Unidad de Microanálisis Elemental, UCM, using a Leco CHNS-932 combustion microanalyzer (Tres Cantos, Spain).

All manipulations were performed under an inert atmosphere of argon using Schlenk techniques or in a MBraun inert-gas glovebox. Deuterated solvents were purchased from Euriso-top and dried over 4 Å molecular sieves. All aldehyde substrates were obtained from commercial sources and distilled prior to use. Complexes 1 and 2 were prepared according to literature procedures [13 (link), 14 (link)]. ¹H, ¹³C{¹H}, and ³¹P{¹H} NMR spectra were recorded on a Bruker AVANCE-250 spectrometer. ¹H and ¹³C{¹H} NMR spectra were referenced internally to residual protio-solvent and solvent resonances, respectively, and are reported relative to tetramethylsilane (δ = 0 ppm). ³¹P{¹H} NMR spectra were referenced externally to H₃PO₄ (85%) (δ = 0 ppm).

Melting points were determined on a Büchi melting point B-540 apparatus (BÜCHI Labortechnik AG, Flawil, Switzerland) and are uncorrected. Element analyses were performed on a Thermo Finnigan EA1112 (San Jose, CA, USA) at the spectropole of the Aix-Marseille University. Both ¹H- and ¹³C-NMR spectra were determined on a Bruker Avance 250 spectrometer (Wissembourg, France) at the Service de RMN de la Faculté de Pharmacie de Marseille of the Aix-Marseille University and on a Bruker Avance III NanoBay 300 MHz spectrometer at the spectropole of Aix-Marseille University. The ¹H- and the ¹³C-chemical shifts are reported from CDCl₃ peaks: ¹H (7.26 ppm) and ¹³C (77 ppm) or Me₂SO-d6 (39.6 ppm). Multiplicities are represented by the following notations: s, singlet; d, doublet; t, triplet; q, quartet; m, a more complex multiplet, or overlapping multiplets. The following adsorbents were used for column chromatography: silica gel 60 (Merck, particle size 0.063–0.200 mm, 70–230 mesh ASTM, (Merck, Darmstadt, Germany). Thin Layer Chromatography (TLC) was performed on 5 cm × 10 cm aluminum plates coated with silica gel 60 F254 (Merck) in an appropriate solvent.