Compound 39: Bis(ethyl 5-hydroxy-1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate)tetrakis(acetato)dirhodium

DOI: 10.14469/hpc/11376 Metadata

Created: 2022-10-11 14:15

Last modified: 2024-07-03 14:02

Author: Henry Rzepa

License: Creative Commons: Public Domain Dedication 1.0

Funding: (none given)

Description

1H and 13C primary NMR and crystal data for Bis(ethyl 5-hydroxy-1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate)tetrakis(acetato)dirhodium (39): [Rh2(OAc)4] (92.0 mg, 0.208 mmol, 1.00 equiv) was added with stirring to pyrazolone 8 (230 mg, 0.833 mmol, 4.00 equiv) in MeCN (4.0 mL) and the mixture was heated at reflux at 85 °C for 18 h, cooled to room temperature and evaporated to dryness. The residue was redissolved in CH2Cl2 (5.0 mL) and the complex was precipitated with the addition of hexanes (15 mL). The mixture was cooled in an ice-bath, the precipitate was collected by filtration and dried in vacuo. Rh-pyrazolone complex 39 (202 mg, 0.203 mmol, 98%) was obtained as a purple-red solid, essentially pure by its 1H NMR spectrum. Crystals suitable for X-ray crystallography were obtained from the CH2Cl2/hexanes filtrate. 1H-NMR (400 MHz, CD2Cl2): δ (ppm) = 9.34 (s, 2H), 8.12 (s, 2H), 7.45 (d, J = 8.4 Hz, 4H), 6.89 – 6.79 (m, 4H), 5.61 (s, 4H), 4.38 (q, J = 7.1 Hz, 4H), 3.76 (s, 6H), 1.84 (s, 11H), 1.38 (t, J = 7.1 Hz, 6H). 13C{1H}-NMR (101 MHz, CD2Cl2): δ (ppm) = 191.6, 159.7, 157.5, 139.9, 130.3, 128.7, 114.0, 95.8, 61.2, 55.6, 50.5, 23.8, 14.6. IR (Diamond-ATR, neat) νmax (cm-1) = 1700, 1627, 1611, 1591, 1512, 1436, 1247, 1176, 1031, 775, 695. HRMS (ES-ToF) m/z: [M + H]+ calc. for (C36H45N4O16Rh2)+: 995.0935, found: 995.0932. m.p.: 195 – 199 °C (EtOH) (decomp.). Anal. Calcd for C36H44N4O16Rh2: C, 43.48; H, 4.46; N, 5.63. Found: C, 43.37; H, 4.42; N, 5.57.

Member of collection / collaboration

DOIDescription
10.14469/hpc/10386 Syntheses and Characterization of Main Group, Transition Metal, Lanthanide and Actinide Complexes of Bidentate Acylpyrazolone Ligands

Members

DOIDescription
10.14469/hpc/11587 NMR Data for Compound 39.
10.14469/hpc/11586 IR Data for Compound 39.
10.14469/hpc/11377 Primary Crystal data for Compound 39. Bis(ethyl 5-hydroxy-1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate)tetrakis(acetato)dirhodium

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