Structural Prediction of Bis{(di-p-anisole)-1,4-azabutadiene}-bis[triphenylphosphine]ruthenium(II) Using ³¹P NMR Spectroscopy

Abstract

The present paper reports the use of 31P NMR spectroscopy to predict the isomer structures of [bis{4-methoxy-phenyl-[3-(4-methoxy-phenyl)-allylidene]-amino}]-bis[triphenylphosphine]ruthenium(II), also known as bis{(di-p-anisole)-1,4-azabutadiene}-bis[triphenylphosphine]ruthenium(II), complexes. The complexation reaction was carried out under refluxing condition of (di-p-anisole)-1,4-azabutadiene (compound 1), triphenylphosphine (PPh3), and ruthenium chloride in the ratio of 2 : 2 : 1 for five hours. In addition, ruthenium(II) complexes were also characterized using FTIR and UV-Vis spectroscopy to support the formation of ruthenium(II) complexes. 31P NMR spectroscopic study on ruthenium(II) complexes suggested that there are three isomers present after the complexation reaction and all the ruthenium complexes demonstrate octahedral geometry.

Ru(II)-Anionic-Naked-NHC Complexes as Cooperative Lewis Pairs: Parallels in Structure and FLP-type Chemical Reactivity

“…31 P{ 1 H} NMR spectrum also shows two peaks at δ 23.89 and 32.44 ppm, along with a peak at -6.00 ppm for free triphenylphosphine ligand in solution. 69,91 In 13 C{ 1 H} NMR, the resonance for Ru-Ccarbene as triplet signal observed at δ = 204.49 for the bisphosphine complex 1, and a doublet signal at δ 202.74 ppm can be assigned for the monophosphine complex 1a generated in solution (see SI Fig S8). To confirm the phosphine dissociated form 1a, CuI was used as a phosphine scavenger.…”

Conformational Mobility and Proton Transfer in Hydrogen-Bonded Dimers and Trimers of Phosphinic and Phosphoric Acids

“…For example, isotropic 31 P NMR chemical shifts, δP, could be used to estimate the π-accepting properties of carbenes in a series of carbine–phosphinidene adducts . The 31 P NMR spectroscopy also could be used to distinguish between nonequivalent isomers of organometallic complexes , and between enantiomers of chiral molecules. , Moreover, the sensitivity of δP to the noncovalent interactions was used to construct various scales of Brønsted and Lewis acidities . Most often, trialkylphosphines (R 3 P) and trialkylphosphine oxides (R 3 PO) are used as phosphorous probes.…”