Gold(I)-triphenylphosphine-arylazoimidazole: Synthesis and spectral (H,C, COSY,HMQC NMR) characterization

The reaction of Au(OSO₂CF₃)(PPh₃)] with arylazoimidazole in dichloromethane followed by NH₄PF₆ leads to Au(RAaiR′)(PPh₃)]PF₆ (RAaiR′ = p-R-N=N-C₃H₂-NN-1-R′), abbreviated as N,N′/-chelator, where N (imidazole) and N (azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c), and R′ = Me (I), CH₂CH₃ (II), CH₂Ph (III)]. IR spectra of the complexes show -C=H- and -N=N-stretchings at 1590 and 1370 and at 1100, 755, 695, 545, and 505 cm⁻¹ due to the presence of the triphenylphosphine ring. The ¹H NMR spectral measurements suggest that methylene (-CH₂-) in (RAai)Et gives a complex of the AB type multiplet with a coupling constant of ∼7.6 Hz while in RAaiCH₂Ph it shows AB type quartets with coupling constant of av. 7.2 Hz. Considering the arylazoimidazole moity, there are different carbon atoms in the molecule giving different peaks in the ¹³C NMR spectrum of the complexes. In the ¹H-¹H COSY spectrum of the present complexes, the absence of any off-diagonal peaks extending from δ = 14.12 and 9.55 ppm confirms their assignment of no proton on N(1) and N(3), respectively. Contour peaks in the ¹H-¹³C HMQC spectrum in the present complexes, the absence of any contours at δ = 157.12, 160.76, 155.67, and 157.68–160.2 ppm assign them to the C(2), C(6), C(12), and C(PPh₃) carbon atoms, respectively. The solution structure and stereoretentive transformation in each step have been established from the ¹H NMR results. The article was submitted by the authors in English.