1 H{ 15 N} GHMQC study of 5,7‐diphenyl‐1,2,4‐triazolo[1,5‐ a ]pyrimidine and 1 H, 13 C and 15 N NMR coordination shifts in Au(III) chloride complexes of 1,2,4‐triazolo[1,5‐ a ]pyrimidines

The 1 H{ 15 N} NMR spectrum of 5,7‐diphenyl‐1,2,4‐triazolo[1,5‐ a ]‐pyrimidine ( 3 ) was measured by GHMQC, unambiguously assigned and compared with the spectra of 1,2,4‐triazolo[1,5‐ a ]pyrimidine ( 1 ) and 5,7‐dimethyl‐1,2,4‐triazolo[1,5‐ a ]pyrimidine ( 2 ). A series of Au(III) chloride complexes of general formula AuLCl 3 , where L = 1 , 2 , 3 , was synthesized and studied by 1 HH{ 15 N} GHMQC and 1 H{ 13 C} GHMBC. Low‐frequency shifts of 72–74 ppm ( 15 N) and 5–6 ppm ( 13 C) were observed upon complexation by Au(III) ions for the coordination site N‐3 and adjacent C‐2, C‐3a atoms, respectively. The 13 C signals of C‐5, C‐6, C‐7 and the 1 H resonances of H‐2, H‐6 were shifted to higher frequency. Comparison with analogous Pd(II), Pt(II) and Pt(IV) complexes revealed that in the case of Au(III) coordination the 15 N shifts were relatively smaller, whereas those for 13 C and 1 H were larger. Copyright © 2002 John Wiley & Sons, Ltd.