[1,2,3]Triazolo[1,5-a]pyridyl phosphines reflecting the influence of phosphorus lone pair orientation on spectroscopic properties

A series of new triazolopyridine-based phosphines has been prepd. These compds. revealed unexpected spectroscopic patterns. In particular, the NMR spectra are highly dependent on the relative conformational preference of the phosphine substituent at C7. Here, we report on their complete NMR anal., X-ray structures and DFT calcns. that confirm the particular arrangement of the phosphorus lone pair orbital related to the substituent pattern of the chosen phosphine