How do weak Z-X-X and stronger X-Z-X interactions affect NMR chemical shifts of chalcogenide dihalides, R2Z·X2? Theoretical background on the structural prediction of R2Z·X2 through chemical shifts in solutions

The mechanism is clarified for the high applicability of criteria to distinguish molecular complexes (MC) from pseudo‐trigonal bipyramidal adducts (TBP) of chalcogenide dihalogens in solutions, based on the NMR chemical shifts. The criteria are theoretically investigated employing MC and TBP of MeSeMe ( 1 ), EtSeEt ( 3 ), PhSePh ( 7 ), PhSPh ( 8 ), and PhSeH ( 22 ) with chlorine and/or bromine. The adducts of (CH 2 CH) 2 Se ( 26 ), H 2 C(CHCH)...