Weak interactions and tautomerism in 3,5-dinitrosubstituted 2- and 4-hydroxypyridines and products of their reaction with [O(AuPPh3)3]BF4: Synthesis, X-ray structure, IR and UV spectroscopy, and quantum chemical calculations

Products of the interaction of 3,5-dinitrosubstituted ortho- and para- hydroxypyridines with [O(AuPPh 3 ) 3 ][BF 4 ] are investigated by X-ray crystallography, IR and UV spectroscopy. The structure of the parent organic molecules are investigated by the spectroscopic methods and ab initio quantum chemical calculations. The calculation and spectroscopy show that the corresponding organic molecules can exist in both tautomeric forms. The reaction with the ortho isomer results in the N-aurated dimer {[NC 5 H 2 (NO 2 ) 2 O](AuPPh 3 )} 2 bound through interaction. Under similar conditions, the para isomer yields a salt of composition [O(AuPPh 3 ) 3 ][NC 5 H 2 (NO 2 ) 2 O].