Formaldoxime hydrogen bonded complexes with ammonia and hydrogen chloride

• 1:1 and 1:2 CH2NOH complexes with NH3 and HCl are trapped in the argon matrices.
• Formaldoxime complexes with ammonia are stabilized by strong OH⋯N bond.
• Formaldoxime complexes with HCl are stabilized by strong N⋯HCl bond.
• Hydrogen bonds in the cyclic 1:2 complexes show strong cooperativity.

An infrared spectroscopic and MP2/6–311++G(2d,2p) study of hydrogen bonded complexes of formaldoxime with ammonia and hydrogen chloride trapped in solid argon matrices is reported. Both 1:1 and 1:2 complexes between formaldoxime and ammonia, hydrogen chloride have been identified in the CH2NOH/NH3/Ar, CH2NOH/HCl/Ar matrices, respectively, their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes present in the argon matrices the OH group of formaldoxime acts as a proton donor for ammonia and the nitrogen atom acts as a proton acceptor for hydrogen chloride. In the 1:2 complexes ammonia or hydrogen chloride dimers interact both with the OH group and the nitrogen atom of CH2NOH to form seven membered cyclic structures stabilized by three hydrogen bonds. The theoretical spectra generally agree well with the experimental ones, but they seriously underestimate the shift of the OH stretch for the 1:1 CH2NOH⋯NH3 complex.

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