Abstract The molecule HNO complexed to N-methylenemethylamine (H 2 C N CH 3) was prepared by photolyzing N, N-dimethylnitrosamine [(CH 3) 2 N NO] in low temperature matrices. The infrared absorptions of six isotopic such complexed HNO species were measured and assigned. Based on these results a complex between HNO and the amine involving a hydrogen bond is proposed. The bands associated with the hydrogen bond, N ...