Crystal structures of two organic salts of 1,2,3,4-tetrahydro-1,10-phenanthroline

Two organic salts of 1,2,3,4-tetrahydro-1,10-phenanthroline (tphen), namely (oaH)(tphenH) (1) and (ssa)(tphenH)·H₂O (2) (oaH₂ is oxalic acid, ssaH is 5-sulfosalicylic acid), were synthesized and structurally characterized. Both compounds contain tphenH⁺ cations but illustrate different crystal structures. The tphenH⁺ cations show a cross-stacking packing model in 1 but display a herringbone packing model in 2.