Guanidinium Alkynesulfonates with Single‐Layer Stacking Motif: Interlayer Hydrogen Bonding Between Sulfonate Anions Changes the Orientation of the Organosulfonate R Group from “Alternate Side” to “Same Side”

Hydrolyses of HC?CSO₃SiMe₃ ( 1 ) and CH₃C?CSO₃SiMe₃ ( 2 ) lead to the formation of acetylenic sulfonic acids HC?CSO₃H?2.33 H₂O ( 3 ) and CH₃C?CSO₃H?1.88 H₂O ( 4 ). These acids were reacted with guanidinium carbonate to yield [⁺C(NH₂)₃][HC?CSO₃^?] ( 5 ) and [⁺C(NH₂)₃][CH₃C?CSO₃^?] ( 6 ). Compounds 1 – 6 were characterized by spectroscopic methods, and the X‐ray crystal structures of the guanidinium salts were determined. The X‐ray results of 5 show that the guanidinium cations and organosulfonate anions associate into 1D ribbons through ${{rm R}{{2hfill atop 2hfill}}}$ (8) dimer interactions, whereas association of these ions in 6 is achieved through ${{rm R}{{2hfill atop 2hfill}}}$ (8) and ${{rm R}{{1hfill atop 2hfill}}}$ (6) interactions. The ribbons in 5 associate into 2D sheets through ${{rm R}{{2hfill atop 2hfill}}}$ (8) dimer interactions and ${{rm R}{{3hfill atop 6hfill}}}$ (12) rings, whereas those in 6 are connected through ${{rm R}{{1hfill atop 2hfill}}}$ (6) and ${{rm R}{{2hfill atop 2hfill}}}$ (8) dimer interactions and ${{rm R}{{4hfill atop 6hfill}}}$ (14) rings. Compound 6 exhibits a single‐layer stacking motif similar to that found in guanidinium alkane‐ and arenesulfonates, that is, the alkynyl groups alternate orientation from one ribbon to the next. The stacking motif in 5 is also single‐layer, but due to interlayer hydrogen bonding between sulfonate anions, the alkynyl groups of each sheet all point to the same side of the sheet.