A series of hybrid inorganic-organic copper(II) hydroxy n-alkylsulfonate with a triangular lattice, Cu-2(OH)(3-)(CnH2n+1SO3) (11 = 6, 8, 10), are prepared by anion exchange, starting from copper hydroxy nitrate Cu-2(OH)(3-)NO3. These compounds show a layered structure as determined by X-ray diffraction, with interlayer distances of 14.3-34.8 Angstrom in alternation with interdigitated bilayer packing. Magnetic properties have been investigated by means of dc and ac measurements. All the compounds show similar metamagnet behaviors, with a Neel temperature of about 11 K. A subtle difference in the ac magnetic Susceptibility among the compounds is understood by the existence of hydrogen bonding between the sulfonate headgroup and the hydroxide anion. A detailed molecular structure of the alkyl chains incorporated to the inorganic copper hydroxide layer is also discussed from the FTIR data.