syn,E-1-cyclopentano-4-ethyl-3-thiosemicarbazone and syn,E-1-cyclopentano-4 phenyl-3-thiosemicarbazone

The structures of two thiosemicarbazones are described: syn E-1-cyclopentan o-4-ethyl-3-thiosemicarbazone (1) and syn,E-1-cyclopentano-4-phenyl-3-thios emicarbazone (2). Crystal data: for 1: tetragonal, P4(3) (#78), a = b = 8.9 22(7) Angstrom, c = 12.899(13) Angstrom, and Z = 4; for 2: monoclinic a = 1 5.163(18) Angstrom, b = 7.482(5) Angstrom, c = 12.467(15) Angstrom, beta = 119.04(7)degrees, and Z = 4. In 1, molecules are linked by hydrogen-bonding into infinite chains with non-planar 9-ring subunits in which thioamides i nteract with the H-N-C-N-N groups of neighbors. Thioamide groups in 2 form dimers linked by N-B ... HS hydrogen-bonds with a planar 8-ring as in solid state structures of carboxylic acids. The semicarbazide syn conformation f osters formation of N-H ... N intramolecular hydrogen-bonding in each struc ture. The solid state structures are consistent with their infrared and pro ton nuclear magnetic resonance spectra.