A series of oxorhenium(V) complexes with 2-aminoethanethiolate (act), [ReO(aet-NS)(D-pen-N,O,S)] (2), [{ReO(aet-N,S)(2)}(2)O] (3), [ReO(Cl)(aet-N,S)(2)] (4), and [ReO(aet-NS)(Haet-S)(2)]Cl-2 ([5]Cl-2) was newly prepared starting from ReO4-. The reaction of NH4ReO4 with a 1:1 mixture of Haet . HCl and D-H(2)Pen (D-penicillamine) in the presence of SnCl2. 2H(2)O in water gave 2, 3, and the known complex [ReO(D-Hpen-N,S)(D-pen-N,O,S)] (1). These complexes were fractionally precipitated by controlling the pH of the reaction solution. The complex 2 was also prepared in a higher yield by a similar reaction using methanol as a solvent. The crystal structure of 2 was determined by X-ray crystallography; 2 crystallizes in the tetragonal space group P4(3) with a = 9.621(1), c = 12.911(1) Angstrom, V = 1195.0(3) Angstrom (3), and Z = 4. The oxorhenium(V) core in 2 is coordinated by a bidentate-N,S act ligand and a tridentate-N,O,S D-pen ligand, having a distorted octahedral geometry with a cis-N cis-S configuration in the equatorial plane perpendicular to the O-Re-O axis. The 1:2 reaction of NH4ReO4 with Haet . HCl in the presence of SnCl2. 2H(2)O in methanol produced 4, which is interconvertible with 3, while the corresponding 1:3 reaction resulted in the isolation of [5]Cl2. The complexes 4 and 5 were also structurally characterized; 4 crystallizes in the monoclinic space group P2(1)/c with a = 6.839(1), b = 10.0704(6), c = 14.1075(8) Angstrom, beta = 91.729(8)degrees, V = 971.2(2) Angstrom (3), and Z = 4, while [5]Cl-2 crystallizes in the triclinic space group P (1) over bar with a = 11.938(3), b = 12.366(3), c = 5.819(1) Angstrom, alpha = 102.71(2), beta = 101.28(2), gamma = 75.41(2)degrees, V = 802.0(3) Angstrom (3), and Z = 2. In 4, the oxorhenium(V) core is octahedrally coordinated by two bidentate-NS act ligands, which form a cis-N cis-S configurational equatorial plane with a Cl- ion trans to the oxo ligand. On the other hand, the oxorhenium(V) core in [5](2+) is coordinated by one bidenate-N,S act and two monodentate-S Haet ligands, having a distorted trigonal-bipyramidal geometry with S and N donors at the apical positions.