Complexes [PPh3Cu(Tr-Mes,(Me))] (1), [PPh3CU(Tr-Me,Tr-o-Py)] (2), and [PPh3Cu(Br(Mes)pz(o-py))] (3) (Tr-Mes,Tr-Me = hydrotris[1,4-dihydro-3-methyl-4-mesityl-5-thioxo-1,2,4-triazolyl]borate ; Tr-Me,Tr-o-Py = hydrotris[1,4-dihydro-4-methyl-3-(2-pyridyl)-5thioxo-1,2,4-triazolyl]bor ate; Br(Mes)pz(o-Py) = hydro[bis(thioxotriazolyl)-3-(2-pyridyl)pyrazolyl]borate; PPh3 = triphenylphosphine) were synthesized by the reaction of dinuclear complexes [Cu(Tr-Mes,Tr-Me)](2), [Cu(Tr-Me,Tr-o-Py)](2), [Cu(Br(Mes)pz(o-py))](2), and PPh3. 1-3 were characterized by H-1, C-13, and P-31 NMR spectroscopy and ESI-mass spectrometry. Crystal structure analyses were performed for 1 and 2. Both complexes crystallize in the triclinic P (1) over bar space group with the metal in a slightly distorted tetrahedral geometry (S3P coordination) bound by a kappa(3)-S-3 ligand and a PPh3 molecule. The solution molecular structures were investigated by means of variable-temperature (210-310 K, CDCl3, 1-2; 200-310 K, CD2Cl2, 3) and NOESY NMR spectroscopy. The solution structures of 1-2 are in accordance with the X-ray structures, and the complexes do not exhibit fluxional behavior. On the other hand, 3 is subject to an equilibrium between two species with a coalescing temperature of similar to 260 K. DFT geometry optimizations suggest that the major species of 3 consists of the Br(Mes)pz(o-Py) ligand bound to Cu(1) in the kappa(3)_S2H fashion with two C=S groups and a [(CuH)-H-...-B] interaction. A PPh3 completes the copper coordination (S2HP coordination). The complex [TuCu-(Tr-Mes,Tr-Me)] (4) (Tu = thiourea) was crystallized using an excess of Tu with respect to [Cu(Tr-Me,Tr-2-Py)](2) (approximately a 6:1 ratio). The metal adopts a distorted tetrahedral geometry with an overall S3H coordination determined by the bound kappa(3)-S2H ligand (two C=S groups and a [B-H... Cu] interaction) and by a Tu. The reactivity of dinuclear complexes [Cu(Tr-Mes,Tr-Me)](2), [Cu(Tr-Me,Tr-o-Py)](2), and [Cu(Br(Mes)pz(o-Py))](2) with monodentate ligands was investigated by means of NMR titrations with PPh3, Tu. and pyridine (Py), and formation constants for the adducts [DCu(L)] (D monodentate donor, L = tripodal ligand) were determined.