In the exploration of sulfur-delivery reagents useful for synthesizing models of the tetracopper-sulfide cluster of nitrous oxide reductase, reactions of Ph3Sb=S with Cu(I) complexes of N,N,N',N'-tetramethyl-2R,3R-cyclohexanediamine (TMCHD) and 1,4,7-trialkyltriazacyclononanes (R(3)tacn; R = Me, Et, iPr) were studied. Treatment of [(R(3)tacn)Cu(NCCH3)]SbF6 (R = Me, Et, or iPr) with 1 equiv of S=SbPh3 in CH2Cl2 yielded adducts [(R(3)tacn)Cu(S=SbPh3)]SbF6 (1-3), which were fully characterized, including by X-ray crystallography. The adducts slowly decayed to [(R(3)tacn)(2)Cu-2(mu-eta(2):eta(2)-S-2)](2+) species (4-6) and SbPh3, or more quickly in the presence of additional [(R(3)tacn)Cu(NCCH3)]SbF6 to 4-6 and [(R(3)tacn)Cu(SbPh3)]SbF6 (7-9). The results of mechanistic studies of the latter process were consistent with rapid intermolecular exchange of S=SbPh3 between 1-3 and added [(R(3)tacn)Cu(NCCH3)]SbF6, followed by conversion to product via a dicopper intermediate formed in a rapid pre-equilibrium step. Key evidence supporting this step came from the observation of saturation behavior in a plot of the initial rate of loss of 1 versus the initial concentration of [(Me(3)tacn)Cu(NCCH3)]SbF6. Also, treatment of [(TMCHD)Cu(CH3CN)]PF6 with S=SbPh3 led to the known tricopper cluster [(TMCHD)(3)Cu-3(mu(3)-S)(2)](PF6)(3) in good yield (79%), a synthetic procedure superior to that previously reported (Brown, E. C.; York, J. T.; Antholine, W. E.; Ruiz, E.; Alvarez, S.; Tolman, W. B. J. Am. Chem. Soc. 2005, 127, 13752-13753).