The reaction of [Mn(dmptacn)OH2](2+) and [Ni(dmptacn)OH2](2+) (dmptacn = 1,4-bis(2-pyridylmethyl)-1,4,7-triazacyclononane) with each cyano ligand on ferricyanide results in the assembly of heteropolynuclear cations around the cyanometalate core and reduction of Fe-III to Fe-II. In [{Mn(dmptacn)CN}(6)Fe][ClO4](8).5H(2)O (1) and [{Ni(dmptacn)-CN}(6)Fe][ClO4](8).7H(2)O (2), ferrocyanide is encapsulated by either six Mn-Il or Ni-II dmptacn moieties. These same products are obtained when ferrocyanide salts are used in the synthesis instead of ferricyanide. A binuclear complex, [{Mn(dmptacn)}(2)CN][ClO4](3) (3), has also been formed from KCN and [Mn(dmptacn)OH2](2+). For both Mn-II and Ni-II, the use of the pentadentate dmptacn ligand facilitates the formation of discrete cations in preference to networks or polymeric structures. 1 crystallizes in the trigonal space group R3 (No. 148) with a = 30.073(3) Angstrom, c = 13.303-(4) Angstrom, and Z = 3 and is composed of heptanuclear [{Mn(dmptacn)CN}(6)Fe](8+) cations whose charge is balanced by perchlorate counteranions. Weak H-bonding interactions between neighboring heptanuclear cations and some perchlorate counterions generate an infinite 1D chain of alternating [{Mn(dmptacn)CN}(6)Fe](8+) and ClO4- ions running along the c-axis. Complex 3 crystallizes in the orthorhombic space group Pbcn (No. 60) with a = 16.225(3) Angstrom, b = 16.320(2) Angstrom, c = 18,052(3) Angstrom, and Z = 8 and is composed of binuclear [{Mn(dmptacn)}(2)CN](3+) cations in which the cyano-bridged Mn-II centers are in a distorted trigonal prismatic geometry, Variable temperature magnetic susceptibility measurements have revealed the presence of a weak ferromagnetic interaction between the paramagnetic Mn-II centers in 1, mediated either by the -NC-Fe-CN- bridging units or by Mn-NH...ClO4-...NH-Mn intercluster pathways.