Variation of heterometallic structural motifs based on [W(CN)(8)](3-) anions and Mn-II ions as a function of synthetic conditions

Reactions of [W(CN)(8)](3-/4-) anions with complexes of Mn2+ ion with tridentate organic ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) lead to a series of heterobimetallic complexes. The crystal structures of these compounds are derived from the same basic structural fragment, namely a W2Mn2, square constructed of alternating cyanide-bridged W and Mn ions. In [Mn-II(tptz)(OAc)(H2O)(2)](2){[Mn-II(tptz)(MeOH)(1.58)(H2O)(0.42)](2)[W-v(CN)(8)](2)}center dot 5MeOH center dot 9.85H(2)O (3), isolated molecular squares are co-crystallized with mononuclear cationic Mn-II complexes. The structure of {[Mn-II(tptz)(MeOH)(2)- [W-IV(CN)(8)]center dot 2MeOH}(infinity) (4) is based on an infinite chain of vertex-sharing squares, while {[Mn-2(II)(tptz)(2)(MeOH)(3)-(OAc)][W-v(CN)(8)]center dot 3.5MeOH center dot 0.25H(2)O}infinity (5) and {[Mn-2(II)(tptz)(2)(MeOH)(3)Wv(CN)(8)][Mn-II(tptz)(MeOH)W-v(CN)(8)] center dot 2H(2)O center dot MeOH}(8) (7) are derived from such an infinite chain by removing one of the W-C N-Mn linkages in each of the squares. The decanuclear cluster [Mn-6(II)(tptz)(6)(MeOH)(4)(DMF)(2)W-4(V)- (CN)(32)]center dot 8.2H(2)O center dot 2.3MeOH (6) is a truncated version of structure 4 and consists of three vertex-sharing W2Mn2 squares. The structure of [Mn-II(tptz)(MeOH)(NO3)](2)[Mn-II(tptz)(MeOH) (DMF)](2)[W-v(CN)(8)](2)center dot 6MeOH (8) consists of a hexanuclear cluster, in which the central W2Mn2 square is extended by two Mn side-arms attached via CN- ligands to the W corners of the square. The magnetic behavior of these heterobimetallic complexes (except for 4) is dominated by antiferromagnetic coupling between Mn-II and W-v ions mediated by cyanide bridges. Compounds 3, 6, and 8 exhibit high spin ground states of S=4, 13, and 9, respectively, while 5 and 7 exhibit behavior typical of a ferrimagnetic chain with alternating spin centers. Complex 4 contains diamagnetic W-IV centers but holds promise as a potential photomagnetic solid.