New heterospin complexes have been obtained by combining the binuclear complexes [{Cu(H
2O)L
1}Ln(O
2NO)
3] or[{CuL
2}Ln(O
2NO)
3] (L
1 =
N,
N'-propylene-di(3-methoxysalicylideneiminato); L
2 =
N,
N'-ethylene-di(3-methoxysalicylideneiminato); Ln = Gd
3+, Sm
3+, Tb
3+), with the mononuclear [CuL
1(2)] and the nickel dithiolene complexes [Ni(mnt)
2]
q- (
q= 1, 2; mnt = maleonitriledithiolate), as
follows:
1fin.gif">[{CuL
1}
2Ln(O
2NO){Ni(mnt)
2}]·Solv·CH
3CN (Ln = Gd
3+, Solv =CH
3OH (
1), Ln = Sm
3+, Solv = CH
3CN (
2)) and [{(CH
3OH)CuL
2}
2Sm(O
2NO)][Ni(mnt)
2] (
3) with [Ni(mnt)
2]
2-, [{(CH
3CN)CuL
1}
2Ln(H
2O)][Ni(mnt)
2]
3·2CH
3CN (Ln = Gd
3+ (
4), Sm
3+ (
5), Tb
3+ (
6)), and [{(CH
3OH)CuL
2}{CuL
2}Gd(O
2NO){Ni(mnt)
2}][Ni(mnt)
2]·CH
2Cl
2 (
7) with [Ni(mnt)
2]
f">-. Trinuclear, almost linear, [CuLnCu] moti
fs are
found in all the compounds.In the isostructural
1 and
2, two trans cyano groups
from a [Ni(mnt)
2]
2- unit bridge two trimetallic nodes through axialcoordination to the Cu centers, thus leading to the establishment o
f in
finite chains.
3 is an ionic compound, containingdiscrete [{(CH
3OH)CuL
2}
2Sm(O
2NO)]
2+ cations and [Ni(mnt)
2]
2- anions. Within the series
4-
6, layers o
f discrete [CuLnCu]
3+moti
fs alternate with stacks o
f interacting [Ni(mnt)
2]
f">- radical anions,
for which two overlap modes, providing two di
fferenttypes o
f stacks, can be disclosed. The strength o
f the intermolecular interactions between the open-shell species isestimated through extended Hückel calculations. In compound
7, [Ni(mnt)
2]
f">- radical anions coordinate group one o
f theCu centers o
f a trinuclear [Cu
2Gd] moti
f through a CN, while discrete [Ni(mnt)
2]
f">- units are also present, overlapping inbetween, but also with the coordinated ones. Furthermore, the [Cu
2Gd] moieties dimerize each other upon linkage bytwo nitrato groups, both acting as chelate toward the gadolinium ion
from one unit and monodentate toward a Cu ion
from the other unit. The magnetic properties o
f the gadolinium-containing complexes have been determined. Ferromagneticexchange interactions within the trinuclear [Cu
2Gd] moti
fs occur. In the compounds
4 and
7, the [Ni(mnt)
2]
f">- radicalanions contribution to the magnetization is clearly observed in the high-temperature regime, and most o
f it vanishes upontemperature decrease, very likely because o
f the rather strong anti
ferromagnetic exchange interactions between theopen-shell species. The extent o
f the exchange interaction in the compound
7, which was
found to be anti
ferromagnetic,between the coordinated Cu center and the corresponding [Ni(mnt)
2]
f">- radical anion, bearing mostly a 3p spin type, wasestimated through CASSCF/CASPT2 calculations. Compound
6 exhibits a slow relaxation o
f the magnetization.