Three bis(1,4,7-triazacyclonon-1-yl) ligands,1,2-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene(L
1), 1,3-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene (L
2), and1,4-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene(L
3), have beensynthesized and their nickel(II) and copper(II) coordinationchemistry investigated. Reaction of L
1 withexcessNi
2+ ions affords a mixture of mononuclear and binuclearcomplexes, which are readily separated by cationexchange chromatography and crystallized as their perchlorate salts,[NiL
1](ClO
4)
2 (
1)and[Ni
2L
1(H
2O)
6](ClO
4)
4·4H
2O (
2). Similar treatment ofL
2 and L
3 with excess Ni
2+ ionsaffords exclusively the binuclear complexes[Ni
2L
2(H
2O)
6](ClO
4)
4(
3) and[Ni
2L
3(H
2O)
6](ClO
4)
4·3H
2O(
4), respectively. Reaction of all three ligandswithexcess Cu
2+ ions also yields binuclear complexes, whichmay be isolated as neutral species,[Cu
2LBr
4]·
xDMF(
5,L = L
1,
x = 1;
6, L =L
2,
x = 0;
7, L = L
3,
x = 0), or as perchlorate salts,[Cu
2L(H
2O)
4](ClO
4)
4·
xH
2O(
8, L =L
1,
x = 5;
9, L = L
2,
x = 4;
10, L = L
3,
x= 5). The mononuclear copper(II) complex of L
1is prepared byreaction of L
1 with Cu
2+ ions in a 1:1 moleratio and isolated as its perchlorate salt,[CuL
1](ClO
4)
2·2H
2O(
11).The X-ray structures of complexes
1·H
2O,
4,
5, and
11 have been determined.Compound
1·H
2O crystallizesinthe monoclinic space group
P2
1/
c (No.14) with
a = 9.212(3) Å,
b =17.805(8) Å,
c = 16.501(6) Å,
=103.36(3)
,
V = 2633(1) Å
3, and
Z= 4;
4, in the monoclinic space group
P2
1/
c (No. 14) with
a =9.108(4) Å,
b =25.857(5) Å,
c = 17.524(2) Å,
=92.73(2)
,
V = 4122(2) Å
3, and
Z = 4;
5, in the trigonal space group
P3
121(No. 152) with
a = 10.889(5) Å,
c =22.220(9) Å,
V = 2281(1) Å
3, and
Z = 3; and
11, in the monoclinicspacegroup
P2
1/
c (No. 14) with
a = 9.45(1) Å,
b = 19.51(2) Å,
c = 15.10(1) Å,
= 96.93(8)
,
V = 2763(4) Å
3, and
Z = 4. The nickel(II) and copper(II)centers in the mononuclear complexes,
1·H
2Oand
11, lie in distortedoctahedral environments, sandwiched by the two facially coordinatingtriamine rings of L
1. In complex
4,thetwo triamine rings of L
3 coordinate to separatenickel(II) centers, with the distorted octahedral coordinationsphereabout each of the metal centers being completed by water molecules.Similarly, in complex
5, the two triaminerings of L
1 bind separate copper(II) centers, with thedistorted square pyramidal coordination sphere about eachof the metal centers being completed by bromide anions.