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"Tritopic" picolinic dihydrazone ligands with tridentate coordination pockets are designed to produce homoleptic [3 x 3] nonanuclear square grid complexes on reaction with transition-metal salts, and many structurally documented examples have been obtained with Mn(II), Cu(II), and Zn(II) ions. However, other oligomeric complexes with smaller nuclearities have also been discovered and identified structurally in some reactions involving Fe(II), Co(II), Ni(II), and Cu(II), with certain tritopic ligands. This illustrates the dynamic nature of the metal-ligand interaction and the conformationally flexible nature of the ligands and points to the possible involvement of some of these species as intermediates in the [3 x 3] grid formation process. Examples of mononuclear, dinuclear, hexanuclear, heptanuclear, and nonanuclear species involving Fe(II), Co(II), Ni(II), and Cu(II) salts with a series of potentially heptadentate picolinic dihydrazone ligands with pyrazine, pyrimidine, and pyridine end groups are described in the present study. Iron and cobalt complexation reactions are complicated by redox processes, which lead to mixed-oxidation-state Co(II)/Co(III) systems when starting with Co(II) salts, and reduction of Fe(III) to Fe(II) when starting with Fe(III). Magnetic exchange within the polynuclear structural frameworks is discussed and related to the structural features.

A series of [3 x 3] Mn(II)(9), antiferromagnetically coupled, alkoxide-bridged, square grid complexes, derived from a group of "tritopic" dihydrazide ligands, is described. The outer ring of eight Mn(II) centers in the grids is isolated magnetically from the central Mn(II) ion, leading to an S = 0 ground state for the ring, and an S = 5/2 ground state overall in each case. Exchange in the Mn(II)(8) ring can be represented by a 1D chain exchange model. Rich electrochemistry displayed by these systems has led to the production of Mn(II)/Mn(III) mixed-oxidation-state grids by both electrochemical and chemical means. Structures are reported for [Mn(9)(2poap)(6)](C(2)N(3))(6).10H(2)O (1), [Mn(9)(2poap)(6)](2)[Mn(NCS)(4)(H(2)O)](2)(NCS)(8).10H(2)O (2), [Mn(9)(2poapz)(6)](NO(3))(6).14.5H(2)O (3), [Mn(9)(2popp)(6)](NO(3))(6).12H(2)O (4), [Mn(9)(2pomp)(6)](MnCl(4))(2)Cl(2).2CH(3)OH.7H(2)O (5), and [Mn(9)(Cl2poap)(6)](ClO(4))(9).7H(2)O (6). Compound 1 crystallized in the tetragonal system, space group P4(2)/n, with a = 21.568(1) A, c = 16.275(1) A, and Z = 2. Compound 2 crystallized in the triclinic system, space group P, with a = 25.043(1) A, b = 27.413(1) A, c = 27.538(2) A, alpha = 91.586(2) degrees, beta = 113.9200(9) degrees, gamma = 111.9470(8) degrees, and Z = 2. Compound 3 crystallized in the triclinic system, space group P, with a = 18.1578(12) A, b = 18.2887(12) A, c = 26.764(2) A, alpha = 105.7880(12) degrees, beta = 101.547(2) degrees, gamma = 91.1250(11) degrees, and Z = 2. Compound 4 crystallized in the tetragonal system, space group P4(1)2(1)2, with a = 20.279(1) A, c = 54.873(6) A, and Z = 4. Compound 5 crystallized in the tetragonal system, space group I, with a = 18.2700(2) A, c = 26.753(2) A, and Z = 2. Compound 6 crystallized in the triclinic system, space group P, with a = 19.044(2) A, b = 19.457(2) A, c = 23.978(3) A, alpha = 84.518(3) degrees, beta = 81.227(3) degrees, gamma = 60.954(2) degrees, and Z = 2. Preliminary surface studies on Au(111), with a Mn(II) grid complex derived from a sulfur-derivatized ligand, indicate monolayer coverage via gold-sulfur interactions, and the potential for information storage at high-density levels.

The tritopic ligand 2poap self-assembles in the presence of Zn(NO(3))(2) and Fe(NO(3))(3) to form homoleptic [3 x 3] nonanuclear M(9) (M = Zn(II), Fe(III)) square grid structures and with Pb(ClO(4))(2) to form a dimerized linear trinuclear [Pb(3)](2) structure. Cl2poap and Cl2poapz form self-assembled homoleptic [3 x 3] Mn(II)(9) square grids with Mn(ClO(4))(2) and Mn(NO(3))(2), respectively, but an unusual incompletely metalated Fe(III)(5) square grid is formed on reaction of Cl2poap with Fe(ClO(4))(3). X-ray structures are reported for [Mn(9)(Cl2poap-2H)(6)](ClO(4))(6).10H(2)O (3), [Mn(9)(Cl2poapz-2H)(6)] (NO(3))(6).22H(2)O (4), [Zn(9)(2poap-2H)(3)(2poap-H)(3)](NO(3))(9).24H(2)O (5), [Pb(3)(2poap-2H) (ClO(4))(4)](2).8H(2)O (6), and [Fe(5)(Cl2poap-H)(6)](ClO(4))(9).34.5H(2)O (7). Compound 3 crystallized in the monoclinic system, space group P(-)1, with a = 18.179(1) A, b = 18.857(1) A, c = 25.871(2) A, alpha = 70.506(2) degrees, beta = 86.440(1) degrees, gamma = 75.175(2) degrees, and z = 2. Compound 4 crystallized in the monoclinic system, space group P(-)1, with a = 16.900(2) A, b = 20.02393) A, c = 25.663() A, alpha = 84.743(3) degrees, beta = 84.885(2) degrees, gamma = 67.081(2) degrees, and z = 2. Compound 5 crystallized in the monoclinic system, space group P(-)1, with a = 18.482(1) A, b = 18.774(1) A, c = 28.112(2) A, alpha = 104.020(1) degrees, beta = 97.791(1) degrees, gamma = 117.036(1) degrees, and z = 2. Compound 6 crystallized in the monoclinic system, space group P(-)1, with a = 10.0513(6) A, b = 11.0958(6) A, c = 17.334(1) A, alpha = 100.932(1) degrees, beta = 100.387(1) degrees, gamma = 94.565(1) degrees, and z = 2. Compound 7 crystallized in the monoclinic system, space group P(-)1, with a = 19.164(1) A, b = 19.587(2) A, c = 26.673(2) A, alpha = 76.430(2) degrees, beta = 78.834(2) degrees, gamma = 64.973(1) degrees, and z = 2. Compound 3 exhibits intramolecular antiferromagnetic exchange within the nonanuclear [Mn(9)(mu-O)(12)] grid structure (J = -4.6 cm(-1)), while the analogous nonanuclear complex [Fe(9)(2poap-2H)(6)](NO(3))(15).18H(2)O (8) is dominated by intramolecular antiferromagnetic coupling at high temperatures but exhibits a low-temperature feature indicative of additional ferromagnetic interactions. The isolated pentanuclear Fe(5) [4 + 1] square grid in 7, with distant Fe-Fe bridging, exhibits very weak antiferromagnetic coupling (J = -0.2 cm(-1)). Mössbauer spectroscopy data are consistent with high-spin Fe(III)(9) and Fe(III)(5) structures.

The mononuclear, high-spin Fe(III) complex [Fe(Hpoap-H)(NO3)(H2O)2](NO3)2 acts as a ligand and reacts with copper(II) perchlorate to produce the spin-coupled, mixed-metal, dimeric octanuclear complex [(poap-H)4Cu3Fe(NO3)]2(ClO4)4(NO3)4·12H2O, which contains three Cu(II) centers and one high-spin Fe(III) center in an alkoxy-bridged square gridlike structural arrangement within each subunit. Variable temperature magnetic data indicate antiferromagnetic exchange between copper pairs and ferromagnetic exchange between Fe−Cu pairs.

A series of tetranuclear copper(II) and nickel(II) complexes is described, all of which form by a strict self-assembly process involving just a single ligand and the metal salt. The ligands POAP, POAPZ, PZOAP, and 6POAP contain terminal pyridine and pyrazine residues bound to a central flexible diazine subunit (N−N) and contain two potentially bridging groups (alkoxo and diazine). In all cases but one the metals are linked by alkoxo oxygens alone, forming essentially square [M4(μ2-O)4] clusters. A rectangular copper(II) complex [Cu4(μ2-N2)2(μ2-O)2] involves a mixture of two alkoxo and two diazine bridges. The square Cu4O4 clusters exhibit ferromagnetic coupling between the metal centers, associated with the orthogonal arrangement of magnetic orbitals, while for the Ni4O4 clusters the nickel(II) centers are coupled antiferromagnetically. The [Cu4(μ2-N2)2(μ2-O)2] cluster exhibits strong antiferromagnetic coupling through a trans Cu(N-N)Cu bridging arrangement, typical for systems of this sort. X-ray structu...

A series of dinuclear complexes of the tetradentate dipyridyl-diazine ligand PAHAP with Mn(II), Fe(II), Fe(III), Co(III), and Ni(II) salts is reported in which three ligands wrap themselves around the six-coordinate metal centers in a rare spiral-like fashion. A similar Fe(II) complex is found for the dipyrazinyl-diazine ligand PZHPZ. The ligands are severely twisted with dihedral angles between the metal chelate ring mean planes on each ligand in the range 50-70 degrees, values close to the expected twist angle for orthogonality between the bridging nitrogen atom p orbitals. Full structures are reported for the dinuclear complexes [Mn(2)(PAHAP)(3)](ClO(4))(4).5H(2)O (1), [Fe(2)(PAHAP)(3)](NO(3))(4).3H(2)O (2), [Fe(2)(PZHPZ)(3)](NO(3))(4).5H(2)O (5), [Co(2)(PAHAP)(3)](NO(3))(6).5H(2)O (6), and [Ni(2)(PAHAP)(3)][Ni(H(2)O)(6)](NO(3))(6).4.5H(2)O (7). Other derivatives [Fe(2)(PAHAP)(3)](ClO(4))(4).4H(2)O (3), [Fe(2)(PAHAP)(3)](ClO(4))(6).4.5H(2)O (4), [Ni(2)(PAHAP)(3)](ClO(4))(4).5H(2)O (8), and [Fe(PHAAP-H)(H(2)O)(2)(NO(3))](NO(3))(2) (9) are also reported. Complex 1 crystallized in the monoclinic system, space group C2/c, with a = 13.4086(2) Å, b = 32.0249(1) Å, c = 14.3132(2) Å, alpha = 90 degrees, beta = 115.635(1) degrees, gamma = 90 degrees, and Z = 4. Complex 2 crystallized in the cubic system, space group Pathremacr;, with a = b = c = 21.0024(1) Å, alpha = beta = gamma = 90 degrees, and Z = 8. Complex 5 crystallized in the monoclinic system, space group P2/n, with a = 14.039(3) Å, b = 11.335(6) Å, c = 14.6517(15) Å, beta = 96.852(11) degrees, and Z = 1. Complex 6 crystallized in the trigonal system, space group Rthremacr;c(h), with a = b = 17.386(2) Å, c = 32.15(2) Å, alpha = beta = 90 degrees, gamma = 120 degrees, and Z = 4. Complex 7 crystallized in the trigonal system, space group Rthremacr;c, with a = b = 17.3737(3) Å, c = 33.235(6) Å, alpha = beta = 90 degrees, gamma = 120 degrees, and Z = 27. Weak ferromagnetic coupling was observed for 1 (2J = 2.1 cm(-)(1)), and no coupling was observed for the dinuclear Ni(II) centers in 7 and 8. 2, 3, and 5 are low-spin Fe(II) systems.

A series of dinuclear copper(II) complexes of three polydentate diazine ligands (PAHAP, PHMAP, and PAHOX) is reported. The PAHAP and PHMAP complexes involve tetradentate ligand coordination with an N−N bridge between the metal centers. For PAHOX, one case involves oxime (N−O) bridges, while, in another, μ2-SO4 bridges are present. Free rotation of the copper magnetic planes around the N−N bond occurs for the PAHAP complexes and is influenced by secondary ligand steric effects (cis), but, for PHMAP, additional coordination fixes the complex in a trans configuration. Preliminary structures are reported for [Cu2(PAHAP)(NCS)4(DMF)2]·2DMF (1) and [Cu2(PAHAP)(bipy)2(NO3)2](NO3)2·4H2O (2), and full structures are reported for [Cu2(PAHAP)(aln)2(H2O)2](NO3)2·3H2O (3), [Cu2(PAHAP)(gly)2(NO3)(H2O)](NO3)·3H2O (4), [Cu2(PHMAP-H)(NO3)3(H2O)(MeOH)] (6), [Cu2(PAHOX-H)2](ClO4)2 (7), and [Cu(PAHOX)(SO4)]2·2H2O (8). Complex 3 crystallized in the triclinic system, space group P1 (No. 2), with a = 17.503(4) A, b = 18.378(4) ...

The ligand 1-oxa-4,7-dithiacyclononane (L) and its complexes [Pd(L)Cl(2)], [Cu(L)(2)][ClO(4)].CH(3)CN, [Cu(L)Br](2), and [Co(L)(2)][ClO(4)](2).2CH(3)NO(2) have been prepared. Crystal data are as follows. For monoclinic [Pd(L)Cl(2)], C(6)H(12)Cl(2)OPdS(2): space group P2(1)/n; a = 8.464(2), b = 12.199(2), c = 10.384(2) Å; beta = 105.09(1) degrees; Z = 4; R = 0.024, R(w) = 0.033 for 1721 reflections. For monoclinic [Cu(L)(2)][ClO(4)].CH(3)CN, C(14)H(27)ClCuNO(6)S(4): space group P2(1)/n; a = 7.743(2), b = 19.515(5), c = 15.017(2) Å; beta = 102.85(2) degrees; Z = 4; R = 0.036, R(w) = 0.038 for 3124 reflections. For triclinic [Cu(L)Br](2), (C(6)H(12)BrCuOS(2))(2): space group Ponemacr;; a = 7.809(5), b = 8.880(3), c = 7.567(2) Å; alpha = 92.44(3), beta = 102.85(2), gamma = 99.30(4) degrees; Z = 2; R = 0.027, R(w) = 0.027 for 1494 reflections. For monoclinic [Co(L)(2)][ClO(4)](2).2CH(3)NO(2), C(14)H(30)Cl(2)CoN(2)O(14)S(4): space group P2(1)/c; a = 10.333(3), b = 14.293(6), c = 9.365(4) Å; beta = 100.89(3) degrees; Z = 2; R = 0.067, R(w) = 0.058 for 1517 reflections. The ligand displays a variety of conformations in these structures. The palladium complex does not undergo 1,4-heteroatom binding site fluxional processes but does dissociate in dimethyl sulfoxide. An apical Pd.O (2.968(3) Å) interaction has been detected by both NMR and X-ray studies. The Cu(I) cation is tetrahedral with a [2+2] mode of ligand coordination. [Cu(L)Br](2) involves two Br bridges between coppers and two thioether sulfurs from a ligand to complete each copper's tetrahedral coordination sphere. Surprisingly, the cyclic voltammetric behavior of the copper complexes is similar to that of 1,4,7-trithiacyclononane complexes. The cation [Co(L)(2)](2+) is pseudooctahedral with nearly regular angles at cobalt but a long (2.235(6) Å) Co-O bond due to Jahn-Teller distortion. The complex [Co(L)(2)][ClO(4)](2) is magnetically dilute and low-spin over the temperature range 5-292 K.

A series of dicopper(II) complexes with two tetradentate (N4) diazine ligands (PAHAP (1), PMHAP (2)) is reported, in which the two dx2-z2 type copper centers are bridged by a single N−N bond. Varying the coligands leads to a situation where the angle between the copper planes can be varied. For small angles (

Picolyl hydrazide ligands have two potentially bridging functional groups (micro-O, micro-N-N) and consequently can exist in different coordination conformers, both of which form spin-coupled polynuclear coordination complexes, with quite different magnetic properties. The complex [Cu(2)(POAP-H)Br(3)(H(2)O)] (1) involves a micro-N-N bridge (Cu-N-N-Cu 150.6 degrees ) and exhibits quite strong antiferromagnetic coupling (-2J = 246(1) cm(-)(1)). [Cu(2)(PZOAPZ-H)Br(3)(H(2)O)(2)] (2) has two Cu(II) centers bridged by an alkoxide group with a very large Cu-O-Cu angle of 141.7 degrees but unexpectedly exhibits quite weak antiferromagnetic exchange (-2J = 91.5 cm(-)(1)). This is much weaker than anticipated, despite direct overlap of the copper magnetic orbitals. Density functional calculations have been carried out on compound 2, yielding a similar singlet-triplet splitting energy. Structural details are reported for [Cu(2)(POAP-H)Br(3)(H(2)O)] (1), [Cu(2)(PZOAPZ-H)Br(3)(H(2)O)(2)] (2), [Cu(2)(PAOPF-2H)Br(2)(DMSO)(H(2)O)].H(2)O (3), [Cu(4)(POMP-H))(4)](NO(3))(4).2H(2)O (4), and PPOCCO (5) (a picolyl hydrazide ligand with a terminal oxime group) and its mononuclear complexes [Cu(PPOCCO-H)(NO(3))] (6) and [Cu(PPOCCO-H)Cl] (7). Compound 1 (C(12)H(13)Br(3)Cu(2)N(5)O(4)) crystallizes in the monoclinic system, space group P2(1)/c, with a = 15.1465(3) A, b = 18.1848(12) A, c = 6.8557(5) A, beta = 92.751(4) degrees, and Z = 4. Compound 2 (C(10)H(13)Br(3)Cu(2)N(7)O(4)) crystallizes in the triclinic system, space group P, with a = 9.14130(1) A, b = 10.4723(1) A, c = 10.9411(1) A, alpha = 100.769(1), beta = 106.271(1) degrees, gamma = 103.447(1) degrees, and Z = 2. Compound 3 (C(23)H(22)Br(2)Cu(2)N(7)O(5.5)S) crystallizes in the monoclinic system, space group P2(1)/c, with a = 12.406(2) A, b = 22.157(3) A, c = 10.704(2) A, beta = 106.21(1) degrees, and Z = 4. Compound 4(C(52)H(48)Cu(4)N(20)O(18)) crystallizes in the monoclinic system, space group P2(1)/n, with a = 14.4439(6) A, b = 12.8079(5) A, c = 16.4240(7) A, beta = 105.199(1) degrees, and Z = 4. Compound 5 (C(15)H(14)N(4)O(2)) crystallizes in the orthorhombic system, space group Pna2(1), with a = 7.834(3) A, b = 11.797(4) A, c = 15.281(3) A, and Z = 4. Compound 6(C(15)H(13)CuN(5)O(5)) crystallizes in the monoclinic system, space group P2(1)/c, with a = 8.2818(9) A, b = 17.886(2) A, c = 10.828(1) A, beta = 92.734(2) degrees, and Z = 4. Compound 7 (C(15)H(13)CuClN(4)O(2)) crystallizes in the orthorhombic system, space group Pna2(1), with a = 7.9487(6) A, b = 14.3336(10) A, c = 13.0014(9) A, and Z = 4. Density functional calculations on PPOCCO are examined in relation to the anti-eclipsed conformational change that occurs on coordination to copper(II).

The structures and magnetic properties of self-assembled copper(II) clusters and grids with the "tritopic" ligands 2poap (a), Cl2poap (b), m2poap (c), Cl2pomp (d), and 2pomp (e) are described [ligands derived by reaction of 4-R-2,6-pyridinedicarboxylic hydrazide (R = H, Cl, MeO) with 2-pyridinemethylimidate (a-c, respectively) or 2-acetylpyridine (d, R = Cl; e, R = H)]. Cl2poap and Cl2pomp self-assemble with Cu(NO(3))(2) to form octanuclear "pinwheel" cluster complexes [Cu(8)(Cl2poap-2H)(4)(NO(3))(8)].20H(2)O (1) and [Cu(8)(Cl2pomp-2H)(4)(NO(3))(8)].15H(2)O (2), built on a square [2 x 2] grid with four pendant copper arms, using "mild" reaction conditions. Similar reactions of Cl2pomp and 2pomp with Cu(ClO(4))(2) produce pinwheel clusters [Cu(8)(Cl2pomp-2H)(4)(H(2)O)(8)](ClO(4))(8).7H(2)O (3) and [Cu(8)(2pomp-2H)(4)(H(2)O)(8)](ClO(4))(8) (4), respectively. Heating a solution of 1 in MeOH/H(2)O produces a [3 x 3] nonanuclear square grid complex, [Cu(9)(Cl2poap-H)(3)(Cl2poap-2H)(3)](NO(3))(9).18H(2)O (5), which is also produced by direct reaction of the ligand and metal salt under similar conditions. Reaction of m2poap with Cu(NO(3))(2) produces only the [3 x 3] grid [Cu(9)(m2poap-H)(2)(m2poap-2H)(4)](NO(3))(8).17H(2)O (6) under similar conditions. Mixing the tritopic ligand 2poap with pyridine-2,6-dicarboxylic acid (picd) in the presence of Cu(NO(3))(2) produces a remarkable mixed ligand, nonanuclear grid complex [Cu(9)(2poap-H)(4)(picd-H)(3)(picd-2H)](NO(3))(9).9H(2)O (7), in which aromatic pi-stacking interactions are important in stabilizing the structure. Complexes 1-3 and 5-7 involve single oxygen atom (alkoxide) bridging connections between adjacent copper centers, while complex 4 has an unprecedented mixed micro-(N-N) and micro-O metal ion connectivity. Compound 1 (C(76)H(92)N(44)Cu(8)O(50)Cl(4)) crystallizes in the tetragonal system, space group I, with a = 21.645(1) A, c = 12.950(1) A, and Z = 2. Compound 2 (C(84)H(88)N(36)O(44)Cl(4)Cu(8)) crystallizes in the tetragonal system, space group I, with a = 21.2562(8) A, c = 12.7583(9) A, and Z = 2. Compound 4 (C(84)H(120)N(28)O(66)Cl(8)Cu(8)) crystallizes in the tetragonal system, space group I4(1)/a, with a = 20.7790(4) A, c = 32.561(1) A, and Z = 4. Compound 7(C(104)H(104)N(46)O(56)Cu(9)) crystallizes in the triclinic system, space group P, with a = 15.473(1) A, b = 19.869(2) A, c = 23.083(2) A, alpha = 88.890(2) degrees, beta = 81.511(2) degrees, gamma = 68.607(1) degrees, and Z = 2. All complexes exhibit dominant intramolecular ferromagnetic exchange coupling, resulting from an orthogonal bridging arrangement within each polynuclear structure.

The complex [(PAH)(4)Cu(II)(4)Cu(I)(2)Br(10)] (1) (PAH = picolinamide hydrazone) containing a Cu(II)(4)Cu(I)(2) hexanuclear cluster, with two well-separated Cu(II)(2) dinuclear centers, results from a redox reaction involving a hydrolytically unstable ligand, salicilyl picolinamide hydrazone, and CuBr(2) in aqueous acetonitrile. The Cu(II) centers are axially bridged via long bromine contacts, leading to ferromagnetic exchange (2J = 4.04 cm(-)(1)). Density functional calculations have been carried out, giving a comparable singlet-triplet splitting energy. 1 crystallizes in the triclinic system, space group Ponemacr;, with a = 9.253(3) A, b = 18.159(3) A, c = 7.199(5) A, alpha = 91.31(3) degrees, beta = 107.35(4) degrees, gamma = 104.22(2) degrees, and Z = 2.

A series of trigonal bipyramidal pentanuclear complexes involving the alkoxo-diazine ligands poap and p3oap, containing the M(5)[mu-O](6) core is described, which form by a strict self-assembly process. [Co(5)(poap-H)(6)](ClO(4))(4).3H(2)O (1), [Mn(5)(poap-H)(6)](ClO(4))(4).3.5CH(3)OH.H(2)O (2), [Mn(5)(p3oap-H)(6)](ClO(4))(4).CH(3)CH(2)OH.3H(2)O (3), and [Zn(5)(poap-H)(6)](ClO(4))(4).2.5H(2)O (4) are homoleptic pentanuclear complexes, where there is an exact match between the coordination requirements of the five metal ions in the cluster, and the available coordination pockets in the polytopic ligand. [Zn(4)(poap)(poap-H)(3)(H(2)O)(4)] (NO(3))(5).1.5H(2)O (5) is a square [2 x 2] grid with a Zn(4)[mu-O](4) core, and appears to result from the presence of NO(3), which is thought to be a competing ligand in the self-assembly. X-ray structures are reported for 1, 4, and 5. 1 crystallized in the monoclinic system, space group P2(1)/n with a = 13.385(1) A, b = 25.797(2) A, c = 28.513(3) A, beta = 98.704(2) degrees, and Z = 4. 4 crystallized in the triclinic system, space group P1 with a = 13.0897(9) A, b = 18.889(1) A, c = 20.506(2) A, alpha = 87.116(1) degrees, beta = 74.280(2) degrees, gamma = 75.809(2) degrees, and Z = 2. 5 crystallized in the monoclinic system, space group P2(1)/n with a = 14.8222(7) A, b = 21.408(1) A, c = 21.6197(9) A, beta = 90.698(1) degrees, and Z = 4. Compounds 1-3 exhibit intramolecular antiferromagnetic coupling.