Synthesis and structural characterization of tetradentate (N₂O₂) ligand complexes of zinc

The potentially tetradentate-N₂O₂ ligands, N, N′-bis (o-hydroxybenzyl)-l, 2-diaminoethane (SaleanH₄), N, N′-bis (o-hydroxybenzyl)-l, 3-diaminopropane (SalpanH₄), N, N′-bis (o-hydroxybenzyl)-l, 4-diaminobutane (SalbanH₄), N, N′-bis (o-hydroxybenzyl)-l, 6-diaminohexane (SalhanH₄), N, N′-bis (o-hydroxybenzyl)-l, 2-diaminobenzene(SalophanH₄), and N, N′-bis (o-hydroxybenzyl)-l, 2-diamino-4, 5-dimethylbenzene (SalomphanH₄), have been synthesized and used to prepare the series of zinc complexes, [SaleanH₂Zn]₂ (l), [SalpanH₂Zn] ₂ (2), [SalbanH₂Zn]₂ (3), [SalhanH₂Zn] ₂ (4), [SalophanH₂Zn]₂ (5), and [SalomphanH₂Zn]₂ (6), Compounds (2) and (5) have been structurally characterized with single-crystal x-ray diffractometry. The molecules consist of oxygen-bridged zinc dimers. Unique structures for (5) were determined from crystals grown from MeOH (5a) and DMF (5b). The structures possess varying numbers of solvent molecules in the unit cell. Crystal Data: (2) Space Group P1 with a = 13.076(3) Å, b = 13.137(3) Å, c = 13.228(3) Å, α = 72.09 (3)°, β = 69.18 (3)°, γ = 70.71(3)°, V = 1957.5 (8) ų and Z = 2. With 478 parameters refined on 3899 reflections having F > 4.0 σ(F), the final R factors were R = 0.0733 and R_w = 0.0796; (5a) Space Group P1 with a = 10.271 (3) Å, b = 10.447 (4) Å, c = 11.950 (2) Å, α = 64.510 (0)°, β = 73.310 (0)°, γ = 85.520 (0)°, V = 1107.1 (7) ų and Z = 2. With 271 parameters refined on 2190 reflections having F > 4.0σ(F), the final R factors were R = 0.0678 and R_w = 0.0787; (5b) Space Group P1 with a = 13.109 (3) Å, b = 13.577(2) Å, c = 16.540 (4) Å, α = 93.45(2)°, β = 105.04(2) °, γ = 92.85 (2)°, V = 2830.8 (10) ų and Z = 2. With 661 parameters refined on 3082 reflections having F > 4.0 σ(F), the final R factors were R = 0.0575 and R_w = 0.0626.