Synthesis, crystal structures and characterization of four coordination polymers based on 5-amino-2,4,6-triiodoisophthalic acid

Formation of a Metallomacrocycle Possessing Nitrogen Donors Assembled in the Cavity and Unique Water Clusters

2,2'-Bipyridyl (bpy) is widely used as a chelating unit for metal complexation but is not usually considered as a hydrogen-bonding unit. This is because the metal-free bpy units are usually in a transoid conformation, and the two nitrogen lone pairs are pointed to the opposite sides. We now report a metallomacrocycle whose three metal-free bpy units are in a cisoid conformation and are fixed in the cavity. The complexation of nickel(II) only at the salen units of the triangular bpytrisalen ligand produced this rigid and planar macrocycle. Its cavity is surrounded by hydrogen-bond acceptors (N of bpy and O of salen), and it was found that unique pentagonal prism clusters of water molecules templated by the cavity were formed in the crystal. This study has not only increased the variation of the synthetic methodologies of multinuclear complexes but has also provided the structural platform on which multiple bpy units exert hydrogen-bonding functions.

The crystal structure of catena-poly[(1,10-phenanthroline-κ2 N,N′)-(μ3-2-hydroxybenzene-1,3-dicarboxylato-κ5 O,O′:O″,O‴:O‴)cadmium(II)], C20H12CdN2O5

C20H12CdN2O5, monoclinic, P2/c (no. 13), a = 8.6308(6) Å, b = 10.5180(6) Å, c = 18.6325(11) Å, β = 102.210(6)°, V = 1653.17(18) Å3, Z = 4, R gt(F) = 0.0374, wR ref(F 2) = 0.0856, T = 250 K.

The crystal structure of poly[(1,10-phenanthroline-κ2 N,N′)-(μ 4-2-chlorobenzene-1,3-dicarboxylato-κ5 O:O′:O″:O‴) cadmium(II)] monohydrate, C20H13CdClN2O5

C20H13CdClN2O5, monoclinic, P21/n (no. 14), a = 11.4994(9) Å, b = 13.1171(10) Å, c = 13.0233(10) Å, β = 109.126(8)°, V = 1856.0(3) Å3, Z = 4, R gt(F) = 0.0341, wR ref(F 2) = 0.0779, T = 293 K.

Crystal structure of catena-poly[qua-(μ2-2-aminoisophthalat-κ3 O,O′:O′′)(1,10-phenanthroline-κ2 N,N′)manganese(II)] C20H15MnN3O5

C20H15MnN3O5, monoclinic, P21/c (no. 14), a = 10.0223(5) Å, b = 9.3406(5) Å, c = 18.6978(10) Å, β = 99.322(6)°, V = 1727.27(16) Å3, Z = 4, R gt (F) = 0.0376, wR ref (F 2) = 0.0873, T = 250 K.

Halogen bonding in cadmium(II) MOFs: its influence on the structure and on the nitroaldol reaction in aqueous medium

A solvothermal reaction of Cd(II) with the dicarboxyl-functionalized arylhydrazone pro-ligands, 5-(2-(2,4,6-trioxotetrahydro-pyrimidin-5(2H)-ylidene)hydrazineyl)isophthalic acid (H₅L¹) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazineyl)isophthalic acid (H₃L²), or their halogen bond donor centre(s) decorated analogs 2,4,6-triiodo-5-(2-(2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)hydrazineyl)isophthalic acid (H₅L³) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazineyl)-2,4,6-triiodoisophthalic acid (H₃L⁴), leads to the formation of known [Cd(H₃L¹)(H₂O)₂]_n (1) and new {[Cd(HL²)(H₂O)₂(DMF)]·H₂O}_n (2), [Cd(H₃L³)]_n (3) and {[Cd₂(μ-H₂O)₂(μ-H₂L⁴)₂(H₂L⁴)₂]·2H₂O}_n (4) coordination compounds, respectively. The aggregation of mononuclear units via Cd-OC and Cd-OH₂ coordination and C_Ar-I⋯I types of intramolecular halogen bonds lead to a dinuclear tecton 4. Both C_Ar-I⋯O and C_Ar-I⋯I types of intermolecular halogen bonds play a fundamental role in the supramolecular architectures of the obtained metal-organic frameworks 3 and 4. Theoretical (DFT) calculations confirmed the presence of the C_Ar-I⋯O and C_Ar-I⋯I halogen bonds in 3 and 4 and allowed their characterisation. The formation of intermolecular noncovalent interactions between the attached iodine substituents to the hydrazone ligands and polar solvent (water or methanol) molecules promoted, at least in part, the solubility of the corresponding complexes (3 and 4), which act as homogeneous catalyst precursors in the Henry reaction between aldehydes and nitroethane. The corresponding β-nitroalkanol products were obtained in good yields (66-79%) and with good diastereoselectivity (threo/erythro ca. 72 : 28) in water at room temperature.

Copper(ii) complexes with phosphorylated 1,10-phenanthrolines: from molecules to infinite supramolecular arrays

Supramolecular architectures based on copper(ii) complexes with diethoxyphosphoryl substituted 1,10-phenanthrolines are reported.