| Abstract |
A solvothermal reaction of Cd(II) with the dicarboxyl-functionalized arythydrazone pro-ligands, 5-(2-(2,4,6-trioxotetrahydro-pyrimidin-5(2H)-ylidene)hydrazineyl)isophth alic 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)hydraz ineyl)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)]center dot H2O\(n) (2), [Cd(H3L3)](n) (3) and \[Cd-2(mu-H2O)(2)(mu-H2L4)(2)(H2L4)(2)]center dot 2H(2)O)(n) (4) coordination compounds, respectively. The aggregation of mononuclear units via Cd-O=C and Cd-OH2 coordination and C-Ar-I center dot center dot center dot I types of intramolecular halogen bonds lead to a dinuclear tecton 4. Both C-Ar-I center dot center dot center dot O and C-Ar-I center dot center dot center dot 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 center dot center dot center dot O and C-Ar-I center dot center dot center dot 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 beta-nitroalkanol products were obtained in good yields (66-79\%) and with good diastereoselectivity (threolerythro ca. 72 : 28) in water at room temperature. |
