Exploitation of a Half-Conjugate Polydentate Salamo–Salen Hybrid Ligand and Its Two Phenoxide-Bridged Heterohexanuclear 3d–s Double-Helical Cluster Complexes

Abstract

A half-conjugate polydentate Salamo–Salen hybrid ligand, H 5 L, containing two unique N2O2 pockets was first designed so that these metal ions in the complexes appear in different coordination modes. Two heterohexanuclear 3d–s double-helical cluster complexes, [Zn4Ca2 L 2(μ1-OAc)2(EtOH)2]·2EtOH (1; EtOH = ethanol) and [Zn4Sr2 L 2(μ2-OAc)2(MeOH)2]·2CH2Cl2 (2; MeOH = methanol), are reported that are formed through the reaction of H 5 L with zinc­(II) and calcium­(II) acetate or strontium­(II) acetate, respectively. IR spectral analysis of the two complexes showed the existence of monodentate- and bidentate-coordinated acetate ions. The fluorescence properties of the ligand and its two heterohexanuclear complexes were explored in MeOH and water solutions, separately. In addition, theoretical calculations (density functional theory, interaction region indicator, and bond order) were performed to further understand the formation of a single-molecular double helix and the electron distribution characteristics of the two complexes.

A phenoxy-bridged trinuclear Ni(ii) complex: synthesis, structural elucidation and molecular docking with viral proteins

“…The Ni–O bond distances were relatively shorter than Ni–N distances, and this observation is closely related to the findings with similar trinuclear nickel( ii ) complexes in the literature. 53 The crystal structure of the Ni( ii ) complex consists of a discrete zero dimensional trinuclear complex [Ni 3 (μ-L) 2 (bipy) 3 ]( 1 ). The H 3 L ligands in the trinuclear complex[Ni 3 (μ-L) 2 (bipy) 3 ]( 1 ) are tri-deprotonated to give L 6− .…”

“…The average bond distances of each Ni centre are found within the normal ranges as reported in the literature for the six coordinated trinuclear Ni( ii ) complexes. 51–53 The X-ray crystallography shows that each bridging phenoxo oxygen atom is more or less symmetrically bound with Ni–O bond distances in the range between 2.070(2)[Ni(1)–O(1), Ni(2)–O(1)] Å and 2.02(2), and 2.041(19) [Ni(2)–O(2) and Ni(1)#1–O(2)] Å. None of these distances falls outside the range of average Ni-O(phenoxo) distances observed in other hexacoordinated trinuclear Ni( ii ) complexes reported [1.971(2)–2.102(7) Å].…”

Tunable Construction of Sandwich-Type Double-[1 + 1] and Half-Folded [2 + 2] Schiff-Base Complexes Controlled by the Combination of Primary and Secondary Template Effects

“…Moreover, two dinuclear intermediates 11 and 12 were isolated successfully when the preorganized synthetic strategy was used by the treatment of H 2 hpdd/Fe III S1) of complexes 1−12 was appointed to the ligand-to-metal charge-transfer transition (LMCT) of coordination interactions, which is consistent with the absorption peak of similar Schiff-base skeletons. 69,70 For double-[1 + 1] and [2 + 2] macrocyclic Ni II complexes 3 and 8, the strongest absorption peak for the former (378 nm) exhibits a blue shift of 11 nm in comparison with that of the latter (389 nm). In fact, the different λ max values stem from the conformation of macrocyclic ligands.…”

A supramolecular fluorescence array sensor for toxic heavy metal ion detection in environmental water and rice seedling extracts

“…Chemical sensors, such as nanomaterials, 11 metal–organic frameworks, 12 polymers, 13 fluorescence chemosensors, 14–17 and supramolecular optical array sensors, have been widely used in the field detection of a variety of heavy metals. 18 Of interest, fluorescent probes can detect bioactive molecules such as Cys, Hcy, and GSH 19 and formaldehyde and sulfenic acids 20 in plants.…”