Secondary Ligand-Directed Assembly of Cd^II Coordination Architectures: From 0D to 3D Complexes Based on Ferrocenyl Carboxylate

Abstract

To investigate the influence of spatial extended direction and flexibility of secondary ligand on the resulting structure, eight new ferrocene-containing complexes with various dimensionalities have been synthesized by the reactions of Cd II salts and 1,1 0 -bis(3-carboxy-1-oxopropyl)ferrocene (H 2 bfcs) with series of rationally selected N-heterocyclic spacers. When the small organic molecule 4-aminopyridine (apy) was employed as a secondary ligand, a one-dimensional (1D) linear complex {[Cd(bfcs)(apy) 2 ] 3 H 2 O} n (1) was furnished, while the use of bis(azole) bridging ligands resulted in the formation of a 1D ribbon complex {[Cd(bfcs)(bbbm,4-bis(imidazole-1 -ylmethyl)benzene). In addition, the tripodal bridging secondary ligand led to an unusual three-dimensional (3D) layer pillar complex {[Cd 2 (bfcs)(titb) 2 Cl 2 ] 3 2CH 3 OH 3 4H 2 O} n (6) (titb =1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene). Employment of a flexible multidentate molecule tris(2-benzimidazolylmethyl)amine (ntb) as the secondary ligand gave birth to a mononuclear complex [Cd(bfcs)(ntb)] 3 DMF 3 5H 2 O (7) and a binuclear complex [Cd 2 -(bfcs)(ntb) 2 ] 3 bfcs 3 5H 2 O (8), in which ntb adopted the chelating coordination mode. It can be observed from the coordination architectures of 1-8 that secondary ligands had great effects on the spatial connective fashions of Cd II centers, resulting in the formation of various dimensional complexes.

Crystal structure of catena-poly[μ2-2,2′-(1,3-phenylene)diacetato-κ4 O,O′:O′′,O′′′)-(μ2-1,6-bis(2-methyl-1H-benzo[d]imidazol-1-yl)hexane-κ2 N:N′)cadmium(II)], C32H34CdN4O4

“…the figure). The Cd-O and Cd-N bond distances lie in the ranges of 2.293(4)-2.441(4) Å and 2.286(5)-2.293(4) Å, respectively, which is well comparable with reported ones [9]. The hbmb adopts symmetrical trans-conformation with the N donor · · · N-C sp3 · · · C sp3 torsion angle of 61.297°.…”

Synthesis and crystal structure of 1D Cd-amine coordination polymer and its luminescent properties

“…The absorption bands of mpda in the compound are shifted to lower wavenumbers by 25 cm -1 compared with those of the free mpda ligand, which is consistent with the coordination of mpda to the metal ion center via the amino nitrogen atoms [31] . In the IR spectrum of compound 1, the absorption bands centered at 3290 and 3255 cm -1 are attributed to N-H bonds asymmetric and symmetric stretching vibrations, respectively.…”

Synthesis, Structure, and Photoluminescence Property of a New Cd(II) Complex Based on 4-(2′,3′-Dicarboxylphenoxy) Benzoic Acid

“…As shown in Figure 1a, Cd1 adopts a distorted pentagonal bipyramid configuration constituted by five carboxylic oxygen atoms from three HL 2¡ ligands with Cd-O distance of 2.3118-2.6101 A and two oxygen atoms from two coordinated water with Cd-O bond lengths of 2.2371-2.3285 A , which is in normal range as observed in other Cd (II) polymers. [16,17] It should be noted that two carboxylate groups from one HL 2¡ ligand adopt different coordination modes: one is bidentate bridging mode, the other tridentate coordination mode to link Cd 2C ions, to form a 2D layer along the ab plane, as depicted in Figure 1b. There are two (5) Symmetry transformations used to generate equivalent atoms: (Figure 1c).…”