A new self-assembled μ6-sulfato hexanuclear cobalt(II) complex of a symmetric dinucleating ligand: Synthesis and X-ray structural analysis

Diversity of carboxylate binding in a new tetranuclear zinc cluster: correlation between spectroscopic investigations and carboxylate binding modes

“…Significantly low values of separation for syn-anti bidentate bridging have been observed in the literature. 11,28,29 In addition, the asymmetric and symmetric carboxylate stretches are observed at 1607 and 1388 cm 21 respectively, (D = 219 cm 21 ) which suggest the monodentate terminal coordination of the acetate and benzoate groups. 29,30 Generally, the order of D (D = n as(COO2) 2 n s(COO2) ) for divalent metal carboxylates is followed by D (bridging) , D (monodentate).…”

“…9 The ligand H 5 L has recently been shown to bind zinc(II) ions and cobalt(II) ions to yield mono-and hexanuclear zinc(II) complexes and tetra-and hexanuclear cobalt(II) complexes showing the bridging potential of carboxylates. 9,21,22 Very recently, the unusual amide and carboxylate binding modes of a similar amide and carboxylate rich polydentate ligand have been explored in a self-assembled heptanuclear zinc cluster. 15 We report here synthesis, characterization and spectroscopic investigations correlating the diverse binding modes of carboxylates of a new tetranuclear zinc-carboxylate cluster.…”

“…In particular, the flexible backbone of the ligand allows for various zinc-oxygen-zinc angles and various carboxylate bridges to coordinate between the dinuclear units, highlighting the versatility of the ligand. 9,15,21,23 A core structure of the complex 1 is shown in Fig. 5.…”

Synthesis and characterization of a novel cyclic tetranuclear CoII4 cluster consisting of a quadrilateral core

“…It has been shown that the magnetic behavior of high-spin cobalt(II) complexes has long been known to provide many traps for several number of ligands that can give rise to low- [11] or high-spin [12] tetrahedral or octahedral complexes or those with other geometries [13]. Recently, we have reported the selfassembled μ 6 -sulfato hexanuclear cobalt(II) and zinc(II) complexes of the symmetrical carboxylate rich dinucleating ligand, H 5 ccdp where it has been observed that the stable μ 6 -SO 4 group sitting at the center of the molecular structure provided a templating unit and stabilizing factor for both the Co 6 and Zn 6 clusters [14,15]. We have also reported a heptanuclear zinc complex showing the unusual amide coordination modes of a similar carboxylate and amide rich dinucleating ligand [16].…”

Synthesis, Characterization and Spectroscopic Investigation of Novel Tetra‐Iron(III) Complexes and D‐Glucose under Redox Conditions

“…This type of flexibility has also been demonstrated with several mono-, bi-, tetra-, and hexanuclear Cu(II), Co(II), Ni(II), and Zn(II) complexes of the H 5 ccdp ligand. [10,23,[47][48][49][50] The interatomic distance between O (19) and O (20) For both [Fe 2 ] units within the tetranuclear core, the ccdp 5À ligand binds in a cis-fashion to the two Fe(III) ions through its aliphatic and aromatic carboxylate groups. Interestingly, the carboxylate arms on the bridging naphtholato groups are oriented in an orthogonal fashion with respect to one another.…”