Alkali‐Metal‐Templated Self‐Assembly of Nickel(II) [12‐MC‐3] Metallacoronates Based on Bis(pyrazol‐1‐yl)acetato Ligands

Abstract

The syntheses and structures of four new bis(pyrazol-1-yl)acetate-or bis(3,5-dimethylpyrazol-1-yl)acetate-based bisligand nickel(II) complexes [Ni(bdmpzmp) 2 ] (1), [Ni-(bdmpzpen) 2 ] (2), [Ni(bdmpza) 2 ] (3), and [Ni(bpza) 2 ] (4) are described. The results of single crystal structure determinations reveal for all four complexes κ 3 -coordination of the scorpionate ligands. The sterically hindered bis(3,5-di-tert-butyl-pyrazol-1yl)acetateto (bdtbpza) ligand allows the synthesis of the nickel(II) chlorido complex [Ni(bdtbpza)Cl] (5). Furthermore, controlled formation of a novel trinuclear linear complex [Ni(bdmpza) 2 {Ni(acac)(bdmpza)} 2 ] (6) [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] by a self-assembling reaction and alkali metal-mediated template syntheses of [Na{Ni(acac)- [a]

Bis(4-carboxylpyrazol-1-yl)acetic acid: a scorpionate ligand for complexes with improved water solubility

“…S16 †). After purification the remaining solid residue shows signals characteristic for the C S symmetrical complex 6a with singlets at 7.63 (CH), 8.55 (C pz H) and 8.93 (C pz H) ppm in the 1 H NMR spectrum recorded in dmso-d 6 . The carboxylic protons are found at 13.33 ppm.…”

“…2 Reports concerning these heteroscorpionate complexes range from polymerization catalysis, 2 potential radiodiagnostics, 3 CO releasing molecules (CORMs) 4 and main group chemistry 5 to early and late transition metal organometallics 2 and even supramolecular coordination chemistry. 6 Many variations have been accomplished in these ligands over the years 7 to establish chirality, 8,9 steric hindrance by bulky substituents 10 as well as the suitability for copolymerization 11 or solid phase fixation. 12 Surprisingly, improving their water solubility was not in the focus of these ligand variations so far, although good solubility in aqueous medium, especially under physiological conditions (37 °C, pH = 7.4 by PBS buffered solution) is crucial for biologically relevant investigations.…”

“…2 Reports concerning these heteroscorpionate complexes range from polymerization catalysis, 2 potential radiodiagnostics, 3 CO releasing molecules (CORMs) 4 and main group chemistry 5 to early and late transition metal organometallics 2 and even supramolecular coordination chemistry. 6 Many variations have been accomplished in these ligands over the years 7 to establish chirality, 8,9 steric hindrance by bulky substituents 10 as well as the suitability for copolymerization 11 or solid phase fixation. 12…”

A Novel Tetranuclear Silver Compound with bis(3,5-dimethylpyrazol-1-yl)acetate: a Simple Synthesis Yielding Complex Crystal Structure

“…Such tetradentate coordination of bdmpza ligand is observed very rarely, only in four crystal structures where the bdmpza is coordinated to two different metal centres. 27,28 Contrary to the first bdmpza ligand, the second bdmpza ligand is bound tridentately via both of its N-atoms and additional O from deprotonated carboxylate group; such tridentate coordination of bdmpza is prevalent, it appears in more than 90% of crystal structures with bdmpza in a role of ligand. 9 As a consequence of the described coordination modes of bdmpza ligands, both symmetry independent silver ions are coordinated differently (the relevant bonds and angles around the metal centres are given in Table 2).…”

Study of the Coordination Modes of Hybrid NNCp Cyclopentadienyl/Scorpionate Ligands in Ir Compounds

“…The ligands based on the poly­(pyrazol-1-yl)­methane moiety are among the most versatile ligands as they are able to coordinate to a wide variety of metal centers . In particular, the chemistry of scorpionate ligands, based on bis­(pyrazol-1-yl)­methane, has been considerably extended in terms of their coordination chemistry − and catalytic applications. − In this field, a wide range of metal compounds supported by NNE-heteroscorpionate ligands (E = N, O, S) has been reported. − However, metal complexes which contain NNCp-heteroscorpionate ligands have been less studied. − This kind of ligand can be also seen as a linked cyclopentadienyl-donor ligand with great versatility in its coordination modes. Thus, hybrid cyclopentadienyl/heteroscorpionate ligands based on the bis­(pyrazol-1-yl)­methane moiety have shown different coordination modes in a range of metal complexes such as Li, Mg, group 3 and rare earth metals, group 4 metals, and Zn (Chart ).…”