Nickel(II) complexes of bidentate N–N′ ligands containing mixed pyrazole, pyrimidine and pyridine aromatic rings as catalysts for ethylene polymerisation

A Three-Dimensional Nickel(II) Framework from a Semi-Flexible Bipyrimidyl Ligand Showing Weak Ferromagnetic Behavior

“…As depicted in Figure 1, the two crystallographically distinct Ni(II) ions both show a six coordination of the NiN 4 Br 2 coordination environment in an elongated distorted octahedral geometry, where four nitrogen atoms (N6, N7 and their symmetrical equivalents for Ni1; N3, N5 and their symmetrical equivalents for Ni2) from the bpym ligands and two Br − anions (Br1, Br2 for Ni1; Br3 and its symmetrical equivalent for Ni2) occupy equatorial and axial positions, respectively. The Ni centers in 1 have Ni−N bond distances of 2.100(2) to 2.139(2) Å, Ni−Br bond distances of 2.572(3) to 2.5884(6) Å, cis N−Ni−N angles of 88.61(9) to 95.13(13)°, cis Br−Ni−N angles of 87.70(6)−94.51(6)°, trans N−Ni−N angles of 177.25(8)−179.18(12)° and trans Br−Ni−Br angles of 173.40(2)−180.000(1)°, which are consistent with the values for the reported Ni(II) compounds [30,31,32]. Compound 1 contains two types of bridging bpym ligands, one of which adopts a syn - μ -bridging mode with two pyrimidyl rings twisted in 40.20(4)° that connect the Ni centers through its two N atoms (N7 and N8) in one pyrimidyl ring (Scheme 1, mode A).…”

Thorium–Organic Framework Constructed with a Semirigid Triazine Hexacarboxylic Acid Ligand: Unique Structure with Thorium Oxide Wheel Clusters and Iodine Adsorption Behavior

“…In terms of ligand design, considering the advantages of using triazine-functionalized polycarboxylic ligands to construct MOFs in the formation of a variety of topological structures and adsorption properties, we chose the semirigid triazine hexacarboxylic acid ligand H 6 TTHA (Scheme ). − On one hand, compared with the rigid tricarboxylic acid ligands, it has six flexible aminodiacetate arms, which may take a variety of geometric conformations, such as syn–syn , anti–anti , and syn–anti ; − it has six carboxyl groups that may take a more abundant coordination mode with the central metal, such as monodentate, bidentate, and monobidentate, bridging, chelating, etc., resulting in a more diverse topological structure. , On the other hand, it has abundant adsorption sites such as nitrogen-rich triazine ring-containing rich nitrogens, N of NH-, which is advantageous to adsorb specific guest molecules such as iodine to promote its adsorption. H 6 TTHA ligands and transition metal ions, alkali metal ions, alkaline earth metal ions, rare earth ions, and uranyl ions have been used to construct many MOFs with diverse topological structures and have exhibited significant application in the realms of luminescence, sensing, adsorption, etc. ,,− Bruce et al prepared seven homobimetallic or heterobimetallic complexes using H 6 TTHA and metal ions such as sodium, nickel, chromium, rhodium, zinc, and potassium in a one-pot method, which is the first time heterobimetallic complexes containing H 6 TTHA ligands have been correctly characterized .…”

A Uranyl-Organic Framework Featuring Two-Dimensional Graphene-like Layered Topology for Efficient Iodine and Dyes Capture

“…38−40 On the other hand, this ring consists of three nitrogen atoms which can form a rich and varied network structure. 41 Many transition metal compounds and rare earth compounds constructed by TATAB ligands have been reported, which show excellent performance in luminescent sensing and adsorption. 42−46 As we know, the crystal structure constructed by tripodal ligand of H 3 TATAB in the family of uranyl complex has not been reported yet.…”

“…In the design of organic ligands, we consider triazine tricarboxylate ligand H 3 TATAB containing amino functional groups (Scheme h). On the one hand, it possesses an uncommon aromatic moiety which can form anion-p interactions and p–p stacking. − On the other hand, this ring consists of three nitrogen atoms which can form a rich and varied network structure . Many transition metal compounds and rare earth compounds constructed by TATAB ligands have been reported, which show excellent performance in luminescent sensing and adsorption. − As we know, the crystal structure constructed by tripodal ligand of H 3 TATAB in the family of uranyl complex has not been reported yet.…”