A Novel 1:1 Co-Crystal of Bis(1,10-Phenanthroline)(1,10-Phenanthroline-5,6-Dione)Nickel(II) Hexafluorophosphate and Tris(1,10-Phenanthroline)Nickel(II) Hexafluorophosphate Complexes, [Ni(phen)2(phen-dione)] [Ni(phen)3] (PF6)4

Abstract

The purpose of this study was to investigate whether co-crystals form by simply mixing pure solutions of [Ni(phen) 3 ](PF 6 ) 2 and [Ni(phen) 2 (phen-dione)](PF 6 ) 2 where phen is 1,10-phenanthroline and phen-dione is 1,10-phenanthroline-5,6-dione. The 1:1 cocrystal, [Ni(phen) 2 (phen-dione)][Ni(phen) 3 ](PF 6 ) 4 ÁCH 3 CN has been characterized by elemental analysis, IR, paramagnetic NMR, and UV-vis spectroscopies, cyclic voltammetry, and single crystal X-ray structure analysis. The title complex crystallized in triclinic crystal system (z = 2) with space group of Pī, a = 13.201 (2) Å , b = 14.782(3) Å , c = 22.294(4) Å , a = 81.575(15) o , b = 88.756(15) o , c = 88.032(15) o and V = 4300.1(14) Å 3 . A careful inspection of the packing pattern in the lattice reveals that non-covalent interactions of three different types, viz.C-HÁÁÁF, C=OÁÁÁH-C and C-HÁÁÁp interactions, are active in the lattice. The coordination around the Ni(II) centers is a distorted octahedral, with bite angles of 78.3-79.8 o for the chelating phen and phen-dione ligands. Cyclic voltammetry of this co-crystal shows that the Ni(III/II) couple is quasireversible. The effective magnetic moment (l eff ) of the co-crystal was measured to be 2.87 BM per Ni(II) ion by Evans method. The magnitude of l eff is consistent with magnetic moment for octahedral Ni(II) complexes.

Conjugation of a Silver-Based Coordination Polymer with Curcumin: A New Case of an Inorganic Polymeric Co-crystal

“…In addition, new categories of multicomponent crystals are currently under development. In particular, the rare polymeric co-crystals in which at least one component is a polymer are promising materials since the choice of a polymeric drug and/or co-former could represent an ingenious pharmaceutical strategy to modulate the stability, the solubility, and the release of poorly soluble drugs. − However, polymeric co-crystals as well as inorganic co-crystals have been infrequently obtained due to the fact that, in order to obtain a co-crystal, the starting materials should possess structural similarity, comparable potential energies, and almost identical crystallization kinetics. , Indeed, although a great number of organic co-crystals are known, few examples of co-crystals including a metal complex have been reported so far. − Metal complexes with their precise geometries hardly exhibit lattice packing forces and crystallization kinetics similar to small organic compounds. Many examples of inorganic co-crystals are actually composed of two parent metal complexes , or geometrical isomers of the same coordination compound …”

“…42−48 Metal complexes with their precise geometries hardly exhibit lattice packing forces and crystallization kinetics similar to small organic compounds. Many examples of inorganic co-crystals are actually composed of two parent metal complexes 44,45 or geometrical isomers of the same coordination compound. 49 In the past, we have been strongly involved in investigations concerning the formation of silver-based coordination compounds obtained through the interaction between the Ag(I) ion and 4,4′-disubstituted-2,2′-bipyridines where the careful choice of the substituents on the bipyridyl ligand and the nature of the counterions played a fundamental role in the modulation of the desired properties, such as liquid crystallinity.…”

Crystal Structures, Photoluminescence, and Magnetism of Two Novel Transition-Metal Complex Cocrystals with Three-Dimensional H-Bonding Organic Framework or Alternating Noncovalent Anionic and Cationic Layers

“…For example, a survey of the Cambridge Structural Database reveals that many cocrystal compounds of carboxylate salts contain the neutral carboxylic acid molecules and numerous neutral pyridyl derivative residues in the cocrystals of corresponding pyridinium derivatives. In contrast, the cocrystals containing metal coordination compounds are infrequently reported, and this situation is due to the fact that, commonly, the metal complexes have different coordination modes, and the compounds with different coordination modes rarely possess similar lattice packing forces and exhibit similar crystallization kinetics. − …”