[(4-Bromo­phen­yl)(2-pyridyl­methyl­idene)amine-κ2 N,N′]bis­(1,1,1,5,5,5-hexa­fluoro­pentane-2,4-dionato-κ2 O,O′)cobalt(II)

In the title complex, [Co(C5HF6O2)2(C12H9BrN2)], the CoII atom exhibits a pseudo-octa­hedral coordination geometry, comprising two N-donor atoms from a bidentate chelate (4-bromo­phen­yl)(2-pyridyl­methyl­idene)amine (ppaBr) ligand [Co—N = 2.098 (2) and 2.209 (2) Å] and four O-donor atoms from two bidentate chelate 1,1,1,5,5,5-hexa­fluoro­pentane-2,4-dionate (hfac) ligands [Co—O range = 2.0452 (19)–2.0796 (19) Å]. The packing of the structure involves weak π–π inter­actions between the pyridyl and benzene rings of neighbouring ppaBr ligands [centroid–centroid distance = 3.928 (2) Å] and inter­actions between the Br atom on the ppaBr ligand and the hfac ligand [Br⋯C = 3.531 (2) Å]

Tris(phenanthroline-κ2 N,N′)cobalt(II) tetra­fluoridoborate acetonitrile solvate

In the crystal structure of the title compound, [Co(C12H8N2)3](BF4)2·CH3CN, the mol­ecular packing involves dimers of distorted octahedrally coordinated cations which are held together by one π–π [centroid–centroid = 3.542 (4) Å] and two C—H⋯π inter­actions [2.573 (4) Å] resulting in a P4AE (Parallel Fourfold Aryl Embrace) motif. The anions are found in aryl boxes formed from the phenanthroline ligands

(Di-2-pyridyl­amine-κ2 N,N′)[hydro­tris­(3,5-diphenyl­pyrazol-1-yl-κN 2)borato]nickel(II) bromide dichloro­methane monosolvate

In the title compound, [Ni(C45H34BN6)(C10H9N3)]Br·CH2Cl2, the NiII atom is five-coordinated by the tridentate hydro­tris­(3,5-diphenyl­pyrazol­yl)borate ligand and a bidentate di-2-pyridyl­amine ligand in a distorted square-pyramidal geometry. In the crystal, inter­molecular N—H⋯Br and C—H⋯Br hydrogen bonds link the Ni complex cations and the Br− ions, forming a chain along the c axis

[Tris(3,5-diphenyl­pyrazol­yl)hydro­borato]nickel(II) bromide

In the title tris­(pyrazol­yl)borate (TpPh2) complex, [NiBr(C45H34BN6)], the Ni, Br and B atoms lie on a crystallographic threefold axis and a distorted NiN3Br tetra­hedral geometry arises for the metal ion. In the crystal, C—H⋯(C=C) and C—H⋯π inter­actions help to establish the polar crystal packing

[4-Bromo-N-(pyridin-2-yl­methyl­idene)aniline-κ2 N,N′]bis­(1,1,1,5,5,5-hexa­fluoro­pentane-2,4-dionato-κ2 O,O′)nickel(II)

The title compound, [Ni(C5HF6O2)2(C12H9BrN2)], the NiII atom exhibits a pseudo-octa­hedral coordination geometry. The structure packs through C—H⋯Br inter­actions, forming a hydrogen-bonded ladder. There are also strong hydrogen-bonding inter­actions between two of the O atoms of the β-diketonate ligands and two H atoms on the pyridine ring of the Schiff base ligand

Tris(5-methyl-3-phenyl-1H-pyrazol-1-yl)methane

The first crystal structure of a second-generation tris­(pyrazol­yl)methane, namely the title compound, C31H28N6, is reported. The mol­ecule exhibits a helical conformation with an average twist of 35.1°. In addition, there are C—H⋯π inter­actions of 3.202 (2) Å between the pyrazole C—H group and neighbouring phenyl groups

Slow relaxation of magnetization in a bis-mer-tridentate octahedral Co(II) complex

Reaction of a rigid tridentate ligand o-[(1H-imidazol-2-yl)methylideneamino]phenol (2-H(2)imap) with Co(ClO4) in the presence of NaN3, or Co(NO3)(2) without a base yields [Co-II(2-Himap)(2)] 1 and [Co-III(2-Himap) (2)]NO3 center dot MeOH2, respectively. Both complexes exhibit a mer-octahedral geometry with the cobalt centre being distorted along an octahedral-trigonal prismatic pathway. The packing in 1 and 2 is dominated by H-bonding forming 2D sheets and 1D chains, respectively. Detailed dc and ac magnetic studies indicate that 1 is a field-induced single-ion magnet (SIM) with D = 36.7 cm(-1) and E = 2.0 cm(-1). Extensive ab initio calculations support these conclusions and suggest that relaxation of the magnetization occurs principally through direct quantum tunnelling in the ground state, with the Raman process dominant in an applied field. This contrasts with the recently reported series of mer-[Co(L)(2)] (L = monoanionic NNO donor ligand; Inorg. Chem., 2017, 56, 6056-6066) complexes where D is negative, as these compounds have a more ambiguous geometry, and highlights the importance of supramolecular interactions in subtly altering the coordination sphere thereby impacting the magnetic behaviour

(8-Aminoquinoline-κ2N,N′)bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato-κ2O,O′)cobalt(II)

In the title compound, [Co(C5HF6O2)2(C9H8N2)], the CoII centre exhibits a pseudooctahedral coordination geometry, comprising two N-atom donors from the bidentate aminoquinoline ligand and four O-atom donor atoms from two bidentate chelating 1,1,1,5,5,5-hexafluoropentane-2,4-dionate ligands. In the crystal, molecules are linked via pairs of N—H...O hydrogen bonds, forming inversion dimers. These dimers are further connected through π–π interactions between neighbouring quinoline rings [centroid–centroid distance = 3.472 (2) Å], and stack along the c axis

Unexpected Formation of a Disulfide from 2-Mercaptopyridine and Co(II)

The reaction between the Co(II) ion and 2-mercaptopyridine in the presence of base yields a disulfide Co(II) complex, namely [CoCl2(2,2¢-dipyridyldisulfide)] 1. The structure has been determined by single crystal X-ray crystallography. The Co(II) ion coordinates to two chlorine atoms and two nitrogen atoms in a tetrahedral fashion. This result provides insight into the formation of 2,2¢-dipyridyldisulfide from 2-mercaptopyridine

Interplay of Halogen and Hydrogen Bonding in a Series of Heteroleptic iron(III) Complexes

The influence of the halogen substituent on crystal packing and redox properties is investigated in a series of heteroleptic complexes [Fe(qsal-X)(dipic)]MeOH (qsal-X = 4-halogen-2-[(8-quinolylimino)methyl]phenolate; dipic = 2,6-pyridinedicarboxylate; X = F 1, Cl 2, Br 3 and I 4).Compounds 1 and 2 exhibit triclinic symmetry (P1̅), whereas 3 and 4 crystallise in monoclinic P21/n. The crystal packing shows self-sorting of the ligands with - interactions between the qsal-X ligands and overlap of the dipic ligands to form a 1D chain, that is supported by C-H···O interactions. In 1 and 2, the cross-section of the 1D chain is square, while for 3 and 4, it is rectangular. In the former, the dipic ligands interact through C=O··· interactions, while - interactions are found in 3 and 4. Neighbouring chains are connected via - interactions involving the quinoline rings, but their relative position is driven by the preference of 1 and 2, for C-H···X interactions, whereas 3 and 4 form O···X halogen bonds. The nature and topology of the electron density of these interactions have been investigated using molecular electrostatic potential (MEP) mapping, quantum theory of atoms in molecules (QTAIM) and ‘non-covalent interactions’ (NCI) analysis. UV-Visible experiments show MLCT bands associated with the qsal-X ligands, confirming the structure is stable in solution. Electrochemical studies reveal slight tuning of the Fe3+/Fe2+ redox couple showing a linear relationship between E° and the Hammett parameter σp.</div