Dibromido[1,1′-dibutyl-2,2′-(pentane-1,1-di­yl)di-1H-benzimidazole]­copper(II)

In the title compound, [CuBr2(C27H36N4)], the CuII ion exhibits a distorted tetra­hedral coordination geometry provided by two bromide ions and by chelation of two imine N-atom donors from a bis­(benzimidazole) ligand. Chelation results in a six-membered boat-shaped ring which links the benzimidazole groups. Each bis­(benzimidazole) fragment contains three n-butyl substituents, two of which have the expected trans conformation; the third exhibits the higher-energy cis conformation, an orientation consistent with several short intra­molecular C—H⋯Br inter­actions. Essentially planar (r.m.s. deviations of 0.0101 and 0.0183 Å) benzimidazole groups are oriented so as to give the bis­(benzimidazole) fragment a V-shaped appearance in profile with the cis and trans n-butyl groups directed to opposite sides of the planes. In the crystal, columns of mol­ecules along the b-axis direction form layers parallel to the (202) planes. Within a given column, the mol­ecules are linked by C—H⋯Br hydrogen bonds. The mol­ecules in adjacent columns are also linked by inter­molecular C—H⋯π interactions, forming a three-dimensional network

{Bis[5-methyl-3-(trifluoro­meth­yl)pyrazol-1-yl]borato}{tris­[5-methyl-3-(trifluoro­meth­yl)pyrazol-1-yl]borato}cobalt(II): a structure containing a B—H⋯Co agostic inter­action

The title compound, [Co(C10H10BF6N4)(C15H13BF9N6)], is a neutral CoII complex which contains one each of the anionic ligands, bis­(3-trifluoro­methyl-5-methyl­pyrazol-1-yl)borate (Bp) and tris­(3-trifluoro­methyl-5-methyl­pyrazol-1-yl)borate (Tp). A distorted octa­hedral coordination geometry results from ligation of an H atom, which is part of an agostic B—H⋯Co inter­action (H⋯Co = 2.17 Å), and by five imine N atoms, two from a Bp ligand and three from a Tp ligand. In the crystal, mol­ecules form layers parallel to the (10) planes, and the layers are linked along the a axis by C—H⋯F hydrogen bonds. An intra­molecular C—H⋯F inter­action also occurs

(E)-1,2-Bis(1-propyl-5,6-dimethyl-1H-benzimidazol-2-yl)ethene

In the title compound, C26H32N4, the essentially planar (r.m.s. deviations of 0.0053 and 0.0242 Å) benzimidazole fragments are trans with respect to a central ethene fragment, and are canted in opposite directions by 2.78 (6) and 5.87 (6)° with respect to the ethene plane, giving the mol­ecule a propeller conformation. The terminal ethyl fragments of the pendant n-propyl groups protrude to either side of the benzimidazole planes. Overall, the mol­ecule exhibits a pseudo-center of symmetry at the mid-point of the ethene fragment. Both π–π stacking and typical C—H⋯π inter­actions are notably absent, as are inter­molecular hydrogen bonds. When viewed along the a axis, the structure appears as criss-crossed layers of mol­ecules with the planar fragments separated along the c-cell direction by the protruding ethyl groups

2-(2-Thien­yl)-4,5-dihydro-1H-imidazole

In title compound, C7H8N2S, the five-membered rings are twisted by a dihedral angle of 5.17 (10)°. Two inter­molecular N—H⋯N and C—H⋯N hydrogen bonds to the same acceptor N atom form seven-membered rings, producing R 2 1(7) ring motifs. These inter­actions link neighbouring mol­ecules into one-dimensional chains extended along the c axis. The crystal structure is further stabilized by weak inter­molecular C—H⋯π inter­actions

2-(3-Chloro­phen­yl)-4,5-dihydro-1H-imidazole

In the title compound, C9H9ClN2, a substituted imidazoline, the six- and five-membered rings are twisted from each other, making a dihedral angle of 17.07 (5)°. In the crystal structure, a short Cl⋯Cl [3.3540 (3) Å] inter­action is observed. Neighbouring mol­ecules are linked together by inter­molecular N—H⋯N hydrogen bonds into a one-dimensional infinite chain along the [101] direction and short Cl⋯Cl contacts link the chains into a three-dimensional network. There is also a significant π-stacking inter­action between the planar sections of the six- and five-membered rings

2-(4,5-Dihydro-1H-imidazol-2-yl)­pyridine

In the mol­ecule of the title compound, C8H9N3, a new imidazoline derivative, the six- and five-membered rings are slightly twisted away from each other, forming a dihedral angle of 7.96 (15)°. In the crystal structure, neighbouring mol­ecules are linked together by inter­molecular N—H⋯N hydrogen bonds into extended one-dimensional chains along the a axis. The pyridine N atom is in close proximity to a carbon-bound H atom of the imidazoline ring, with an H⋯N distance of 2.70 Å, which is slightly shorter than the sum of the van der Waals radii of these atoms (2.75 Å). The crystal structure is further stabilized by inter­molecular C—H⋯π and π–π inter­actions (centroid-to-centroid distance 3.853 Å)

2-p-Tolyl-4,5-dihydro-1H-imidazole

In the mol­ecule of the title compound, C10H12N2, the six- and five-membered rings are almost co-planar, forming a dihedral angle of 3.56 (8)°. In the crystal structure, neighbouring mol­ecules are linked together by inter­molecular N—H⋯N hydrogen bonds into one-dimensional infinite chains along the c axis. The crystal structure, is further stabilized by weak inter­molecular C—H⋯π and π–π stacking [centroid–centroid distance = 3.8892 (9) Å] inter­actions

2-Amino­pyridinium (2-amino­pyridine)trichloridonickelate(II)

In the title compound, (C5H7N2)[NiCl3(C5H6N2)], the NiII atom is four-coordinated by three chloride anions and one N atom of a 2-amino­pyridine ligand, forming a distorted tetra­hedral coordination. In the crystal structure, cations and complex anions are linked into chains along the a, b and c axes by N—H⋯Cl hydrogen bonds, leading to the formation of a three-dimensional framework

Synthesis and characterization of the tetranuclear iron(III) complex of a new asymmetric multidentate ligand. A structural model for purple acid phosphatases

The ligand, 2-((2-hydroxy-5-methyl-3-((pyridin-2-ylmethylamino)methyl)benzyl)(2-hydroxybenzyl)amino)acetic acid (H(3)HPBA), which contains a donor atom set that mimics that of the active site of purple acid phosphatase is described. Reaction of H(3)HPBA with iron(III) or iron(II) salts results in formation of the tetranuclear complex, [Fe-4(HPBA)(2)(OAc)(2)(mu-O)(mu-OH)(OH2)(2)]ClO4 center dot 5H(2)O. X-Ray structural analysis reveals the cation consists of four iron(III) ions, two HPBA(3-) ligands, two bridging acetate ligands, a bridging oxide ion and a bridging hydroxide ion. Each binucleating HPBA(3-) ligand coordinates two structurally distinct hexacoordinate iron(III) ions. The two metal ions coordinated to a HPBA(3-) ligand are linked to the two iron(III) metal ions of a second, similar binuclear unit by intramolecular oxide and hydroxide bridging moieties to form a tetramer. The complex has been further characterised by elemental analysis, mass spectrometry, UV-vis and MCD spectroscopy, X- ray crystallography, magnetic susceptibility measurements and variable-temperature Mossbauer spectroscopy

Multifaceted SlyD from Helicobacter pylori: implication in [NiFe] hydrogenase maturation

SlyD belongs to the FK506-binding protein (FKBP) family with both peptidylprolyl isomerase (PPIase) and chaperone activities, and is considered to be a ubiquitous cytosolic protein-folding facilitator in bacteria. It possesses a histidine- and cysteine-rich C-terminus binding to selected divalent metal ions (e.g., Ni2+, Zn2+), which is important for its involvement in the maturation processes of metalloenzymes. We have determined the solution structure of C-terminus-truncated SlyD from Helicobacter pylori (HpSlyDΔC). HpSlyDΔC folds into two well-separated, orientation-independent domains: the PPIase-active FKBP domain and the chaperone-active insert-in-flap (IF) domain. The FKBP domain consists of a four-stranded antiparallel β-sheet with an α-helix on one side, whereas the IF domain folds into a four-stranded antiparallel β-sheet accompanied by a short α-helix. Intact H. pylori SlyD binds both Ni2+ and Zn2+, with dissociation constants of 2.74 and 3.79 μM respectively. Intriguingly, binding of Ni2+ instead of Zn2+ induces protein conformational changes around the active sites of the FKBP domain, implicating a regulatory role of nickel. The twin-arginine translocation (Tat) signal peptide from the small subunit of [NiFe] hydrogenase (HydA) binds the protein at the IF domain. Nickel binding and the recognition of the Tat signal peptide by the protein suggest that SlyD participates in [NiFe] hydrogenase maturation processes