Benzyl­tributyl­ammonium 6,7-dihydroxy­naphthalene-2-sulfonate

The title mol­ecular salt, C19H34N+·C10H7O5S−, is a charge-control agent used for toners in electrophotography. There are two formula units in the asymmetric unit. Both anions form inversion dimers connected by pairs of O—H⋯O hydrogen bonds between the –OH group of one anion and a sulfonic O atom of the neighboring one. The two dimers A and B are characterized by a step between the least-squares planes of the naphthalene atoms of 0.85 and 2.30 Å. Further O—H⋯O bonds link the dimers into a two-dimensional network propagating in (110) such that dimer A is hydrogen-bonded to four B units and vice versa. One of the tert-butyl chains in one of the cations is disordered over two sets of sites in a 0.56:0.44 ratio

Benzyl­tributyl­ammonium 4,6-dihydroxy­naphthalene-2-sulfonate

The title mol­ecular salt, C19H34N+·C10H7O5S−, is a charge-control agent used for toners in electrophotography with a high melting point of 508 K. In the crystal structure, the anions form inversion dimers, linked by pairs of O—H⋯O hydrogen bonds. Further O—H⋯O links between dimers generate anionic sheets propagating in (010). One of the n-butyl chains of the cation is disordered over two sets of sites in a 0.53:0.47 ratio

Benzyl­tributyl­ammonium 4-hydroxy­naphthalene-2-sulfonate

The title compound, C19H34N+·C10H7O4S−, is a charge-control agent used for toners in electrophotography. In the crystal structure, centrosymmetric anions associate through O—H⋯O hydrogen bonds formed between the O—H group of one anion and the sulfonate O atom of a neighbor. The components of the dimer are offset with respect to each other so that the separation between the two parallel naphthalene skeletons is about 1.6 Å. The ethyl residues of two of the butyl groups are disordered and were modelled over two postions (site occupancies = 0.33/0.67 and 0.34/0.66)

Benzyl­tributyl­ammonium 7-hydroxy­naphthalene-1-sulfonate

The title compound, C19H34N+·C10H7O4S−, is a charge-control agent used for toners in electrophotography. The anions form one-dimensional chains by O—H⋯O hydrogen bonds in a zigzag fashion along the c axis between the OH group of one anion and the sulfonate O atom of a neighboring anion. One of the n-butyl chains of the cation is disordered over two sites in a 0.77:0.23 ratio

Diacetonitrile­tetra­kis{μ2-3-anilinocarbonyl-1-[(5-chloro-2-oxidophen­yl)diazen­yl]-2-naphtholato}tetra­aqua­diiron(III)disodium(I) dihydrate

The title compound, [Fe2Na2(C23H14ClN3O3)4(C2H3N)2(H2O)4]·2H2O, is a hydrated Fe–azo complex dimer that is used as a charge-control agent in electrophotography. The mol­ecule is a centrosymmetric dimer with two octa­hedral FeIII units linked by two bridging five-coordinate NaI cations. Each FeIII atom is chelated by the N and two O atoms from two 3-anilinocarbonyl-1-[(5-chloro-2-oxidophen­yl)diazen­yl]-2-naph­tholate ligands. The Na+ cation is coordinated by a carbonyl O atom from the two ligands of each octa­hedral FeIII unit, two water mol­ecules and the N atom of an acetonitrile mol­ecule. Two solvent water mol­ecules complete the structure. In the crystal structure, the dimeric mol­ecules are bridged by a pair of discrete inter­molecular O—H⋯O hydrogen bonds, one of which involves a sodium-bound water mol­ecule and a hydrate water, and the other a 5-chloro­phenolate O atom and a water molecule to form an extended chain along b

Diacetonitrile­tetra­kis{μ2-3-anilinocarbonyl-1-[(5-chloro-2-oxidophen­yl)diazen­yl]-2-naphtholato}tetra­aqua­diiron(III)disodium(I) dihydrate. Corrigendum

Corrigendum to Acta Cryst. (2008), E64, m240–m241

Benzyl­tributyl­ammonium 6-hydroxy­naphthalene-2-sulfonate

The title compound, C19H34N+·C10H7O4S−, is a charge-control agent for toners used in electrophotography. Inter­moleclar O—H⋯O hydrogen bonding between the OH group of one anion and the sulfonate O atom of a neighboring anion leads to the formation of one-dimensional chains along the b axis. In addition, C—H⋯O hydrogen bonds are observed. One of the n-butyl chains of the cation is disordered over two sites in a 0.88:0.12 ratio

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements