Anna Larsen

Designing ionic liquids with boron cluster anions: alkylpyridinium and imidazolium [nido-C2B9H11] and [closo-CB11H12] carborane salts

A range of new alkylpyridinium and imidazolium carborane salts with [nido-C(2)B(9)H(12)](-), [closo-CB(11)H(12)](-), and [RC(2)B(11)H(11)](-) (R = methyl or butyl) anions have been prepared and characterized by physical and thermal methods, including the solid state structures of five of the salts determined by single crystal X-ray diffraction. The tendency of the salts to form low-melting ionic liquids has been assessed; all the salts studied with [nido-C(2)B(9)H(12)](-) anions melted below 100 degrees C and, significantly, have melting points that are 25-85 degrees C lower than those of the corresponding [closo-CB(11)H(12)](-) analogs, demonstrating that a wider range of boron-rich ionic liquid materials can be readily accessed.

N-butylpyridinium undecachlorocarbadodecaborate and comparison with similar compounds.

The title compound, C(9)H(14)N(+)·CHB(11)Cl(11)(-), was obtained in the course of our continuing studies of the low-melting salts of closo- and nido-carborane cage anions with alkylpyridinium and dialkylimidazolium cations. The title compound is the first example of a pyridinium salt of a perchlorinated carborane anion. The structure consists of one N-butylpyridinium cation counterbalanced by one perchlorinated carborane cage anion per asymmetric unit. By changing the counter-ion, different packings are observed, and to try to understand this the new structure is compared with five similar compounds.

Hexakis(acetonitrile-κN)ruthenium(II) bis­(hexa­bromo­carbadodeca­borate) aceto­nitrile solvate

The title compound, [Ru(NCCH3)6](CH6B11Br6)2·CH3CN, consists of the ’naked’ ruthenium(II) cation surrounded by six acetonitrile molecules, each coordinated via the nitrogen atoms in a linear or nearly-linear fashion in a typical octahedral over-all arrangement. The cation is balanced by the two hexa-bromocarborane cage anionic fragments [CB11H6Br6]. Weak C—H⋯Br and B—H⋯Br interactions link neighboring anions.

(Glycol-κ2O,O′)nitros­yl(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) bis­(tri­fluoro­methane­sulfonate)

The title compound, [Ru(C10H15)(NO)(HOCH2CH2OH)](CF3SO3)2, possesses a three-legged piano-stool geometry around the Ru atom, with an average Ru—O distance of 2.120 (6) Å and an Ru—N—O angle of 159.45 (14)°. The ethyleneglycol ligand forms a non-planar metallacyclic ring by chelating the Ru atom via the O atoms. The O⋯O distances of 2.554 (2) and 2.568 (2) Å are indicative of hydrogen bonding between coordinated ethyleneglycol and outer-sphere trifluoromethanesulfonate fragments. The crystal packing is stabilized by ionic forces and several CH3⋯·F (2.585 and 2.640 Å) and CH3⋯O interactions (2.391, 2.678, 2.694 and 2.699 Å) between the pentamethylcyclopentadienyl ligand and trifluoromethanesulfonate anion. There is noticeable short intermolecular contact [2.9039 (16) Å], between an O atom of the SO3 group and a C atom of the pentamethylcyclopentadienyl ligand.

Crystal structure of 1-butyl-2,3-di-methyl-imidazolium dicarba-7,8-nido-undeca-borate.

In the title molecular salt, C9H17N2 +·C2H12B9 −, the carborane cage has a bridging B—H—B bond on the open B3C2 face. The butyl side chain of the cation adopts an extended conformation [C—C—C—C = 179.6 (1)°]. In the crystal, the imidazolium ring is almost coplanar with the open face of the carborane anion. The cations stack in the [010] direction and the dihedral angle between the imidazolium rings of adjacent cations is 68.45 (6)°. The butyl chains extend into the space between carborane anions.

(Glycol-κ2 O,O′)nitros­yl(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) bis­(tri­fluoro­methane­sulfonate). Corrigendum

Corrigendum to Acta Cryst. (2008), E64, m293.

Erratum: (Glycol-κO,O')nitros-yl(η-penta-methyl-cyclo-penta-dien-yl)ruthenium(II) bis-(tri-fluoro-methane-sulfonate). Corrigendum.

Corrigendum to Acta Cryst. (2008), E64, m293.

(Glycol-κ2O,O′)nitrosyl(η5-pentamethylcyclopentadienyl)ruthenium(II) bis(trifluoromethanesulfonate). Corrigendum

Corrigendum to Acta Cryst. (2008), E64, m293.

Erratum: Di-μ-nitrosyl-bis-[(η-penta-methyl-cyclo-penta-dien-yl)ruthenium(0)](Ru-Ru). Corrigendum.

Corrigendum to Acta Cryst. (2007), E63, m2596.