Synthesis of nitrogen mustards on cobalt(III).

Bis(bidentate) and bis(tridentate) Co(III) complexes of -(2-hydroxyethyl)ethane-1,2-diamine (heen), 2-[(2-aminoethyl)amino]ethan-1-olate (heen-H), or -(2-chloroethyl)ethane-1,2-diamine (ceen) ligands have been synthesised, and a range of reaction conditions established for their syntheses by different routes. They can all be ultimately derived from (OC-6-12')-[Co(heen)(NO)]NO and provide access to the amine chloride nitrogen mustard complex, (OC-6-12')-[Co(ceen)(Cl)]Cl. Although complex isomeric mixtures were obtained from the reaction of (OC-6-12')-[Co(heen)(NO)]NO under different reaction conditions, ultimately, the amine chlorido configuration around the Co(III) metal centre of the (OC-6-12')-[Co(ceen)(Cl)]Cl complex was favoured.

Enantioselective synthesis of hydantoins by chiral acid-catalysed condensation of glyoxals and ureas.

Hydantoins are important scaffolds in natural products and pharmaceuticals, with only a few synthetic strategies available for their asymmetric preparation. We herein describe a single-step enantioselective synthesis of 5-monosubstituted hydantoins condensation of glyoxals and ureas in the presence of a chiral phosphoric acid at room temperature. Products were formed in up to 99% yield and 98 : 2 e.

Size-activity threshold of titanium dioxide-supported Cu cluster in CO oxidation.

Development of non-noble metal cluster catalysts, aiming at concurrently high activity and stability, for emission control systems has been challenging because of sintering and overcoating of clusters on the support. In this work, we reported the role of well-dispersed copper nanoclusters supported on TiO in CO oxidation under industrially relevant operating conditions. The catalyst containing 0.

A Discrete Chloride Monohydrate: A Solid-State Structural and Spectroscopic Characterization.

The solid-state structure of a discrete chloride monohydrate species, [Cl(HO)], is reported for the first time. It was isolated as a salt of the tris(dipropylamino)cyclopropenium cation and has been structurally characterized by X-ray and neutron diffraction. Infrared (IR), far-infrared, and Raman spectroscopic studies were also carried out.

Pyrazine-bridged Cu(ii) chains: diaquabis(n-methyl-2-pyridone)copper(ii) perchlorate complexes.

A family of pyrazine-bridged, linear chain complexes of Cu(ii) of the formula [CuL(HO)(pz)](ClO) [pz = pyrazine; L = n-methyl-2(1H)-pyridone, n = 3 (1), 5 (2), and 6 (3)] has been prepared. Single-crystal X-ray diffraction shows six-coordinate, pyrazine-bridged chains with trans-pairs of ancillary ligands. The substituted pyridine molecules exist in their pyridone tautomers and are coordinated through the carbonyl oxygen atom.

Solvent Dependent Spin-Crossover and Photomagnetic Properties in an Imidazolylimine Fe Complex.

The synthesis and physico-chemical characterization of an Fe complex [Fe(L1) ](ClO ) ⋅CH CN⋅0.5H O, 1, incorporating a bidentate imidazolylimine-based ligand are reported. Complex 1 crystallises as the mer-isomer and the crystal lattice is replete with hydrogen bonding interactions between ClO anions, solvent molecules and imidazole N-H groups.

Nanostructured TiO anatase-rutile-carbon solid coating with visible light antimicrobial activity.

TiO photocatalyst is of interest for antimicrobial coatings on hospital touch-surfaces. Recent research has focused on visible spectrum enhancement of photocatalytic activity. Here, we report TiO with a high degree of nanostructure, deposited on stainless steel as a solid layer more than 10 μm thick by pulsed-pressure-MOCVD.

Clinical Utility of Multi-Energy Spectral Photon-Counting Computed Tomography in Crystal Arthritis.

Objective: To determine whether novel multi-energy spectral photon-counting computed tomography (SPCCT) imaging can detect and differentiate between monosodium urate (MSU), calcium pyrophosphate (CPP), and hydroxyapatite (HA) crystal deposits ex vivo.

Methods: A finger with a subcutaneous gouty tophus and a calcified knee meniscus excised at the time of surgery were obtained. The finger was imaged using plain x-ray, dual-energy CT (DECT), and multi-energy SPCCT.

Synthesis and physical properties of tris(dialkylamino)cyclopropenium dicyanamide ionic liquids.

The synthesis and properties of 16 tris(dialkylamino)cyclopropenium (TDAC) cations with the dicyanamide (DCA) anion, [N(CN)], are described. - and -symmetric cations ([C(NR)]DCA (R = Me, Et, Pr, Bu, Pent, Hex, Dec) and [C(NRMe)]DCA (R = Bu, St), respectively) were synthesised by reaction of CClH with the corresponding amine. Reaction of the alkoxydiaminocyclopropenium salt [C(NEt)(OMe)] with amines led to a series of -symmetric salts [C(NEt)(NR)]DCA (R = Me, Bu, Hex) and two -symmetric salts and [C(NEt)(NRMe)]DCA (R = Me, Bu).

Varied spin crossover behaviour in a family of dinuclear Fe(ii) triple helicate complexes.

Dinuclear triple-helicate complexes of the formula [Fe2L3](BF4)4·solv (solv = CH3CN, CHCl3, H2O) have been synthesised and structurally characterised. The bis-bidentate ligands, L, present either strong-field 2-pyridylimine (1) or weaker-field 2-imidazolylimine (2) and 4-imidazolylimine (3) coordination spheres about Fe(ii) centres in an octahedral geometry. Whereas 1 is pervasively diamagnetic, spin crossover (SCO) behaviour is observed in 2 and 3 and has been studied using variable-temperature structural, UV-visible spectroscopic, magnetic and photo-magnetic techniques.

Ferromagnetic Exchange in Bichloride Bridged Cu(II) Chains: Magnetostructural Correlations between Ordered and Disordered Systems.

The synthesis, structure, magnetic properties, and theoretical analysis of a new phase of dichloro(2-chloro-3-methylpyridine)copper(II) (2) and its isomorphous analogue dichloro(2-bromo-3-methylpyridine)copper(II) (3) are reported. Both complexes crystallize in the orthorhombic space group Pbca and present square pyramidal Cu(II) ions bridged into chains by chloride ions with each copper(II) bearing a single pyridine ligand. Variable temperature magnetic susceptibility measurements were well fit by a uniform one-dimensional ferromagnetic chain model with 2, J = 69.

Cyclopropenium Cations Break the Rules of Attraction to Form Closely Bound Dimers.

The crystal structures of tris(ethylmethylamino)-cyclopropenium chloride and tris(diethylamino)-cyclopropenium iodide reveal the presence of closely bound dicationic dimers formed from two closed-shell monomer units. The distances between the C3 centroids of the staggered monomers are at the short end of those normally found in π-stacked neutral arenes, let alone charged aromatic rings. Computational analysis reveals that short-range interactions are dominated by strong dispersion forces, enabling metastable dicationic dimers to form without covalent intermolecular bonding.

Unexpected furanose/pyranose equilibration of N-glycosyl sulfonamides, sulfamides and sulfamates.

De-protected arabino N-glycosyl sulfamides, sulfonamides and sulfamates were found to mutarotate and convert from the furanose to the thermodynamically more stable pyranose form in aqueous solution. The presence of a strongly electron withdrawing group in the alkyl chain stopped mutarotation and furanose/pyranose equilibration, allowing the isolation of the first unprotected furanose N-glycosyl sulfonamide.

Deliberate boxes and accidental wheels.

This report describes systems which combine the structural and reactive motifs of a dinucleating terpyridine-aminomethylpyridine ligand, L, with the coordination preferences and flexibilities of particular divalent metal ions to form a series of closely related box structures in a deliberate fashion. The ligand also produces unprecedented decanickel wheel complexes. Halogen to aromatic hydrogen interactions may be important in stabilising the decanickel wheel structures.

2-Amino-5-iodopyridinium bromide hemihydrate and 2-amino-5-iodopyridinium chloride monohydrate.

The hydrobromide and hydrochloride salts of 2-amino-5-iodopyridine were prepared from aqueous solutions. The hydrobromide salt, C5H6IN2(+)·Br(-)·0.5H2O, crystallizes as a hemihydrate, and exhibits hydrogen bonding and π-stacking which stabilize the crystal structure.

Synthesis, structural and magnetic characterisation of iron(II/III), cobalt(II) and copper(II) cluster complexes of the polytopic ligand: N-(2-pyridyl)-3-carboxypropanamide.

Herein we describe the synthesis, structural and magnetic characterisation of three transition metal cluster complexes that feature the polytopic ligand N-(2-pyridyl)-3-carboxypropanamide (H2L): [Fe3(III)Fe2(II)(HL)6(O)(H2O)3][ClO4]5·3MeCN·4H2O, 1, [Co8(HL)8(O)(OH)4(MeOH)3(H2O)]-[ClO4]3·5MeOH·2H2O, 2, and [Cu6(L(ox))4(MeOH)(H2O)3]·MeOH, 3. Complex 1 is a mixed valence penta-nuclear iron cluster containing the archetypal {Fe3(III)O} triangular basic carboxylate cluster at its core, with two Fe(II) ions above and below the core coordinated to three bidentate pyridyl-amide groups. The structure of the octanuclear Co(II) complex, 2, is based upon a central Co4 square with the remaining four Co(II) centres at the 'wing-tips' of the complex.

Chemically-synthesised, atomically-precise gold clusters deposited and activated on titania.

Synchrotron XPS was used to investigate a series of chemically-synthesised, atomically-precise gold clusters Au(n)(PPh(3))(y) (n = 8, 9, 11 and 101, with y depending on cluster size) immobilized on titania nanoparticles. The gold clusters were washed with toluene at 100 °C or calcined at 200 °C to remove the organic ligand. From the position of the Au 4f(7/2) peak it is concluded that cluster size is not altered through the deposition.

Heterodinuclear ruthenium(II)-cobalt(III) complexes as models for a new approach to selective cancer treatment.

Heterodinuclear ruthenium(II)-cobalt(III) complexes have been prepared as part of investigations into a new approach to selective cancer treatment. A cobalt(III) centre bearing amine ligands, which serve as models for cytotoxic nitrogen mustard ligands, is connected by a bridging ligand to a ruthenium(II)-polypyridyl moiety. Upon excitation of the ruthenium centre by visible light, electron transfer to the cobalt(III) centre results in reduction to cobalt(II) and consequent release of its ligands.

High diastereoselectivity in borohydride reductions of coordinated imines.

Borohydride reduction of the imine groups in a pyruvate-derived cobalt(III) complex, (OC-6-33')-[Co(Aim(2)trien)](2)[ZnCl(4)], occurs with high diastereoselectivity. The major diastereoisomeric product, (OC-6-33'-ARSSR,CSRRS)-[Co(A(2)trien)]Cl has been isolated and crystallographically characterised. The results from base-induced isomerisation of the major isomer allow us to conclude that most of the remaining material from the reduction reactions (consisting of minor diastereoisomers) differs from the major isomer only in the relative configuration of the coordinated amines.

Trinuclear copper(I) complex containing 3,4,9,10,15,16-hexamethyl-1,6,7,12,13,18-hexaazatrinaphthylene: a structural, spectroscopic, and computational study.

The compound [(Cu(PPh(3))(2))(3)(HATNMe(6))](BF(4))(3) has been synthesized and characterized by X-ray crystallography, resonance Raman spectroscopy, and density functional theory (DFT) calculations. The X-ray structure of solvated [(Cu(PPh(3))(2))(3)(HATNMe(6))](BF(4))(3) [rhombohedral, R3, a = b = 21.6404(4) A, c = 53.

3,3'-Dibromo-5,5'-di-tert-butyl-2,2'-dimethoxy-biphen-yl.

The title compound, C(22)H(28)Br(2)O(2), crystallizes in a staggered arrangement to minimize the inter-actions of its ortho substituents, with a dihedral angle of 84.2 (3)° between the two aromatic rings. Short C-H⋯O hydrogen-bonding inter-actions between meth-oxy groups result in a one-dimensional polymeric chain of mol-ecules lying parallel to the b axis.

Site-specific electronic couplings in dyads with MLCT excited states. Intramolecular energy transfer in isomeric Ru(II)-Ru(II) cyclometalated complexes.

The rod-like binuclear complexes [(ttpy)Ru(tpy-ph(2)-phbpy)Ru(ttpy)](4+) and [(ttpy)Ru(tpy-ph(2)-tpy)Ru(phtbpy)](4+) (for abbreviations, see text) have been synthesized and characterized. In both complexes, the polypyridine Ru(II) centers have (N--N--N)Ru(N--N--N) and (N--N--N)Ru(C--N--N) coordination environment. The two isomeric species differ in whether the cyclometalating carbon resides on the bridging or on the terminal ligand.

4-[4-(Methyl-sulfan-yl)phen-yl]-6-phenyl-2,2'-bipyridine.

The structure of the title compound, C(23)H(18)N(2)S, is revealed by X-ray diffraction to be almost planar over all four aromatic rings; the pendant rings are at angles of 10.18, 14.12 and 15.

(η-Benzene)(2,2'-bipyridine-κN,N')chloridoruthenium(II) chloride methanol sesquisolvate.

In the title compound, [RuCl(C(6)H(6))(C(10)H(8)N(2))]Cl·1.5CH(4)O, the Ru(II) atom is in a distorted octa-hedral environment coordinated by an η(6)-benzene ring, a chelating 2,2'-bipyridine ligand and a chloride ion. The asymmetric unit is completed by a chloride anion and two methanol mol-ecules, one of which is disordered about a centre of inversion with an occupancy of 0.