Tris(2,2'-bipyridine-[kappa]2N,N')cobalt(II) bis­(hexa­fluoridophosphate)

In the title compound, [Co(C10H8N2)3](PF6)2, the CoII atom is coordinated by the six N atoms of three 2,2'-bipyridyl ligands and adopts a highly distorted octa­hedral geometry. The crystal used was a merohedral twin, the refined ratio of twin components being 0.820 (1):0.180 (1). The crystal structure features weak C-H...F inter­actions, forming a three-dimensional network

Bis(iminopyridyl)phthalazine as a sterically hindered compartmental ligand for an M-2 (M = Co, Ni, Fe, Zn) centre; Applications in ethylene oligomerisation

The new bis(iminopyridyl)phthalazine ligand, 1,4-{(2,6-i-Pr2C6H3)Ndouble bond; length as m-dashCMe)C5H3N}2C8H4N2 (L), has been prepared in good yield using a combination of palladium-mediated cross coupling and condensation strategies. Reaction of L with three equivalents of CoX2 (X = Cl, Br) in n-BuOH at elevated temperature generates, on crystallisation from bench acetonitrile, the paramagnetic tetrahalocobaltate salts [(L)Co2X(μ-X)(NCMe)m(OH2)n](CoX4) (X = Cl, m = 2, n = 1 1a; X = Br, m = 2, n = 0 1b) as acetonitrile or mixed acetonitrile/aqua adducts; a similar product is obtained from the reaction of FeCl2 with L and has been tentatively assigned as [(L)Fe2Cl(μ-Cl)(OH2)3](FeCl4) (2). By contrast, reaction of L with NiX2(DME) (X = Cl, Br; DME = 1,2-dimethoxyethane), under similar reaction conditions, affords the halide salts [(L)Ni2X2(μ-X)(OH2)2](X) (X = Cl 3a, X = Br 3b) as aqua adducts. Structural determinations on 1 and 3 reveal L to adopt a bis(tridentate) bonding mode allowing the halide-bridged metal centres to assemble in close proximity (M⋯M range: 3.437–3.596 Å). Unexpectedly, on reaction of L with ZnCl2, the neutral bimetallic [(L)Zn2Cl4] (4b) complex is formed in which the ZnCl2 units fill inequivalent binding sites within L (viz. the Nphth,Npy,Nim and Npy,Nim pockets). Complex 4b could also be obtained by the sequential addition of ZnCl2 to L to form firstly monometallic [(L)ZnCl2] (4a) and then on further ZnCl2 addition 4b; the fluxional behaviour of diamagnetic 4a and 4b is also reported. On activation with excess methylaluminoxane (MAO), 1–3 display modest activities for ethylene oligomerisation forming low molecular weight waxes with methyl-branched products predominating for the nickel systems (3). On the other hand, the iron catalyst (2) gives exclusively α-olefins while the cobalt systems (1) are much less selective affording equal mixtures of α-olefins and internal olefins along with lower levels of vinylidenes and tri-substituted alkenes. Single crystal X-ray structures are reported for L, 1a, 1b, 3a, 3b and 4

Crystal structure of (aceto-nitrile-κN)iodido-(2-(naphthalen-1-yl)-6-{1-[(2,4,6-tri-methyl-phen-yl)imino]ethyl}-pyridine-κ(2)N,N')copper(I).

In the mononuclear title complex, [CuI(C2H3N)(C26H24N2)], the Cu(I) ion has a distorted tetra-hedral coordination environment, defined by two N atoms of the chelating 2-(naphthalen-1-yl)-6-[(2,4,6-tri-methyl-phen-yl)imino]-pyridine ligand, one N atom of an aceto-nitrile ligand and one iodide ligand. Within the complex, there are weak intra-molecular C-H⋯N hydrogen bonds, while weak inter-molecular C-H⋯I inter-actions between complex mol-ecules, help to facilitate a three-dimensional network

Preparation of single enantiomers of chiral at metal bis-cyclometallated iridium complexes

Reaction of [Ir(C^N)[subscript 2]Cl][subscript 2] with chiral bidentate N^OH ligands provides complexes [Ir(C^N)[subscript 2](N^O)] as a 1 : 1 mixture of diastereomers which can be separated by crystallisation. A pure diastereomer can be converted to [Ir(C^N)[subscript 2](bipy)][CF[subscript 3]CO[subscript 2]] with complete retention of stereochemistry at the metal

2-(2-Methyl-5-nitro-1H-imidazol-1-yl)ethyl 3-bromo­benzoate

The mol­ecule of the title compound, C13H12BrN3O4, is non-planar, as indicated in the dihedral angle of 59.5 (4)° formed between the least-squares planes through the imidazole and benzene rings. In the crystal, mol­ecules are connected via C-H...O contacts, forming a supra­molecular chain

Electrophilic fluorination using a hypervalent iodine reagent derived from fluoride

The air and moisture stable fluoroiodane 8, readily prepared on a 6 g scale by nucleophilic fluorination of the hydroxyiodane 7 with TREAT-HF, has been used as an electrophilic fluorinating reagent for the first time to monofluorinate 1,3-ketoesters and difluorinate 1,3-diketones in good isolated yields

Triazoles from N-Alkynylheterocycles and Their Coordination to Iridium

N-alkynylheterocycles (benzimidazole and indazole) are converted to triazoles by click chemistry, and the resulting triazoles react with [IrCl₂Cp*]₂. The benzimidazole-triazole coordinates in a monodentate fashion through the benzimidazole, whereas the indazole-triazole is bidentate through coordination of both heterocycles. Reaction of the benzimidazole-triazole with methyliodide gives a benzimidazolium salt that deprotonates on coordination to afford a rare example of a bidentate NHC–triazole

Preparation of iodonium ylides: probing the fluorination of 1,3-dicarbonyl compounds with a fluoroiodane

The isolation of iodonium ylide 8, from the reaction of fluoroiodane 1 with ethyl 3-oxo-3-phenylpropanoate 5 in the presence of potassium fluoride, provides strong evidence that 1,3-dicarbonyl compounds undergo an addition reaction with fluoroiodane 1 to form an iodonium intermediate which can be deprotonated to generate an iodonium ylide. In the presence of TREAT-HF, however, the iodonium intermediate reacts to form the 2-fluoro-1,3-dicarbonyl product and we propose that fluoroiodane 1 simulates electrophilic fluorination via an addition/substitution mechanism. Further evidence to support this mechanism was obtained by successfully reacting the isolated iodonium ylide 8 with TREAT-HF, hydrochloric acid, acetic acid and p-toluenesulfonic acid to form the 2-fluoro-, 2-chloro-, 2-acetyl- and 2-tosyl-1,3-ketoesters respectively

Fluorinations of unsymmetrical diaryliodonium salts containing ortho-sidearms; influence of sidearm on selectivity.

Activated aromatics were reacted with two different fluoroidoane reagents 1 and 2 in the presence of triflic acid to prepare only the para-substituted diaryliodonium salts. With fluoroiodane 1 the unsymmetrical diaryliodonium salts contained an ortho-propan-2-ol sidearm, whereas the alcohol sidearm was eliminated to form an ortho-styrene sidearm in the reaction with fluoroiodane 2. Only the diaryliodonium salts containing a styrene sidearm were fluorinated successfully to deliver para-fluorinated aromatics in good yields

The Cancer Stem Cell Potency of Group 10-Azadiphosphine Metal Complexes

The cancer stem cell (CSC) potency of a series of structurally analogous Group 10-azadiphosphine metal complexes is reported. The complexes comprise a Group 10 metal (Ni for 1, Pd for 2, or Pt for 3), an azadiphosphine ligand, and two chloride ligands. The complexes exhibit micromolar potency towards bulk breast cancer cells and breast CSCs cultured in monolayer systems. The cytotoxicity of the complexes is comparable to or better than clinically used metallopharmaceuticals, cisplatin and carboplatin, and the gold-standard anti-breast CSC agent, salinomycin. Notably, the breast CSC mammosphere inhibitory effect and potency of the complexes is dependent on the Group 10 metal present, increasing in the following order: 3<2<1. This study highlights the importance of the metal within a given series of structurally related compounds to their breast CSC mammosphere activity and reinforces the therapeutic potential of Group 10 coordination complexes as anti-CSC agents