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17β-Hydroxysteroid dehydrogenase type 3 (17β-HSD3) is expressed at high levels in testes and seminal vesicles; it is also present in prostate tissue and involved in gonadal and non-gonadal testosterone biosynthesis. The enzyme is membrane-bound, and a crystal structure is not yet available. Selective aryl benzylamine-based inhibitors were designed and synthesised as potential agents for prostate cancer therapeutics through structure-based design, using a previously built homology model with docking studies. Potent, selective, low nanomolar IC50 17β-HSD3 inhibitors were discovered using N-(2-([2-(4-chlorophenoxy)phenylamino]methyl)phenyl)acetamide (1). The most potent compounds have IC50 values of approximately 75 nM. Compound 29, N-[2-(1-Acetylpiperidin-4-ylamino)benzyl]-N-[2-(4-chlorophenoxy)phenyl]acetamide, has an IC50 of 76 nM, while compound 30, N-(2-(1-[2-(4-chlorophenoxy)-phenylamino]ethyl)phenyl)acetamide, has an IC50 of 74 nM. Racemic C-allyl derivative 26 (IC50 of 520 nM) was easily formed from 1 in good yield and, to determine binding directionality, its enantiomers were separated by chiral chromatography. Absolute configuration was determined using single crystal X-ray crystallography. Only the S-(+)-enantiomer (32) was active with an IC50 of 370 nM. Binding directionality was predictable through our in silico docking studies, giving confidence to our model. Importantly, all novel inhibitors are selective over the type 2 isozyme of 17β-HSD2 and show

The β-diketiminato magnesium hydride, [(BDI)MgH]]2, reacts with alkenes and catalyses their hydrosilylation with PhSiH3., The dimeric β-diketiminato magnesium hydride, [(BDI)MgH]2, reacts at 80 °C with the terminal alkenes, 1-hexene, 1-octene, 3-phenyl-1-propene and 3,3-dimethyl-butene to provide the respective n-hexyl, n-octyl, 3-phenylpropyl and 3,3-dimethyl-butyl magnesium organometallics. The facility for and the regiodiscrimination of these reactions are profoundly affected by the steric demands of the alkene reagent. Reactions with the phenyl-substituted alkenes, styrene and 1,1-diphenylethene, require a more elevated temperature of 100 °C with styrene providing a mixture of the 2-phenylethyl and 1-phenylethyl products over 7 days. Although the reaction with 1,1-diphenylethene yields the magnesium 1,1-diphenylethyl derivative as the sole reaction product, only 64% conversion was achieved over a 21 day timeframe. Reactions with the α,ω-dienes, 1,5-hexadiene and 1,7-octadiene, provided divergent results. The initial 5-alkenyl magnesium reaction product of the shorter chain diene undergoes 5-exo-trig cyclisation via intramolecular carbomagnesiation to provide a cyclopentylmethyl derivative, which was shown by X-ray diffraction analysis to exist as a three-coordinate monomer. In contrast, 1,7-octadiene provided a mixture of two compounds, a magnesium oct-7-en-1-yl derivative and a dimagnesium-octane-1,4-diide, as a result of single or two-fold activation of the terminal C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C double bonds. The magnesium hydride was unreactive towards internal alkenes apart from the strained bicycle, norbornene, allowing the characterisation of the resultant three-coordinate magnesium norbornyl derivative by X-ray diffraction analysis. Computational analysis of the reaction between [(BDI)MgH]2 and 1-hexene using density functional theory (DFT) indicated that the initial Mg–H/C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C insertion process is rate determining and takes place at the intact magnesium hydride dimer. This exothermic reaction (ΔH = –14.1 kcal mol–1) traverses a barrier of 18.9 kcal mol–1 and results in the rupture of the dinuclear structure into magnesium alkyl and hydride species. Although the latter three-coordinate hydride derivative may be prone to redimerisation, it can also provide a further pathway to magnesium alkyl species through its direct reaction with a further equivalent of 1-hexene, which occurs via a lower barrier of 15.1 kcal mol–1. This Mg–H/C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C insertion reactivity provides the basis for the catalytic hydrosilylation of terminal alkenes with PhSiH3, which proceeds with a preference for the formation of the anti-Markovnikov organosilane product. Further DFT calculations reveal that the catalytic reaction is predicated on a sequence of Mg–H/C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C insertion and classical Si–H/Mg–C σ-bond metathesis reactions, the latter of which, with a barrier height of 24.9 kcal mol–1, is found to be rate determining.

Reactions of a magnesium‐based pinacolatoboryl nucleophile with the electrophilic organoboranes, 9‐BBN and Ph3B, provide facile B−B′ single bond formation. Although the Ph3B derivative is thermally stable, when heated, the unsymmetrical diborane(5) anion derived from 9‐BBN is found to isomerize to two regioisomeric species via a proposed mechanism involving dehydroboration of the borabicyclo[3.3.1]nonane and syn‐diboration of the resultant alkenyl carbocycle.

Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent Ca2+-releasing second messenger known to date, but the precise NAADP/Ca2+ signalling mechanisms are still controversial. We report the synthesis of small-molecule inhibitors of NAADP-induced Ca2+ release based upon the nicotinic acid motif. Alkylation of nicotinic acid with a series of bromoacetamides generated a diverse compound library. However, many members were only weakly active or had poor physicochemical properties. Structural optimisation produced the best inhibitors that interact specifically with the NAADP/Ca2+ release mechanism, having no effect on Ca2+ mobilized by the other well-known second messengers d-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] or cyclic adenosine 5′-diphospho-ribose (cADPR). Lead compound (2) was an efficient antagonist of NAADP-evoked Ca2+ release in vitro in intact T lymphocytes and ameliorated clinical disease in vivo in a rat experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis. Compound (3) (also known as BZ194) was synthesized as its bromide salt, confirmed by crystallography, and was more membrane permeant than 2. The corresponding zwitterion (3a), was also prepared and studied by crystallography, but 3 had more desirable physicochemical properties. 3 Is potent in vitro and in vivo and has found widespread use as a tool to modulate NAADP effects in autoimmunity and cardiovascular applications. Taken together, data suggest that the NAADP/Ca2+ signalling mechanism may serve as a potential target for T cell- or cardiomyocyte-related diseases such as multiple sclerosis or arrhythmia. Further modification of these lead compounds may potentially result in drug candidates of clinical use.

The Mannich reaction of the zirconium MOF [Zr6 O4 (OH)4 (bdc-NH2 )6 ] (UiO-66-NH2 , bdc-NH2 =2-amino-1,4-benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2-mercaptoimidazole led to post-synthetic modification (PSM) through C-N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2-mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO-66-NH2 , but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol-containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4 O(bdc-NH2 )3 ] (IRMOF-3), but a similar reaction on [Zn2 (bdc-NH2 )2 (dabco)] (dabco=1,4-diazabicyclo[2.2.2]octane) gave [Zn3 (bdc-NH2 )1.32 (bdc-NHCH2 pyz)1.68 (dabco)]⋅2 C7 H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution-recrystallisation process that is triggered by the "free" pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the "free" nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc-NH2 )] (MIL-68(In)-NH2 ) stop after the first step, and the product was identified as [In(OH)(bdc-NH2 )0.41 (bdc-NHCH2 OCH3 )0.30 (bdc-N=CH2 )0.29 ], with addition of the heterocycle prevented by steric interactions.

The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc‐NH2)6] (UiO‐66‐NH2, bdc‐NH2=2‐amino‐1,4‐benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2‐mercaptoimidazole led to post‐synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2‐mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO‐66‐NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol‐containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc‐NH2)3] (IRMOF‐3), but a similar reaction on [Zn2(bdc‐NH2)2(dabco)] (dabco=1,4‐diazabicyclo[2.2.2]octane) gave [Zn3(bdc‐NH2)1.32(bdc‐NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc‐NH2)] (MIL‐68(In)‐NH2) stop after the first step, and the product was identified as [In(OH)(bdc‐NH2)0.41(bdc‐NHCH2OCH3)0.30(bdc‐N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.

Dehydrocoupling reactions between the boranes HBpin and 9-borabicyclo[3.3.1]nonane and a range of amines and anilines ensue under very mild reaction conditions in the presence of a simple β-diketiminato magnesium n-butyl precatalyst. The facility of the reactions is suggested to be a function of the Lewis acidity of the borane substrate, and is dictated by resultant pre-equilibria between, and the relative stability of, magnesium hydride and borohydride intermediates during the course of the catalysis.

A series complexes based on 2,2′-bipyrrolidine based salan ligands have been prepared and either isotactic or heterotactic PLA have been prepared., In this paper we have prepared a series of Ti(iv), Hf(iv) and Al(iii) complexes based on bipyrrolidine salan pro-ligands. The Hf(iv) complexes have all been characterised in the solid-state, the chiral ligands coordinate to Hf(iv) in an α-cis manner whereas the meso ligand coordinates in a β-cis geometry. The Hf(iv) complexes are all active for the ROP of rac-lactide in the melt, with the fluxional meso complex affording a strong isotactic bias P m = 0.84. As expected Hf(3)(OiPr)2 polymerised l-LA faster than rac-LA (k app = 5.9 × 10–3 min–1 vs. 3.8 × 10–3 min–1). For Ti(iv) complexes atactic PLA was formed. The salan pro-ligands have also been complexed to Al(iii), and the novel Al–Me and Al-OiPr complexes were characterised in the solid and solution state. Al(1)(OiPr) was fluxional on the NMR timescale, whereas Al(3)(OiPr) was locked in solution with no exchange. Interestingly, the Al(iii) complexes of 3H2 produce PLA with a very strong heterotactic bias P r upto 0.87, whereas atactic PLA is produced with 1H2. For Al(3)(OiPr) a linear relationship is observed with M n and conversion. Experiments with the addition of an equivalent of rac-LA to the selective initiators have also been performed and are discussed.

Mild methods for the deprotection of organic substrates are of fundamental importance in synthetic chemistry. A new room temperature method using a catalytic amount of Cu(OTf)2 is reported. This allows use of the tert-butyl group as an amide protecting group. The methodology is also extended to Boc-deprotection.

A SAR translation strategy adopted for the discovery of tetrahydroisoquinolinone (THIQ)-based steroidomimetic microtubule disruptors has been extended to dihydroisoquinolinone (DHIQ)-based compounds. A steroid A,B-ring-mimicking DHIQ core was connected to methoxyaryl D-ring mimics through methylene, carbonyl, and sulfonyl linkers, and the resulting compounds were evaluated against two cancer cell lines. The carbonyl-linked DHIQs in particular exhibit significant in vitro antiproliferative activities (e.g., 6-hydroxy-7-methoxy-2-(3,4,5-trimethoxybenzoyl)-3,4-dihydroisoquinolin-1(2H)-one (16 g): GI50 51 nM in DU-145 cells). The broad anticancer activity of DHIQ 16 g was confirmed in the NCI 60-cell line assay giving a mean activity of 33 nM. Furthermore, 6-hydroxy-2-(3,5-dimethoxybenzoyl)-7-methoxy-3,4-dihydroisoquinolin-1(2H)-one (16 f) and 16 g and their sulfamate derivatives 17 f and 17 g (2-(3,5-dimethoxybenzoyl)-7-methoxy-6-sulfamoyloxy-3,4-dihydroisoquinolin-1(2H)-one and 7-methoxy-2-(3,4,5-trimethoxybenzoyl)-6-sulfamoyloxy-3,4-dihydroisoquinolin-1(2H)-one, respectively) show excellent activity against the polymerization of tubulin, close to that of the clinical combretastatin A-4, and bind competitively at the colchicine binding site of tubulin. Compounds 16 f and 17 f were also shown to demonstrate in vitro anti-angiogenic activity. Additionally, X-ray and computational analyses of 17 f reveal that electrostatic repulsion between the two adjacent carbonyl groups, through conformational biasing, dictates the adoption of a "steroid-like" conformation that may partially explain the excellent in vitro activities.

Treatment of CuCl with 1 equiv of the in situ prepared N-mesityl-substituted diamidocarbene 6-MesDAC produced a mixture of the dimeric and trimeric copper complexes [(6-MesDAC)CuCl]2 (1) and [(6-MesDAC)2(CuCl)3] (2). Combining CuCl with isolated, free 6-MesDAC in 1:1 and 3:2 ratios gave just 1 and 2, respectively, while increasing the ratio to >5:1 allowed the isolation of small amounts of the tetrameric copper complex [(6-MesDAC)2(CuCl)4] (3). Efforts to bring about metathesis reactions of 1 with MOtBu (M = Li, Na, K) proved successful only for M = Li to afford the spectroscopically characterized ate product [(6-MesDAC)CuCl·LiOtBu·2THF] (5). Attempts to crystallize this species instead gave a 1:1 mixture of 1 and the monomer [(6-MesDAC)CuCl] (6). The X-ray structures of 1–3 and 1 + 6, along with the cation [Cu(6-MesDAC)2]+ (4), have been determined., Treatment of CuCl with the diamidocarbene 6-MesDAC generated [(6-MesDAC)CuCl]2, [(6-MesDAC)2(CuCl)3], and [(6-MesDAC)2(CuCl)4]. Efforts to convert the dimer to a Cu−OtBu complex led instead to a partially metathesized ate complex; attempts at crystallization afforded instead a 1:1 mixture of [(6-MesDAC)CuCl]2 and [(6-MesDAC)CuCl].

International audience; Relativistic density functional theory calculations, both with and without the effects of spin–orbit coupling, have been employed to model hydride NMR chemical shifts for a series of [Ru(NHC)4(L)H]0/+ species (NHC = N-heterocyclic carbene; L = vacant, H2, N2, CO, MeCN, O2, P4, SO2, H−, F− and Cl−), as well as selected phosphine analogues [Ru(R2PCH2CH2PR2)2(L)H]+ (R = iPr, Cy; L = vacant, O2). Inclusion of spin–orbit coupling provides good agreement with the experimental data. For the NHC systems large variations in hydride chemical shift are shown to arise from the paramagnetic term, with high net shielding (L = vacant, Cl−, F−) being reinforced by the contribution from spin–orbit coupling. Natural chemical shift analysis highlights the major orbital contributions to the paramagnetic term and rationalizes trends via changes in the energies of the occupied Ru dπ orbitals and the unoccupied σ*Ru–H orbital. In [Ru(NHC)4(η2-O2)H]+ a δ-interaction with the O2 ligand results in a low-lying LUMO of dπ character. As a result this orbital can no longer contribute to the paramagnetic shielding, but instead provides additional deshielding via overlap with the remaining (occupied) dπ orbital under the Lz angular momentum operator. These two effects account for the unusual hydride chemical shift of +4.8 ppm observed experimentally for this species. Calculations reproduce hydride chemical shift data observed for [Ru(iPr2PCH2CH2PiPr2)2(η2-O2)H]+ (δ = −6.2 ppm) and [Ru(R2PCH2CH2PR2)2H]+ (ca. −32 ppm, R = iPr, Cy). For the latter, the presence of a weak agostic interaction trans to the hydride ligand is significant, as in its absence (R = Me) calculations predict a chemical shift of −41 ppm, similar to the [Ru(NHC)4H]+ analogues. Depending on the strength of the agostic interaction a variation of up to 18 ppm in hydride chemical shift is possible and this factor (that is not necessarily readily detected experimentally) can aid in the interpretation of hydride chemical shift data for nominally unsaturated hydride-containing species. The synthesis and crystallographic characterization of the BArF4− salts of [Ru(IMe4)4(L)H]+ (IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene; L = P4, SO2; ArF = 3,5-(CF3)2C6H3) and [Ru(IMe4)4(Cl)H] are also reported.

A new approach is reported for tailoring the pore geometry in five series of multivariate metal-organic frameworks (MOFs) based on the structure [Zn-2(bdc)(2)(dabco)] (bdc = 1,4-benzenedicarboxylate, dabco = 1,8-diazabicyclooctane), DMOF-1. A doping procedure has been adopted to form series of MOFs containing varying linker ratios. The series under investigation are [Zn-2(bdc)(2-x)(bdc-Br)(x)(dabco)]center dot nDMF 1 (bdc-Br = 2-bromo-1,4-benzenedicarboxylate), [Zn-2(bdc)(2-x)(bdc-I)(x)(dabco)]center dot nDMF 2 (bdc-I = 2-iodo-1,4-benzenedicarboxylate), [Zn-2(bdc)(2-x)(bdc-NO2)(x)(dabco)]center dot nDMF 3 (bdc-NO2 = 2-nitro-1,4-benzenedicarboxylate), [Zn-2(bdc)(2-x)(bdc-NH2)(x)(dabco)]center dot nDMF 4 (bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) and [Zn-2(bdc-Br)(2-x)(bdc-I)(x)(dabco)] nDMF 5. Series 1-3 demonstrate a functionality-dependent pore geometry transition from the square, open pores of DMOF-1 to rhomboidal, narrow pores with increasing proportion of the 2-substituted bdc linker, with the rhomboidal-pore MOFs also showing a temperature-dependent phase change. In contrast, all members of series 4 and 5 have uniform pore geometries. In series 4 this is a square pore topology, whilst series 5 exhibits the rhomboidal pore form. Computational analyses reveal that the pore size and shape in systems 1 and 2 is altered through non-covalent interactions between the organic linkers within the framework, and that this can be controlled by the ligand functionality and ratio. This approach affords the potential to tailor pore geometry and shape within MOFs through judicious choice of ligand ratios.

Reaction between a -diketiminato magnesium hydride and carbon monoxide results in the isolation of a dimeric cis-enediolate species through the reductive coupling of two CO molecules. Under catalytic conditions with PhSiH3, an observable Mg formyl species may be intercepted for the mild reductive cleavage of the CO triple bond.

Sequential reactions between a 2,6-di-iso-propylphenyl-substiuted -diketiminato magnesium n-butyl derivative and P4¬ allow the highly discriminating synthesis of unusual [nBu2P4]2 and [nBu2P8]2 cluster dianions.

The two-coordinate ring-expanded N-heterocyclic carbene copper(I) complexes [Cu(RE-NHC)2]+ (RE-NHC = 6-Mes, 7-o-Tol, 7-Mes) have been prepared and shown to be effective catalysts under neat conditions for the 1,3-dipolar cycloaddition of alkynes and azides. In contrast, the cationic diamidocarbene analogue [Cu(6-MesDAC)2]+ and the neutral species [(6-MesDAC)CuCl]2 and [(6-MesDAC)2(CuCl)3] show good activity when the catalysis is performed on water.

Activation of O2 by the three-coordinate Ni(I) ring-expanded N-heterocyclic carbene complexes Ni(RE-NHC)(PPh3)Br (RE-NHC = 6-Mes, 1; 7-Mes, 2) produced the structurally characterized dimeric Ni(II) complexes Ni(6-Mes)(Br)(μ-OH)(μ-O-6-Mes′)NiBr (3) and Ni(7-Mes)(Br)(μ-OH)(μ-O-7-Mes′)NiBr (4) containing oxidized ortho-mesityl groups from one of the carbene ligands. NMR and mass spectrometry provided evidence for further oxidation in solution to afford bis-μ-aryloxy compounds; the 6-Mes derivative was isolated, and its structure was verified. Low-temperature UV–visible spectroscopy showed that the reaction between 1 and O2 was too fast even at ca. −80 °C to yield any observable intermediates and also supported the formation of more than one oxidation product. Addition of O2 to Ni(I) precursors containing a less electron-donating diamidocarbene (6-MesDAC, 7) or less bulky 6- or 7-membered ring diaminocarbene ligands (6- or 7-o-Tol; 8 and 9) proceeded quite differently, affording phosphine and carbene oxidation products (Ni(O═PPh3)2Br2 and (6-MesDAC)═O) and the mononuclear Ni(II) dibromide complexes (Ni(6-o-Tol)(PPh3)Br2 (10) and (Ni(7-o-Tol)(PPh3)Br2 (11)) respectively. Electrochemical measurements on the five Ni(I) precursors show significantly higher redox potentials for 1 and 2, the complexes that undergo oxygen atom transfer from O2.

The reactions of 1,2-bis(tetrazol-5-yl)benzene (1), 1,3-bis(tetrazol-5-yl)benzene (2), 1,4-bis(tetrazol-5-yl)benzene (3), 1,2-(Bu3SnN4C)2C6H4 (4), 1,3-(Bu3SnN4C)2C6H4 (5) and 1,4-(Bu3SnN4C)2C6H4 (6) with 1,2-dibromoethane were carried out by two different methods in order to synthesise pendant alkyl halide derivatives of the parent bis-tetrazoles. This lead to the formation of several alkyl halide derivatives, substituted at either N1 and N2 on the tetrazole ring, as well as the surprising formation of several vinyl derivatives. The crystal structures of both 1,2-[(2-vinyl)tetrazol-5-yl)]benzene (1-N, 2-N’) (1b) and 1,3-bis[(2-bromoethyl)tetrazol-5-yl]benzene (2-N, 2-N’) (5d) are discussed.