Mono-and bimetallic aluminum complexes bearing bidentate NS or tetradentate NSSN ligands have been synthesized via reaction of AlMe3 with the corresponding proligand and spectroscopically characterized. In these complexes the aluminum centers are surrounded by anionic nitrogen and neutral sulfur atoms that, together with the carbon atoms of the alkyl groups, produce tetrahedral coordination geometries. In the bimetallic complexes the two metal centers are linked by a thioether-bridge of different lengths. The solid state structure of the complexes featuring the thioethyl or thiopropyl bridge were determined by X-ray diffraction studies. Both mono-and bimetallic aluminum complexes display fluxional behaviors in solution. After proper activation, all complexes were able to promote the ring opening polymerization of L-lactide in toluene solution. The polymerizations were well controlled as testified by the linear increase of the molecular weights with the conversions and the narrow polydispersity indexes. The highest activity was observed for the bimetallic complex bearing the NSSN ligand with the shortest bridge (ethyl bridge) with a turnover frequency of 11.6 molLA center dot molAl-1 center dot h-1 (toluene, 80 degrees C). The activity decreased as the distance between the two metal centers increased. Moreover, the activity of the bimetallic complex with the ethyl bridge was higher than those of the monometallic ones. These findings suggest that a cooperative interaction between two aluminum centers is operative in the bimetallic complex with the shortest bridge.

In an assisted self-assembly approach starting from the [Mn6O2(piv)(10)(4-Me-py)(2)(pivH)(2)] cluster a family of Mn-Ln compounds (Ln=Pr-Yb) was synthesised. The reaction of [Mn6O2(piv)(10)(4-Me-py)(2)(pivH)(2)] (1) with N-methyldiethanolamine (mdeaH(2)) and Ln(NO3)(3) . 6H(2)O in MeCN generally yields two main structure types: for Ln=Tb-Yb a previously reported Mn(5)Ln(4) motif is obtained, whereas for Ln=Pr-Eu a series of Mn(7)Ln(3) clusters is obtained. Within this series the Gd-III analogue represents a special case because it shows both structural types as well as a third Mn(2)Ln(2) inverse butterfly motif. Variation in reaction conditions allows access to different structure types across the whole series. This prompts further studies into the reaction mechanism of this cluster assisted self-assembly approach. For the Mn(7)Ln(3) analogues reported here variable-temperature magnetic susceptibility measurements suggest that antiferromagnetic interactions between the spin carriers are dominant. Compounds incorporating Ln=Nd-III(2), Sm-III(3) and Gd-III (5) display SMM behaviour. The slow relaxation of the magnetisation for these compounds was confirmed by ac measurements above 1.8 K.

The present study details the highly effective and controlled ring-opening polymerization (ROP) of alpha-chloro-epsilon-caprolactone (1, alpha Cl epsilon CL), a cyclic ester that has been little explored thus far in ROP catalysis, using Zn- and Al-based catalysts [Zn(C6F5)(2)(toluene)] (4), [N,N '-bis(3,5-di-tert-butylsalicylidene)1,3-diaminopropanato]aluminium(III)benzyloxide (5) and [N,N '-bis(3,5-di-tert-butylsalicylidene)1,3-diamino-2,2 '-dimethylpropanato]aluminium(III)benzyloxide] (6). Chain-length-controlled P alpha Cl epsilon CL material is produced under solution ROP conditions, as deduced from GPC, NMR, MALDI-TOF, and kinetic data. In contrast, the ROP of 1 is ill-defined under bulk ROP conditions due to partial thermal degradation of the polymer chain (presumably through C-Cl cleavage), reflecting the limited stability of P alpha Cl epsilon CL. The Al Catalysts 5 and 6 are highly active ROP catalysts of alpha Cl epsilon CL at room temperature (TOF up to 2,400 hr(-1)) to afford well-defined P(alpha Cl epsilon CL). In the case of Catalyst 6, carrying out the ROP of alpha Cl epsilon CL under immortal conditions (with BnOH as chain transfer agent) is clearly beneficial to ROP activity and control, with no apparent side-reaction of chloro-functionalized PCL chains as the ROP proceeds. The controlled character of these ROPs was further exploited for the production of chain-length-controlled PLLA-b-P alpha Cl epsilon CL diblocks through sequential ROP of l-lactide and alpha Cl epsilon CL, affording copolymers with improved thermal and biodegradable properties.

The straightforward combination of commercial picolinaldehyde and 2-aminopyridine led to the preparation of N ,1di(pyridin-2-yl)methanimine ligand HL 1 .Under aerobic conditions, HL 1 self-assembles with manganese (Mn) ions to afford two high-spin mononuclear Mn(III) complexes of general formula [MnL 2 2 ] + Cl (1) and [MnL 2 2 ] + (NO 3 ) (2).Their synthesis is mediated via (in situ) ligand transformation and oxidation of initial Mn(II) ions.Such unexpected reorganization contributes in the stabilization of the complexes.The mononuclear compounds 1 and 2 display unusual Jahn-Teller distortion along the z-axis, as evidenced by single-crystal X-ray diffraction and do exhibit an S = 2 ground spin state.

We report the synthesis and structural characterisation of new Mn19 and Mn18M analogues, [MnIII12MnII7(μ4-O)8(μ3-OCH3)2(μ3-Br)6(HLMe)12(MeOH)6]Br2 (2) and [MnIII12MnII6Sr(μ4-O8(μ3-Cl)8(HLMe)12(MeCN)6]Cl2 cluster (3), where H3LMe is 2,6-bis(hydroxymethyl)-p-cresol. The electrochemistry of 2 and 3 has been investigated and their activity as catalysts in the oxidation of benzyl alcohol has been evaluated. Selective oxidation of benzyl alcohol to benzaldehyde by O2 was achieved using 1 mol% of catalyst with conversions of 74% (2) and 60% (3) at 140 °C using TEMPO as a co-catalyst. No partial conversion of benzaldehyde to benzoic acid was observed. The results obtained revealed that different operative parameters - such as catalyst loading, temperature, time, solvent and the presence of molecular oxygen - played an important role in the selective oxidation of benzyl alcohol.

A family of undecanuclear Fe–Ln clusters, comprising butterfly motifs, was explored and two are found to behave as single molecule magnets.

Cu(i)-Catalyzed 1,3-dipolar cycloaddition was used to construct a luminescent monolayer for an ICT-showing pyrrolidino-perylene association (5PMI) on glass surfaces, which represents a rare perylene chromophore, to date, anchored to a solid surface.

Mononuclear salen-supported Ga amido and alkoxide complexes, structurally characterized herein, mediate the controlled and iso-selective polymerization ofrac-lactide.

Correction for ‘Artificial miniaturized luminescent materials based on perylene-covered glass surfaces’ by Samir Mameri et al., New J. Chem., 2017, 41, 6083–6088.

The cover picture shows the ultraviolet (UV) irradiation of a novel sophisticated chromophore-containing ligand chelated to luminescent trivalent lanthanide metal ion i.e., Europium(III) or Terbium(III). This ligand is based on two O-bridged quinolines bearing carboxylate moieties to reinforce both the coordination to the central metal ion and the solubility in water solutions. The ligand functions as an 'antenna' which absorbs incident light and transfers the excitation to the central metal ion, which then deactivates by undergoing its typical luminescent emission (visible). Thus, this paper reports the efficient 7-step methodology developed for the synthesis of this new heterocycle which was characterized in the solid state and in solution, and it reports the study of its coordination and sensitization ability for lanthanide ions in aqueous solution. Notably, the resulting mononuclear complexes are stable and display in other respects interesting luminescence quantum yields and lifetimes in water solution, e.g. 9.5% and τ = 523μs, for Eu(III). More information can be found in the Full Paper by De Bettencourt-Dias and Mameri et al. (DOI: 10.1002/slct.201601223). (Design: Dr. Samir Mameri and Dr. Hassan Hammoud).

The combination of substituted N-diethanolamine and pivalic (or benzoic) acid ligands has proved to be an extremely fruitful route for assembling in solution 3d/4f blends of metal ions within coordination clusters. In this article we wish to focus on the analysis of the synthetic routes for accessing 3d-Dy(III) coordination clusters with an overall [(MDy4III)-Dy-III(mu(3)-X)(4)(O2CBut)(4)(O2CBut)(8)(x-dea)(4)].solv formulation, where M = Mn, x = tert-butyl, X = N-3 (1), X = OCN (2), X= NO3 (3); M = Cr, x = methyl, X= N-3 (4); solv = MeCN or toluene, and [(FeDY4III)-D-III(mu 3-OH)(4)(O2CC6H4CFH3)(12)(n-bdea)(4)].2CH(3)CN (5). The metal topology in the aggregates can be described as consisting of a "Dy-4-square inscribed in a M-4-square". Complexes 1-4 were prepared from reaction of t-butyldiethanolamine (t-bdeaH(2)) or methyldiethanolamine (mdeaH2) with preformed polynuclear compounds or simple salts of transition metals (Mn(II) and Cr(II)), Dy(NO3)(3).6H(2)O and in the presence or absence of NaN3 or NaNCO if appropriate. Complex 5 was obtained from the reaction between n-bdeaH(2) and Dy(NO3)3.6H(2)O with [Fe3O(m-CH3C6H4COO)(6)(H2O)(C2H2OH)(2)](NO3).2H(2)O. It was found that the nature of the central bridging ligands, i.e. N-3, OCN or NO3, does not appear to have significant influence on the structural features of the isolated manganese derivatives. Concerning the synthesis of the Fe derivative, it was found important to use a different type of diethanolamine ligand and a different carboxylic acid as well. (C) 2016 Elsevier B.V. All rights reserved.

The reaction of aroylhydrazone ligand H2L with Ni(II) metal ions afforded, upon crystallization under aerobic conditions, a novel heptanuclear Ni(II) cluster without this ligand (template effect of aroylhydrazone ligand). The heptanuclear [Ni-7(II)] compound 1 displays a metallic core which can be presented as a vertex shared dicubane structure. Noteworthy, (i) this ligand is used for the first time in coordination chemistry, and (ii) this cluster does represent the first example in Nickel chemistry that possesses this topology with a structure not supported by any organic bridging ligand. (C) 2016 Elsevier B.V. All rights reserved.

A novel ligand based on a O-bridged symmetrical bis-quinoline containing carboxylate moieties has been synthesized and its coordination and sensitization ability for lanthanide ions has been studied in aqueous solution. The efficient 7-step methodology developed starts from commercial 8-methylquinoline. This new heterocycle, which was characterized in the solid state and in solution, displays interesting spectroscopic properties in water with an absorption below 350 nm. The coordination behaviour of this ligand with trivalent lanthanide cations (Ln= Eu, Tb and Gd) in solution leads to the formation of stable complexes with [LnL] stoichiometry, which were isolated from neutral water solutions containing equimolar amounts of cations and ligand. The photophysical properties of the mononuclear complexes of Eu and Tb were studied in aqueous solution by absorption, excitation and emission spectroscopy. Comparison of the luminescence lifetimes of the Eu and Tb complexes in H2O and D2O reveals the presence of 1 water molecule in the first coordination sphere of the metal ions. The sensitized emission efficiency of the Eu complex in water is good, as demonstrated by a quantum yield of 9.5(7)%. The analogous Tb(III) complex displays an emission efficiency of 2.0 (1)%. This low value is indicative of incomplete energy transfer, which is supported by a decay lifetime that can be fit to a double exponential, due to residual ligand emission.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The selective demethylation of methoxy groups of several multifunctionalized 1,3,5-trimethoxycalix[6]arene-based receptors has been achieved. It is shown in this study that the best reagent is trimethylsilyl iodide (TMSI) and that the conformation adopted by the calixarene core is crucial for both the selectivity and the efficiency of the process. A key feature appears to be the "in" or "out" orientation of the methoxy substituents relative to the macrocyclic cavity. If projected inward, the reaction is slow and not selective. If projected outward, the reaction is fast and selective. A strategy that consists of exploiting the host-guest properties of the receptors to change their conformation and to permit their selective demethylation has been developed. Four cases of such a supramolecular assistance are reported, demonstrating the efficiency of the strategy. Such an allosteric control is highly reminiscent of biological processes allowing selective transformation of multifunctional molecules.

Coordination clusters of 3d metals continue to attract the intense interest of the scientists from the synthetic inorganic chemistry, bioinorganic chemistry and molecular magnetism communities. We review here the synthetic strategies employed in a continuous effort to obtain new and potentially magnetically interesting dinuclear molecules based on iron, manganese, chromium, and cobalt metal ions. The reported systems are pure homometallic 3d materials. We have focused on describing aspects of the synthesis, the crystal structures and the magnetic behaviour of these coordination compounds with low nuclearity. A deep solid-state and magnetic characterization of these systems has allowed us to gain evidence regarding the role played by weak exchange interactions and geometrical factors on the slow dynamics of the magnetization. In addition, the analysis through ab initio calculations has provided a valuable insight into the influence of organic periphery, bridging ligands, and remote substituents on the exchange coupling constant (J). In the case of a dinuclear complex based on manganese, the largest ferromagnetic interaction between two Mn-III has been observed (J = 19.7 cm(-1)). (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.