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Two model porphyrin metal-organic frameworks were used for the incorporation of Rh(i) species by a post-synthetic metallation under mild conditions. As a result, new rhodium MOFs (Rh/MOFs), Rh/PCN-222 and Rh/NU-1102, were synthesized and structurally characterized. To illustrate the potential of this catalytic platform, we use Rh/MOFs as phosphine-free heterogeneous catalysts in the hydrogenation of unsaturated hydrocarbons under mild reaction conditions (30 °C and 1 atm H2). We found that for our Rh/MOFs an activation step is required during the first run of the catalytic process. The presence of Rh-CO moieties allowed us to monitor the activation pathway of the catalyst under a H2 atmosphere, by in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). After activation, the catalyst remains highly active during the subsequent catalytic cycles. This simple post-synthetic modification approach presents new possibilities for the utilization of Rh-based catalytic systems with robust porphyrin-based MOFs as supports.

Recent developments in porous coordination polymers make them attractive candidates for various potential applications including systems for controlled drug administration. Drug delivery systems based on metal–organic frameworks (MOF) are usually constructed either by non-covalent adsorption of drug molecules inside the pores of the material or by covalent modification of organic linkers. Herein, we propose alternative method for incorporation of drug molecules inside MOFs by binding them to the metal node using Solvent-Assisted Ligand Incorporation (SALI). We tested NU-1000 platform which contains 8-connecting Zr6-nodes, which can bind up to 4 carboxylate-based ligands. Using SALI technique we successfully anchored three model drug molecules containing carboxylate groups: ketoprofen, nalidixic acid and levofloxacin with drug loadings reaching 30 wt% yielding guest@NU-1000 materials. Our study shows that NU-1000 is stable in phosphate concentrations present in blood plasma, whereas drug molecules can be released from guest@NU-1000 under these conditions without decomposition of the MOF framework. We also observed that the drug release kinetics strongly depends on the size of the guest molecules.

The conversion of 2,4,6-tris(4′-bromophenyl)-1,3,5-triazine to the respective triboronic acid was successfully accomplished by a simple triple Br/Li exchange followed by boronation. Further dehydrative condensation reactions with 2,3,6,7,10,11-hexahydroxytriphenylene or 2,3,6,7-tetrahydroxy-9,10-dilalkylanthracenes (R = Me, Et) resulted in materials featuring good porosity and sorption properties with the nitrogen uptake exceeding 500 cm3/g (STP) and SBET up to 1267 m2/g (T = 77.2 K). In addition, simple dehydration of this compound was employed for the preparation of a hybrid 2D COF composed of triazine, boroxine, and benzene rings. The formation of materials was confirmed by the IR analysis and NMR studies on water-decomposed samples. All obtained COFs exhibit high thermal stability with decomposition temperatures in the range of 400–600 °C. They also show quite different morphology ranging from regular 0.5–4 μm spherical and ellipsoidal clusters to 5–12 μm bent rodlike particles. The PXRD studies suppo...

A model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state was investigated via combined crystallographic and spectroscopic techniques contributed substantially by theoretical modelling. The complex appeared to exhibit luminescence thermochromism, i.e. red phosphorescence at room temperature which changes to green when lowering the temperature to 90 K. The low-energy emissive state was assigned as a cluster-centred triplet, 3CC. The emission from this state predicted in TDDFT (~635 nm) matches the experimental red band observed at 660&ndash, 715 nm. In contrast, the nature of the high-energy &ldquo, green&rdquo, band was less straightforward. The next reached cluster-centred triplet excited state occurred to be energetically close to the experimental value of ~545 nm. The two excited states also exhibit significant metal-to-ligand and ligand-to-metal charge transfer characteristics, especially for solid-state distorted geometries. In both cases the cluster core was expected to become notably contracted when compared to the ground state. Time-resolved photocrystallographic results supported the computationally predicted core contraction upon excitation. Additionally, the differences between the spectroscopic behaviour of the related tetra- and hexanuclear copper(I) complexes, Cu4 and Cu6 (i.e., [(PhCO2)6Cu6]) in the crystalline state were discussed and examined. It appeared that crystal packing may constitute an important factor as far as the lack of luminescence thermochromism in the latter case is concerned. Synopsis: Structure&ndash, property relationships characterising a model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state were investigated via combined crystallographic and spectroscopic techniques contributed by theoretical modelling, and compared with the properties of the related [(PhCO2)6Cu6] (Cu6) complex.

Solvent-assisted ligand incorporation (SALI) is useful for functionalizing the channels of metal-organic framework (MOF) materials such as NU-1000 that offer substitutionally labile zirconium(IV) coordination sites for nonbridging ligands. Each of the 30 or so previous examples relied upon coordination of a carboxylate ligand to achieve incorporation. Here we show that, with appropriate attention to ligand/node stoichiometry, SALI can also be achieved with phosphonate-terminated ligands. Consistent with stronger M(IV) coordination of phosphonates versus carboxylates, this change extends the pH range for retention of incorporated ligands. The difference in coordination strength can be exploited to achieve stepwise incorporation of pairs of ligands-specifically, phosphonates species followed by carboxylate species-without danger of displacement of the first ligand type by the second. Diffuse reflectance infrared Fourier-transform spectroscopy suggests that the phosphonate ligands are connected to the MOF node as RPO2(OH)¯ species in a moiety that leaves a base-accessible -OH moiety on each bound phosphonate.

Electrophoretic deposition (EPD) is used to assemble metal-organic framework (MOF) materials in nano- and micro-particulate, thin-film form. The flexibility of the method is demonstrated by the successful deposition of 4 types of MOFs: NU-1000, UiO-66, HKUST-1, and Al-MIL-53. Additionally, EPD is used to pattern the growth of NU-1000 thin films that exhibit full electrochemical activity.

A family of group 13 organometallic macrocyclic phthalates [(MMe2)2(μ-O2C)2-1,2-C6H4]2 (where M = Al (1), Ga (2), In (3)) is prepared, and the reactivity of these homologous carboxylates toward various monodentate Lewis bases is investigated. The studies provide the first structurally characterized methylindium [{(Me2In)(μ-O2C)2-1,2-C6H4}{Me2In(THF)}]n (4) and methylaluminum [{(Me2Al)(μ-O2C)2-1,2-C6H4}{Me2Al(py-Me)}]n (5) 1D coordination polymers stabilized by dicarboxylate ligands as a result of disruption of the parent tetranuclear macrocyclic structural motifs in 3 and 1 by the incoming donor ligands. The molecular and crystal structures of the reported compounds are examined by spectroscopic studies and single-crystal X-ray diffraction.

International audience; A new synthetic procedure was developed to obtain a novel mononuclear chiral square-pyramidal (acetato) bis(aminoalkoxido) Mn-III complex from a heterometallic Zn-II/Mn-II system with a crucial role for O-2 in the process. The resulting compound was characterized spectroscopically and crystallo-graphically, and its magnetic properties were determined. The MnIII ion exhibits magnetic anisotropy with a zero-field splitting D parameter equal to -2.95 cm(-1).

The octet-compliant group 13 organometallics with highly polarized bonds in the metal coordination sphere exhibit a significant tendency to maximize their coordination number through the formation of adducts with a wide range of neutral donor ligands or by self-association to give aggregates containing tetrahedral and higher coordinated aluminium centres, and even in some cases molecular complexes equilibrate with ionic species of different coordination numbers of the metal centre. This work provides a comprehensive overview of the structural chemistry landscape of the group 13 carboxylates. Aside from a more systematic approach to the general structural chemistry of the title compounds, the structure investigations of [R2M(μ-O2CPh)]2-type benzoate complexes (where M = B, Al and Ga) and their Lewis acid–base adducts [(R2M)(μ-O2CPh)(py-Me)] are reported. DFT calculations were also performed to obtain a more in-depth understanding of both the changes in the bonding of group 13 organometallic carboxylate adducts with a pyridine ligand.

An atom-efficient and mild synthesis of a series of oxozinc carboxylates [Zn(4)(μ(4)-O)(O(2)CR)(6)] [where R = Ph (2a), p-PhC(6)H(4) (2b), p-MeC(6)H(4) (2c), and p-MeSC(6)H(4) (2d)] from well-defined alkylzinc precursors and H(2)O is described. The molecular and crystal structures of the resulting complexes have been determined by single-crystal X-ray diffraction. A closer examination of their crystal structure provides a direct picture of the effect of the nature of substituents on the molecular self-assembly of the octahedral oxozinc through noncovalent interactions. It was revealed that these discrete oxozinc clusters can form diverse types of noncovalent assemblies ranging from structures representing zeolitic topologies in the case of 2a to soft porous materials with gated voids or open channels for the remaining molecular clusters.

Thin films of the metal-organic framework (MOF) NU-1000 were grown on conducting glass substrates. The films uniformly cover the conducting glass substrates and are composed of free-standing sub-micrometer rods. Subsequently, atomic layer deposition (ALD) was utilized to deposit Co(2+) ions throughout the entire MOF film via self-limiting surface-mediated reaction chemistry. The Co ions bind at aqua and hydroxo sites lining the channels of NU-1000, resulting in three-dimensional arrays of separated Co ions in the MOF thin film. The Co-modified MOF thin films demonstrate promising electrocatalytic activity for water oxidation.

The installation of ferrocene molecules within the wide-channel metal-organic framework (MOF) compound, NU-1000, and subsequent configuration of the modified MOF as thin-film coatings on electrodes renders the MOF electroactive in the vicinity of the ferrocenium/ferrocene (Fc(+)/Fc) redox potential due to redox hopping between anchored Fc(+/0) species. The observation of effective site-to-site redox hopping points to the potential usefulness of the installed species as a redox shuttle in photoelectrochemical or electrocatalytic systems. At low supporting electrolyte concentration, we observe bias-tunable ionic permselectivity; films are blocking toward solution cations when the MOF is in the ferrocenium form but permeable when in the ferrocene form. Additionally, with ferrocene-functionalized films, we observe that the MOF's pyrene-based linkers, which are otherwise reversibly electroactive, are now redox-silent. Linker electroactivity is fully recovered, however, when the electrolyte concentration is increased 10-fold, that is, to a concentration similar to or exceeding that of an anchored shuttle molecule. The findings have clear implications for the design and use of MOF-based sensors, electrocatalysts, and photoelectrochemical devices.

Organozinc hydroxides ,R ZnOH, possessing the proton-reactiv ea lkylzinc group and the CO2-reactive Zn¢OH group, represent an intriguing group of organometallic pre- cursors for the synthesis of novel zinc carbonates .C ompre- hensive experimental and computational investigations on 1) solution an ds olid-stat eb ehavior of tBuZnOH (1 )s pecies in the presence of Lewis bases, namely ,T HF and 4-methyl- pyridine ;2 )s tep-by-step sequence of the reactio nb etween 1 and CO2 ;a nd 3) the effect of ad onor ligand and/or an excess of tBu2Zn as an external proto na cceptor on the reac- tion course are reported. DFT calculations for the insertion of carbon dioxide into the dinuclea ra lkylzinc hydroxide 12 are fully consisten tw ith 1 HN MR spectroscopy studies and indi- cate that this process is am ultistep reaction, in which the in- sertion of CO2 seems to be the rate-determining step. More- over ,D FT studies show that the mechanism of the rearrange- ment between key intermediates, that is, the primary alkyl- zinc bicarbonate with ap roximal position of hydrogen and the secondary alkylzinc bicarbonate with ad istal positio no f hydrogen, most likely proceeds through internal rotatio no f the dinuclear bicarbonate.

Crystallization of Me3In from hexane solution at ambient temperature allows for the isolation of a new phase that cannot be obtained by classical sublimation routes. The crystal structure analysis revealed that this new polymorph of Me3In crystallizes in the rhombohedral space group R3 h. The primary structural effect of the In-CH3‚‚‚In intermolecular interactions results in the formation of cyclic hexamers with 12-membered (InC)6 rings of an extended-chair conformation. The shortest intermolecular In‚‚‚C contact is 3.028(4) A with In‚‚‚H distances between 2.74 and 2.79 A. The hexamers are further linked by longer In-CH3‚‚‚In bridges into the 3D network. In addition, the tetragonal form of Me3In was redetermined at 100 K. The presented results demonstrate that the impact of both crystallization conditions and the character of intermolecular forces on clustering events is evident. Finally, the network topology of a family of the group 13 trimethyls is analyzed and correlated.

The X-ray structure analysis of the alkylaluminum and -indium compounds derived from methyl thiosalicylate, Me2Al(SC6H4-2-CO2Me) and [Me2In(µ-SC6H4-2-CO2Me)]2, revealed that the intermolecular S···C(π) interaction between the Al–S thiolate units and the ester π-surface can effectively compete with the hypercoordinate sulfur–metal dative bond. The former compound exists as the noncovalently bonded

The reaction of (t)Bu(2)Zn with water was investigated which led to isolation of the novel hexameric tert-butylzinc hydroxide. The resulting zinc hydroxide cluster appears to be an ideal predesigned single-source precursor which decomposes smoothly in one step at only ca. 120 °C into ZnO nanoparticles.

Alkylzinc alkoxides, (RZnOR')4 ,h ave received much attention as efficient precursors of ZnO nanocrystals (NCs), and their "Zn4O4 "h eterocubane core has been regarded as a" preorganized ZnO". Ac omprehensive investigation of the synthesis and characterization of an ew family of tert-butyl- (tert-butoxy)zinc hydroxides, ((tBu)4Zn4(m3-OtBu)x(m3-OH)4¢x ), as model single-source precursors of ZnO NC si sr eported. The direct reaction between well-defined (tBuZnOH)6 (16) and (tBuZnOtBu)4 (24 )i nv arious molar ratios allows the isola- tion of new mixed cubane aggregates as crystalline solids in ah igh yield :( ( tBu)4Zn4(m3-OtBu)3(m3-OH)) (3), ((tBu)4Zn4(m3- OtBu)2(m3-OH)2 )( 4), ((tBu)4Zn4(m3-OtBu)(m3-OH)3 )( 5). The re- sulting products were characterize di ns olution by 1 HN MR and IR spectroscopy ,a nd in the soli ds tate by single-crystal X-ray diffraction .T he thermal transformations of 2-5 were monitored by in situ variable-temperature powder X-ray dif- fraction and thermogravimetric measurements. The investi- gation showe dt hat the Zn¢ OH groups appeared to be ad e- sirable feature for the solid-state synthesis of ZnO NCs that significantly decreased the decomposition temperature of crystalline precursors 3-5.

The synthesis of a permanently porous pillared-paddlewheel metal–organic framework (MOF) was achieved through transmetalation of Zn(II) with Ni(II). The MOF can be treated with liquid water, leading to the reversible displacement of 50% of its pillars by water molecules and resulting in a most unusual crystalline and permanently porous structure.

Dichloroaluminum benzoate and its adducts with Lewis bases show a large structural variety from molecular complexes to ionic species as indicated by X-ray diffraction, spectroscopic studies, and quantum-chemical calculations.

The database analysis of intermolecular S···C(π) distances involving a metal-bonded thiolate sulfur atom and various C(π)-centered Lewis acid domains provided evidences for M–S···C(π) contacts as resulting from specific noncovalent interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Over the past two decades, crystalline microporous materials have attracted major interest, owing to their applications in gas sorption, separation, catalysis, and sensing. Microporous crystalline materials can be constructed from coordinatively or covalently linked building blocks where rigid or semi-rigid molecular scaffolds separate void spaces of different size and geometry. Prominent examples of porous materials showing polymeric structures include zeolites, hybrid metal–organic frameworks (MOFs) or porous coordination polymers (PCPs), covalent organic frameworks (COFs), and Hbonded supramolecular organic frameworks (SOFs). The formation of bonding interactions between building units is an important factor that defines and controls the stability and robustness of these porous polymeric materials. However, discrete molecules may also pack in the solid state to form 3D assemblies that exhibit high permanent porosity. The resulting noncovalent porous materials (NPMs) are distinct from the above polymeric systems, as they are held together by weak noncovalent crystal-packing forces. Modifications of structure by cocrystallization of different building blocks can tune the microcavities in the solid state, and the material can thus conform to the shape or functionality of guest molecules. Moreover, these materials can be highly solubile, an important advantage in their processing to form porous thin films. NPMs can exhibit extrinsic and/or intrinsic porosity. Intrinsic porosity is associated with the structure of the single-molecule-containing voids, clefts, or cavities, as has been demonstrated for calixarenes, cucurbiturils, cyclodextrins, organic cage compounds, or discrete small organic molecules. In contrast, materials with extrinsic porosity are those where individual molecules pack in the solid-state to form structures with empty spaces between the individual molecules. As discrete molecules tend to form close-packed solids with minimal void volume, extrinsic porosity in NPMs remains a rare phenomenon. The rational design and preparation of NPMs showing extrinsic porosity based on molecular metal complexes is highly challenging and few examples have been reported. We have demonstrated previously that alkylzinc hydroxides RZnOH can be efficiently transformed into multinuclear alkyzinc carbonate nanoclusters or nanomaterials, such as discrete nanoparticulate zinc carbonate aerogels and ZnO nanoparticles. As shown in Scheme 1a, the reactivity of the RZnOH species can be rationalized in terms of the presence of both a proton-reactive Zn C bond and CO2-reactive Zn OH groups. We argued that introduction of an additional auxiliary ligand L to the RZnOH system, followed by CO2 fixation, could lead to the formation of novel molecular building blocks for new extrinsic NPMs. Herein, we report such a strategy in which the construction of a nanosized cluster [Zn10(m6-CO3)4(L)12] (WUT-1; WUT=Warsaw University of Technology) is achieved by fixation of CO2 by the tetranuclear hydroxo precursor [Zn4(m3-OH)2(L)4(tBu)2] (1

A series of dichloroaluminum carboxylates [Cl(2)Al(O(2)CR)](2) (were R = Ph (1a), (t)Bu (1b), CHCH(2) (1c) and C(11)H(23) (1d)) were prepared and extended investigations on their structure and reactivity toward various Lewis bases and H(2)O performed. Compounds [Cl(2)Al(O(2)CR)](2) and their adducts with Lewis bases show a large structural variety, featuring both molecular and ionic forms with different coordination numbers of the metal center and various coordination modes of the carboxylate ligand. Upon addition of a Lewis base of moderate strength the molecular form [Cl(2)Al(O(2)CR)](2) equilibrates with new ionic forms. In the presences of 4-methylpyridine the six-coordinate Lewis acid-base adducts [Cl(2)Al(λ(2)-O(2)CR)(py-Me)(2)] [R = Ph (3a), (t)Bu (3b)] with a chelating carboxylate ligand were formed. The reactions of 1a, 1b, and 1d with 0.33 equiv of H(2)O in THF-toluene solution lead to oxo carboxylates [(Al(3)O)(O(2)CR)(6)(THF)(3)] [AlCl(4)] [where R = Ph (4a(THF)), (t)Bu (4b(THF)), and C(11)H(23) (4d(THF))] in high yield. The similar reaction of 1c in tetrahydrofuran (THF) afforded the chloro(hydroxo)aluminum acrylate [(ClAl)(2)(OH)(O(2)CC(2)H(3))(2) (THF)(4)][AlCl(4)] (5), while the hydrolysis of 1b in MeCN lead to the hydroxoaluminum carboxylate [Al(2)(OH)(O(2)C(t)Bu)(2)(MeCN)(6)][AlCl(4))(3)] (6). All compounds were characterized by elemental analysis, (1)H, (27)Al NMR, and IR spectroscopy, and the molecular structure of 1a, 3a, 3b, 4a(THF), 4b(THF), 4b(py-Me'), 5, and 6 were determined by single-crystal X-ray diffraction. The study provides a platform for testing transformations of secondary building units in Al-Metal-Organic Frameworks toward H(2)O and neutral donor ligands.

The present work is a critical review of metal exchange (transmetalation) involving metal nodes and metalated struts in metal–organic frameworks. Particular emphasis is given to drawing parallels between different examples of transmetalation in order to understand the influence of coordination environment, solvents, nature of the metals and other variables on the process. We hope that the present review will be of use to those involved in the incorporation of various metal centers to create isostructural MOFs and study their properties.

We report on the activation of CO2 by the well-defined alkylzinc hydroxide (tBuZnOH)6 in the absence and presence of tBu2Zn as an external proton acceptor. The slight modifications in reaction systems involving organozinc precursors enable control of the reaction products with high selectivity leading to the isolation of the mesoporous solid based on ZnCO3 nanoparticles or an unprecedented discrete alkylzinc carbonate [(tBuZn)2(μ5-CO3)]6 cluster with the Zn-C bond intact, respectively.

Herein, we present the first examples of solvent-assisted linker exchange (SALE) in zeolitic imidazolate frameworks (ZIFs). By exposing the ZIF CdIF-4 to excess solutions of 2-nitroimidazole and 2-methylimidazole under solvothermal conditions, we were able to obtain a previously reported ZIF CdIF-9 in high yield, as well as synthesize a new ZIF, Solvent-Assisted Linker-Exchanged Material-1 (SALEM-1). The parent and daughter ZIFs are isostructural (RHO zeolitic topology) and highly porous. Despite the high thermal and chemical stability of ZIFs, single crystal-to-single crystal linker exchange appears to be a suitable tool for the modification and functionalization of these materials. We anticipate that the addition of SALE to the arsenal of known synthetic techniques for ZIFs will significantly facilitate the quest to obtain interesting and useful ZIF compounds, including compounds that cannot be synthesized directly.