This study reports on the synthesis, structural characterization and gas sorption studies of a homometallic 2D Cd2+ MOF and two heterometallic 3D Cd2+/Ca2+ and Cd2+/Sr2+ -MOFs based on the angular tetracarboxylic ligand 3,3′,4,4′-sulfonyltetracarboxylic acid (H4STBA). The homometallic 2D Cd2+ MOF with the formula [NH2(CH3)2]+2[Cd(STBA)]2−n·nDMF·1.5nH2O—(1)n·nDMF·1.5nH2O was synthesized from the reaction of CdCl2·H2O and 3,3′,4,4′-diphthalic sulfonyl dianhydride (3,3′,4,4′-DPSDA) with stoichiometric ratio of 1:1.3 in DMF/H2O (5/2 mL) at 100 °C. The two heterometallic Cd2+/Ca2+ and Cd2+/Sr2+ compounds were prepared from analogous reactions to this afforded (1)n·nDMF·1.5nH2O with the difference that the reaction mixture also contained AE(NO3)2 (AE2+ = Ca2+ or Sr2+) and, in particular, from the reaction of AE(NO3)2, CdCl2·H2O and 3,3′,4,4′-DPSDA with stoichiometric ratio 1:1.1:1.4 in DMF/H2O (5/2 mL) at 100 °C. Notably, compounds [CdCa(STBA)(H2O)2]n·0.5nDMF—(2)n·0.5nDMF and [CdSr(STBA)(H2O)2]n·0.5nDMF—(3)n·0.5nDMF are the first heterometallic compounds Mn+/AE2+ (M = any metal ion) reported containing ligand H4STBA. The structure of (1)n·nDMF·1.5nH2O comprises a 2D network based on helical 1D chain secondary building unit (SBU) [Cd2+(STBA)4−)]2−. The 2D sheets are linked through hydrogen bonding interactions, giving rise to a pseudo-3D structure. On the other hand, compounds (2)n·1.5nH2O and (3)n·1.5nH2O display 3D microporous structures consisting of a helical 1D chain SBU [Cd2+AE2+(STBA)4−)]. All three compounds contain rhombic channels along c axes. The three MOFs exhibit an appreciable thermal stability, up to 350–400 °C. Gas sorption measurements on activated materials (2)n and (3)n revealed moderate BET surface areas of 370 m2/g and 343 m2/g, respectively, along with CO2 uptake capacity of 2.58 mmol/g at 273 K.

With the aim of assessing the role and impact of pseudohalides on the molecular and supramolecular structures of copper(II)/heavily substituted imidazole complexes, the synthesis and characterization of the complexes {[Cu(N3)2(HL)]}n (1), {[Cu{N(CN)2}2(HL)]·Me2CO}n (2·Me2CO) and [Cu(NCO)2(HL)2]·MeCN (3·MeCN) have been carried out; HL is the 4,5-diphenylimidazole ligand. The organic molecule behaves as a monodentate ligand through the pyridine-type nitrogen atom of the imidazole ring. The 1D polymer 1 is made up of undulating {-Cu-(N3)2-Cu-(N3)2-} chains, with the HL ligands extending from both sides of the chains. The square pyramidal metal ions are alternately doubly bridged by two different types (basal-basal and basal-apical) of end-on azido groups. In 2·Me2CO, the N(CN)2- ions behave as end-to-end (μ-1,5 or 2.101) ligands forming a 2D polymeric lattice, consisting of four-membered CuII rings interconnected by four dicyanamido bridges; the five-coordinate CuII ion adopts a geometry intermediate between square pyramidal and trigonal bipyramidal. The metal centre in the mononuclear complex 3·MeCN is bonded to two HL ligands and two terminal isocyanato groups; the coordination geometry of CuII is closest to a seesaw conformation. The crystal structures of the complexes are built with a variety of supramolecular interactions, including the synthons N-H⋯X (X = N and O), which are critically discussed. The IR spectra of the compounds are discussed in terms of the coordination modes of the pseudohalido ligands. The magnetic properties of 1 and 2 have also been studied in the temperature and field ranges of 1.8-300 K and 0-50 kOe, respectively. Complex 1 exhibits both ferromagnetic and antiferromagnetic CuII⋯CuII exchange interactions propagated through the two different end-on bi-azido bridges, whereas the exchange interactions are negligible (if any) in the 2D polymer 2 as a consequence of the μ-1,5 ligation mode of the dicyanamido ligand and the resultant long CuII⋯CuII distances.

In the course of an investigation of the supramolecular behaviour of copper(II) complexes with the 5-phenylimidazole/perchlorate ligand system (`blend') remarkable solvatomorphism has been observed. By employing a variety of crystallization solvents (polar protic, polar/non-polar aprotic), a series of 12 crystalline solvatomorphs with the general formula [Cu(ClO4)2(LH)4]·x(solvent) have been obtained [LH = 5-phenylimidazole, x(solvent) = 3.3(H2O) (1), 2(methanol) (2), 2(ethanol) (3), 2(1-propanol) (4), 2(2-propanol) (5), 2(2-butanol) (6), 2(dimethylformamide) (7), 2(acetone) (8), 2(tetrahydrofurane) (9), 2(1,4-dioxane) (10), 2(ethyl acetate) (11) and 1(diethyl ether) (12)]. The structures have been solved using single-crystal X-ray diffraction and the complexes were characterized by thermal analysis and infrared spectroscopy. The solvatomorphs are isostructural (triclinic, P 1), with the exception of compound 9 (monoclinic, P21/n). The supramolecular structures and the role of the various solvents is discussed. All potential hydrogen-bond functionalities, both of the [Cu(ClO4)2(LH)4] units and of the solvents, are utilized in the course of the crystallization process. The supramolecular assembly in all structures is directed by strong recurring Nimidazole–H...Operchlorate motifs leading to robust scaffolds composed of the [Cu(ClO4)2(LH)4] host complexes. The solvents are located in channels and, with the exception of the disordered waters in 1 and the diethyl ether in 12, participate in hydrogen-bonding formation with the [Cu(ClO4)2(LH)4] complexes, serving as both hydrogen-bond acceptors and donors (for the polar protic solvents in 2–6), or solely as hydrogen-bond acceptors (for the polar/non-polar aprotic solvents in 7–11), linking the complexes and contributing to the stability of the crystalline compounds.

Starch is a major renewable polysaccharide for bioethanol production and biochemical saccharification of starchy substrates to glucose constitutes a widely accepted industrial process. Potato and commercial starch were used as feedstocks in saccharification conducted employing carbonaceous materials (untreated char and biochar) as immobilization carriers for Aspergillus niger and Aspergillus awamori, while biochar oxidation using HNO3, H3PO4, and H2O2 was applied to improve bioprocess efficiency. Application of untreated materials exhibited that using char content of 3.2 % (w/w) incorporating particle diameter between 0.3-0.5 cm maximized the glucose yield demonstrating 0.61 g glucose g starch- 1 using immobilized cells of A. niger. Biochar oxidized using 1 % and 30 % (v/v) H2O2 incorporated the lowest pore size (2.860 and 0.724 mu m) and maximal content of oxygen (26.01 % and 30.53 %) on the surface of the biomaterial respectively. Brunauer-Emmett-Teller (BET) analysis demonstrated slight increase of oxidized biochar's specific surface area using 1 % (v/v) H2O2 (38 m 2 g- 1 ) and 0.2 M HNO3 (44 m 2 g- 1 ) as compared with the untreated carrier (30 m2 g-1). Hydrolysis performed employing A. niger immobilized on biochar oxidized using 1 % (v/v) H2O2 substantially enhanced the bioprocess as compared with the use of untreated materials exhibiting 0.77 g glucose g starch- 1 , which corresponds to 70.3 % of the maximum theoretical yield, and tripled the glucose titre. The significant improvement of starch hydrolysis achieved using biochar modified via the specific chemical treatment could be potentially attributed to the concurrent amelioration of specific surface area and oxygen content monitored. The study has shown that fine-tuning the surface properties of biochar through chemical treatment could enable the development of advanced immobilized biocatalysts for biotechnological application.

Three new polynuclear clusters with the formulae [Mn 10 O 4 (OH)(OMe){(py) 2 C(O) 2 } 2 {(py) 2 C(OMe)(O)} 4 (MeCO 2 ) 6 ](ClO 4 ) 2 ( 1 ), Na[Mn 12 O 2 (OH) 3 (OMe){(py) 2 C(O) 2 } 6 {(py) 2 C(OH)(O)} 2 (MeCO 2 ) 2 (H 2 O) 10 ](ClO 4 ) 8 ( 2 ) and [Mn 12 O 4 (OH) 2 {(py) 2 C(O) 2 } 6 {(py) 2 C(OMe)(O)}(MeCO 2 ) 3 (NO 3 ) 3 (H 2 O)(DMF) 2 ](NO 3 ) 2 ( 3 ) were prepared from the combination of di-2-pyridyl ketone, (py) 2 CO, with the aliphatic diols (1,3-propanediol (pdH 2 ) or 1,4-butanediol (1,4-bdH 2 )) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of 1 – 3 . The crystal structures of 1 – 3 are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current ( dc ) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within 1 – 3 . Alternating current ( ac ) magnetic susceptibility studies revealed the presence of out-of-phase signals below 3.0 K for 2 and 3 indicating the slow relaxation of the magnetization vector, characteristic of single-molecule magnets; the U eff value of 2 was found to be 23 K and the preexponential factor τ 0 ~7.6×10 −9  s.

The utilization of various crystallization solvents (polar protic, polar and non-polar aprotic) within the 5-phenylimidazole/tetrafluoroborate/copper( ii ) system resulted in seventeen solvatomorphs.

A new family of 2-D 8-connected rare earth (RE) MOFs based on a hexanuclear (RE3+)(6) secondary building unit (SBU), the increase of the dimensionality through single-crystal-to-single-crystal (SCSC) linker installation reactions and the turn-on of the temperature sensing capability upon these reactions are reported. The reaction of RE(NO3)(3) with 4,4 '-(hydroxymethylene)dibenzoic acid (H2BCPM) in the presence of 2-fluorobenzoic acid (HFBA) in DMF/H2O at 115 degrees C afforded compounds [RE6(mu(3)-OH-/F-)(8)(BCPM)(4)(NO3)(2)(H2O)(4)](n) (UCY-17(RE); RE: Y, Gd, Tb, Dy, Ho, Er) which represent rare examples of 2D 8-c MOFs based on a hexanuclear (RE3+)(6) SBU. The excellent quality of single crystals of UCY-17(Tb) and the distance between the terminal nitrate ions prompted us to investigate the SCSC exchange of NO3- anions by various dicarboxylate ligands aiming to bridge adjacent 2D nanosheets and form 3-D analogues. These SCSC linker installation reactions afforded a series of 3-D, 10-connected mixed linker MOFs with the general formulae [RE6(mu(3)-OH-/F-)(8)(BCPM)(4)(L)(H2O)(4)](n) (UCY-17(Tb)/L; H2L = H2BDC (1,4-benzenedicarboxylic acid), H(2)ABDC (2-aminobenzene-1,4-dicarboxylic acid), H2FBDC (2-fluorobenzene-1,4-dicarboxylic acid), and H2NDC (1,4-naphthalenedicarboxylic acid)). The exchanged analogues of UCY-17(Gd) and UCY-17(Eu0.05Tb0.95) were synthesized and the thermometric properties of the latter were investigated. These studies revealed that there is no thermal evolution of the emission properties for the pristine MOF UCY-17(Eu0.05Tb0.95) whereas the exchanged analogues exhibit significant thermometric properties at higher temperatures (>270 K). The maximum thermal sensitivity of most exchanged derivatives appears at physiological temperatures and ranges between 300 and 355 K. Overall, this work proposes a promising strategy for increasing the dimensionality of 2-D MOFs and controlling the thermometric performances of mixed Eu0.05Tb0.95 MOFs.

The conjugation of the uracil (a nucleobase) analogue, 6-methyl-thiouracil (MTUC), with the mitochondriotropic agent of Tri-o-Tolyl-Phosphine (TOTP) through palladium(II) leads to the formation of the metallodrug of formula [PdCl(TOTP)(MTUC)] ( 1 ). The metallodrug was characterized in solid state using Attenuated Total Reflectance-Fourier Transform Infra-Red (ATR-FTIR) spectroscopy and X-ray diffraction crystallography (XRD), while its behavior in solution was examined through Ultra Violet (UV) and 1 H NMR spectroscopies. The in vitro cytotoxicity of 1 was assessed against human breast adenocarcinoma cell lines: MCF-7 (hormone-dependent (HD)) and MDA-MB-231 (hormone-independent (HI)), as well as fetal lung fibroblast (MRC-5) cells. The MCF-7 cell morphology suggests apoptotic pathway, and this was confirmed by Acridine Orange/Ethidium Bromide (AO/EB) Staining, and the loss of the permeabilization of the mitochondrial membrane. The binding affinity of 1 toward the calf thymus (CT) DNA was clarified.

The initial use of 2-(pyridin-2-yl)propane-1,3-diol (pypdH(2)) in Mn cluster chemistry has afforded two new mixed-valence polynuclear Mn clusters, namely, [Mn-8 Omicron(5)(pypd)(hmp)(3)(O2CCMe3)(8)] (1) and [Mn-16 Omicron(10)(N-3)(2)(pypd)(2){(py)(2)CO2}(4)(O2CEt)(12)] (2) (hmp(-) = deprotonated 2-hydroxymethylpyridine; (py)(2)CO22- = deprotonated gem-diol form of di-2-pyridyl ketone). Compound 1 features a novel [(Mn7MnII)-Mn-III(mu(4)-O)(2)(mu(3)-O)(3)(mu-OR)(5)](8+) structural core resembling a supertetrahedron T3, lacking two apexes, while complex 2 has a [(Mn14Mn2II)-Mn-III(mu(4)-O)(4)(mu(3)-O)(6)(mu-N-3)(2)(mu(3)-OR)(2)(mu-OR)(8)](14+) core consisting of two [Mn-8] subunits related to 1 and thus is a dimeric analogue of 1. Direct current (dc) magnetic susceptibility studies revealed the presence of dominant antiferromagentic exchange interactions between the Mn ions in complexes 1 and 2 and small ground state spin values for both compounds. Overall, this work highlights the capability of polyol-like chelates like pypdH(2) to stabilize high nuclearity 3d metal clusters based on polynuclear building blocks.

The combined use of 2-(2-pyridyl)-1,3-propane-diol (pypdH(2)) and 2-hydroxymethyl-2-(2-pyridyl)-1,3-propane-diol (pyptH(3)) in Cu2+/4f chemistry has afforded a new family of isostructural [Cu6M4(pypt)(4)(pypdH)(4)(NO3)(8)] [M = Gd (1), Tb (2), Dy (3), and Y (4)] complexes. These compounds are based on an unprecedented three-layered symmetric [Cu6M4(mu-OR)(16)](8+) structural core, formed from the connection of the metal ions by bridging alkoxide arms of the organic ligands. Direct current magnetic susceptibility studies for complexes 1-3 revealed the presence of dominant ferromagnetic exchange interactions, suggesting the existence of large spin ground state values. Alternating current magnetic studies indicate the presence of slow-magnetic relaxation in 1-3.

Three new polynuclear clusters with the formulae [Mn10O4(OH)(OMe){(py)(2)C(O)(2)}(2){(py)(2)C(OMe)(O)}(4)(MeCO2)(6)](ClO4)(2)(1),Na[Mn12O2(OH)(3)(OMe){(py)(2)C(O)(2)}(6){(py)(2)C(OH)(O)}(2)(MeCO2)(2)-(H2O)(10)](ClO4)(8)((2)) and[Mn12O4(OH)(2){(py)(2)C(O)(2)}(6){(py)(2)C(OMe)(O)}-(MeCO2)(3)(NO3)(3)(H2O)(DMF)(2)](NO3)(2)(3) were prepared from the combination of di-2-pyridylketone,(py)(2)CO, with the aliphatic diols(1,3-propanediol(pdH2) or 1,4-butanediol(1,4-bdH(2))) in Mn carboxylate chemistry. There ported compounds do not include the aliphaticdiols employed in this reaction scheme; however ,their use is essential for the formation of 1-3. The crystal structures of 1-3 are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current(dc) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within 1-3. Alternating current(ac) magnetic susceptibility studies revealed the presence of out-of-phase signals below 3.0 K for 2 and 3 indicating he slow relaxation of the magnetization vector, characteristic of single-molecule magnets; the U (eff) value of 2 was found to be 23 K and the pre exponential factor tau(0)similar to 7.6x10(9) s.

The synthesis, characterization, and single-crystal-to-single-crystal (SCSC) exchange reactions of a new 3D Cu2+ MOF based on 5-aminoisophthalic acid (H(2)AIP), [Cu-6(mu(3)-Omicron Eta)(3)(Alpha Iota Rho)(4)(H Alpha Iota Rho)](n)6nDMFnH(2)O - UCY-166nDMFnH(2)O, are reported. It exhibits a 3D structure based on two [Cu-4(mu(3)-OH)(2)](6+) butterfly-like secondary building units, differing in their peripheral ligation, bridged through HAIP(-)/AIP(2-) ligands. This compound displays the capability to exchange the coordinating ligand(s) and/or guest solvent molecules through SCSC reactions. Interestingly, heterogeneous reactions of single crystals of UCY-166nDMFnH(2)O with primary alcohols resulted not only in the removal of the lattice DMF molecules but also in an unprecedented structural alteration that involved the complete or partial replacement of the monoatomic bridging mu(3)-OH- anion(s) of the [Cu-4(mu(3)-OH)(2)](6+) butterfly structural core by various alkoxy groups. Similar crystal-to-crystal exchange reactions of UCY-166nDMFnH(2)O with long-chain aliphatic alcohols (CxH2x+1OH, x = 8-10, 12, 14, and 16) led to analogues containing fatty alcohols. Notably, the exchanged products with the bulkier alcohols UCY-16/n-CxH2x+1OHS ' (x = 6-10, 12, 14, and 16) do not mix with H2O being quite stable in this solvent, in contrast to the pristine MOF, and exhibit a hydrophobic/superhydrophobic surface as confirmed from the investigation of their water contact angles and capability to remove hydrophobic pollutants from aqueous media.

The synthesis, crystal structures, Mössbauer spectra and variable temperature dc and ac magnetic susceptibility studies of a new family of trinuclear heterometallic Fe3+/Ln3+ complexes, [Fe2Ln(PhCO2)3((py)2CO2)((py)2C(OMe)O)2(NO3)Cl] (Ln = Gd (1/Gd), Tb (1/Tb), Dy (1/Dy), and Ho (1/Ho)), where (py)2CO22- and (py)2C(OMe)O- are the anions of the gem-diol and hemiketal derivatives of di-2-pyridyl ketone, are reported. Compounds 1/Ln are based on an asymmetric "V-shaped" [Fe3+(μ-OR)Ln(μ-OR)2Fe3+]6+ structural core formed from the connection of the two terminal Fe3+ centers to the central Ln3+ ion either through one or two alkoxide groups originating from the alkoxide-type bridging ligands. Direct current magnetic susceptibility studies reveal the presence of weak antiferromagnetic interactions between the Fe3+ ions. Alternating current magnetic studies indicate the presence of a slow-magnetic relaxation process in 1/Dy with an energy barrier Ueff = 6.7 (±0.3) K and a pre-exponential factor, τ0 = 2.2 (±0.4) × 10-7 s. The electronic, magnetic and relaxation properties of the complexes were further monitored by variable temperature 57Fe Mössbauer spectroscopy. At T > 80 K the spectra from the complexes comprise two quadrupole doublets the hyperfine parameters of which reflect the distinct coordination environment of the two Fe3+ terminal sites. At T < 20 K, the Mössbauer spectra for 1/Dy are affected by magnetic relaxation effects. At 1.5 K, the spectrum of 1/Dy comprises well defined magnetic sextets indicating relaxation times slower than the characteristic time of the Mössbauer technique (10-7 s) in agreement with the dynamic magnetic measurements. 1/Gd exhibits broad unresolved magnetic sextets at 1.5 K indicating that the spin relaxation time is of the order of the Mössbauer characteristic time at this temperature. For 1/Tb, 1/Ho the Mössbauer spectra exhibit slight broadening even at the lowest available temperature consistent with magnetic relaxation times less than 10-7 s.

The combination of 2-pyridyl oximes or 2-pyridinemethanol and a hydroxo-functionalized dicarboxylic acid has provided access to a family of coordination polymers.

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 combined use of di-2-pyridyl ketone ((py)2CO) with various diols in Mn cluster chemistry has afforded five new compounds, namely, [Mn11O2(OH)2{(py)2CO2}5(pd)(MeCO2)3(N3)3(NO3)2(DMF)4](NO3)∙2DMF∙H2O (1∙2DMF∙H2O), [Mn11O2(OH)2{(py)2CO2}5(mpd)(MeCO2)3(N3)3(NO3)2(DMF)4](NO3) (2), [Mn12O4(OH)2{(py)2CO2}4(mpd)2(Me3CCO2)4(NO3)4(H2O)6](NO3)2∙2MeCN (3∙2MeCN), [Mn4(OMe)2{(py)2C(OMe)O}2(2-hp)2(NO3)2(DMF)2] (4), and [Mn7{(py)2CO2}4(2-hp)4(NO3)2(DMF)2](ClO4)∙DMF (5∙DMF) ((py)2CO22− and (py)2C(OMe)O− = gem-diol and hemiketal derivatives of di-2-pyridyl ketone, pdH2 = 1,3-propanediol, mpdH2 = 2-metly-1,3-propanediol, 2-hpH2 = 2-(hydroxymethyl)phenol). Complexes 1 and 2 are isostructural, possessing an asymmetric [MnIII5MnII6(μ4-O)(μ3-O)(μ3-OH)(μ-OH)(μ3-OR)2(μ-OR)10(μ-N3)]8+ core. Compound 3 is based on a multilayer [MnIII8MnII4(μ4-O)2(μ3-O)2(μ3-OH)2(μ-OR)12]10+ core, while complex 4 comprises a defective dicubane core. The crystal structure of 5 reveals that it is based on an unusual non-planar [MnIII5MnII2(μ-OR)12]7+ core with a serpentine-like topology. Direct current (dc) magnetic susceptibility studies revealed the presence of dominant antiferromagnetic exchange interactions in complex 3, while ferromagnetic coupling between the Mn ions was detected in the case of compound 5. Fitting of the magnetic data for complex 4 revealed weak antiferromagnetic interactions along the peripheral MnII∙∙∙MnIII ions (Jwb = −0.33 (1) cm−1) and ferromagnetic interactions between the central MnIII∙∙∙MnIII ions (Jbb = 6.28 (1) cm−1).

Metal-organic frameworks (MOFs) have attracted considerable interest as emerging heterogeneous catalysts for organic transformations of synthetic utility. Herein, a Lewis-acidic MOF, {[Cu3(PEIP)2(5-NH2-mBDC)(DMF)]·7DMF}∞, denoted as Cu(ΙΙ)-PEIP, has been synthesized via a one-pot process and deployed as an efficient heterogeneous catalyst for a Diels–Alder cycloaddition. Specifically, the [4 + 2] cycloaddition of 13 substituted azachalcone dienophiles with cyclopentadiene has been investigated. MOF-catalyzed reaction conditions were optimized, leading to the selection of water as the solvent, in the presence of 10% mol sodium dodecyl sulfate (SDS) to address substrate solubility. The Cu(II)-PEIP catalyst showed excellent activity under these green and mild conditions, exhibiting comparable or, in some cases, superior efficiency to a homogeneous catalyst often employed in Diels–Alder reactions, namely, Cu(OTf)2. The nature of the azachalcone substituent played a significant role in the reactivity of the dienophiles, with electron-withdrawing (EW) substituents enhancing conversion and electron-donating (ED) ones exhibiting the opposite effect. Coordinating substituents appeared to enhance the endo selectivity. Importantly, the Cu(II)-PEIP catalyst can be readily isolated from the reaction mixture and recycled up to four times without any significant reduction in conversion or selectivity.

The initial use of a tetradentate Schiff base (LH2) derived from the 2 : 1 condensation between 2-hydroxyacetophenone and cyclohexane-1,2-diamine in 4f-metal chemistry is described. The 1 : 2 reaction of Ln(NO3)3·xH2O (Ln = lanthanoid or yttrium) and LH2 in MeOH/CH2Cl2 has provided access to isostructural complexes [Ln(NO3)3(L'H2)(MeOH)] in moderate to good yields. Surprisingly, the products contain the corresponding Schiff base ligand L'H2 possessing six aliphatic -CH2- groups instead of the -CH-(CH2)4-CH- unit of the cyclohexane ring, i.e. an unusual ring-opening of the latter has occurred. A mechanism for this LnIII-assisted/promoted LH2 → L'H2 transformation has been proposed assuming transient LnII species and a second LH2 molecule as the H2 source for the reduction of the cyclohexane moiety. DFT calculations provide strong evidence for the great thermodynamic stability of the products in comparison with analogous complexes containing the original intact ligand. The structures of the PrIII, SmIII, GdIII, TbIII, and HoIII complexes have been determined by single-crystal X-ray crystallography. The 9-coordinate LnIII centre in the molecules is bound to six oxygen atoms from the three bidentate chelating nitrato groups, two oxygen atoms that belong to the bidentate chelating organic ligand, and one oxygen atom from the coordinated MeOH group. In the overall neutral bis(zwitterionic) L'H2 ligand, the acidic H atoms are clearly located on the imino nitrogen atoms and this results in the formation of an unusual 16-membered chelating ring. The coordination polyhedra defined by the nine donor atoms around the 4f-metal-ion centres can be best described as distorted, spherical capped square antiprisms. The EuIII, TbIII, and DyIII complexes exhibit LnIII-based luminescence in the visible region, with the coordinated L'H2 molecule acting as the antenna. Ac magnetometry experiments show that the DyIII member of the family behaves as an SIM at zero field and under external dc fields of 0.1 and 0.2 T without the enhancement of the peaks' maxima, suggesting that QTM is not the relaxation path. The GdIII complex behaves, rather unexpectedly, as a SIM with two different magnetic relaxation paths occurring at very close temperatures; this behaviour is tentatively attributed to a very small axial zero-field splitting (D ∼ 0.1 cm-1), which cannot be detected by magnetization or susceptibility experiments. The prospects of the present, first results in the lanthanoid(III)-LH2 chemistry are discussed.

The synthesis, characterisation and capability to selectively detect vapours of volatile organic compounds (VOCs) and nitroaromatic explosives of a new family of 2-dimensional rare earth (RE) MOFs based on a hexanuclear (RE3+)(6) secondary building unit (SBU) is reported. The reaction of RE(NO3)(3) with 4,4'-sulfonyldibenzoic acid (H(2)SDBA) in the presence of 2-fluorobenzoic acid (HFBA) in DMF/MeOH at 100 degrees C afforded compound [RE6(mu-OH/F)(8)(SDBA)(4)(NO3)(2)(H2O)(6)](n) (UCY-15(RE); RE: Y, Eu, Gd, Tb, Dy, Ho, Er). The structure of UCY-15(RE) comprises a microporous 8-connected 2D network based on a (RE3+)(6) SBU and the angular dicarboxylate ligand SDBA 2- and contains rhombic channels along b and c axes. Gas sorption studies on activated UCY-15(Y) indicated a moderate BET surface area of 417 m(2) g(-1). Photoluminescence (PL) studies in the visible region of UCY-15(RE) (RE: Y, Eu, Gd, Tb) revealed that SDBA(2-) is able to sensitize Eu3+ and Tb3+ ions. Thin films of UCY-15(RE) (RE: Y, Eu, Tb) embedded in polydimethylsiloxane (PDMS) were fabricated and evaluated for their sensing capability for vapours of selected VOCs and nitroaromatic compounds revealing different response to each analyte tested. A series of trimetallic analogues UCY-15(Y100-x-yEuxTby) (x, y = 5, 7.5, 10) were prepared aiming to superior sensing materials that combine the PL signals of UCY-15(Y), UCY-15(Eu) and UCY-15(Tb). The analogue UCY-15(Y87.5Eu7.5Tb5) achieved the emission of white light whereas UCY-15(Y87.5Eu5Tb7.5)@PDMS films were shown to selectively recognize the tested analytes. Overall, this work highlights the capability of microporous 2D MOFs containing highly accessible emissive centers to recognise vapours of selected analytes.