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Porous materials displaying tailor-made pore sizes and shapes are particularly interesting in a great variety of real and potential applications where molecular recognition is needed, such as shape-selective catalysis, molecular sieving, and selective adsorption. Classically, apart from silica, materials most commonly used for catalysis and catalyst supports have been those based on high surface aluminas, owing to their thermal, chemical, and mechanical stability and their low cost. Earlier aluminas with high surface areas (~500 m/g) had been prepared using structure-directing agents. However, they were X-ray amorphous materials and their porosity was purely textural, characterized by wide pore size distributions. More recently, the discovery by researchers at Mobil of the M41S family of mesoporous silicas synthesized by using micellar aggregates as templates, has promoted considerable development in the synthesis of materials with uniform pores in the mesoporous range. However, in the case of mesoporous aluminum oxide, the usual strategies used in the synthesis of mesoporous silica have not always yielded satisfactory results and only a few papers have reported on surfactant-assisted synthesis of mesoporous alumina. Davis and co-workers have reported the preparation of aluminas with narrow pore size distributions by the use of anionic surfactants but their solids always have an approximately constant pore size (ca. 20 Š) that cannot be tailored by changing the surfactant length. Conversely, Pinnavaia and co-workers report the use of neutral polyethylene oxides as directing agents for the synthesis of mesoporous solids for which both the d spacing and the pore diameters increase as the surfactant size does. In both cases, the synthetic pathway is based on typical procedures originally used for mesoporous silicas: the variation of the micelle diameter is achieved by increasing the surfactant chain length and/or addition of hydrophobic organic molecules. However, the scarcity and diversity of the reported results suggest that there is still a long way to go to obtain real control of the synthetic procedures for the preparation of mesoporous aluminas. In this context, we show that self-assembling processes leading to the formation of mesoporous aluminas can be controlled by adequately balancing such processes and the hydrolysis and condensation reactions occurring at the inorganic phase. This method has allowed us to isolate for the first time mesoporous aluminum oxides using cationic surfactants and, what is more important, to tune their pore size by the sole adjustment of the molar ratio of the reactants. Thermally stable aluminas with different pore diameters, henceforth denoted as ICMUV-1, were synthesized using CTABr (cetyltrimethylammonium bromide) as surfactantdirecting agent in a water/TEA (triethanolamine) medium. A constant 2/1 Al/CTABr molar ratio was always used, and the pore size adjustment was achieved by changing the Al (or surfactant)/water/TEA molar ratio. A typical synthetic procedure is as follows: 1) A solution containing 0.4 g (10 mmol) of NaOH in 2 mL of water was added to 40 mL of TEA and heated at 120 C for 5 min to evaporate the water. Over this solution, 10.9 mL (40 mmol) of Al sec-butoxide was slowly added with stirring. The resulting clear solution was then heated at 150 C for 10 min (solution I). 2) 7.28 g (20 mmol) of CTABr was dissolved in 40 mL of water at 60 C (solution II). 3) Solution I was slowly added, with vigorous stirring, to solution II at 60 C, and the mixture was allowed to age for 72 h to give a white suspension. The aged solid was then filtered, washed with ethanol, and dried at 30 C. Finally, the assynthesized mesostructured composite was calcined for 5 h at 500 C under air atmosphere to favor surfactant decomposition, and a mesoporous solid with a pore size of 33 Š was obtained. Solids with different pore sizes have been obtained by adjusting the Al (or surfactant)/water/TEA molar ratio in the range from 2/111/15 to 2/195/4 (see Table 1). In all cases, the samples have high thermal stability, as measured by the permanence of their X-ray diffraction peak after heating at 900 C.

Hybrid mesoporous systems containing a gate-like ensemble functionalised with imidazolium groups and a dye are used for the selective colorimetric sensing of long-chain carboxylates. Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es

[EN] Pyrylium-containing mesoporous materials have been used for the chromo-fluorogenic sensing of biogenic amines in an aqueous environment., We thank the Ministerio de Ciencia y Tecnología (MAT2003- 08568-C03-02) for support. F.S. is thankful for a Ramón y Cajal contract. B.G.A. thanks the Generalitat Valenciana and M.C. thanks the Caja de Ahorros del Mediterraneo for a Doctoral Fellowship. A.B.D. thanks the Alexander-von-Humboldt Foundation for a Research Fellowship.

Porous pure and doped silicas with pore sizes at two length scales (meso/macroporous) have been prepared and shaped both as powders and monoliths through a one-pot surfactant assisted procedure by using a simple template agent and starting from atrane complexes as inorganic precursors.

A new colourimetric and fluorimetric method for fluoride determination in aqueous samples based on the specific reaction between fluoride and silica has been developed and applied on real samples.

We describe here for the first time the surfactant-assisted synthesis of thermally stable mesoporous pure TiO 2 having a high surface area. Our synthetic approach to the chemistry of this system is based on the equilibrium between the hydrolysis and condensation reactions of the inorganic species and the organic–inorganic self-assembling processes. The use of titanatrane complexes helps to retard the hydrolysis and condensation reactions, thus allowing us to overcome the difficulties in preparing titanium dioxide mesoporous materials starting from highly reactive Ti-alkoxides. The mesoporous material has been characterized by TEM, XRD and N 2 adsorption–desorption isotherms and displays a typical wormhole-like pore structure.

The use of complexing agents to generate polynuclear precursor species containing both Al and Si allows the synthesis of thermally stable mesoporous aluminosilicates including solely tetrahedrally coordinated aluminium, in which the Si/Al ratio can be modulated down to a minimum Si/Al value of 1.06(4). Cabrera Medina, Saul, Saul.Cabrera@uv.es ; El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Latorre Saborit, Julio, Julio.Latorre@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es

Thermally stable porous aluminophosphates (ICMUV-3) with P/Al molar ratios in the range 0.15

A unified synthetic strategy has allowed us to rationalize the preparative chemistry of the layered oxovanadium phosphates M(VOPO(4))(2).nH(2)O. Thus, we have been able to isolate as single phases with reasonable yields both all the previously characterized phosphates and a new solid containing Ba(2+) cations as guest species as well as to prepare new related derivatives involving arsenate anions. In order to organize the experimental results, we have used two complementary models: a simple restatement of the partial charge model (PCM), and the valence matching principle (VMP) (derived from the bond valence method). The crystal structure of the new barium lamellar derivative, Ba(VOPO(4))(2).4H(2)O, has been solved from X-ray single crystal data. The cell is monoclinic (space group Pn; Z = 1) with a = 6.3860(3) Å, b = 12.7796(9) Å, c = 6.3870(5) Å, and beta = 90.172(6) degrees. Its structure, like it occurs with the other members of the M(VOPO(4))(2).nH(2)O family, can be thought of as derived from that of the well-known lamellar solid VOPO(4)(.)2H(2)O. Ba(2+) cations are located in the interlamellar space with an environment defined by 12 oxygen atoms. A comparative study of this family shows significant crystallochemical correlations with the radius of the guest cations.

A general synthetic approach to rationalize the solution preparative chemistry of oxovanadium phosphates containing organic species as structural directing agents is presented. Careful attention is payed to the hydrolysis and condensation processes involving the ionic species in solution, and a simple restatement of the partial charge model (PCM) has been used in order to organize the experimental results. The structure of a new V(IV)-Fe(III) bimetallic oxovanadium phosphate, [H(3)N(CH(2))(2)NH(3)](2)[H(3)N(CH(2))(2)NH(2)] [Fe(III)(H(2)O)(2)(V(IV)O)(8)(OH)(4)(HPO(4))(4)(PO(4))(4)].4H(2)O, has been determined by X-ray single crystal diffraction methods. This compound crystallizes in the monoclinic system, space group P2(1)/n and the cell dimensions are as follows: a = 14.383(3) Å, b = 10.150(2) Å, c = 18.355(4) Å, and beta = 90.39(3) degrees (Z = 2). The existence of a complex intercrossing channel system, including a very large channel of 18.4 Å of diameter (in which both water molecules and ethylenediamine species are located), is the more interesting feature of this structure. Thermal decomposition, including the dehydration/rehydration process, has been studied by thermal analysis and variable temperature X-ray powder diffraction techniques. A complementary SEM study of the different intermediate decomposition products is presented.

A new colourimetric and fluorimetric method for fluoride determination in aqueous samples based on the specific reaction between fluoride and silica has been developed and applied on real samples.

Porous pure and doped silicas with pore sizes at two length scales (meso/macroporous) have been prepared and shaped both as powders and monoliths through a one-pot surfactant assisted procedure by using a simple template agent and starting from atrane complexes as inorganic precursors.

Silica nanoparticles containing polyamines and thiol groups have been used as probes for the selective detection of Tetryl. © 2011 The Royal Society of Chemistry., Financial support from the Spanish Government (project MAT2009-14564-C04-01) and Generalitat Valencia (project PRO-METEO/2009/016) is gratefully acknowledged. Y.S. is grateful to the Spanish Ministry of Science and Innovation for a grant.

We report herein a new optical sensor for the colorimetric monitoring of aqueous amines designed by anchoring a suitable reactand on a hybrid material that was further incorporated on a polymeric matrix. An azo chromophore containing a trifluoroacetophenone moiety was used as signalling reporter. In this system colour modulation is a consequence of the reversible reaction of the amine with the trifluoroacetyl group that results in the formation of a hemiaminal. Based on this approach but at the same time trying to enhance selectivity the chromoreactand was anchored in a first step onto suitable mesoporous nanoscopic hydrophobic pockets. As a mesoporous system we selected a UVM-7 solid (a MCM41-type material) containing a homogeneous distribution of pores of about 3 nm and a specific surface area of over 1000 m2/g. This material was chemically modified to yield a trifluoroacetylazobenzene indicator dye within the pores, resulting in the hybrid material S3. It was found that whereas the analogous trifluoroacetylazobenzene dye in solution gives an unspecific response, the hybrid material S3 shows enhanced features in terms of selectivity, only reacting with the not-too-large but lipophilic enough aminesn-octylamine and n-decylamine. The material S3 reacts with neither small hydrophilic amines (due to the hydrophobicity of the inner pores in S3) nor very large aliphatic amines (due to the size of the pore). In the second part of this work a composite material (P–S3) was prepared by mixing hydrophilic polyurethane polymer and S3. The X-ray diffraction patterns of P–S3 displays the characteristic intense peak of the MCM-41 type mesoporous material and TEM images show a homogeneous dispersion of the nanometric mesoporous particles into the polymeric matrix. The measurements were carried out in a flow-through module connected to an optical fibre via a Y-probe at pH 9.5 (borax buffer). The P–S3 composite retains the favourable features in terms of selectivity shown by S3 and only displays a clear change in colour for n-octylamine or n-decylamine, but no response to the remaining linear primary amines. The response time of the sensor P–S3 to solutions of these amines was in the range of a few seconds, the regeneration time was between 5 to 10 min and the detection limit was 6 × 10−4 mol L−1. The sensor response was reproducible and reversible.

Mesoporous silica matrices functionalized with a fluorescent solvatochromic dye have been employed as optical sensor materials for volatile organic compounds. Re-functionalisation of the polar silica surface of the parent solid by passivation of the silanol groups with hexamethyldisilazane yielded a hydrophobic hybrid sensory material with improved performance in terms of the spectroscopic response, the detectable polarity range of organic vapours, response times and reversibility, and minimized interference from environmental humidity. Polar vapours such as methanol and acetone for instance are indicated by a shift in absorption of ca. 40 and 30 nm, and a ca. 10-fold fluorescence enhancement. With the present system, acetone vapours can be detected down to 300 ppmV.

A number of functionalised mesoporous solids containing anchored anthrylmethylamine groups have been prepared using different co-hydrolysis or grafting synthetic routes. The solids have been characterised using standard solid-state techniques. Solids with a low loading of the anthrylmethylamine probe show typical well defined and structured emission bands centred at ca. 415 nm. Addition of ATP to suspensions of these solids at pH 2.8 resulted in a quenching of the anthracene emission. These solids showed a cooperative effect that resulted in quite a remarkable improvement in ATP response with respect to the free anthrylmethylamine probe in solution. Certain prepared solids showed a remarkable detection limit for ATP detection in the micromolar range. An equation based on a Langmuir-type analysis has been developed and used to obtain binding constants (adsorption constants) for the interaction of the solids with ATP and with some related anions. Some other solids containing larger amounts of anthrylmethylamine groups have also been prepared. In these cases a dual monomer–excimer fluorescence emission was observed. ATP addition to these solids resulted in an enhancement of the excimer emission band.

Investigation of several UVI–CuII oxide fields has shown the existence of only one quaternary oxide, UBa2CuO6. This adopts a cation-ordered perovskite structure with a= 5.78473(8)A and c= 8.8424(2)A in tetragonal space group I4/mmm. Magnetic susceptibility measurements show a Curie–Weiss behaviour, characteristic of localised copper(II) spins at high temperatures (50–300 K), with antiferromagnetic ordering below 10 K.

Oxovanadium phosphates constitute a crystallochemically very rich family that, in turn, results in a seemingly intricate magnetochemistry including from isolated dimers to 3-D systems. This magnetic diversity is due, in part, to the possible participation of phosphate groups in the spin transfer between VIV centers. This way, 31P solid-state NMR becomes a key tool in determining the exchange paths involving phosphorus orbitals. The magnetic behavior of several layered oxovanadium phosphates M(VOPO4)2·4H2O (M = Na+, Ca2+, Ba2+, and Pb2+) has been investigated. Like it occurs in the case of other previously studied lamellar derivatives, the best fit of the temperature-dependent magnetic susceptibility data is obtained for a 2-D model. This is consistent with chairlike V(OPO)2V exchange pathways (i.e., through di-μ-(O,O‘)phosphate bridges). Both these results and those previously available for other oxovanadium phosphates can be nicely correlated with the structural data focusing the attention on the topolog...

A synthetic strategy has been devised for the preparation of new compounds in which terpyridyl fragments are linked to 1,4,8,11-tetraazacyclotetradecane (cyclam). Reaction of excess cyclam with 4′-[(4-bromomethyl)phenyl]-2,2′:2″,6′-terpyridine afforded the ligand 1-[4′-p-tolyl-(2,2′:6′,2″-terpyridyl)]-1,4,8,11-tetraazacyclotetradecane (L1) in which the tetraaza macrocycle was covalently attached to one benzyl-terpyridyl fragment. Under similar conditions reaction of cyclam with excess 4′-[(4-bromomethyl)phenyl]-2,2′:2″,6′-terpyridine gave the tetra substituted cyclam derivative 1,4,8,11-[4′-p-tolyl-(2,2′:6′,2″-terpyridyl)]-1,4,8,11-tetraazacyclotetradecane (L2). The multidentate ligand L2 was crystallographically characterised by single-crystal X-ray diffraction techniques. Reaction of L1 with [Ru(mtpy)Cl3] gave the heteroleptic ruthenium(II) complex [Ru(L1)(mtpy)][PF6]2 (mtpy = 4′-methyl-2,2′:6′2″-terpyridine). The fluorescent intensity of the metallo-receptor [Ru(L1)(mtpy)][PF6]2 was quenched selectively in the presence of copper(II) in an aqueous environment. To gain insight into the nature of this interaction, potentiometric titrations on [Ru(L1)(mtpy)]2+ in the presence of Cu2+ were carried out. The quenching of the emission intensity was associated with the presence of the copper {Cu[Ru(L1)(mtpy)]}4+ complex in solution. The receptor 1-[4′-methyl-(2,2′:6′,2″-terpyridyl)]-1,4,8,11-tetraazacyclotetradecane (L3), in which the cyclam fragment is separated from the terpyriyl by a methylene group, has also been synthesised by reaction of 4′-bromomethyl-2,2′:2″,6′-terpyridine and cyclam. With L3 as starting material, the ruthenium complex [Ru(L3)(mtpy)]2+ was prepared in order to evaluate the effect that the nature of the spacer has on the quenching of the fluorescence upon addition of Cu2+.

Titanium content in mesoporous titanosilicate catalysts has been modulated up to a minimum Si/Ti value of 1.9 by using complexing agents able to coordinate both Si and Ti atoms and harmonize the reactivity of the resulting precursors avoiding subsequent phase segregation and leading to chemically very homogeneous materials. El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es

Reactions of 4′-[4-(bromomethyl)phenyl]-2,2′:6′,2′′-terpyridine with 4,10-diaza-15-crown-5 and 1-aza-12-crown-4 in dichloromethane yielded the ligands L1 and L3, respectively. Reaction of an excess of 4′-[4-(bromomethyl)phenyl]-2,2′:6′,2′′-terpyridine with 4,10-diaza-15-crown-5 yielded L2, while treatment of the same terpyridine ligand with 1,4,7,10,13-pentaazacyclopentadecane afforded L4. Reactions of L1, L3, and L4 with Ru(mtpy)Cl3 (mtpy = 4′-methyl-2,2′:6′,2′′-terpyridine) in methanol yielded the metallo receptors [Ru(L1)(mtpy)][PF6]2, [Ru(L3)(mtpy)][PF6]2, and [Ru(L4)(mtpy)][PF6]2 after precipitation with ammonium hexafluorophosphate and column chromatography. On treating L3 with RuCl3, the homoleptic ruthenium complex [Ru(L3)2][PF6]2 was obtained. The synthesized metallo receptors contain oxa-aza crown or polyazacycloalkane moieties as recognition sites and [Ru(tpy)2]2+ cores as the signal-generating centre. The electronic spectra of the complexes are as expected for an Ru(tpy)22+ chromophore, with the main Ru[d(π)] tpy(π*) MLCT transition at ca. 484 nm and intense ligand-centred transitions in the UV region. One of the most interesting aspects of these ruthenium complexes is their multicomponent nature, as they contain both coordination sites and fluorescent Ru(tpy)22+ cores. The cations [Ru(L1)(mtpy)]2+, [Ru(L3)(mtpy)]2+, and [Ru(L3)2]2+ display an emission maximum at ca. 650 nm, the intensity of which is pH dependent, showing an enhancement upon protonation. The metallo receptor [Ru(L1)(mtpy)]2+ selectively senses Hg2+ in preference to Cu2+, Cd2+, and Pb2+. The emission intensity vs. pH curve for [Ru(L2)(mtpy)]2+ in the presence of Cu2+ and Hg2+ ions is close to that of the free receptor, but the presence of Cd2+ or Pb2+ enhances the emission intensity in the range pH 4−6. For the [Ru(L3)2]2+ complex, Cd2+, Pb2+, and Hg2+ induce an enhancement of the fluorescence of the Ru(tpy)22+ core in the range pH 3.5−7.5. These results are compared with those obtained for the metallo receptor [Ru(L4)(mtpy)]2+ containing a polyazacycloalkane moiety as the binding domain.

The synthesis of the Schiff base N,N-ethylenebis((ferrocenylmethylidene)amine), (η 5 -C 5 H 5 )Fe[(η 5 -C 5 H 4 )CH=N-(CH 2 ) 2 N=CH(η 5 -C 5 H 4 )]Fe(η 5 -C 5 H 5 ) , its Parent amine (η 5 -C 5 H 4 )Fe[(η 5 -C 5 H 4 )CH 2 NH(CH 2 ) 2 NHCH 2 (η 5 -C 5 H 4 )]Fe(η 5 -C 5 H 5 ),Fe 2 L , and the complex [Cu(Fc 2 L) 2 (NO 3 ) 2 ].2CH 3 OH are reported.

A new lamellar mesostructured oxovanadium(V) phosphate, (DDAH)0.9(Cl)0.9VOPO4·1.5H2O (DDA = dodecylamine), has been synthesized through a S+X-I0 cooperative mechanism using protonated dodecylamine ...