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Stepwise self-assembly processes using new lanthanide metalloligands (Ln-MLs) and silver salts have been successfully applied to isolate 4f-4d heterometallic coordination networks of four different structural types. In particular, the new lanthanide tetrakis-chelate complexes NEt4[Ln(L1)4] [HL1 = 1,3-bis(4'-cyanophenyl)-1,3-propanedione; Ln = Eu (1a), La (1b), Nd (1c), Tb (1d)] and NEt4[Ln(L2)4] (HL2 = 1,3-bis(4'-pyridyl)-1,3-propanedione; Ln = Eu (1e), Nd (1f)] have been synthesized, characterized, and reacted with different silver salts. The use of NEt4[Ln-(L1)4] allowed then to isolate and characterize i) neutral onedimensional ladder-like species of formula [Ln(L1)4Ag] [Ln = Eu (2a), La(2b), Nd(2c), Tb(2d)] and ii) their supramolecular isomers [Ln(L1)4Ag] [Ln = Eu (3a), La (3b), Nd (3c), Tb (3d)] showing a very unstable 2D network structure, iii) the cationic 2D species [Ln(L1)4Ag2]X [Ln = Eu, X = PF6-, CF3SO3-, ClO4- (4a-4c); Ln = Tb, Nd, La X = PF6 - (4d-4f)], and, only for lanthanum, iv) a fourth 2D species of formula [La(L1)4(H2O)Ag] (5) and SQL topology. Of the eight nitrile groups on the MLs potentially coordinating, only a partial number is used for networking with Ag(I), that is, only two in families 2 and 3 and four in family 4 and in network 5. Finally, the four structural types are rationalized in terms of a new "pincer-like" secondary building unit (SBU) consisting of a silver cation coordinating two central carbon atoms (γ carbon) of two different diketonate ligands on the same ML. Therefore, it is shown that compounds 5, 4, and 2-3 contain, respectively, none, one, or two of such pincer-like SBUs. The luminescence properties of the Ln-MLs and some of their polymeric species have been also investigated in solution and in the solid state.

Silica based cellulose nanocomposites obtained from (3-mercaptopropyl)trimethoxysilane or vinyltrimethoxysilane and 3-butynoate-substituted zirconium-oxoclusters were prepared and their surface morphology, wettability, and thermo-mechanical properties were studied. The composites showed a hydrophobic surface, high strength, and resistance to thermal degradation and aging; in comparison to the untreated paper they required a higher temperature to activate combustion and generated less heat during all thermal processes.

Inorganic–organic hybrid copolymers are promising materials where the size of the inorganic/organic domains, the phase continuity and the interface between the domains play an important role in their behavior. Two types of hybrid copolymers composed of 3-butynoate-substituted zirconium-oxoclusters covalently bonded to a (3-mercaptopropyl)trimethoxysilane or a vinyltrimethoxysilane matrix are investigated in bulk. Their properties are directly correlated with the degree of condensation of the silanes and the alkyne-3-mercaptopropyl or alkyne-vinyl interface. Both copolymers show storage moduli and glass-transition temperatures (TgG″) above 130 MPa and 230°C. However, the more impressive results are achieved with the (3-mercaptopropyl)trimethoxysilane copolymer where a TgG″ of about 300°C holds over six dynamical mechanical spectroscopy analyses. In addition to their excellent thermo-mechanical proprieties, the copolymers show unreacted 3-mercaptopropyl or vinyl groups which could be employed either in direct usage of the materials or for post-functional modifications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Paper is an organic material widely used in cultural heritage and mainly composed of cellulose mixed with lignin, hemicellulose and small amounts of additives. This paper deals with siloxane coatings on pure cellulose paper, applied by sol–gel dipping in sols prepared with different siloxane precursors (tetraethoxysilane, methyl triethoxysilane, dimethyl diethoxysilane, trimethyl monoethoxysilane). The coated samples were characterized using various techniques (Fourier Transform Infrared Spectroscopy FT-IR, Nuclear Magnetic Resonance NMR and Scanning Electron Microscopy and Energy Dispersive Spectroscopy SEM–EDS), measuring their mechanical properties, flame resistance and contact angles, and a colorimetric test. The coated samples’ behavior was more hydrophobic the higher the methyl number of siloxane precursor, regardless of the coating’s thickness. Increasing the thickness improved the mechanical and thermal properties. The thickest coatings were obtained using a double coating process and a basic catalyst for the hydrolysis step, but this latter condition facilitated the formation of surface agglomerates, which make the paper too stiff and yellow.

A new zirconium nano building block (ZrNBB) was prepared by the reaction of Zirconium tetrapropoxide with 3-butynoic acid in an alkoxide/acid at a 1 : 3 or 1 : 6 molar ratio. The complex was characterized by FTIR, 1H-NMR and 13C-NMR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, energy-dispersive X-ray analysis, and elementary analysis. A spontaneous alkyne-to-allene isomerization process was observed for ZrNBB. A bulk sample was also prepared and analyzed via dynamical mechanical spectroscopy in compression mode. The zirconium complex was then embedded in a polymeric matrix by radical copolymerization with vinyl trimethoxysilane. The inorganic–organic hybrid material was chemically and thermally stable. The shear storage modulus and loss modulus were measured to determine the mechanical properties of the material. The preliminary results are presented. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Five novel bpca-based Cu(II) polynuclear coordination compounds [Hbpca = bis(2-pyridylcarbonyl)amine] were prepared using the [Cu(bpca)(H2O)2](NO3)·2H2O (1) building block and characterized by single crystal X-ray diffraction. We have also isolated and characterized two new crystal forms of the starting species, with lower water contents. Three of the new products are dinuclear complexes obtained by reacting 1 with different rigid or flexible spacer ligands: [Cu2(bpca)2(H2O)2(bipy)](NO3)2·6H2O (2) (bipy = 4,4′-bipyridine) and [Cu2(bpca)2(H2O)2(bpete)](NO3)2·xH2O (3) [bpete = (E)-1,2-di(pyridin-4-yl)ethane] are linear dumbbell-like species with Cu⋯Cu separations of 11.075 and 13.275 A, respectively. The third dinuclear compound, [Cu2(bpca)2(H2O)2(bpx)](NO3)2·8H2O (4) [bpx = 1,4-bis((1H-pyrazol-1-yl)methyl)benzene], with the flexible bpx ligand, assumes an unusual S-shaped conformation and shows a quite shorter Cu⋯Cu contact of 6.869 A only. We have also obtained a chiral 1D neutral polymeric complex, [Cu3(bpca)2(bipy)3(NO3)4]·6H2O (5), that shows a central linear –Cu–bipy–Cu– chain, with all these Cu atoms connected to two lateral [Cu(bpca)(NO3)2]− groups on two opposite sides by means of bipy spacers. An unprecedented type of Cu(II) neutral trinuclear complex, [Cu3(bpca)2(H2O)2(NO3)2] (6), was obtained which has a centrosymmetric structure with two external [Cu(bpca)(NO3)2]− units chelating on a central copper atom via the two pairs of carbonyl groups of the bpca ligands. The central metal is octahedral with two axial water molecules, while the two lateral Cu atoms are in square pyramidal geometry; the Cu⋯Cu separation is 5.205 A. The magnetic properties of 6 have been rationalized through a ferromagnetic coupling between the central metal ion and the peripheral ones which are coupled by a smaller antiferromagnetic interaction. DFT calculations have been also performed in order to give a better insight into magnetic interactions.

In this work a new simple method to improve the bulk properties of paper is presented. Co-polymerization of vinyl functionalised zirconia oxoclusters with vinyl trimethoxysilane was carried out onto paper. The coating process was evaluated also taking into account the specific weight of hybrid polymer left on the paper after one or two deposition steps, and with or without a thermal treatment of curing. The effectiveness of the coating process in consolidating and protecting paper was investigated by measurements with High Temperature Differential Scanning Calorimetry, Dynamical Mechanical Spectroscopy, tensile testing, contact angle, along with Environmental Scanning Electron Microscopy. The coating process does not affect the morphology and appearance of the paper, but modifies its mechanical, surface and thermal properties.

We report herein the synthesis of the porphyrins 5,10,15,20-tetrakis(4-carboxybiphenyl)-porphyrin (H2TCBP) and 5,10,15,20-tetrakis(4-carboxy-2,6-dimethylbiphenyl)porphyrin (H2TCDMBP) bearing diphenyl units on meso-positions, and of their cobalt and silver derivatives. The silver complexes of H2TCDMBP and of H2TCPP ( H2TCPP = 5 ,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) were investigated by X-ray crystallography and their supramolecular organization elucidated. Co(TCBP) was reacted with copper formate, yielding a polymeric compound that showed a catalytic activity in the benzylic amination of hydrocarbons using arylazide as aminating agent.

This review focuses on P,N-ligands capable of establishing binucleating interactions and on the resulting bimetallic complexes. The work is grouped by the type of P,N-binucleating ligand backbones which are closely responsible for the chemistry of their correspondent bimetallic complexes. The P,N-binucleating ligands are classified according to their length (the number of atoms between the N- and P-donor), their backbone structure (the relative disposition of the N- and P-donor), and the presence or not of additional donor atoms. Similarities between the structures of the bimetallic complexes obtained with P,N-ligands inside each group are highlighted. Based on the analysis of the different groups, the structure of new metallo/P,N-ligand complexes not yet synthesized can be hypothesized. A summary of the few examples of P,N-binucleating ligand based bimetallic complexes that have catalytic activity is given.

The reactions of Mn(II) nitrate with the flexible ligand 1,4-bis(imidazol-1-ylmethyl)benzene (bix) (reagent ratios 1:2–1:3) yield novel interesting coordination networks including, besides the ladder-like species [Mn(bix)1.5(NO3)2] and the 2-fold interpenetrated three-dimensional (3D) cds network [Mn(bix)2(NO3)2], the exceptional [Mn2(bix)3(NO3)4]·2CHCl3, which is comprised of two different supramolecular isomers, namely, brickwall layers and one-dimensional (1D) molecular ladders, polycatenated to give a 3D (2D + 1D) architecture.

This article describes the preparation and characterization of hybrid materials obtained from the polymerization of vinyl-substituted zirconium oxo-clusters [Zr6O4(OH)4(OOCCH2CHCH2)12(n-PrOH)]2·4(CH2CHCH2COOH) (Zr12) and 2-hydroxyethyl methacrylate (HEMA). The zirconium oxo-clusters serve as cross-linking agents, forming a 3D network by means of the copolymerization of their vinylic ligands with HEMA. To optimize the conditions for cross-linking, the polymerization was monitored with a differential scanning calorimeter. The resulting hybrid materials were also characterized using thermo-mechanical techniques. There was evidence not only of a greater rigidity above Tg, but also of a better thermal stability for several hybrid formulations than for simple poly-2-hydroxyethyl methacrylate. After immersion in water, the hybrids containing 20 or 60% w/w zirconium oxo-clusters also showed a stable behavior with an equilibrium swelling at about 27 and 18% w/w of water, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41568.

The influence of an additional gas on the hydroformylation of cyclohexene in the presence of Co2(CO)6(PBu3)2 has been tested. The rate of the hydroformylation is reduced by the presence of an appropriate amount of dinitrogen, argon or xenon as additional gas. The conversion decreases as the pressure of the additional gas increases. Helium, on the other hand, does not show any influence. These results are in agreement with the previous data reported for the hydroformylation of the same olefin in the presence of Co2(CO)8 even if the entity of the reduction of the reaction rate is now less evident. The reduced influence of the additional gas may be attributed to the more severe conditions necessary to perform the reaction or to the higher stability of the catalytic system. The analogy between these two catalytic systems is confirmed by the comparable influence displaced by the additional gas. This influence on the reaction rate may be attributed, on a molecular basis, to a competition among the additional gas and dihydrogen and/or olefin to a coordinatively unsaturated place on the catalytically active complex. The formation of an additional gas containing complex reduces the concentration of the active cobalt intermediate available for the catalysis and, as a consequence, the hydroformylation rate. These data are not sufficient to identify the step of the catalytic process influenced by the presence of the additional gas, however, indicate the involvement of a dihydrogen or an olefin containing complex in the rate determining step of the hydroformylation. The formation of a cobalt complex containing an additional gas as ligand (dinitrogen, argon or xenon) in the conditions required to perform the hydroformylation is supported by these experiments.

Novel inorganic-organic hybrid copolymers based on vinyl- or (3-mercaptopropyl)-trimethoxysilane and an organically modified zirconium-oxocluster were investigated as a wood preservation treatment. The copolymers were prepared using a modified sol-gel strategy not involving alkoxysilane pre-hydrolysis and were applied on wood through a dip coating method. Even though the copolymers were mainly present on the surface of the wood, EDX analysis showed also a uniform distribution of silicon and zirconium in the cell wall but not in the lumina. The grafting of the copolymers on wood was confirmed through FTIR, (13)C and (29)Si MAS NMR analysis. The copolymer obtained from (3-mercaptopropyl)trimethoxysilane was post-functionalized with the methacrylic ester of thymol; introduced for testing as a biocide. Preliminary accelerated biological tests against the brown rot fungus Coniophora puteana, showed resistance to the fungus for the samples coated with the vinyltrimethoxysilane copolymer, while uneven results were obtained for the samples coated with the (3-mercaptopropyl)trimethoxysilane copolymer, even when functionalized with the ester of thymol.

The modular engineering of heterometallic nanoporous metal-organic frameworks (MOFs) based on novel tris-chelate metalloligands, prepared using the functionalised β-diketone 1,3-bis(4'-cyanophenyl)-1,3-propanedione (HL), is described. The complexes [M(III)L(3)] (M=Fe(3+), Co(3+)) and [M(II)L(3)](NEt(4)) (M=Mn(2+), Co(2+), Zn(2+), Cd(2+)) have been synthesised and characterised, all of which exhibit a distorted octahedral chiral structure. The presence of six exo-oriented cyano donor groups on each complex makes it a suitable building block for networking through interactions with external metal ions. We have prepared two families of MOFs by reacting the metalloligands [M(III)L(3)] and [M(II)L(3)](-) with many silver salts AgX (X=NO(3)(-), BF(4)(-), PF(6)(-), AsF(6)(-), SbF(6)(-), CF(3)SO(3)(-), tosylate), specifically the [M(III)L(3)Ag(3)]X(3)·Solv and [M(II)L(3)Ag(3)]X(2)·Solv network species. Very interestingly, all of these network species exhibit the same type of 3D structure and crystallise in the same trigonal space group with similar cell parameters, in spite of the different metal ions, ionic charges and X(-) counteranions of the silver salts. We have also succeeded in synthesising trimetallic species such as [Zn(x)Fe(y)L(3)Ag(3)](ClO(4))((2x+3y))·Solv and [Zn(x)Cd(y)L(3)Ag(3)](ClO(4))(2)·Solv (with x+y=1). All of the frameworks can be described as sixfold interpenetrated pcu nets, considering the Ag(+) ions as simple digonal spacers. Each individual net is homochiral, containing only Δ or Λ nodes; the whole array contains three nets of type Δ and three nets of type Λ. Otherwise, taking into account the presence of weak Ag-C σ bonds involving the central carbon atoms of the β-diketonate ligands of adjacent nets, the six interpenetrating pcu networks are joined into a unique non-interpenetrated six-connected frame with the rare acs topology. The networks contain large parallel channels of approximate hexagonal-shaped sections that represent 37-48% of the cell volume and include the anions and many guest solvent molecules. The guest solvent molecules can be reversibly removed by thermal activation with retention of the framework structure, which proved to be stable up to about 270°C, as confirmed by TGA and powder XRD monitoring. The anions could be easily exchanged in single-crystal to single-crystal processes, thereby allowing the insertion of selected anions into the framework channels.

Nine novel coordination polymers have been obtained from the self-assembly reactions of the flexible ligand 4,4′-bis(imidazol-1-ylmethyl)biphenyl (bimb) with different metal salts and their structures and supramolecular architectures have been characterized by single crystal X-ray analysis. Three of them contain 1D polymers, namely [Cd(bimb)(OTs)2(H2O)2] (3), [Cd(bimb)2(H2O)2](OTs)2·4MeOH (4) and [Cu(bimb)2(H2O)2](SO4)·2H2O·2(acetone) (7), consisting of single-stranded chains (3) or ribbons of rings (4 and 7) that are joined viaH-bond bridges to give layers of (4,4) topology (sql). Three polymeric products contain 2D frameworks, i.e. the two nitrate species [Cd(bimb)2(NO3)2] (2) and [Cu(bimb)2(NO3)2] (8), that are isostructural and contain flat sql layers, and [Zn2(bimb)3(SO4)2]·(bimb)·Solv (9), comprised of interdigitated (6,3) honeycomb-like (hcb) layers threaded by the free bimb ligands. Also three 3D networks have been isolated, namely [Cd(bimb)(H2O)(SO4)]·Solv (1), containing 1D Cd(bimb) undulated single chains that are cross-linked by bridging sulfate anions and water molecules to give an overall 3D array with the diamond topology (dia), [Co(bimb)2(SO4)] (5) that consists of ribbons of rings spanning two distinct directions of propagation bridged by the sulfate anions to generate a 3D single net with the CdSO4 type topology (cds), and [Co2(bimb)5(H2O)2](NO3)4·4EtOH·2H2O (6), the first case of a 3D network assembled exclusively with the use of the bimb spacer, that contains ribbons and single chains cross-linked to give an overall 3D single cds array. Three forms of the uncoordinated ligand, i.e. bimb, bimb·H2O and [bimbH](PF6), were also isolated and structurally characterized to obtain a more complete information about the conformations of the bimb molecule.

The title compound, [Pd(2)(C(13)H(8)N(2)O(2))(C(15)H(11)O(2))(2)], crystallized from a mixture of ethanol and n-hexa-nes. The structure is the first example of β-diketonate in a dianionic κ(2)C-coordination complex containing a Pd(II)-Pd(II) bond. Both Pd(II) atoms adopt a pseudo square-planar coordination geometry. The mol-ecular packing involves π-inter-actions between the phenyl rings of the 1,3-diphenyl-propane-1,3-dionato ligands with centroid-centroid distances in the range 3.823 (2)-3.868 (2) Å.