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Solvothermal reactions between the tritopic pyrazole-based ligand 1,3,5-tris((1H-pyrazol-4-yl)phenyl)benzene (H3BTPP) and nickel(ii) perchlorate or copper(ii) nitrate afforded two new metal-organic frameworks, Ni3(BTPP)2·solvent (Ni-BTPP) and CuI4CuII2(OH)2(BTPP)2·solvent (Cu-BTPP). Powder diffraction structure determination methods were employed to determine the crystal and molecular structure of the copper(i,ii) derivative: triangular [Cu3N6(μ3-OH)] nodes are connected to six nearby ones by the pyrazolate ligands, thus constructing flat two-dimensional layers that stack to form slit-like one-dimensional channels. Thermogravimetric analyses highlighted both the thermal stability and the permanent porosity of these two materials. Porosity was confirmed by N2 adsorption at 77 K, yielding Langmuir specific surface areas of 1923(3) m2 g−1 and 874(8) m2 g−1 for Ni-BTPP and Cu-BTPP, respectively. Additionally, Ni-BTPP adsorbed 1.73 mmol g−1 (7.6 wt%) of CO2 at the mild conditions of 298 K and 1 bar. [ABSTRACT FROM AUTHOR]

Copper(I) thiocyanate derivatives were prepared by the reaction of CuNCS with pyridine (py) and tertiary monophosphine ligands [PR3 in general; in detail: PPh3, triphenylphosphine, P(4-FPh)3, tris(4-fluorophenyl)phosphine)], as well as the potentially bidentate ligand diphenyl(2-pyridyl)phosphine (PPh2py). Mechanochemical methods were used in some cases to investigate stoichieometries that were not easily accessible by conventional solution syntheses. Three forms of the resulting adducts of CuNCS/PR3/py-base (1:3- n: n) stoichiometry-all containing four-coordinate copper(I) atoms and monodentate N-thiocyanate groups-were confirmed crystallographically. Mononuclear arrays are defined for [(PPh2py)3- n(py) nCu NCS], n = 0, 1, 2, the monodentate thiocyanate being N-coordinated in all; two polymorphs are observed for the n = 2 complex, both crystallizing in monoclinic P21 ( Z = 2) cells with similar cell dimensions, but with aromatic components eclipsed about the Cu-P bond in the PPh3 complex, and staggered in the PPh2py complex. Bridging thiocyanate groups are found in the 1:1:1 CuNCS/PPh2py/2-methylpyridine (mpy) and P(4-FPh)3/mpy complexes, wherein centrosymmetric dimers with eight-membered central rings are obtained: [(R3P)(mpy)Cu( NC S)2Cu(PR3)(mpy)], as is also the case in the parent 1:2 CuNCS/PPh2py adduct [(pyPh2P)2Cu( NC S)2Cu(PPh2py)2]. For the 1:1:1 Cu NC S/P(4-FPh)3/py and PPh3/Brmpy (Brmpy = 3-bromo-4-methylpyridine) adducts, and, likely, Cu NC S/PPh2py/py (1:1:1), single-stranded polymers of the form [ ···Cu( NC S)(PR3)(py-base)(Cu) ···](∞|∞) with linearly bridging NCS ligands were obtained. Some derivatives, representative of all forms, display medium to strong green to blue luminescence when excited with radiation at 365 nm. The 31P CPMAS NMR spectroscopic data clearly differentiate the inequivalent phosphorus positions within each system, showing a wide range of 1 J(31P,63/65Cu) values ranging from 965 Hz for [Cu( NCS)(PPh2py)3] to 1540 Hz for dimeric [(4-FPh)3P(mpy)Cu( NC S)2Cu(P(4-FPh)3)(mpy)], reflecting the large variations in the Cu-P bond length. [ABSTRACT FROM AUTHOR]

The reaction between the flexible,bis(pyrazolato)-based ligand4,4′-bis((3,5-dimethyl-1H-pyrazol-4-yl)methyl)biphenyl(H2DMPMB) and late transition metal ions allowed the isolationof the two series of thermally stable metal–organic frameworks [M(DMPMB)](M = Co, Zn, Cd) and [M2(DMPMB)](M = Cu, Ag). X-ray powder diffraction(XRPD) structure determinations demonstrated that the anticonformation adopted by the ligand, juxtaposed to its exo-tetradentate coordination mode, induces the formation of a 3-D architecturewith nonpervious 1-D channels in the three isomorphous species [M(DMPMB)]and of corrugated 2-D layers in [Cu2(DMPMB)]. Coupling thermogravimetricanalyses and variable temperature XRPD highlighted that the five materialsare thermally stable at least up to 300 °C, both under nitrogenand in air, the Cd(II) derivative decomposing only at the remarkablyhigh temperature of 500 °C. No thermal event could be detected;all the materials preserve their structural motifs up to decomposition.The adsorption properties of the five compounds were assayed toward N2at77 K: while no adsorption was observed for [Cd(DMPMB)], the other species possess estimated BET and Langmuir specific surfaceareas in the ranges 64(1)–526(3) m2/g and 142(4)–713(27)m2/g, respectively, thus being an example of the interestingphenomenon known as “porosity without pores”. Finally,the luminescence properties of the Zn(II), Cd(II), and Cu(I) derivativeswere investigated. [ABSTRACT FROM AUTHOR]

The solvothermal reaction betweenthe rigid spacer 3,3′,5,5′-tetramethyl-4,4′-bipyrazole(H2Me4BPZ) and a number of transition metalsalts promoted the formation of the coordination polymers [M(Me4BPZ)] (M = Zn, 1; Co, 2; Cd, 3; Cu, 4). Ab initioX-ray powderdiffraction analyses revealed the main structural aspects of the fourmaterials. 1and 2are representative examplesof the so-called isoreticular strategy: isostructural to [M(BPZ)]and [M(BDP)] (H2BPZ = 4,4′-bipyrazole; H2BDP = 1,4-bis(1H-pyrazol-4-yl)benzene), they featurethree-dimensional (3-D) porous networks containing square-shaped channels.In 3, tetrahedral Cd(II) ions are arranged within homochiralhelices reciprocally linked by radial Me4BPZ spacers, overallcreating a 3-D nonporous network. Finally, the 3-D porous frameworkof 4comprises square Cu4nodes linked toeight neighboring ones by the bridging spacers. Thermogravimetricanalyses, coupled to variable-temperature X-ray powder diffraction,demonstrated the remarkable thermal robustness of all the materials,decomposing above 300 °C, and their stability for consecutiveheating–cooling cycles. N2and CO2adsorptionmeasurements at 77 and 273 K, respectively, were employed to probethe permanent porosity of the materials and to give a coherent pictureof their textural properties including specific surface areas, micro-and mesopore volumes, as well as size distributions. [ABSTRACT FROM AUTHOR]

A family of fifteen quaternary ammonium salts (QAs), bearing the 1,2-bis(4-pyridyl)ethane core, were obtained using for the first time two different green methods, such as microwave (MW) and ultrasounds (US) irradiation, with very good yields and in much shorter times compared to the classical method, and an assay on their antimicrobial action against Escherichia coli (E. coli) was carried out. While 12 to 24 h were required for complete alkylation of 1,2-bis(4-pyridyl)ethane by reactive halogenated derivatives in anhydrous solvent under reflux conditions, MW and US irradiation reduced the reaction time and the desired products were achieved in a few min. One of the aims of this study was to evaluate the antibacterial potential of the synthesized QAs against pathogenic bacteria, along with their impact on germination activity of wheat seeds (Triticum aestivum L.). The antibacterial activity of the QAs against Escherichia coli was explored by determining the minimum inhibitory concentration (MIC). The MIC values varied from 0.312 to 2.5 mg/mL, highlighting the lowest values attained for the derivatives containing methoxy, chlorine and benzofurane functional groups. The viability of aerobic bacteria was determined with the Tetrazolium/Formazan Test, a method that was found to be the best alternative approach with respect to the difuzimetric method. Seeds of Triticum aestivum L. were used for the evaluation of the germination indicators, such as seed germination (SG), the relative seed germination (RSG), the relative radicle growth (RRG), and the seed germination index (GI). The toxicity studies of QAs 1, 4 and 7, at two different concentrations, showed no inhibitory effect on seed germination. [ABSTRACT FROM AUTHOR]

Adducts of a number of tertiary pnicogen ligands ER(3) (triphenyl-phosphine and -arsine (PPh(3),AsPh(3)), diphenyl,2-pyridylphosphine (PPh(2)py), tris(4-fluorophenyl)phosphine (P(C(6)H(4)-4F)(3)), tris(2-tolyl)phosphine (P(o-tol)(3)), tris(cyclohexyl)phosphine (PCy(3))), with silver(I) thiocyanate, AgSCN are structurally and spectroscopically characterized. The 1:3 AgSCN : ER(3) complexes structurally defined (for PPh(3),AsPh(3) (diversely solvated)) take the form [(R(3)E)(3)AgX], the thiocyanate X = NCS being N-bound, thus [(Ph(3)E)Ag(NCS)]. A 1:2 complex with PPh(2)py, takes the binuclear form [(pyPh(2)P)(2)Ag()Ag(PPh(2)py)(2)] with an eight-membered cyclic core. 1:1 complexes are defined with PPh(2)py, P(o-tol)(3) and PCy(3); binuclear forms [(R(3)P)Ag()Ag(PR(3))] are obtained with P(o-tol)(3) (two polymorphs), while novel isomeric tetranuclear forms, which may be envisaged as dimers of dimers, are obtained with PPh(2)py, and, as further polymorphs, with PCy(3); these latter may be considered as extensions of the 'cubane' and 'step' forms previously described for [(R(3)E)AgX](4) (X = halide) complexes. Solvent-assisted mechanochemical or solvent-assisted solid-state synthesis methods were employed in some cases, where complexes could not be obtained by conventional solution methods, or where such methods yielded a mixture of polymorphs unsuitable for solid-state spectroscopy. The wavenumbers of the ν(CN) bands in the IR spectra are in broad agreement with the empirical rule that distinguishes bridging from terminal bonding, but exceptions occur for compounds that have a double SCN bridged dimeric structure, and replacement of PPh(3) with PPh(2)py apparently causes a significant decrease in ν(CN) to well below the range expected for bridging SCN in these structures. (31)P CP MAS NMR spectra yield additional parameters that allow a correlation between the structures and spectra.