The new ligands bis(pyrazol-1-yl)(pyridine-4yl)methane (bpzm4py) (L1) and bis(3,5-dimethylpyrazol-1yl)(pyridine-4-yl)methane (bpz*m4py) (L2) were synthesized and were made to react with different metallic starting materials. In the case of Pd(II), chloride or allyl trinuclear complexes were synthesized, in which the central palladium is bonded to two ligands through the pyridine moiety. Mononuclear [Pd(allyl)L]X complexes were also isolated. On using other M(II) centers (M = Co, Ni, Zn), which could adopt an octahedral geometry, box-like cyclic dimers formed by the self-assembly of two metal centers and two ligands in a head-to-tail disposition were obtained. All metal ions exhibited a distorted octahedral geometry. A complex of Ag(I) with similar cyclic dimers connected through difluorophosphate anions to generate zigzag chains was also crystallized. The silver center was five-coordinate and the chain interactions gave rise to the formation of sheets. In the solid state, different noncovalent interactions were present in the molecular and supramolecular structures, including hydrogen bonds, π−π stacking and anion−π or CH−π interactions. Examples of possible synergy between some of these interactions were found. Where possible, the solution chemistry was analyzed and correlated with the solid state structure. The existence of polynuclear species in solution was evaluated and the effect of some noncovalent interactions on the NMR resonances was observed.

The silver-nucleoside complex [Ag(i)-(N3-cytidine)2]+, 1, self-assembles to form a supramolecular metal-mediated base-pair array highly analogous to those seen in metallo-DNA.

Fabrication of macro-scale polysaccharide, proteinaceous, micellular and covalently crosslinked hydrogels for housing cell-free protein synthesis reactions.

Mesoporous carbonaceous materials (Starbons®) derived from low-value/waste bio-resources separate CO2 from CO2 /N2 mixtures. Compared to Norit activated charcoal (AC), Starbons® have much lower microporosities (8-32 % versus 73 %) yet adsorb up to 65 % more CO2 . The presence of interconnected micropores and mesopores is responsible for the enhanced CO2 adsorption. The Starbons® also showed three-four times higher selectivity for CO2 adsorption rather than N2 adsorption compared to AC.

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The self-assembly of the ligands bis(pyrazol-1-yl)(pyridine-4-yl)methane (L 1 ) and bis(3,5-dimethylpyrazol-1-yl)(pyridine-4-yl)methane (L 2 ) with AgBF4 leads to three types of species: L1 gives rise to the formation of a boxlike cyclic dimer (1) while L 2 leads to two different coordination polymers that are sequence isomers. With dependence on the crystallization conditions, either a homochiral helix (2) with spontaneous resolution or a zigzag polymer is formed (3). By means of solid-state circular dichroism studies, the presence of both enantiomers in 2 is observed, enriched locally in colonies of crystals. The homochiral motif is stable, even upon removal of guest solvent molecules. The noncovalent interactions in the crystalline structure are clearly affected by the presence of the methyl groups on the pyrazolyl rings. The behavior of the compounds in solution is discussed.

The new ligands bis­(pyrazol-1-yl)­(pyridine-3-yl)­methane (bpzm3py, 1) and bis­(3,5-dimethylpyrazol-1-yl)­(pyridine-3-yl)­methane (bpz*m3py, 2) have been synthesized. Box-like cyclic dimers have been obtained by reaction of the ligands with Zn­(NO3)2, namely, [Zn­(NO3)2L]2 (L = 1, complex 3; L = 2, complex 4), after the self-assembly of two metal centers and two ligands in a head-to-tail fashion. In 3 and 4 the pyridine rings exhibit planar chirality and the two pR,pR and pS,pS enantiomers coexist in the crystal. A two-step self-assembly process using 3 as an SBU and sodium 1,4-benzenedicarboxylate (Na2BDC) as a linker leads to the formation of hexanuclear cyclic helicates with a distorted trigonal prism form [Zn2(BDC)­(1)2(H2O)4]3(BDC)3 (5) constituted by cyclic dimers and μ2,κ2-BDC connectors that are oriented diagonally. The chiral recognition that is observed means that the three dimers of the helicate have the same chirality. In the 3-D structure, chains of helicates of the same chirality are formed and these interdigitate with chains of opposite chirality connected by hydrogen bonds and through a column of π–π stacking interactions involving alternate pyridine and benzene rings.

A study of the self-assembly of different silver salts and the potentially ditopic ligands bis­(pyrazol-1-yl)­(pyridine-4-yl)­methane (L1) and bis­(3,5-dimethylpyrazol-1-yl)­(pyridine-4-yl)­methane (L2) was undertaken and species’ with discrete or polymeric structures were obtained. Reactions with L1 always yielded derivatives that had a box-like cyclic dimer structure with two metal centers and two ligands. However, on using ligand L2, the resulting structure strongly depended on the coordination ability of the anion. On using anions that have coordinating ability (X = NO3 –, CF3SO3 –, PF2O2 –), a similar box-like structure was formed. However, the use of anions with lower coordinating ability (X = PF6 –, ClO4 –) led to coordination polymers with a helical disposition. Spontaneous resolution was observed in the two compounds, and only one enantiomer was present in the crystals studied. Solid-state circular dichroism spectroscopy was applied to bunches of crystals, and the results indicate that growth of single colonies of homochiral crystals starting from single nucleation points may take place. When the helical complexes were recrystallized, box-like cyclic dimers were obtained. The presence or absence of methyl groups on the pyrazolyl rings had a strong influence on the supramolecular structure. In solution, the box-like dimers containing L1 were more stable than those of L2.