LEGO® bricks as building blocks for centimeter-scale biological environments

LEGO bricks are commercially available interlocking pieces of plastic that are conventionally used as toys. We describe their use to build engineered environments for cm-scale biological systems, in particular plant roots. Specifically, we take advantage of the unique modularity of these building blocks to create inexpensive, transparent, reconfigurable, and highly scalable environments for plant growth in which structural obstacles and chemical gradients can be precisely engineered to mimic soil.

Organically-functionalised supertetrahedra as building blocks for hybrid materials

The crystal structures of gallium sulfides prepared under solvothermal conditions, using 4-picoline as a solvent, are described. These materials contain [Ga10S16(NC6H7)4]2− clusters, in which the terminal S2− anions have been replaced by covalently bonded 4-picoline molecules. Whilst these phases contain isolated supertetrahedral clusters separated by organic moieties, linkage of such clusters via organic ligands is possible under suitable reaction conditions. These organically-functionalised supertetrahedra could therefore be used to design novel Metal-Organic frameworks (MOFs) in which the normally-encountered metal centers are replaced by supertetrahedral clusters.

The use of colloidal ferrofluid as building blocks for nanostructured layer-by-layer films fabrication

The electrostatic layer-by-layer technique has been exploited as an useful strategy for fabrication of nanostructured thin films, in which specific properties can be controlled at the molecular level. Ferrofluids consist of a colloidal suspension of magnetic grains (with only a few nanometers of diameter) with present interesting physical properties and applications, ranging from telecommunication to drug delivery systems. In this article, we developed a new strategy to manipulate ferrofluids upon their immobilization in nanostructured layered films in conjunction with conventional polyelectrolytes using the layer-by-layer technique. We investigated the morphological, optical, and magnetic properties of the immobilized ferrofluid as a function of number of bilayers presented in the films. Ferrofluid/polyelectrolyte multilayers homogeneously covered the substrates surface, and the magnetic and optical properties of films exhibited a linear dependence on the number of bilayers adsorbed.

Synthesis and structure of 1,3,5-tris(diorganohydroxysilyl)benzenes. Novel building blocks in supramolecular silanol chemistry

The 1,3,5-tris(diorganohydroxysilyl)benzenes 1,3,5-(HOR₂Si)₃C₆H₃ (TMSB, R = Me; TPSB, R = Ph) have been prepared and fully characterized by X-ray crystallography. The crystal structure of TMSB features pairwise connected layers, in which the molecules are involved in interlayer hydrogen bonding. The supramolecular hydrogen bond motif may be described as a 12-membered ring that adopts a chair conformation. TPSB forms an equimolar inclusion complex with water, which is associated via hydrogen bonding and apparently fills a void in the crystal packing. In this case, the supramolecular hydrogen bond motif may be described as an eight-membered ring. Two of the water molecules are also associated, giving rise to a water dimer entrapped in the silanol matrix. Besides the hydrogen bonds, the crystal structure of the TPSB·H₂O complex reveals intra- and intermolecular C-H··· π stacking of most of the phenyl groups. Electrospray mass spectrometry shows that TPSB undergoes supramolecular complex formation with a variety of N-donors such as 4-(dimethylamino)pyridine, N,N,N',N'-tetramethylethylenediamine, imidazole, 2-(dimethylamino)pyridine, and 2,2'-dipyridylamine.

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Novel organotin and organotellurium complexes : building blocks for new materials?

The research produced a series of novel oranotin and organotellurium compounds that are potential building blocks for new materials. In particular, one carbonate cluster has practical applications in the fixation and recovery of carbon dioxide gas from the atmosphere.

Polymeric colorants: Statistical copolymers of indigo building blocks with defined structures

Statistical copolymers of indigo (1a) and N-acetylindigo (1b) building blocks with defined structures were studied. They belong to the class of polymeric colorants. The polymers consist of 5,5′-connected indigo units with keto structure and N-acetylindigo units with uncommon tautomeric indoxyl/indolone (=1H-indol-3-ol/3H-indol-3-one) structure (see 2a and 2b in Fig. 1). They formed amorphous salts of elongated monomer lengths as compared to monomeric indigo. The polymers were studied by various spectroscopic and physico-chemical methods in solid state and in solution. As shown by small-angle-neutron scattering (SANS) and transmission-electron microscopy (TEM), disk-like polymeric aggregates were present in concentrated solutions (DMSO and aq. NaOH soln.). Their thickness and radii were determined to be ca. 0.4 and ca. 80 nm, respectively. From the disk volumes and by a Guinier analysis, the molecular masses of the aggregates were calculated, which were in good agreement with each other. Defined structural changes of the polymer chains were observed during several-weeks storage in concentrated DMSO solutions. The original keto structure of the unsubstituted indigo building blocks reverted to the more flexible indoxyl/indolone structure. The new polymers were simultaneously stabilized by intermolecular H-bonds to give aggregates, preferentially dimers. Both aggregation and tautomerization were reversible upon dissolution. The polymers were synthesized by repeated oxidative coupling of 1,1′-diacetyl-3,3′-dihydroxybis-indoles 5 (from 1,1′-diacetyl-3,3′-bis(acetyloxy)bis-indoles 6) followed by gradual hydrolysis of the primarily formed poly(N,N′-diacetylindigos) 7 (Scheme). N,N′-Diacetylbis-anthranilic acids 9 were isolated as by-products.

Facile synthesis of guanidine functionalised building blocks

Three useful developments in the preparation of guanidines are presented herein. A collection of bis(Boc)aminoalkylguanidines (n=2, 3, 4 and 6; Boc=tert-butoxycarbonyl), known to be prone to cyclisation, have been synthesised and isolated without chromatography as shelf-stable sulfonate salts in good yield (up to 94%). Secondly, a selection of guanidines tethered to a range of other functional groups, including alkyne, alkene, alcohol, and azide, have been prepared in good yields with no requirement for a purification step, and thirdly an inexpensive, high-yielding (93%), and facile synthesis of N,N'-bis(Boc)guanidine, a key precursor for N,N'-bis(Boc)-N'-triflylguanidine, is described in which the need for chromatographic purification is again obviated.

Thermo-Reversible Sol-Gel Transition of Surface Modified Titanium Poly Oxo Building Blocks

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Níquel (II) e moléculas orgânicas multidentadas como building blocks na construção de sólidos de coordenação porosos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electropolymerization using binuclear nickel(II) Schiff base complexes bearing N4O4 donors as supramolecular building blocks

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)