Fourfold Suzuki-Miyaura and Sonogashira Cross-Coupling Reactions on Tetrahedral Methane and Adamantane Derivatives

Targeted Synthesis of Interpenetration-Free Mesoporous Aromatic Frameworks by Manipulating Catalysts as Templates

Reticular chemistry allows the design and synthesis of mesoporous networks by extending the size of the building blocks. However, interpenetration of the nets easily happens against the designed mesoporous networks, thereby falling short of achieving the intended specific surface area and pore size. Controlling the framework interpenetration has always been a challenge in the synthesis section of reticular chemistry. In this work, based on our previously reported type of highly porous aromatic frameworks (named PAF-1), we extended the tetrahedral building blocks to target an iso-reticular mesoporous PAF-333. A series of Ni(0) ligands with different sizes were employed to confirm that suitable-sized catalyst ligands could successfully inhibit skeleton interpenetration in the coupling reaction through the steric hindrance effect. The obtained mesoporous PAF-333 possessed a pore size of approximately 3.2 nm matching well with the value from the predicted non-interpenetrated structure. PAF-333 showed great high-pressure hydrogen and methane storage potential with a 13.4 wt % H2 uptake at 77 K, 100 bar and a 0.537 g g-1 CH4 uptake at 298 K, 98 bar, ranking at the top of the reported porous adsorbents in the gas storage applications.

Adamantane-type clusters: compounds with a ubiquitous architecture but a wide variety of compositions and unexpected materials properties

The research into adamantane-type compounds has gained momentum in recent years, yielding remarkable new applications for this class of materials. In particular, organic adamantane derivatives (AdR4) or inorganic adamantane-type compounds of the general formula [(RT)4E6] (R: organic substituent; T: group 14 atom C, Si, Ge, Sn; E: chalcogenide atom S, Se, Te, or CH2) were shown to exhibit strong nonlinear optical (NLO) properties, either second-harmonic generation (SHG) or an unprecedented type of highly-directed white-light generation (WLG) - depending on their respective crystalline or amorphous nature. The (missing) crystallinity, as well as the maximum wavelengths of the optical transitions, are controlled by the clusters' elemental composition and by the nature of the organic groups R. Very recently, it has been additionally shown that cluster cores with increased inhomogeneity, like the one in compounds [RSi{CH2Sn(E)R'}3], not only affect the chemical properties, such as increased robustness and reversible melting behaviour, but that such 'cluster glasses' form a conceptually new basis for their use in light conversion devices. These findings are likely only the tip of the iceberg, as beside elemental combinations including group 14 and group 16 elements, many more adamantane-type clusters (on the one hand) and related architectures representing extensions of adamantane-type clusters (on the other hand) are known, but have not yet been addressed in terms of their opto-electronic properties. In this review, we therefore present a survey of all known classes of adanmantane-type compounds and their respective synthetic access as well as their optical properties, if reported.

Non-porous organic crystals and their interaction with guest molecules from the gas phase

Some organic molecules encapsulate solvents upon crystallization. One class of compounds that shows a high propensity to form such crystalline solvates are tetraaryladamantanes (TAAs). Recently, tetrakis(dialkoxyphenyl)-adamantanes have been shown to encapsulate a wide range of guest molecules in their crystals, and to stabilize the guest molecules against undesired reactions. The term ‘encapsulating organic crystals’ (EnOCs) has been coined for these species. In this work, we studied the behavior of three TAAs upon exposition to different guest molecules by means of sorption technique. We firstly measured the vapor adsorption/desorption isotherms with water, tetrahydrofuran and toluene, and secondly, we studied the uptake of methane on dry and wet TAAs. Uptake of methane beyond one molar equivalent was detected for wet crystals, even though the materials showed a lack of porosity. Thus far, such behavior, which we ascribe to methane hydrate formation, had been described for porous non-crystalline materials or crystals with detectable porosity, not for non-porous organic crystals. Our results show that TAA crystals have interesting properties beyond the formation of conventional solvates. Gas-containing organic crystals may find application as reservoirs for gases that are difficult to encapsulate or are slow to form crystalline hydrates in the absence of a host compound.

Wet tetraaryladamantane crystals take up methane in form of methane hydrate structure I, even though they appear non-porous to argon.

Diamondoid architectures from halogen-bonded halides

Halide ions and tetraiodoethynyl-featured tetraphenylmethane are successfully assembled into robust diamond-like networks in the presence of tetraphenylphosphonium cations.

The synthesis of flexible tetrapyridylethanes from pyridylpyrylium dications

Novel tetrapyridylethanes and bis-phenylpyridylmethylenepyrans as potential ligands for coordination chemistry.

Design of 3D 1,3,5,7-tetraphenyladamantane-based covalent organic frameworks as hydrogen storage materials

Four 1,3,5,7-tetraphenyladamantane-based covalent organic frameworks (adm-COFs) have been designed with ctn or bor net topology as hydrogen storage materials.

Solution-phase synthesis of branched DNA hybrids via H-phosphonate dimers

A method for the solution-phase synthesis of branched oligonucleotides with tetrahedral or pseudo-octahedral geometry is described that involves the coupling of 3'-H-phosphonates of protected dinucleoside phosphates and organic core molecules. The dimer building blocks are produced by a synthesis that requires no chromatographic purification and that produces the dimer H-phosphonates in up to 44% yield in less than three days of laboratory work. A total of seven different branched hybrids were prepared, including a new hybrid of the sequence (CG)(4)TBA, where TBA stands for tetrakis(p-hydroxybiphenyl)adamantane that assembles into a material from micromolar aqueous solution upon addition of MgCl(2).