A stacked Ag3–Au3bonded (66 kcal mol−1) complex obtained crystallographically exhibits charge-transfer characteristics arising from multiple cooperative supramolecular interactions.

The trinuclear triangle-shaped system [tris{3,5-bis(heptafluoropropyl)-1,2,4-triazolatosilver(I)}] (1) and the multi-armed square-shaped metalloporphyrin PtOEP or the free porphyrin base H2OEP serve as excellent octopus hosts (OEP=2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine). Coupling of the fluorous/organic molecular octopi 1 and H2OEP or PtOEP by strong quadrupole-quadrupole and metal-π interactions affords the supramolecular assemblies [1⋅PtOEP] or [1⋅H2OEP] (2 a), which feature nanoscopic cavities surrounding the upper triangular and lower square cores. The fluorous/organic biphasic configuration of [1⋅PtOEP] leads to an increase in the phosphorescence of PtOEP under ambient conditions. Guest molecules can be included in the biphasic double-octopus assembly in three different site-selective modes.

AbstractReview: recent advances of fluorous metal‐organic frameworks as porous solids and lighemitting properties; 10 refs.

Supramolecular octopus couples form when a positively quadrupolar cyclic AgI–triazolate trimer with fluorous octopus arms electrostatically attracts a negatively quadrupolar free porphyrin or a PtII porphyrin with shorter alkyl octopus arms. In their Communication on page 4842 ff., C. Yang, M. A. Omary et al. show that in this system, the phosphorescence of the PtII porphyrin is enhanced under ambient conditions as O2 and self-quenching processes are suppressed.

Water cluster formation and methane adsorption within a hydrophobic porous metal organic framework is studied by in situ vibrational spectroscopy, adsorption isotherms, and first-principle DFT calculations (using dW-DF). Specifically, the formation and stability of H2O clusters in the hydrophobic cavities of a fluorinated metal organic framework (FMOF-1) is examined. Although the isotherms of water show no measurable uptake (see Yang et al. J. Am. Chem. Soc. 2011, 133, 18094), the large dipole of the water internal modes makes it possible to detect low water concentrations using IR spectroscopy in pores in the vicinity of the surface of the solid framework. The results indicate that, even in the low pressure regime (100 mTorr to 3 Torr), water molecules preferentially occupy the large cavities, in which hydrogen bonding and wall hydrophobicity foster water cluster formation. We identify the formation of pentameric water clusters at pressures lower than 3 Torr and larger clusters beyond that pressure. The binding energy of the water species to the walls is negligible, as suggested by DFT computational findings and corroborated by IR absorption data. Consequently, intermolecular hydrogen bonding dominates, enhancing water cluster stability as the size of the cluster increases. The formation of water clusters with negligible perturbation from the host may allow a quantitative comparison with experimental environmental studies on larger clusters that are in low concentrations in the atmosphere. The stability of the water clusters was studied as a function of pressure reduction and in the presence of methane gas. Methane adsorption isotherms for activated FMOF-1 attained volumetric adsorption capacities ranging from 67 V(STP)/V at 288 K and 31 bar to 133 V(STP)/V at 173 K and 5 bar, with an isosteric heat of adsorption of ca. 14 kJ/mol in the high temperature range (288-318 K). Overall, the experimental and computational data suggest high preferential uptake for methane gas relative to water vapor within FMOF-1 pores with ease of desorption and high framework stability under operative temperature and moisture conditions.

We demonstrate that fluorous metal-organic frameworks (FMOFs) are highly hydrophobic porous materials with a high capacity and affinity to C(6)-C(8) hydrocarbons of oil components. FMOF-1 exhibits reversible adsorption with a high capacity for n-hexane, cyclohexane, benzene, toluene, and p-xylene, with no detectable water adsorption even at near 100% relative humidity, drastically outperforming activated carbon and zeolite porous materials. FMOF-2, obtained from annealing FMOF-1, shows enlarged cages and channels with double toluene adsorption vs FMOF-1 based on crystal structures. The results suggest great promise for FMOFs in applications such as removal of organic pollutants from oil spills or ambient humid air, hydrocarbon storage and transportation, water purification, etc. under practical working conditions.

1,6-Bis(trimethylammonium)hexane bis(trihalides) 1•(Br 2 ) 2 and mixed bis(trihalides) 2•(I 2 ) 2 and 2•(Br 2 ) 2 have been synthesized by treating the corresponding dihydrated halides 1•(H 2 O) 2 and 2•(H 2 O) 2 with molecular dihalogens (e.g., Br 2 and I 2 ) under gas-solid and solution conditions (Figure 1).[1]Despite the fact that the starting hexamethonium halides are non porous, the trihalides syntheses occur homogeneously, in quantitative yields, and reversibly.In all the cases the halogen bond [2] prevails over the hydrogen bond, and the hydrogen bonded water in the starting material is substituted by the halogen bonded dihalogens to form the crystalline trihalides.The stability of the trihalides is mainly due to cooperative halogen bond and cation templation effect [3].Hexamethonium halides are proven effective solids for the clathration and storage of molecular dihalogens.While the starting salts are not isostructural, all the formed trihalides and mixed trihalides are isostructural.Single crystal X-ray diffraction, powder X-ray diffraction and Raman experiments have confirmed the formation of the solid trihalides.The method we describe is general and can be extended to the preparation of various uncommon trihalides species like interconversion of trihalides and mixed trihalides via solidgas processes.

[(3,5-(CF(3))(2)Pz)(AgL)(2)](+)[Ag(5)(3,5-(CF(3))(2)Pz)(6)(CH(3)CN)](-) (L = 2-(N,N-diethylanilino-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) shows bright and tunable emissions influenced by its supramolecular structure. Columnar stacks are assembled via cooperative interactions that include Ag(I)···Ag(I) argentophilic bonding, π···π stacking and Ag(I)···π interactions.

Playing accordion: Cooling a single crystal of a microporous fluorous metal-organic framework under ambient atmosphere leads to very large breathing upon gas adsorption, during which multiple N(2) molecules are filled into channels and cages (see picture). While the framework exhibits remarkable positive thermal expansion under vacuum, a gigantic apparent negative thermal expansion takes place when the crystal is exposed to N(2) at ambient pressure.