Exploring the Scope of Macrocyclic "Shoe-last" Templates in the Mechanochemical Synthesis of RHO Topology Zeolitic Imidazolate Frameworks (ZIFs)

The macrocyclic cavitand MeMeCH2 is used as a template for the mechanochemical synthesis of 0.2MeMeCH2@RHO-Zn16(Cl2Im)32 (0.2MeMeCH2@ZIF-71) and RHO-ZnBIm2 (ZIF-11) zeolitic imidazolate frameworks (ZIFs). It is shown that MeMeCH2 significantly accelerates the mechanochemical synthesis, providing high porosity products (BET surface areas of 1140 m2/g and 869 m2/g, respectively). Templation of RHO-topology ZIF frameworks constructed of linkers larger than benzimidazole (HBIm) was unsuccessful. It is also shown that cavitands other than MeMeCH2-namely MeHCH2, MeiBuCH2, HPhCH2, MePhCH2, BrPhCH2, BrC5CH2-can serve as effective templates for the synthesis of x(cavitand)@RHO-ZnIm2 products. The limitations on cavitand size and shape are explored in terms of their effectiveness as templates.

Manometric real-time studies of the mechanochemical synthesis of zeolitic imidazolate frameworks

We demonstrate a simple method for real-time monitoring of mechanochemical synthesis of metal–organic frameworks, by measuring changes in pressure of gas produced in the reaction. Using this manometric method to monitor the mechanosynthesis of the zeolitic imidazolate framework ZIF-8 from basic zinc carbonate reveals an intriguing feedback mechanism in which the initially formed ZIF-8 reacts with the CO₂ byproduct to produce a complex metal carbonate phase, the structure of which is determined directly from powder X-ray diffraction data. We also show that the formation of the carbonate phase may be prevented by addition of excess ligand. The excess ligand can subsequently be removed by sublimation, and reused. This enables not only the synthesis but also the purification, as well as the activation of the MOF to be performed entirely without solvent.

We demonstrate a simple method for real-time monitoring of mechanochemical synthesis of metal–organic frameworks, by measuring changes in pressure of gas produced in the reaction.

Synthesis and structure-activity relationship studies of small molecule disruptors of EWS-FLI1 interactions in Ewing's sarcoma

EWS-FLI1 is an oncogenic fusion protein implicated in the development of Ewing's sarcoma family tumors (ESFT). Using our previously reported lead compound 2 (YK-4-279), we designed and synthesized a focused library of analogues. The functional inhibition of the analogues was measured by an EWS-FLI1/NR0B1 reporter luciferase assay and a paired cell screening approach measuring effects on growth inhibition for human cells containing EWS-FLI1 (TC32 and TC71) and control PANC1 cell lines devoid of the oncoprotein. Our data revealed that substitution of electron donating groups at the para-position on the phenyl ring was the most favorable for inhibition of EWS-FLI1 by analogs of 2. Compound 9u (with a dimethylamino substitution) was the most active inhibitor with GI50 = 0.26 ± 0.1 μM. Further, a correlation of growth inhibition (EWS-FLI1 expressing TC32 cells) and the luciferase reporter activity was established (R(2) = 0.84). Finally, we designed and synthesized a biotinylated analogue and determined the binding affinity for recombinant EWS-FLI1 (Kd = 4.8 ± 2.6 μM).

Rim-functionalized cryptophane-111 derivatives via heterocapping, and their xenon complexes

Rim-functionalization of cryptophane-111 narrows the achievable conformational range of the cage, resulting in unprecedentedly crowded Xe@cryptophane complexes.

Methyl 2-(but-3-en-yl)-4-hy-droxy-1,1-dioxo-2H-1λ(6),2-benzothia-zine-3-carboxyl-ate

In the title compound, C₁₄H₁₅NO₅S, the thia­zine ring adopts a sofa conformation and an intra­molecular O—H⋯O hydrogen bond forms an S(6) ring. In the crystal, molecules are linked viaC—H⋯O inter­actions.

Methyl 4-hy-droxy-1,1-dioxo-2-(2-phenyl-eth-yl)-2H-1λ,2-benzothia-zine-3-carboxyl-ate

In the title compound, C₁₈H₁₇NO₅S, the thia­zine ring adopts a half-chair conformation and the dihedral angle between the aromatic rings is 79.41 (6)°. An intra­molecular O—H⋯O hydrogen bond generates an S(6) ring. In the crystal, mol­ecules are linked by weak C—H⋯O inter­actions resulting in infinite sheets along the b and c axes.

Miniemulsion synthesis of metal-oxo cluster containing copolymer nanobeads

Hybrid nanobeads containing either a manganese-oxo or manganese-iron-oxo cluster have been prepared via the miniemulsion polymerization technique. Two new ligand substituted oxo clusters, Mn(12)O(12)(VBA)(16)(H(2)O)(4) and Mn(8)Fe(4)O(12)(VBA)(16)(H(2)O)(4) (where VBA = 4-vinylbenzoate), have been prepared and characterized. Polymerization of the functionalized metal-oxo clusters with styrene under miniemulsion conditions produced monodispersed polymer nanoparticles as small as ~60 nm in diameter. The metal-oxo polymer nanobeads were fully characterized in terms of synthetic parameters, composition, structure, and magnetic properties.

N-(2-Bromo-phen-yl)-4-methyl-N-(4-methyl-phen-ylsulfon-yl)benzene-sulfonamide

In the title compound, C₂₀H₁₈BrNO₄S₂, the mean planes formed by the toluene substituents are inclined at a dihedral angle of 45.34 (8)°. The bromo­benzene group is disordered over two positions with an occupancy ratio of 0.74:0.26, resulting in two conformations of the ring; the two rings are oriented at a dihedral angle of 6.6 (6)° with each other. In the crystal structure, weak C—H⋯O inter­actions connect the mol­ecules in a zigzag manner along the a axis.

Reversible phase transitions within self-assembled fibrillar networks of (R)-18-(n-alkylamino)octadecan-7-ols in their carbon tetrachloride gels

The CCl(4) gel phases of a series of low-molecular-mass organogelators, (R)-18-(n-alkylamino)octadecan-7-ols (HSN-n, where n = 0-5, 18 is the alkyl chain length), appear to be unprecedented in that the fibrillar networks of some of the homologues undergo thermally reversible, gel-to-gel phase transitions, and some of those transitions are evident as opaque-transparent changes in the appearance of the samples. The gels have been examined at different concentrations and temperatures by a wide variety of spectroscopic, diffraction, thermal, and rheological techniques. Analyses of those data and data from the neat gelators have led to an understanding of the source of the gel-to-gel transitions. IR and SANS data implicate the expulsion (on heating the lower-temperature gel) or the inclusion (on cooling the higher-temperature gel) of molecules of CCl(4) that are interspersed between fibers in bundles. However, the root cause of the transitions is a consequence of changes in the molecular packing of the HSN-n within the fibers. This study offers opportunities to design new gelators that are capable of behaving in multiple fashions without entering the sol/solution phase, and it identifies a heretofore unknown transformation of organogels.

Methyl 4-hydroxy-2-isopropyl-1,1-dioxo-2H-1,2-benzothiazine-3-carboxylate

In the crystal structure of the title mol­ecule, C₁₃H₁₅NO₅S, the S and N atoms of the thia­zine ring exihibit the maximum deviations from the least-squares plane of 0.3008 (6) and 0.3280 (7) Å, respectively. The ring therefore adopts a half chair conformation. The thia­zine ring is twisted by an angle of 13.29 (7)° with respect to the aromatic ring. The isopropyl substituent is oriented at a dihedral angle of 53.2 (12)° with respect to the thia­zine ring. An intra­molecular O—H⋯O hydrogen bond occurs. Inter­molecular hydrogen bonding is observed in the crystal structure.

A water-soluble Xe@cryptophane-111 complex exhibits very high thermodynamic stability and a peculiar (129)Xe NMR chemical shift

The known xenon-binding (±)-cryptophane-111 (1) has been functionalized with six [(η(5)-C(5)Me(5))Ru(II)](+) ([Cp*Ru](+)) moieties to give, in 89% yield, the first water-soluble cryptophane-111 derivative, namely [(Cp*Ru)(6)1]Cl(6) ([2]Cl(6)). [2]Cl(6) exhibits a very high affinity for xenon in water, with a binding constant of 2.9(2) × 10(4) M(-1) as measured by hyperpolarized (129)Xe NMR spectroscopy. The (129)Xe NMR chemical shift of the aqueous Xe@[2](6+) species (308 ppm) resonates over 275 ppm downfield of the parent Xe@1 species in (CDCl(2))(2) and greatly broadens the practical (129)Xe NMR chemical shift range made available by xenon-binding molecular hosts. Single crystal structures of [2][CF(3)SO(3)](6)·xsolvent and 0.75H(2)O@1·2CHCl(3) reveal the ability of the cryptophane-111 core to adapt its conformation to guests.

(2S)-3-Carbamoyl-2-(4-meth-oxy-benzene-sulfonamido)-propanoic acid

In the title compound, C(11)H(14)N(2)O(6)S, an amino acid-derived sulfonamide, the acetamido group and the carb-oxy-lic group are oriented at dihedral angles of 45.84 (5)° and 47.97 (5)° respectively, with respect to the aromatic ring. In the crystal, the mol-ecules are connected by N-H⋯O and O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions, forming a three-dimensional network.

2-[4-(2,6-Dimethoxyphenyl)butyl]-1,3-dimethoxybenzene

The title compound, C₂₀H₂₆O₄, crystallizes such that the alkyl chain adopts an all-anti conformation. The crystal packing displays edge-to-face arene–arene inter­actions with a dihedral angle of 87°. The complete molecule is generated by inversion symmetry.

1,3-Bis(bromomethyl)-2-nitrobenzene

In the title compound, C₈H₇Br₂NO₂, an inter­mediate for the synthesis of macrocycles, the NO₂ group makes a dihedral angle of 65.07 (19)° with the arene ring, and the bromo­methyl substituents adopt a trans conformation about the ring such that the mol­ecule closely approximates C2 symmetry.

(1E,3E,5E,7E)-4,4'-(Octa-1,3,5,7-tetra-ene-1,8-di-yl)dipyridine

The title compound, C₁₈H₁₆N₂, crystallizes with one and a half independent mol­ecules in the asymmetric unit, with the half-mol­ecule being completed by crystallographic inversion symmetry. Both independent mol­ecules are almost planar, with the non-H atoms exhibiting r.m.s. deviations from the least-squares mol­ecular plane of 0.175 and 0.118 Å, respectively.

An achiral form of the hexameric resorcin[4]arene capsule sustained by hydrogen bonding with alcohols

The well-known hexameric capsules sustained by self-assembly of resorcin[4]arenes 1 with water molecules (1(6).(H2O)8) are shown to assemble similarly with (+/-)-2-ethylhexanol (2EH) as an achiral 1(6).(2EH)6.(H2O)2 species which further encapsulates 2EH.

Selective Anion Encapsulation by a Metalated Cryptophane with a π-Acidic Interior

Metalation of the exterior arene faces of the molecular capsule (+/-)-cryptophane-E with [Cp*Ru]+ moieties results in a pi-acidic cavity capable of encapsulating anions. The [CF3SO3]- and [SbF6]- salts have been crystallographically characterized and demonstrate the encapsulation of these anions by the metalated cryptophane. 1H and 19F NMR spectroscopy establish the binding of anions in NO2CD3 solution and reveal the relative affinity of the cavity for different anions (KX-/KOTf-): [BF4]- approximately 0, [PF6]- = 1.18, [CF3SO3]- identical with 1, [SbF6]- = 0.30. Variable temperature rate studies reveal the activation barrier for triflate encapsulation to be DeltaG298K = 18.0(8) kcal.mol-1 (DeltaH = 17.5(4) kcal.mol-1 and DeltaS = 2(1) cal.mol-1.K-1).

Multiple nitrene insertions into metal-sulfur bonds of dithiocarbamate complexes: synthesis of sulfido-amido and zwitterionic tetraamido complexes

The iodine(III) reagent, PhI[double bond, length as m-dash]NTs, acts as a source of the nitrene fragment NTs, which undergoes facile insertion into the metal-sulfur bonds of a range of dithiocarbamate complexes. Addition of two equivalents of PhI=NTs to [M(S(2)CNR2)2] affords sulfido-amido complexes [M{SC(NR2)SNTs}2](M=Ni, Cu), which insert two further nitrene fragments to afford zwitterionic tetraamido complexes [M{TsNSC(NR2)SNTs}2](M=Co, Ni, Cu). Crystallographic studies have been carried out on both types of complex allowing possible resonance hydrids of the new ligand types to be assessed.