Chiral Cocrystal Solid Solutions, Molecular Complexes, and Salts of N-Triphenylacetyl-l-Tyrosine and Diamines

The molecular recognition process and the ability to form multicomponent supramolecular systems have been investigated for the amide of triphenylacetic acid and l-tyrosine (N-triphenylacetyl-l-tyrosine, TrCOTyr). The presence of several supramolecular synthons within the same amide molecule allows the formation of various multicomponent crystals, where TrCOTyr serves as a chiral host. Isostructural crystals of solvates with methanol and ethanol and a series of binary crystalline molecular complexes with selected organic diamines (1,5-naphthyridine, quinoxaline, 4,4′-bipyridyl, and DABCO) were obtained. The structures of the crystals were planned based on non-covalent interactions (O–H···N or N–H+···O− hydrogen bonds) present in a basic structural motif, which is a heterotrimeric building block consisting of two molecules of the host and one molecule of the guest. The complex of TrCOTyr with DABCO is an exception. The anionic dimers built off the TrCOTyr molecules form a supramolecular gutter, with trityl groups located on the edge and filled by DABCO cationic dimers. Whereas most of the racemic mixtures crystallize as racemic crystals or as conglomerates, the additional tests carried out for racemic N-triphenylacetyl-tyrosine (rac-TrCOTyr) showed that the compound crystallizes as a solid solution of enantiomers.

On-Demand Guest Release from MOF-5 Sealed with Nitrophenylacetic Acid Photocapping Groups

Recently, we demonstrated that triphenylacetic acid could be used to seal dye molecules within MOF-5, but guest release required digestion of the framework by treatment with acid. We prepared the sterically bulky photocapping group [bis-(3-nitro-benzyl)-amino]-(3-nitro-phenyl)-acetic acid (PC1) can prevent Crystal violet dye diffusion from inside MOF-5 until removed by photolysis.

On-Demand Guest Release from MOF-5 Sealed with Nitrophenylacetic Acid Photocapping Groups

Recently, we demonstrated that triphenylacetic acid could be used to seal dye molecules within MOF-5, but guest release required digestion of the framework by treatment with acid. We prepared the sterically bulky photocapping group [bis-(3-nitro-benzyl)-amino]-(3-nitro-phenyl)-acetic acid (PC1) can prevent Crystal violet dye diffusion from inside MOF-5 until removed by photolysis.

Crystal structure of bis(μ2-methanolato-κO:κO)hexamethylbis(μ2-triphenylacetato-κO:κO′)bis(μ2-triphenylacetato-κ2 O,O′:κO)dialuminiumdilanthanum toluene tetrasolvate

The title compound, [Al2La2(C20H15O2)4(CH3)6(CH3O)2]·4CH3C6H5 or [{La(Ph3CCOO)2(Me3AlOMe)}2]·4CH3C6H5, was formed in a reaction between lanthanum tris(tetramethylaluminate) and triphenylacetic acid (1:1) with unintended partial oxidation. The triphenylacetate ligand exhibits μ2-κ1 O:κ1 O′ bridging and μ2-κ2 O,O′:κ1 O semi-bridging coordination modes, forming a dimeric La2(μ-OCO)4 core. The semi-bridging triphenylacetate group provides additional bonding with an La3+ cation via the π-system of one of its phenyl rings. The trimethylmethoxyaluminate anion, which is coordinated to the La3+ cation by its O atom, displays a rather long La—CMe bond. Two toluene molecules are each disordered over two orientations about centres of symmetry with site occupancy factors of 0.5. The title compound represents the first example of an LnIII complex containing both alkyl alkoxide aluminate and π-bounded arene fragments.