Crystal structure of an aceto-nitrile solvate of 2-(3,4,5-triphen-ylphen-yl)acetic acid.

Crystal growth of 2-(3,4,5-triphen-ylphen-yl)acetic acid () from aceto-nitrile yields a monosolvate, CHO·CHCN, of the space group 1. In the crystal, the title mol-ecule adopts a conformation in which the three phenyl rings are arranged in a paddlewheel-like fashion around the central arene ring and the carboxyl residue is oriented nearly perpendicular to the plane of this benzene ring. Inversion-symmetric dimers of O-H⋯O-bonded mol-ecules of represent the basic supra-molecular entities of the crystal structure.

Compounds Derived from 9,9-Dialkylfluorenes: Syntheses, Crystal Structures and Initial Binding Studies (Part II).

New representatives of 2,4,7-trisubstituted 9,9-dialkyl-9H-fluorenes were prepared and used for crystallographic investigations as well as initial binding studies towards metal ions and carbohydrates. The binding studies, which included H NMR spectroscopic titrations and fluorescence measurements, demonstrated the ability of the tested fluorene-based compounds to act as complexing agents for ionic and neutral substrates. Depending on the nature of the subunits of the fluorene derivatives, "turn on" or "turn off" fluorescent chemosensors can be developed.

Crystal structure of 9,9-di-ethyl-9-fluorene-2,4,7-tricarbaldehyde.

The title compound, CHO, crystallizes in the space group 2/ with one mol-ecule in the asymmetric unit of the cell. The fluorene skeleton is nearly planar and the crystal structure is composed of mol-ecular layers extending parallel to the (302) plane. Within a layer, one formyl oxygen atom participates in the formation of a C-H⋯O bond, which is responsible for the formation of an inversion symmetric supra-molecular motif of graph set (10).

Syntheses of Acyclic and Macrocyclic Compounds Derived from 9,9-Diethylfluorene (Part I).

A series of new 9,9-diethylfluorenes consisting of three side-arms each bearing a heterocyclic, bis(carboxymethyl)amino, bis(carbamoylmethyl)amino, bis(ethoxycarbonylmethyl)amino or an amino group were prepared on the basis of 2,4,7-tris(bromomethyl)-9,9-diethylfluorene. Imidazolyl, benzimidazolyl, pyrazolyl, pyrrolyl, 1,3-dioxoisoindolyl and pyridinium groups were taken into account as heterocyclic units, attached to the aromatic skeleton via -CH-, -CHNHCH- or -CHN=CH- linkers. In addition to the seventeen 2,4,7-trisubstituted 9,9-diethylfluorenes, two macrocyclic compounds were prepared on the basis of 2,7-bis(aminomethyl)-9,9-diethylfluorene.