The cycloplatination of the tetrasubstituted imine 1 leads to the diplatinum organyl3 as the main reaction product, which represents the first example of a new class of metallomesogens exhibiting monotropically a nematic-discotic phase. An X-ray crystal structure of this anti-isomer 3 has been performed. Furthermore, this platinomesogen also shows the induction of a hexagonal columnar mesophase (Dho) on doping with 2,4,7-trinitrofluorenone as an electron acceptor. Compared to the analogous palladomesogen the two mesophases observed are more stable in the case of the platinum liquid crystal.Although the first metal-containing thermotropic liquid crystals were already described in 19 1 0C2], most of the manifold known examples have been synthesized and studied only in recent t i m e~[~-~I . The majority of these mesogens are conventional coordination compounds having metal-heteroatom bonds. However, a relatively small number of examples with at least one metal-carbon bond, so-called metalloorganyls, are also k n o~n [~-~I .In this latter group, in particular of the disc-shaped palladium is a perfect building unit because of its square-planar geometry of coordination. Thus, recently two disc-shaped series of liquid crystalline palladodiscogens containing two or even four palladium atoms have been obtained by ortho-palladation of multisubstituted aromatic imines or bisimines['-'I.On the other hand, analogous cycloplatinatioiis have neither widely been studied nor readily been accomplished. It has been proposed that the problems arising in ortho-platination reactions are at least partly attributed to the poor reactivity of platinum(I1) salts compared to those of palladium(II), leading to slower reaction rates and poorer yields. However, these preparative problems have recently been reduced by the application of an allylchloroplatinum precur~or[~l.Hence, in this paper we report on the synthesis, the X-ray molecular structure, and the mesomorphic properties of the first two platinum atom-containing disc-shaped liquid crystal. Results and DiscussionThe knownL61 imine 1 reacts smoothly under mild conditions with di-p-chloro-bis[(q3-2-methylallyl)platinum] (2)[1°1 with the formation of a liquid crystalline material containing the new chlorobridged dinuclear platinum organyl 3 having eight flexible side chains (see Scheme l)[lll. This product was characterized by IH-, 13C-NMR spectroscopy, X-ray diffraction, and elemental analysis. In consequence of its 'H-NMR data (CDC13 solutions) it is important to note that this platinum mesogen is assumed to be a mixture of two isomers (syn and anti) due to different orientations of the two ligands in the molecule, parallel or antiparallel to each other; attempts to separate the two isomers by TLC or column chromatography were unsuccessful because of decomposition processes. The ratio of the two isomers calculated from the intensity of two types of their proton signals is 83 (anti) to 17 (syn), see Experimental. Due to their positions in the molecular periphery of both isomers the chem...

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A one-pot synthesis of a sixfold functionalized dodecahydrotriphenylene 2 with D3 symmetry starting from 1,2,3,4,5,6-hexakis(eq)(ethoxycarbonylmethyl)cyclohexane (1) is described. methylsilane. The new and straightforward approach to this tetracyclic ring system is based on a triple intramolecularly occurring acyloin condensation by using sodium in the presence of chlorotriThe interest in triphenylene, hydrotriphenylenes, or substitution products thereof has been rekindled in recent years mainly due to studies on inclusion compounds"] and plate-shaped liquid crystalsp1 or the search for organic ferromagnetic materials"]. The first synthesis of such a hydrotriphenylene derivative 2, containing six oxygen functions, starting from the known hexakis-(eq)(ethoxycarbonylmethyl)cyclohexane~51 (1) is decribed here. When 1 is subjected to the conditions of the acyloin condensation by using sodium in the presence of chlorotrimethylsilane[61 2 is obtained in 53% yield.

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