Standing out from the vast majority of metal organic coordination polymers is the class of highly porous basic zinc carboxylates developed by Yaghi and co-workers.[1] Its prototype is MOF-5 (MOF = metal organic framework), in which {Zn 4 O} building blocks are linked together by terephthalate bridges to form a zeolite-like, cubic framework.[2] The extremely high specific surface area [2] of up to 4500 m 2 g À1 and a pore volume of 0.69 cm 3 cm À3 (for MOF-177), which has not been surpassed by any other crystalline substance, and thermal stability (up to 350 8C) opens up fascinating perspectives for the supramolecular host-guest chemistry.[3] Applications for these materials in miniaturized fuel cells and convenient gas-storage devices (for H 2 , CH 4 ), as gas sensors and for gas separation, as catalyst materials, and also for molecular electronics are emerging. [4] A report on the quantitative inclusion of C 60 and large polycyclic dye molecules (e.g. Astrazon Orange R) into the cavities of MOF-177 single crystals attracted our attention. [5] Could these MOF host lattices also be suitable to efficiently and selectively absorb typical metal organic chemical vapor deposition (CVD) precursors, provided these were volatile (gas absorption) or very soluble in nonpolar hydrocarbons and had matching size and shape to fit into the cavity? The release of the metal atoms of the precursors imbedded in the

Thin polycrystalline films of phase-pure MOF-5 were grown directly from supersaturated MOF-5 mother solutions on suitably pretreated alumina and silica substrates. The surface acid/base properties characterized by the isoelectric point of the bare substrates controls the anchoring of MOF-5 nuclei. In addition to COOH-terminated SAMs on SiO2, ALD-Al2O3 proved to be a very good adhesive for selective MOF-5 growth. The adsorption properties of the deposited MOF films on Al2O3 substrates were demonstrated by MOCVD loading with [(η5-C5H5)Pd(η3-C3H5)] as Pd precursor to finally yield the palladium-loaded thin film material {Pd@MOF-5}/Al2O3 as a model of a variety of conceivable MOF-based functional chemical systems at surfaces.

The current upswing in the interest in organoelement chemistry of Group 13 metals is attributed not least to the establishment of the coordination chemistry of R(a)E fragments (E=Al, Ga, In; a=1, 2) at d-block metals (M). Recently the availability of low-valent organoelement compounds as building blocks for synthesis has substantially enriched the structure chemistry of this class of compounds. The M-E bonding conditions and the question of the significance of M(d(pi))-E(p(pi)) backbonding as well as potential applications in materials science, for example, as single-source precursors for the deposition of thin intermetallic films by chemical vapor deposition, are discussed.

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crystal of dimensions 0.37 x 0.37 x 0.27 mm, rhombohedral. R3, a = b = 15.0677(7), c = 48.7214(49) A, 1 = = 1 102 g~m -~, 2 = 6, j~ = 12.22 cm-', 2328 independent reflections, R(Rw) = 0.105(0.103) for 1309 [I > 20(1)] observed reflections. Maximum final difference Fourier peak 0.83 e k ' . Seifert XRD3000-S, four-circle diffractometer, Cu,, radiation, graphite monochromator, 4 2 0 scan, Om,, = 60". Two set of data were collected due to the instability of the crystal, and although the present set was recorded more quickly the decay factor was 7%. Semiempirical Y-scan absorption correction was applied. Refinement on Fo with full matrix. The structure was solved by direct methods [15] and the molecule was located on a threefold crystallographic axis. An anisotropic thermal model was used for the non-hydrogen atoms, while the thermal and positional parameters for H atoms, which were obtained unambiguously from difference Fourier synthesis, were kept fixed during the last cycles of refinement. The water molecules appear to be disordered and the hydrogen atoms of the water molecule situated on the threefold axis could not be located. Moreover, in spite of the high displacement parameters of the C17-C22 atoms no disorder model could be obtained. The weighting scheme was established as to give no trends in