Zeolites and related crystalline microporous oxides-tetrahedrally coordinated atoms covalently linked into a porous framework-are of interest for applications ranging from catalysis to adsorption and ion-exchange. In some of these materials (such as zeolite rho) adsorbates, ion-exchange, and dehydration and cation relocation can induce strong framework deformations. Similar framework flexibility has to date not been seen in mixed octahedral/tetrahedral microporous framework materials, a newer and rapidly expanding class of molecular sieves. Here we show that the framework of the titanium silicate ETS-4, the first member of this class of materials, can be systematically contracted through dehydration at elevated temperatures to 'tune' the effective size of the pores giving access to the interior of the crystal. We show that this so-called 'molecular gate' effect can be used to tailor the adsorption properties of the materials to give size-selective adsorbents suitable for commercially important separations of gas mixtures of molecules with similar size in the 4.0 to 3.0 A range, such as that of N2/CH4, Ar/O2 and N2/O2.

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Purpose-Rarely have studies on the acquisition of knowledge in internationalisation focused on institutional knowledge. The aim of this paper is, therefore, to investigate the acquisition of this knowledge, and its assimilation and exploitation processes in internationalisation. Design/methodology/approach-The paper utilises ten longitudinal revelatory case studies built from multiple semi-structured interviews conducted with three different firm types of SMEs in the pharmaceutical industry and secondary documents to which the researchers obtained proprietary access. Findings-The study enhances our conceptual understanding of the institutional learning process in internationalisation by, for the first time, developing a framework to characterise this process. The study explores and identifies multiple types of institutional knowledge required, the sequencing of their acquisition, sources, and learning methods utilised. It also discusses transferability of this learning across foreign markets and firms' absorptive capacity for that knowledge. Regulatory-specific product knowledge, found to be the most important type required, appeared to affect significantly both market selection and mode of entry, and when acquired insufficiently, prevented internationalisation. Research limitations/ implications-While the sample size is relatively small, and sectorspecific, the findings were consistent across all the SME firms and firm types. They may also be generalisable to other sectors, firm sizes such as MNEs and types, particularly those which are knowledge-based or highly regulated, given that similar institutional knowledge and processes of acquisition are necessary for firms of all sizes in internationalisation. Practical implications-International marketing managers will gain valuable insights, based on a framework proven to propel firms to successful internationalisation, upon how to plan, organise, manage and match their institutional knowledge-seeking and learning activities with their firms' internal capabilities, staffing and other resources in an effective and timely manner. Originality/value-This study contributes to our conceptual understanding of the institutional knowledge learning process in the internationalisation.

The preparation, characterization, properties, and reactivity of a novel quantum-confined CdS nanocluster containing a chemically active aniline surface are described, along with three general methods for the covalent attachment of a wide scope of molecular moieties to the cluster surface. The formation of facile covalent linkages via DCC mediated amidization, secondary amine formation, and thiourea condensation is discussed and, as the introduction of surface functionality is crucial for the eventual realization of molecular electronic devices fabricated from such nanoclusters, several derivatized nanoclusters bearing interesting chromophoric, fluorescent, electroactive, and chiroptical tethered species are described. All three derivatization techniques occur under very mild conditions that have been demonstrated not to disturb the integrity of the nanocluster core.Key words: quantum dot, nanocluster, semiconductor, surface-functionalized, nanostructured.