Search results for "frameworks"
showing 10 items of 120 documents
Homochiral Metal-Organic Frameworks for Enantioselective Separations in Liquid Chromatography
2020
Selective separation of enantiomers is a substantial challenge for the pharmaceutical industry. Chromatography on chiral stationary phases is the standard method, but at a very high cost for industrial-scale purification due to the high cost of the chiral stationary phases. Typically, these materials are poorly robust, expensive to manufacture, and often too specific for a single desired substrate, lacking desirable versatility across different chiral analytes. Here, we disclose a porous, robust homochiral metal–organic framework (MOF), TAMOF-1, built from copper(II) and an affordable linker prepared from natural l-histidine. TAMOF-1 has shown to be able to separate a variety of model…
A Comprehensive Thermogravimetric Analysis Multifaceted Method for the Exact Determination of the Composition of Multifunctional Metal‐Organic Framew…
2020
Thermogravimetric analysis (TGA) has been widely used as a tool to characterise the composition of materials such as Metal-Organic Frameworks (MOFs). However, given their multifunctionality and structural complexity, examples of detailed methodologies for the exact calculation of the composition of complex MOF structures and MOF composites are lacking in the literature. Herein, we introduce a new straightforward methodology – based on the experimental ratio between the mass of a structure and its residue – for the exact calculation of the composition of almost any MOF material. We provide a detailed guide for the application of our methodology to different MOF materials, including MOFs in w…
Innovation capabilities: What are their characteristics and how can they be conceptualized?
2017
Purpose – It has been argued that firms may utilize their resources and capabilities through the development of innovations in the form of new products, services or processes, and empirical research has confirmed that there is a positive relationship between the implementation of innovation activities and future performance of firms. Some firms prove to be better at reproducing innovation success than other firms, and the capacity to do so can be framed as an innovation capability. However, the term innovation capability is ambiguously treated in extant literature. There exist several different definitions of the concept and the distinction between innovation capabilities and other types of…
Argumentation graphs with constraint-based reasoning for collaborative expertise
2018
International audience; Collaborative processes are very important in telemedicine domain since they allow for making right decisions in complex situations with multidisciplinary staff. When modelling these collaborative processes, some inconsistencies can appear. In semantic modelling (conceptual graphs), these inconsistencies are verified using constraints. In this work, collaborative processes are represented using an argumentation system modelled in a conceptual graph formalism where inconsistencies could be particular bad attack relation between arguments. To overcome these inconsistencies, two solutions are proposed. The first one is to weight the arguments evolving in the argumentati…
Improving data quality in construction engineering projects : an action design research approach
2014
Aurthor's version of an article in the journal: Journal of Management in Engineering. Also available from the publisher at: http://dx.doi.org/10.1061/(ASCE)ME.1943-5479.0000202 The topic of data and information quality (DQ/IQ) is a longstanding issue of interest in both academia and practice in the construction engineering field. Poor DQ/IQ has led to poor engineering drawings that, in turn, have led to delays and, eventually, cost overruns. In this paper, a study is reported that took an action design research (ADR) approach to develop and evaluate a DQ/IQ assessment tool, which is called the information quality system (IQS), in a large global engineering and construction company. The eval…
Perspectives on Cluster Evolution: Critical Review and Future Research Issues
2015
The past two decades have witnessed an ever-growing scholarly interest in regional clusters. The focus of research has mainly been on why clusters exist and what characteristics “functioning” clusters hold. Although the interest in more dynamic views on clusters is not new, in recent years, however, more attention has been paid to providing better explanations of how clusters change and develop over time, giving rise to an increasing popularity of different variants of the cluster life cycle approach. This article offers a critical review of various cluster life cycle models. We discuss the key ideas and arguments put forward by their main protagonists and we identify several shortcomings –…
Synthesis of quadruped-shaped polyfunctionalized o-carborane synthons
2011
[EN] o-Carborane derivatives with precisely defined patterns of substitution have been prepared from 8,9,10,12-I-4-1,2-closo-C2B10H8 by replacing the iodine atoms, bonded to four adjacent boron vertices in the cluster, with allyl, and subsequently 3-hydroxypropyl groups. The resulting structures, comprising four pendant arms and two reactive vertices located on opposite sides of a central o-carborane core, can be envisaged as versatile precursors for dendritic growth
Bio-metal-organic frameworks for molecular recognition and sorbent extraction of hydrophilic vitamins followed by their determination using HPLC-UV
2020
A bio-metal-organic framework (bio-MOF) derived from the amino acid L-serine has been prepared in bulk form and evaluated as sorbent for the molecular recognition and extraction of B-vitamins. The functional pores of bio-MOF exhibit high amounts of hydroxyl groups jointly directing other supramolecular host-guest interactions thus providing the recognition of B-vitamins in fruit juices and energy drinks. Single-crystal X-ray diffraction studies reveal the specific B-vitamin binding sites and the existence of multiple hydrogen bonds between these target molecules and the framework. It offered unique snapshots to accomplish an efficient capture of these solutes in complex aqueous matrices. Fo…
A step further in the comprehension of the magnetic coupling in gadolinium(III)-based carboxylate complexes
2013
Three new gadolinium(III) complexes of formula [Gd4(bta) 3(H2O)16]n·12nH2O (1), [Gd4(bta)3(H2O)12] n·18nH2O (2) and [Gd2(H 2bta)(bta)(H2O)2]n·4nH 2O (3) (H4bta = 1,2,4,5-benzenetetracarboxylic acid) have been synthesized and their structures determined by X-ray diffraction. 1 and 3 are three-dimensional compounds whereas 2 exhibits a two-dimensional structure. The ability of the bta4- to adopt different coordination modes accounts for these high dimensionalities although it precludes a rational structural design. The structures of 1-3 have in common the double oxo-carboxylate bridge between gadolinium(III) ions (μ-O: κ2O,O′) either as a discrete units (1 and 2) or as a chain (3) and one (3)…
Linker depletion for missing cluster defects in non-UiO Metal-Organic Frameworks
2021
Defect engineering is a valuable tool to tune the properties of metal–organic frameworks. However, defect chemistry remains still predominantly limited to UiO-type MOFs. We describe the preferential formation of missing cluster defects in heterometallic titanium–organic frameworks of the MUV-10 family when synthesised in sub-stoichiometric linker conditions. Our results show the value of integrating experimental work, computational modelling and thorough characterization in rationalizing the impact of defects over the porosity and structure of this family of materials. Correlation of experiment with computational models reveals the dominance of missing cluster vacancies in the pore size dis…