abstract
The role of pH in the formation of metal-organic frameworks (MOFs) has been studied on magnesium-based carboxylate framework systems [Mg(Pdc)(H2O)(3)](n) (1) and [Mg(Pdc)(H2O)](n) (2) (Pdc=pyridine-2,3-dicarboxylate). The investigation reveals the formation of two different compounds of one- or three-dimensions starting from the same reaction mixture that differs only in pH. Isolated compounds have been characterized by IR and elemental analysis; both compounds were also successfully characterized by single-crystal X-ray diffraction. This study shows that the gradual increase in pH helps to construct a higher-dimensional network. Catalytic activity of compounds 1 and 2 was tested for the Claisen-Schmidt reaction. Compound 2 was successfully dehydrated to produce a coordinately unsaturated compound 2a, which shows higher catalytic activity than 1 or 2 in heterogeneous medium.
keywords
DIRECT ALDOL REACTIONS; HYDROTHERMAL SYNTHESIS; NANOCRYSTALLINE MGO; GAS-ADSORPTION; LEWIS-ACID; TEMPERATURE; DIMENSIONALITY; CONDENSATION; CARBOXYLATES; CATALYSIS
subject category
Chemistry
authors
Sen, R; Saha, D; Koner, S; Mal, D; Brandao, P; Lin, Z
our authors
Paula Cristina Ferreira da Silva Brandão
Assistant Researcher
Rupam Sem
Research Fellowship
Zhi Lin
Principal Researcheracknowledgements
R.S. thanks the Fundacao para a Ciencia e Tecnologia (FCT) for a postdoctoral grant (SFRH/BPD/71798/2010). D.S. thanks the CSIR (ref. no. 09/096(782) 2013-EMR-I) for a Senior Research Fellowship. The Portuguese group is financially supported by FEDER through Programa Operacional Factores de Competitividade COMPETE and national funds through the FCT within the CICECO project FCOMP-01-0124-FERDER-037271 (FCT ref. Pest-C/CTM/LA0011/2013). Financial support from CSIR, New Delhi by a grant (grant no. 01(2542)/11/EMR-II) (to S.K.) is gratefully acknowledged.