Salts as linker sources allow the preparation of high-quality carboxylate-based MOFs under unprecedented sustainable conditions: room temperature and water as the sole solvent.

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have chlorine bridged distorted-octahedral geometry. It has been observed that the dithiocarbamato moiety is symmetrically bonded in all the cases. A three stage TGA profile is observed for all the complexes leading to the formation of respective metal sulfide as the end-product. The molar conductance of 10 -3 mol L -1 solution of the complexes measured in DMSO is indicative of their non-ionic nature. Keywords: dithiocarbamates, transition metals, thermal analysis, symmetrical bonding IntroductionDithiocarbamates are used to stabilize a wide range of oxidation states of different metal ions. 1 A large number of compounds are known where CS 2 binds in η 1 -end on, η 2 -side or in η 3 -coordination modes. 2-4 The major advantage of using the small bite-angle of dithiocarbamato moiety as a stabilizing chelating ligand, is its unique property to remain intact under a variety of reaction conditions. 5 Nowadays copper(II) dithiocarbamate is successfully used as single source precursor for the growth of semiconducting copper sulfide thin films. 6 The iron(II), iron(III) dithiocarbamates have been studied for their spincrossover phenomenon, 7 radical traps for NO, 8 and as antioxidants and pro-oxidants in biological systems. 9 Diethyl dithiocarbamates are also known to inhibit the activity of Cu/Zn-superoxidedismutase (SOD) through the withdrawal of copper from the protein both in vivo and in vitro. 10 Some dialkyl-substituted dithiocarbamates have proved to be an efficient anti-alkylating, anti-HIV and froth-floatation agents. 11 The optical and electrochemical properties of dithiocarbamates can effectively be used to construct sensors for guest molecules and macromolecules. [12][13][14] In this paper, we report a convenient one-pot synthesis of the transition metal dithiocarbamates via template procedure. In the present work, a condensation reaction was carried out between acetylacetone, ethylenediamine, 108 Siddiqi et al. J. Braz. Chem. Soc. carbon disulfide in a single step leading to the formation of a ring like complex ( Figure 1 and Figure 2). ExperimentalHydrated metal chlorides (BDH) acetylacetone, carbon disulfide (Merck) and ethylenediamine (Ranbaxy) were used as received. Methanol was used after distillation. Elemental analyses (C, H, N and S) were carried out with a Flash EA-1112 Analyser, CE Instrument. IR spectra (4000-400 cm -1 ) were recorded on a FT-IR Perkin-Elmer Spectrum BX as KBr disc while the 600-200 cm -1 range were scanned on CsI on Nexus FT-IR Thermo Nicolet, Madison Wisconsin. The conductivity measurements were carried out with a CM-82T Elico conductivity bridge in DMSO. The electronic spectra were recorded on a Cintra 5GBC spectrophotometer in DMSO. Magnetic susceptibility measurements were done with a Sherwood Scientific MSB Auto at room temperature. TGA/DSC was performed with a Universal V3.8 B TA SDT Q600 Build 51 Thermal Analyzer under nitrogen atmosphere using alumina powder as reference material. The heating rate was maintained at 10 °C min -1 . The metal contents were estimated by...

One of the pioneering metal organic framework material, called MOF-2 and having the formula [Zn 2 (BDC) 2 ], still continues awakening interest amongst the scientific community in spite of its layered character. However, the synthesis methods are either experimentally complicated or in two steps through the transformation of MOF-1. Here, we describe the preparation of a high-quality MOF-2 under more sustainable conditions, including room temperature, absence of any amine or any other pHcontroller, partial substitution of the harmful organic solvent (N,N-dimethylformamide) by water, and by simply mixing linker and metal sources, the latter being zinc acetate, carefully selected as a function of their solubility in the solvent mixture. The optimum ratio of Zn(OAc) 2 •4H 2 O to terephthalic acid (H 2 BDC) is 1.74 and H 2 O to DMF is 3. MOF-2 [Zn 2 (BDC) 2 ] has been characterized using powder Xray diffraction, thermogravimetric analysis, N 2 adsorption/desorption and scanning electron microscopy, all of them supporting the good quality of the material.