13 research outputs found
Doubly-linked 1D coordination polymers derived from 2 : 2 metallamacrocyclic Ni(II) complexes with bipodal acylthiourea and exo-biaentate N-donor bridging ligands: Toward potentially selective chemical sensors?
The square planar 2 : 2 metallamacrocyclic Ni(II) complex of 3,3,3′,3′-tetraethyl-1,1′-isophthaloylbis(thiourea) readily forms coordination polymers by axial coordination of various exo-bidentate N-donor linkers: pyrazine, 4,4′-bipyridine, 1,2-bis(4-pyridyl)ethane and 1,2-di(4-pyridyl)ethylene. Steric constraints, together with coordination limited to the axial directions, result in the self-assembly of double-linked ID ladder structures. One compound in particular, with the bridging ligand 1,2-di(4-pyridyl)ethylene, is found to exist as a quasi-polymer, realising only one-third of its potential linkages. On exposure to various solvents, this compound appears to undergo complete polymerisation, both rapidly and fully reversibly with an associated colour change, making it a potential chemical sensor. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.The square planar 2 : 2 metallamacrocyclic Ni(II) complex of 3,3,3′,3′-tetraethyl-1,1′-isophthaloylbis(thiourea) readily forms coordination polymers by axial coordination of various exo-bidentate N-donor linkers: pyrazine, 4,4′-bipyridine, 1,2-bis(4-pyridyl)ethane and 1,2-di(4-pyridyl)ethylene. Steric constraints, together with coordination limited to the axial directions, result in the self-assembly of double-linked ID ladder structures. One compound in particular, with the bridging ligand 1,2-di(4-pyridyl)ethylene, is found to exist as a quasi-polymer, realising only one-third of its potential linkages. On exposure to various solvents, this compound appears to undergo complete polymerisation, both rapidly and fully reversibly with an associated colour change, making it a potential chemical sensor. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.ArticleArticl
Self-assembly of 2:2 metallamacrocyclic complexes of Nill and Pdll with 3,3,3',3'-tetraalkyl-1,1'-isophthaloylbis(thioureas). Crystal and molecular structures of cis-[Pd(l2-S,O)]2 and the adducts of the corresponding Nill complex: [Ni(L1-S,O)(pyridine)2]2 and [Ni(L1-S,O)(4- dimethylaminopyridine)2]2.
NatuurwetenskappeChemie & PolimeerwetenskapPlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]
Targeting water utilities for the threshold problem without waste discharge
Increasing water scarcity and stringent environmental regulation have necessitated effective water conservation policies. Pinch analysis has been proved as one of the powerful tools to locate targets of waste water minimization. Two earlier water pinch targeting methods known as Water Cascade Analysis and Material Recovery Pinch Diagram have focused on the “threshold problems”. However, these methodologies have not systematically analyzed the introduction of external utility. In this work, three scenarios are proposed for this reason. The “Infeasible Threshold Problem” is addressed prior to employing external utility through the proposed scenarios. By systematically analyzing this specific problem, it is revealed that existing Water Cascade Analysis method cannot locate correct infeasible targets. Some adjustments are proposed to deal with this drawback. Moreover, to illustrate the applicability of proposed scenarios, Water Cascade Analysis and Material Recovery Pinch Diagram approaches are utilized for addressing a literature problem as a case study. It is shown that harvesting the impure fresh water source with a higher quality, in the “threshold problem with zero discharge”, leads to more pure fresh water saving
An automated composite table algorithm considering zero liquid discharge possibility in water regeneration–recycle network
In this study, a novel Automated Composite Table Algorithm (ACTA) is developed for targeting the water regeneration–recycle network of single contaminant problem. The ACTA is based on Pinch Analysis, but is automated by taking into consideration the possibility of zero liquid discharge (ZLD) for the water network. In the existing literature, the targeting procedure for ZLD network is based on the graphical tool of Limiting Composite Curve (LCC). However, identification of key parameters (i.e. freshwater, wastewater, regenerated water flowrates, along with pre-regeneration concentrations) is very tedious for highly integrated water network system. The magnification around the turning point of LCC is required to identify the correct pinch points and targeting procedure is done iteratively until the reliable network targets can be determined. These limitations are now overcome by the ACTA, which is an improved version of Composite Table Algorithm that is capable of identifying key parameters algebraically for a given post-regeneration concentration. The newly developed ACTA is capable of handling a wide range of problems including ZLD and non-ZLD network, for both fixed load and fixed flowrate problems