scholarly journals Highly Enantioselective Michael Additions of Indole to Benzylidene Malonate Using Simple Bis(oxazoline) Ligands: Importance of Metal/Ligand Ratio.

ChemInform ◽  
2007 ◽  
Vol 38 (17) ◽  
Author(s):  
Ramesh Rasappan ◽  
Markus Hager ◽  
Anja Gissibl ◽  
Oliver Reiser
Keyword(s):  
Michael Additions ◽  
Ligand Ratio ◽  
Oxazoline Ligands ◽  
Metal Ligand

Influence of the chain length and metal : ligand ratio on the self-organization processes of Cu2+ complexes of [1 + 1] 1H-pyrazole azamacrocycles

2020 ◽  
Vol 49 (25) ◽  
pp. 8614-8624 ◽  
Author(s):  
Alberto Lopera ◽  
Ariadna Gil-Martínez ◽  
Javier Pitarch-Jarque ◽  
Begoña Verdejo ◽  
Salvador Blasco ◽  
...  
Keyword(s):  
Chain Length ◽  
The Self ◽  
Self Organization ◽  
Ligand Ratio ◽  
Chain Lengths ◽  
Metal Ligand

The great versatility of the pyrazole moiety combined with polyamines of different chain lengths gives rise to remarkable coordination features.

Comparative Calorimetric and 1H N.M.R. Studies of the Interaction of Ag(I) With a Series of Mixed-Donor Macrocycles Incorporating Nitrogen, Oxygen and or Sulfur Donor Atoms

1988 ◽  
Vol 41 (9) ◽  
pp. 1347 ◽  
Author(s):  
D Baldwin ◽  
LF Lindoy ◽  
DP Graddon
Keyword(s):  
Stability Constants ◽  
Macrocyclic Ligands ◽  
Enthalpies Of Formation ◽  
Calorimetric Titration ◽  
Ligand Ratio ◽  
Deuterated Derivative ◽  
Titration Data ◽  
Ligand Species ◽  
Metal Ligand ◽  
Sulfur Donor

The interaction of silver ion with a range of mixed-donor macrocyclic ligands incorporating nitrogen, oxygen and/or sulfur donors has been investigated. Complementary calorimetric and n.m.r. studies in acetonitrile (and its deuterated derivative) were used to investigate the nature of the equilibria present as the metal/ ligand ratio was varied. In all systems the formation of a 1 : 1 species was observed, with a 1:2 (metal/ ligand ) species also being formed in the presence of excess ligand in the majority of cases. Enthalpies of formation for the various complexes have been determined. Stepwise stability constants for the respective [ AgL ]+ + L ↔ [AgL2]+ equilibria have been estimated from the calorimetric titration data, and the factors promoting the formation of the 1:2 species are discussed. The studies confirm the enhanced affinity of AgI for thioether donors over ether donors.

Syntheses, structures and magnetism of two Cu(II) coordination polymers of d-camphorate controlled by metal-ligand ratio

2020 ◽  
Vol 502 ◽  
pp. 119387 ◽  
Author(s):  
Fang-Hua Zhao ◽  
Zhong-Lin Li ◽  
Yuan-Chun He ◽  
Mei Zhang ◽  
Jun Han ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Ligand Ratio ◽  
Metal Ligand

scholarly journals A Study of 1-Phenyl-3-Methyl-4-Trichloroacetyl Pyrazolone-5 as an Extractant for Uranium (VI) From Buffered Solutions

2020 ◽  
Author(s):  
Victoria Bennett ◽  
Bamidele Amos-Tautua ◽  
Ayasen Kemeakegha
Keyword(s):  
Aqueous Media ◽  
Colorimetric Method ◽  
Ion Concentration ◽  
Masking Effect ◽  
Ion Concentrations ◽  
Ligand Ratio ◽  
Extraction Processes ◽  
Optimum Extraction ◽  
Metal Ligand

Abstract Chloroform solutions of 1-Phenyl-3-Methyl-4-Trichloroacetylpyrazolone-5 (HTCP) for the extraction of Uranium (VI) (UO22+) from various buffered solutions containing different SO42- ion concentrations was investigated. After extraction processes, colorimetric method was used to determine Uranium(VI) concentrations in aqueous media. Solutions of HTCP in chloroform did not extract U(VI) in buffered solutions containing SO42- ions between pH 0 – 2, which was attributed to the formation of unextractable Sulphate Uranyl (UO2)SO4 complex. However, there was extraction of U(VI) of 88,70 %, 76.84 % and 55.49 % between pH 2.96 – 3.21 for solutions containing 0.01 M, 0.1 M and 1 M SO42- ion respectively. An increase in SO42- ion concentration decreased the optimum extraction of U(VI). The presence of SO42- ion in buffered solutions had a masking effect on the extraction of U(VI). The metal ligand ratio was 1:1 and the adduct complex of the metal characterized as UO2(TCP) was extracted.

Metal–ligand ratio-controlled assembly of two pairs of Co(ii) complexes: syntheses, structures and magnetic properties

CrystEngComm ◽  
2012 ◽  
Vol 14 (13) ◽  
pp. 4478 ◽  
Author(s):  
Fanghua Zhao ◽  
Shuai Jing ◽  
Yunxia Che ◽  
Jimin Zheng
Keyword(s):  
Magnetic Properties ◽  
Controlled Assembly ◽  
Ligand Ratio ◽  
Metal Ligand

Five novel cobalt coordination polymers: effect of metal–ligand ratio and structure characteristics of flexible bis(imidazole) ligands

CrystEngComm ◽  
2010 ◽  
Vol 12 (10) ◽  
pp. 3283 ◽  
Author(s):  
Yang Liu ◽  
Yan Qi ◽  
Yan-Hua Su ◽  
Fang-Hua Zhao ◽  
Yun-Xia Che ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Structure Characteristics ◽  
Ligand Ratio ◽  
Cobalt Coordination ◽  
Imidazole Ligands ◽  
Metal Ligand

scholarly journals Direct and simultaneous spectrophotometric determination of Ni (II) and Co (II) using diethanoldithiocarbamate as complexing agent

2009 ◽  
Vol 34 (2) ◽  
pp. 7-13 ◽  
Author(s):  
P. A. Antunes ◽  
G. Bannach ◽  
G. O. Chierice ◽  
E. T. G. Cavalheiro
Keyword(s):  
Simultaneous Determination ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Natural Waters ◽  
Maximum Absorption ◽  
Complexing Agent ◽  
Mixing Ratios ◽  
Ligand Ratio ◽  
Metal Ligand

A direct spectrophotometric method for simultaneous determination of Co(II) and Ni(II), with diethanoldithiocarbamate (DEDC) as complexing agent, is proposed using the maximum absorption at 360 and 638 nm (Co(II)/DEDC) and 390 nm (Ni/DEDC). Adjusting the best metal/ligand ratio, supporting eletrolite, pH, and time of analysis, linear analytical curves from 1.0 10-6-4.0 10-4 for Co(II) in the presence of Ni 1.0 10-6-1.0 10-4 mol L-1 were observed. No further treatment or calculation processes have been necessary. Recoveries in different mixing ratios were of 99%. Interference of Fe(III), Cu(II), Zn(II) and Cd(II), and anions as NO3-, Cl-, ClO4-, citrate and phosphate has been evaluated. The method was applied to natural waters spiked with the cations.

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