Metal-to-ligand ratio

Similar studies on the Bu2Sn(IV) complexes formed with the same ligands were performed. The synthetic procedure resulted in the formation of Bu2Sn(IV) compounds with a 1 2 metal-to-ligand ratio for pyridinemonocarboxylic acids. 

Another key factor is the choice of reactant proportion. We found that it is necessary to maintain a high metal-to-ligand ratio because a low ratio (such as Ln Cu gly Ac = 1 4 2 2) will lead to the final product being contaminated by a small number of light-blue crystals of CudglyutCICUh. 

For analyzing a catalytical system by the method of inverse titration one has to investigate at least 3 to 4 catalytic reactions for each chosen power of a tenth of the external metal-to-ligand ratio. To achieve this information efficiently in time, we carried out a special experimental procedure on the 1-ml scale (for experimental details see Ref. ), a flow chart is given in Scheme 3.2-1. 

Under physiological conditions (pH = 7.4) complexes with a 1 1 metal to ligand ratio are present GdL(n 3). At pH values lower than 3-4,protonated complexes GdHL can be formed. The protonation constants (KMHL) of the highly stable complexes are in general low, with log KGdHL less than 2.5 (KMHL = [MHL] / [M] [H+]). 

To see the effect of an additional methyl substituent of the — SAr group on the architecture of the network, we treated Cul under analogous reaction conditions and metal to ligand ratio employed for the 1,4-bis(phenylthio)butane-linked derivative 16 with 1,4-bis(/>-tolylthio)butane and with 1,4-bis(o-tolylthio) butane, respectively. In contrast to 9 and 10, we noticed now a very sensible... 

Our studies revealed that, upon treatment of Cul with l,5-bis(phenylthio) pentane in acetonitrile solution, the architecture of the resulting polymeric material depends in a crucial manner on the metal to ligand ratio employed. Performing the reaction in a 2 1 molar ratio gave air-stable crystals of general... 

To evaluate the influence of the organic R group of the RS-thioether function and to allow a comparison with ArS(CH2)4SAr (see above), Cul was reacted with 1,4 bis(cyclohexyl)butane CyS(CH2)4SCy. The colorless crystals obtained by reaction in a 1 1 metal to ligand ratio were found to be of composition... 

A similar mixed ox a- thia macrocycle incorporating a rigid horseshoeshaped aromatic moiety, l,ll,21-trioxa-8,14-dithia[2,9,2]paracyclophane, L40, has been synthesized and reacted with copper iodide in MeCN solution (Scheme 19).160 Its polymeric copper iodide complex [Cu4I4(L40)2] 40 crystallizes, in a 2 1 metal to ligand ratio, as an ID infinite array of cubane-like units consisting of four copper atoms, four i3-iodine atoms, and four sulfur atoms, stemming from four different macrocycles. The Cu—Cu distances are about 2.731 A. Unfortunately, the photophysics of this compound have not been studied. 

Under physiological conditions (pH = 7.4) complexes with a 1 1 metal to ligand ratio are present At pH values lower than 3-4,protonated com-... 

Figure 1. Concentration distribution curves of the system copper(II) - A/ -D-gluconylglycine at a metal to ligand ratio of 1 8, [Cu2+] = S.OxlO" mol dm 3.

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