Lead complexes

Porphyrin, octaethyl-, lead complex cyclic voltammetry, 4, 399 <73JA5140)... 

These results imply that at the specified pH the magnesium complex is appreciably dissociated, whereas the lead complex is stable, and clearly titration of an Mg( II) solution with EDTA at this pH will be unsatisfactory, but titration of the lead solution under the same conditions will be quite feasible. In practice, for a metal ion to be titrated with EDTA at a stipulated pH the value of log K H should be greater than 8 when a metallochromic indicator is used. 

Lead, tris(ethyldithiocarbonato)-stereochemistry. 1,82 structure, 1, 82 Lead bromide, 3.194 Lead bromide hydrate, 3, 195 Lead carboxylatcs, 3,222 Lead complexes, 3,183-223 r 6-arene, 3,220 bivalent... 

Byrne RH (1981) Inorganic lead complexation in natural seawater determined by UV spectroscopy. Nature 290 487-489... 

Water (alkyl lead) Complexation of sample with diethyldithiocarbamate extraction with pentane removal of water butylation extraction with nonane GC/AAS 1.25 ng/L 90-108 Chakra borti et al. 1984... 

Treatment with mineral acid of the insoluble lead complex of D-glucosone regenerates the free sugar.3 38... 

Lead Complexation with ammonium pyrrolidine dithiocarba-mate, collection on C18 microcolumn Graphite furnace AAS 3.5 ng/1 [873]... 

Lead Complexation with DDPA adsorption on Ci8 microcolumn, Laser enhanced ionisation 3.3 pg/1 [360]... 

There are only a few examples of complexes of tin(II) and lead(II)81,82. Figure 10 shows [B(Pz)4]2Sn where the tin atom is four-coordinated in the solid state, adopting a pseudo-trigonal bipyramidal structure with the lone pair of the tin(II) in the equatorial position. The analogous lead complex has also been described83. 

The dication [(oep)Pb(IV)]2+ is unstable. Its absorption spectrum differs from that of doubly oxidized porphyrins of other metals like Zn or Mg, where the ligand is doubly oxidized. Spectrometry and voltammetry indicate that PblV binds weakly to the unoxidized ligand (the Soret and adjacent lines are those of the unoxidized ligand). Another unique aspect of the lead complex is its instability, which stands in contrast to the stable Sn(IV) analog171, implying the inability of PblV to accommodate into the central cavity of the porphyrin plane. 

Phinney, J. T. and Bruland, K. W. (1997). Trace metal exchange in solution by the fungicides Ziram and Maneb (dithiocarbamates) and subsequent uptake of lipophilic organic zinc, copper and lead complexes into phytoplankton cells, Environ. Toxicol. Chem., 16, 2046-2053. 

The reaction of the lithium compound 55, accessible from the iminophosphorane CH2(SiMe3)PPh2=NSiMe3 and BuLi, with PbCl2 gives colorless crystals of the lead complex 56 in 50% yield (Equation (21)).77 Similarly, treatment of PbCl2 with the lithium compound 57 affords yellow crystals of the donor-stabilized lead(ll) diaryl 58 in 70% yield (Equation (22)).78... 

Procedure Weigh accurately 1.7 g of potassium alum and dissolve it in sufficient DW in a flask. Heat the contents of flask over a water-bath for 10 minutes to allow completion of complexation and cool to ambient temperature. Now, add 1 g hexamine to act as buffer and titrate with 0.05 M lead nitrate employing 0.4 ml of xylenol orange solution as an indicator. The colour shall change from that of the indicator (yellow at the pH of the titration) to the corresponding reddish purple, the colour of the lead complex of the indicator. Each ml of 0.05 M disodium edetate is equivalent to 0.02372 g of KA1(S04)2, 12H20. 

Roe, A.L. Hayes, K.F. Chisholm-Brause, C.J. Brown, G.E.Jr. Parks, G.A. (1991) In situX-ray absorption study of lead complexes at -FeOOH/water interfaces. Langmuir 7 367-373... 

The lead complex described by Rudolph [25, 26] also has a single ° Pb NMR... 

The first descriptions of heteronuclear luminescent supramolecular complexes were given by Fackler et al. in 1988 and 1989. In these studies, one gold-thallium and one gold-lead complex were reported. As in the case of the gold-silver dinuclear systems, the extended systems appeared as a result of the unidirectional polymerization of dinuclear or trinuclear units through metal-metal interactions. These were prepared by reaction of the gold precursor [PPN][Au(MTP)2] (PPN = N(PPh3)2 ... 

Figures 4 and 5 for Vaq/Vorg = 5.0 show that removal of organic lead corresponds closely to that which would be obtained for a theoretical 1 1 complex in the absence of sodium chloride. Variations in extraction efficiency are observed for different solvents, but for all of the solvents employed a ratio Cr/Cl = 1.0 is sufficient to reduce an initial triethyl lead chloride level of 10 ppm to <1 ppm. A comparison of solvents used suggests an approximate order of effectiveness (corresponding to solubility of the organo-lead complex Hs PbSCSN Hs and also the neutral species Hs PbCl0 in the solvent) of the form shown in Table IV.

Experimental results indicate that the loadings of the organo lead complex which may be obtained for the solvent kerosene are approximately 300 g/1. If such an order of magnitude can be taken as typical of what might be obtained for common organic solvents, considerable recycle potential exists for the solvent, particularly for effluents containing only trace quantities of organic lead. 

H and 13C NMR spectroscopy have been used to study successive formation of mononuclear and dinuclear complexes with [SJcryptands.483 A heteronudear (Ag+,Pb2+) complex of (77) was described. In the 13C spectra, significant differences were observed for the carbon atoms adjacent to the bridgehead nitrogen atoms, such that the dinuclear silver complex and dinuclear lead complex could be readily distinguished from the heteronudear spedes. The fact... 

---