Lead complexes, divalent

It is apparent from most of the examples previously described that the most common formal oxidation state found for the Group 14 element is E(IV) (E = Ge, Sn, Pb). Relatively few examples of divalent germanium, tin, or lead complexes have been described, and of these, many are not well characterized. Cobalt-containing compounds are no exception in this regard and there appears to be only one report in the literature that describes a species of this type, viz. [Ge Co(CO)4 2], 67, although the precise structure of this complex is unknown (77). Two main synthetic routes are described, Eqs. (4) and (S), the starting complex in the latter reaction being... 

Unfortunately, 207Pb NMR spectra of transition metal-lead complexes have not always been recorded, although U9Sn NMR spectra of analogous tin compounds have been measured. No reason has been given why 207Pb NMR data could not be obtained (e.g. in (Schiff-base) divalent group 14 element species [(Salen)M] M (CO)6 (n - 1, 2 M - Ge, Sn, Pb M = Cr, W).100 The same situation is found for [Salen]Sn(II) and [Salen]Pb(II) derivatives.101... 

Platinates, bis(oxalato)-, 139 cadmium complexes superstructure, 142 cobalt complexes, 140 electrical conductivity, 14] superstructure, 141 thermopower, 141 divalent cation salts, 140 iron complexes structure, 142 lead complexes superstructure, 142 magnesium complexes, 140 electrical conduction, 142 structure, 142 thermopower, 142 modulated superstructure, 139 monovalent cation salts, 139 nickel complexes structure, 141 partially oxidized, 139 Platinates, tetracyano-, 136 anion-deficient salts, 136 electrical conduction, 138 optical properties, 138 cation-deficient salts, 138 oxidation states, 136 partially oxidized, 138 semiconductors, 134 Platinum colloidal... 

The type of catalyst influences the rate and reaction mechanism. Reactions catalyzed with both monovalent and divalent metal hydroxides, KOH, NaOH, LiOH and Ba(OH)2, Ca(OH)2, and Mg(OH)2, showed that both valence and ionic radius of hydrated cations affect the formation rate and final concentrations of various reaction intermediates and products.61 For the same valence, a linear relationship was observed between the formaldehyde disappearance rate and ionic radius of hydrated cations where larger cation radii gave rise to higher rate constants. In addition, irrespective of the ionic radii, divalent cations lead to faster formaldehyde disappearance rates titan monovalent cations. For the proposed mechanism where an intermediate chelate participates in the reaction (Fig. 7.30), an increase in positive charge density in smaller cations was suggested to improve the stability of the chelate complex and, therefore, decrease the rate of the reaction. The radii and valence also affect the formation and disappearance of various hydrox-ymethylated phenolic compounds which dictate the composition of final products. 

Analogous to the reaction of ()(1 D) + H2, the interaction of the divalent S(4D) atom with 112 molecule leads to the reaction complex of I l2S on the ground PES through the insertion mechanism, in contrast to the 121.6-nm photolysis of H2S on the excited PES. The reaction products are formed via a subsequent complex decomposition to SI l(X2l I) + H. The well-depth of reaction complex H2S, 118 kcal/mol is greater than I l20, 90 kcal/mol as referenced to their product channels. The exoergicity for S + H2, however, is 6-7 kcal/mol, substantially smaller than that for O + H2, 43kcal/mol. 

This dye fluoresces after binding Pb+2 and Ca+2 lead is considered an interferant to the determination of calcium by this approach. However, by complexing the divalent lead ion with the heavy metal chelator TPEN (N,N,N ,N -tetrakis(2-pyridylmethyl)ethylene-diamine) prior to the addition of the fluo-3, the fluorescent... 

We have recently prepared some new and very thermolabile CO- and N2 comPlexes derived from titanocene [1] or decamethyltitanocene [2], and have characterized them by their vibrational spectra. As well as "classical" matrix spectroscopy, we have used spectroscopy in liquid xenon (LXe). The application of chemistry and methodology indicates the decamethylsilicocene structure, which represents the first example of a stable jt-complex of divalent silicon [3]. Reaction with CO or N2 leads to the two title complexes [4] ... 

C. Cyclopropenylidene Complexes of Divalent Germanium, Tin, and Lead Amides... 

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