Of anionic ligands

Pu(IV) forms polyatomic complexes with inorganic and organic ligands. As the number of anionic ligands increases, cationic, neutral, and anionic complexes form and the sequential stabiUty constants, typically decrease. For the following reaction, where M is Pu + and L is a ligand,... 

The names of anionic ligands are obtained by substituting the suffix -o for the normal ending. Examples include... 

As with rhodium (and cobalt), introduction of five ammonia molecules is relatively straightforward, but the sixth substitution is difficult, requiring more forcing conditions. One versatile route involves the formation of the pentammine triflate complex ion [Ir(NH3)5(03SCF3)]2+, where the labile triflate group is readily replaced by water, then by a range of anionic ligands [148]. 

The chemical symbols of anionic ligands precede those of neutral ligands in the chemical formula of the complex (but not necessarily in its name). Thus, Cl precedes H20 and NH3. 

Aminopyridinato ligands form a special class of anionic ligands in which an aromatic ring is part of an amidinate system. These ligands have frequently been employed in early transition metal and lanthanide coordination chemistry. Their diverse and interesting chemistry has been described in detail by Kempe et al. ° and will thus be covered here only briefly. Typical reaction pathways leading to titanium aminopyridinato complexes are outlined in Scheme 169. Metathetical as well as salt-free routes have been developed. 

The mechanism of substitution of anionic ligands on [Cr(NH3)5H20]3+ has received both Id and Ia assignments from various authors (23). This dichotomy of viewpoint comes about substantially... 

The above substitution effects appear to be independent of the nature of the ligand (16) since the benzyl compounds behave similarly, Table XI. It would appear from these observations that the introduction of anionic ligand would be sufficient to increase activity of transition metal alkyl compounds for polymerization. This, however, is probably an oversimplifica-... 

Bismuth compounds have been used for treating gastrointestinal disorders for more than two centuries (451). These include bicarbonate, nitrate and salicylate salts, and colloidal bismuth subcitrate. These are all Bi(III) compounds Bi(V) is usually a strong oxidant. Their structures are largely unknown and often contain a mixture of anionic ligands. This reflects the strong tendency of Bi(III) to hydrolyze and form stable hydroxo and oxo complexes. The first pKa of Bi(III) in water is ca. 1.5. Bismuth(III) has a variable coordination number, from 3 to 10. 

The names of anionic ligands always end in an o. Neutral ligands are basically unchanged. Two common exceptions in the case of neutral ligands are NH3 = ammine (note the double m), and H20 = aqua. Other common ligands and their names are listed in Appendix C. 

Figure 1.16 Positions of anionic ligands for various configurational states A = square-planar coordination B = octahedral coordination C = tetrahedral coordination. Cation nuclei are located in center of Cartesian coordinates.

We see only a small variation in rate constants fora variety of anionic ligands. It... 

Table I. Effect of Anionic Ligands on Activity of MoX2(NO)2L2-Derived Disproportionation Catalysts...

Iron-centered paramagnetic complexes formed by reactions between iron salts and nitric oxide in the presence of anionic ligands, and characterized by g = 2.03, were first reported over 20 years ago (22) similar complexes, of the general type [Fe(NO)2X2] +, have subsequently been produced by reactions of iron salts and nitric oxide in the presence of halides and pseudohalides (118), alcohols and alkoxides (119), mercaptides (120, 121), and mercaptopurines and mercaptopy-rimidines (122). 

While some molybdenum complexes such as Mo03(dien) were found to be inactive,236 the rates of molybdenum-catalyzed epoxidation of alkenes were found to be independent of the structure of the complex used, after an induction period representing the time for exchange of anionic ligands by the alkyl hydroperoxide. cis-Dioxomolybdenum(VI) diolates such as (78) were isolated... 

The different orientation of the monomer in systems with Ziegler-Natta catalysts based on Ti or Nd and Co or Ni precursors has been suggested [41] to be determined by the presence in the isospecific catalysts (Ti- and Nd-based ones) of anionic ligands bound to the transition metal and the absence of any anionic ligand in the syndiospecific catalysts (Co- and Ni-based ones). In the... 

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