Notation coordination complexes

In the modern version of Werner s notation, brackets are used in writing cations or anions, but the net charges of the ions are not shown. In the formula [Pt(NH3)( ]Cl4, the portion in brackets represents a positively charged coordination complex in which Pt coordinates six NH3 ligands. The brackets emphasize... 

In Chapter 4 (Sections 4.7 and 4.8) several examples were presented to illustrate the effects of non-coincident g- and -matrices on the ESR of transition metal complexes. Analysis of such spectra requires the introduction of a set of Eulerian angles, a, jS, and y, relating the orientations of the two coordinate systems. Here is presented a detailed description of how the spin Hamiltonian is modified, to second-order in perturbation theory, to incorporate these new parameters in a systematic way. Most of the calculations in this chapter were first executed by Janice DeGray.1 Some of the details, in the notation used here, have also been published in ref. 8. 

Effect of protonation, complex formation with ligands and metal ions and reduction on dissolution rate. The structures given here are schematic short hand notations to illustrate the principal features (they do not reveal the structural properties nor the coordination numbers of the oxides under consideration charges given are relative). 

A short chemical explanation is due for the species MLH and MLH1. MLH represents a complex formed between Cu2+, en and one proton. The notation does not indicate the structure of this species. However, there is little doubt that it would be a protonated ethylenediamine, which is coordinated by only one site, acting as a monodentate ligand. 

A more complex notation is needed for non-stoichiometric phases. Selected simple examples are given below, and more detailed information will be reported when discussing crystal coordination formulae ... 

More complex examples of the use of this notation may be given by the structures of typical fluorides for which ionic-type coordination formulae are here reported ... 

So when there is one fixed complex scalar product on a vector space V, it is consistent to use the notation v for both dual and adjoint. In a unitary basis, the asterisk means coordinate transpose. 

This chapter presents a concise overview of the present conventions in coordination nomenclature. Generally, the IUPAC rules and recommendations have been followed. For the cases where the IUPAC practices seemed to be out of date or incomplete, the author has drawn upon the vast expertise in nomenclature available at Chemical Abstracts Service. Sections 3.2.3 and 3.4 deal with ligand locant notation and the numbering of polynuclear complexes may be considered provisional. These concepts are still under active consideration in the various national and international nomenclature commissions and committees. The presentation is relatively brief, but it is hoped that the nomenclature principles are evident, especially when examples presented are closely... 

The conversion from a connection table to other unambiguous representations is substantially more difficult. The connection table is the least structured representation and incorporates no concepts of chemical significance beyond the list of atoms, bonds, and connections. A complex set of rules must be applied in order to derive nomenclature and linear notation representations. To translate from these more structured representations to a connection table requires primarily the interpretation of symbols and syntax. The opposite conversion, from the connection table to linear notation, nomenclature, or coordinate representation first requires the detailed analysis of the connection table to identify appropriate substructural units. The complex ordering rules of the nomenclature or notation system or the esthetic rules for graphic display are then applied to derive the desired representation. 

When zeolite NH4-Na-Y was treated at 400°C under DB conditions a decrease in the number of observable Al atoms was found as the degree of ammonium exchange increased from 0 to 90 %. In the latter case, only ca. of Al present in the zeolite is observed by 27A1 NMR (see Table XIV). The authors estimate vQ > 1.2 MHz for the unobservable Al. However, extralattice Al can be detected by contacting the zeolite with a 38% solution of acetylacetone (Hacac) in ethanol, whereupon mobile Al(acac)3 complexes are formed, and a very narrow 27A1 NMR line results the solution does not affect framework aluminum. It was found that the amount of six-coordinated (i.e., extra-framework) Al increases from 5 % in 84 De Na-Y 300 SB zeolite to 50% in 84 De Na-Y 500 DB zeolite (in this notation the first number refers to the... 

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