Coordination geometry structures

Figure 2.15 The molecular structure of the [Cun(16)]2+. The hydrogen atoms of ligand 16 have been omitted. The Cu11 center experiences a rather distorted square coordination geometry. Structure redrawn from data deposited at the Cambridge Crystallographic Data Centre CCDC 118957.

An algorithm has been proposed for determining the reaction coordinate, transition structure, and optimized geometry all in a single calculation. The... 

In the vast majority of its compounds Si is tetrahedrally coordinated but sixfold coordination also occurs, and occasional examples of other coordination geometries are known as indicated in Table 9.2 (p. 335). Unstable 2-coordinate Si has been known for many years but in 1994 the stable, colourless, crystalline silylene [ SiNBu CH=CHNBu j, structure (1), p. 336, was... 

Figure 11.16 Coordination geometries of the nitrate group showing typical values for the interatomic distances and angles. Further structural details are in ref. 150.

Figure 13.12 Schematic representation of the structure of the complex anion LSbjCIiiO] " showing the two different coordination geometries about Sb and the unique quadruply bridging Cl atom.

M(NO)(OCOCF3)2(PPh3)2. Both these complexes have 5-coordinate geometries with monodentate carboxylates. The rhodium compound has a square pyramidal structure with bent Rh-N-O (122°) but the iridium compound has a tbp structure with straight equatorial Ir-N—O (178°). The position of i/(N—O) reflects this difference (1800 cm-1 (Ir) and 1665 cm-1 (Rh)). 

Fig. 6. Coordination geometry at silicon structures of the complexes 4 (left) and 5 (right)...

X 16.101 cis-Platin is an anticancer drug with a structure jQ that can be viewed on the Web site, (a) What is the formula and systematic name for the compound cis-jf Platin (b) Draw any isomers that are possible for this compound. Label any isomers that are optically active, (c) What is the coordination geometry of the platinum atom ... 

The X-ray crystal structure of 20 has been determined and a structural model of 20 is shown in Fig. 14. The coordination geometry around the Ru center can be... 

Very often, the tetrad effect is not clearly discernible in the energies of processes in which 4f electrons are conserved. It may, for example, be obscured by irregularities caused by structural variations in either reactants or products. This is especially likely given the willingness of lanthanide ions to adopt a variety of coordination geometries. There is, however, no doubt that tetrad-like patterns are often observed. But does Table 1.2 provide a convincing explanation of what is seen ... 

TiCRjtftc) was prepared starting from Ti(NR2)4 4,5) or TiCl4 (6). The structure of the ethyl compound was elucidated by X-ray studies (7, S). The titanium atom is eight-coordinated by the sulfur atoms of the four chelating ligands and the coordination geometry closely approximates to that of a dodecahedron. 

On the basis of infrared and Raman data 102), the structure is believed to have bridging halogen atoms between the metal atoms, the coordination geometry around each... 

Zn -PDF, 37 pM versus E. coli Fe -PDF), it was successfully used to provide co-crystals bound in the active site of both Co - and Zn -E. coli PDF [58], These structures reveal that the H-phosphonate binds to the metal in a monodentate fashion, adopting a tetrahedral coordination state similar to that of the native resting state of the enzyme. This is in contrast to later co-crystal structures obtained with more potent hydroxamic acid or reverse hydroxamate inhibitors, which bind to the metal in a bidentate fashion vide infra). Presumably these bidentate inhibitors mimic the true transition state of the enzyme, in which the metal centre slips to a penta-coordinate geometry in order to activate the Wformyl carbonyl of the substrate [56, 67]. 

---