Hydrogen ligand names

When the tetradentate ligand trien is substituted by two bidentate ligands, namely ethylenediamine, the resulting compound 2 adopts another type of packing mode, in which each complex cation forms extensive hydrogen bonding interactions with 1,5-... 

Where a chelating ligand is formed by removing two or more hydrogen atoms from a parent compound, the atoms with free valencies, understood to form the bonds to the central atoms, are indicated by using the appropriate ligand name (such as propane-1,3-diyl), cf. Section IR-10.2.3. This is demonstrated in Examples 1-3 below. Note that an alternative nomenclature for such metallacycles is currently being developed. 

The most popular ligand in this area is 3a. It was introduced in 1985 by Y. Qian and co-workers, who have used this ligand extensively in transition-metal chemistry (vide supra). In rare-earth-element chemistry it has been employed mainly by the group of C. Qian," who in 1987 introduced the second most popular ligand, namely, 9a." Their investigations were in part stimulated by the relevance of organo-metallic compounds of these elements to important catalytic reactions such as olefin polymerization and hydrogenation. 

While working at DuPont, Burk developed a new class of bisphosphine ligands, named DuPHOS (20) and BPE (21). These two electron-rich bisphosphine ligands were shown to display a wide substrate scope in the asymmetric hydrogenation of dehydroamino acids [16, 41-43]. Moreover, in subsequent pioneering work these were shown to work effectively as ligands with a variety of metals in a host of important new enantioselective processes. 

In solution, most simple sugars and many of their derivatives occur as equilibrium mixtures of tautomers. The presence of a mixture of two anomers of the same ring size may be indicated in the name by the notation a,P-, e.g. a,P-D-gIucose. In formulae, the same situation can be expressed by separating the representation of the ligands at the anomeric centre from the a and P bonds [see examples (a) and (c)], or by use of a wavy line [(b) and (d)] (particularly if hydrogen atoms are omitted). 

This chapter treats iron complexes with Fe-H bond(s). An H ligand on a transition metal is named in two ways, hydride and hydrido. The term hydrido is recommended to be used for hydrogen coordinating to all elements by lUPAC recommendations 2005 [1], However, in this chapter, the term hydride is used because it has been widely accepted and used in many scientific reports. 

Propyhdyne formed from propene on lr4 supported on y-Al203 was observed by IR and NMR spectroscopies [38]. When ethene or propene was brought in contact with oxide-supported lr4 [39,40], Ire [39,40], or Rhe (A.M. Argo and B.C. Gates BC, impubhshed results) in the presence of H2, hydrocarbon hgands were formed (namely, alkyls and /r-bonded alkenes), which have been inferred from IR spectra to be intermediates in hydrogenation to make alkanes, as discussed later. The population of these hydrocarbon ligands on the supported clusters depends sensitively on the conditions, such as reactant partial pressures and temperature. 

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