Metal block organometallic compounds

The use of bulky monodentate m-terphenyl ligands in the stabilisation of d-block organometallic compounds is surveyed. Importantly, these ligands have facilitated the isolation of hitherto unknown species containing low-coordinate centres and metal-metal multiple bonds. This review reports on these advances with emphasis on the synthesis, structural characterisation and, where possible, reactivity studies of complexes featuring metal-carbon bonds between m-terphenyl ligands and the transition metals. 

Gas Phase Photoelectron Spectra of d- and /-Block Organometallic Compounds Table 10. Ionization energies (eV) of lanthanide and actinide cyclopentadienyl metal halides... 

Table 19.3 Oxidation states of the d-block metals the most stable states are marked in blue. Tabulation of zero oxidation states refers to their appearance in compounds of the metal. In organometallic compounds, oxidation states of less than zero are encountered (see Chapter 23). An oxidation state enclosed in [ ] is rare.

Gatti C, Lasi D (2007) Source function description of metal-metal bonding in d-block organometallic compounds. Earaday Discuss 135 55-78... 

Low oxidation states - An important characteristic of transition metal chemistry is the formation of compounds with low (often zero or negative) oxidation states. This has little parallel outside the transition elements. Such complexes are frequently associated with ligands like carbon monoxide or alkenes. Compounds analogous to Fe(CO)s, [Ni(cod)2] (cod = 1,4-cyclooctadiene) or [Pt(PPh3]3] are very rarely encountered outside the transition-metal block. The study of the low oxidation compounds is included within organometallic chemistry. We comment about the nature of the bonding in such compounds in Chapter 6. 

Orpen, G., Brammer, L., Allen, F. H., Kennard, 0., Watson, D. G., Taylor, R., Tables of bond lengths determined by X-ray and neutron diffraction. Part 2. Organometallic compounds and co-ordination complexes of the d- and / block metals. 

In an important paper, Braga, Grepioni, Desiraju and co-workers highlighted the abundance of C-H OC(M) hydrogen bonds in crystals of organometallic compounds [28b], The use of the CSD to analyse such hydrogen bonds across the series of d-block metals Ti-Ni led to a number of specific findings ... 

Fouling occurs by decomposition of organometallic compounds of the oil and deposition of the generated metals in the porous structure of the catalyst, blocking the active sites and plugging the pores. Long-term accumulation of these metals in the catalyst pores can result in permanent deactivation of the catalyst. 

Compounds of these metals involving either a- or tt-bonds to carbon are generally much more reactive to both air and water than those of the d-block metals. Thus there is no lanthanide equivalent of ferrocene, an unreactive air- and heat-stable compound. They are often thermally stable to 100 °C or more, but are usually decomposed immediately by air (and are not infrequently pyrophoric). Within these limitations, lanthanide organometallic compounds have their own special features, often linked with the large size of these metals. 

Typical Interatomic Distances in Organic Compounds and Organometallic Compounds and Coordination Complexes of the d- and f-block metals... 

Table A.2. Table of average bond lengths in organometallic compounds and coordination complexes of the d- and f-block metals (The following special symbols are used (tt) Refer to the full publication [10] for more complete information, including CSD refcodes and short format references to most excluded values (t) See Figure A.5 ( ) Cluster complexes, no coordination number assigned.) The numbers in column Note refer to the entries in Table A.5...

Compounds containing M—C bonds where M is an 5-block element are readily classified as being organometallic. However, when we come to the p-block, the trend from metallic to non-metallic character means that a discussion of strictly organometallic compounds would ignore... 

Organometallic chemistry of the s- and p-block elements was described in Chapter 18, and we now extend the discussion to organometallic compounds containing J-block metals. This topic covers a huge area of chemistry, and we can only provide an introduction to it, emphasizing the fundamental families of complexes and reactions. 

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