Chemical reactivity mononuclear complexes

There is a marked difference in chemical reactivity between bridging and terminal hydrogens. Terminally bonded hydrogens readily react in a similar manner to that observed for mononuclear hydrides. Thus reactions with chlorinated hydrocarbons such as carbon tetrachloride yield the chloro cluster complexes and chloroform. In contrast, bridging hydrides are stable and may be studied in chlorinated sol-... 

There is a large number of heteroleptic dithiolene complexes—complexes that contain at least one dithiolene and at least one other ligand. This chapter is focused on mononuclear and relatively simple dinuclear complexes. The electrochemistry of heteroleptic dithiolene complexes is only briefly discussed in view of the limited amount of data available. Oxodithiolene complexes are often studied as structural models for Mo and W enzymes and are reviewed in Chapter 10 in this volume (113). Focused here is the chemical reactivity of selected types of heteroleptic dithiolene complexes. 

In general, the N-N bond of mononuclear complexes is not sufficiently weakened to be chemically reactive, and the ligand is usually displaced as an intact nitrogen molecule upon interaction with other ligands [23]. Some of these complexes release ammonia and/or hydrazine when treated with... 

This group demonstrated that both dinuclear complexes 38 and 40 exhibit a remarkably better activity than the mononuclear complexes 39 and 41 at equivalent metal-catalyst concentrations (Table 22.19). The reaction was evaluated/tested against the Monsanto catalyst [Rhl2(CO)2l used in industrial processes, which is formed in situ from [ RhCl(CO)2 2]. In the carbonylation of methanol, 38 outperformed the Monsanto catalyst, whereas 40 demonstrated a similar turnover number. The exceptionally good reactivity could be explained by the formation of thermally stable metal chelate complexes, due to the ort/ o-carborane(12) backbone. NMR spectra of the residue at the end of the reaction showed a high content of phosphine bound to rhodium with a retained bimetallic structure, indicated by the chemical shifts and coupling constants. 

This chapter is intended to cover major aspects of the deposition of metals and metal oxides and the growth of nanosized materials from metal enolate precursors. Included are most types of materials which have been deposited by gas-phase processes, such as chemical vapor deposition (CVD) and atomic layer deposition(ALD), or liquid-phase processes, such as spin-coating, electrochemical deposition and sol-gel techniques. Mononuclear main group, transition metal and rare earth metal complexes with diverse /3-diketonate or /3-ketoiminate ligands were used mainly as metal enolate precursors. The controlled decomposition of these compounds lead to a high variety of metal and metal oxide materials such as dense or porous thin films and nanoparticles. Based on special properties (reactivity, transparency, conductivity, magnetism etc.) a large number of applications are mentioned and discussed. Where appropriate, similarities and difference in file decomposition mechanism that are common for certain precursors will be pointed out. 

The chemistry of bis(alkynyl) metal complexes, including the titanium derivatives, focusing on the synthesis, chemical behavior, structure, and bonding of different type of mononuclear and heterometallic molecules has been discussed in a review.1280 A review focusing the preparation and the reactivity of compounds of the type Cp 2Ti-(ct-C=CR)2 (Cp = Cp, Gp ) has appeared which summarizes special aspects of C-C coupling and cleavage processes in organic reactions.1281... 

In this section, we will describe some examples of surface reactivity, where a metal complex (being mononuclear or cluster) reacts in a chemical sense with some of the functionalities that are present on the solid used as support. The reactions involving grafted organic fragments introduced beforehand in order to play the role of ligands for the metallic entities will be treated in the last section of this chapter. 

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