Carbonyl hydrides structure

Carbonyl hydrides and carbonylate anions are obtained by reducing neutral carbonyls, as mentioned above, and in addition to mononuclear metal anions, anionic species of very high nuclearity have been obtained, often by thermolysis. These are especially numerous for Rh and in certain Rh, Rh and Rhi5 anions have structures conveniently visualized either as polyhedra encapsulating further metal atoms, or alternatively as arrays of metal atoms forming portions of hexagonal close packed or body... 

Some carbonyl hydrides, such as Cr2(CO)ml l, have the hydrogen atom in bridging positions as shown in the structure... 

Two hydrogen bridges are present in some carbonyl hydride complexes. This is illustrated by the structure of the [H2W2(CO)8]2 anion,... 

Hydrogen forms an extensive series of compounds with the metal carbonyls, and the nature of the H bonding within these complexes has been a point of debate for a considerable period. Both the chemistry and structure of metal carbonyl hydride compounds have been exten-... 

In this chapter we have examined examples of polynuclear metal carbonyl complexes as well as simple metal carbonyl hydrides. Consider now the polynuclear carbonyl hydride complex, H,Os,(CO)i2- Rationalize the formulation of this species. From your application of the 18-electron rule, what can you say about the structure of this molecule1 How is it similar to or different from the complex Os COln shown in Figure 5.9 (See Churchill M. R. Wasserman, H. J. Iticrg, Chen. 1980, 19, 2391-2395.)... 

Hydrolysis of (14) readily yields MeOH (78). The carbonyl hydride complex (13) forms by the addition of CO to Zr(C5Me5)2H2 and possibly by the reaction of Zr(C5Me5)2(CO)2 with H2, although only the former route allows its observation. In the absence of the dihydride complex Zr(C5Me5)2H2, (13) reacts with itself on warming from -80°C to 25°C yielding the unusual enediolate dimer (15) with the structure postulated as shown (78). 

As indicated in the introduction, bis-l,3-diphenylphosphino-propane (dppp) and bis-l,2-diphenylphosphinoethane (dppe) were reacted with tris(triphenylphosphine)rhodium(II) carbonyl hydride in toluene-deuterobenzene solution to derive cis-chelate complex hydroformylation catalysts. These complexes were expectedly non-selective terminal hydroformylation catalysts for 1-butene hydroformylation (see Table I) because of their cis-stereochemistry. They were also somewhat less active due to their specific structural features. The structure of these complexes in solution was studied in detail by P-31 NMR spectroscopy. 

Chromium-based reagent systems, for pinacol coupling, 11, 63 Chromium carbenes, in ene-yne metathesis, 11, 272 Chromium carbonyl compounds with bridging hydrides, 5, 206 computational studies and spectroscopy, 5, 203 experimentally determined structures, 5, 204 nitro and nitroso compounds, 5, 205 silatropic migrations, 5, 249 with very weakly bonded ligands, 5, 205 Chromium carbonyl hydrides, preparation and characteristics,... 

Other monomeric carbonyl hydrides whose structures have been investigated are the cis and trans isomers of [H2Re(CO)4]- 49,5°). In neither case have the hydride ligand s been directly located. Trans-[H2 Re(C0)4 ] was prepared in low yield from the pyrolysis of c/s-[H2 Re(CO)4 ], and was isolated as crystals of an unusual mixed salt [NEt4]2[Re4(CO)I6]2 [NEt4]+[H2Re(CO)4] 5°) (Fig. 8). 

When NO donates the odd electron to the central atom the NO+ ion is produced which can replace the isoelectronic CO. Compare the isoelectronic compounds Ni(CO)4, Co(CO)3NO and Fe(CO)2(NO)2, all with the same spatial structure. These, therefore, correspond with the above-mentioned carbonyl hydrides. 

As noted earlier HCo(CO)4 and H2Fe(CO)4 were the first known hydrides. Carbonyl hydrides and carbonylate anions have been intensively studied in part because they are intermediates in many metal catalyzed reactions involving CO and H2. The structure of HMn(CO)5 is shown in Fig. 2-7. 

In solution these carbonyl hydrides act as very weak monobasic acids. The iron and cobalt carbonyl hydrides arc isoelectronic with Ni(CO)4 and have the same tetrahedral structure ... 

A plethora of metal complexes have been stated to catalyze the hydroformylation reaction. Oxo catalysts typically consist of a transition metal atom (M) which enables the formation of a metal carbonyl hydride species. Optionally, these complexes may be modified by ligands (L). A general composition is represented by Structure 1. 

Studies on the structures of the carbonyl hydrides indicate that the CO groups are essentially different from the —COH group it seems proper to designate the two in different ways. The names suggested for compounds 4 and 5 indicate this. 

These compounds may be formed directly from the metal halides by the action of CO (for example, CO and anhydrous C0I2 give Co(CO)l2) or, in the case of iron iiylirectly from the carbonyls or carbonyl hydrides. The only carbonyl fluoride which has been well characterized has the empirical formula Mo(CO)2F4 a dimeric structure with two bridging F atoms has been suggested. The compounds Pt(CO)2p8 and Rh(CO)2p3 have been described as the products of the action of... 

Huo et al. studied the structure and energies of cobalt-carbonyl radicals as well as the cationic and anionic homoleptic mononuclear cobalt-carbonlys and the cobalt-carbonyl hydrides.35 The B3LYP functional was applied with all-electron triple- quality basis. They found that most of these complexes prefer less symmetrical structures and minor structural deformations may result in large energetic differences. 

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