Cluster species

This section briefly considers the proton H+, the hydride ion H, the hydrogen molecule ion H2, the triatomic 2-electron species H3+ and the recently established cluster species +... 

This behavior is illustrated in Fig. 22, and summarized schematically in Fig 23. It is also noteworthy that nonselective photonucleation may also be arranged by irradiation into Cr/Mo overlap regions (350 nm), upon which, growth of all of the cluster species expected was observed, concomitant with the decay of both the Cr and the Mo resonances (115). 

One of the m jor attractions in the metal-atom synthesis of dimer and cluster species is the ability to isolate highly unsaturated species, M Lm, that may then be considered to be models for chemisorption of the ligand, L, on either a bare, or a supported, metal surface (,100). It is quite informative to compare the spectral properties of these finite cluster-complexes to those of the corresponding, adsorbed surface-layers (100), in an effort to test localized-bonding aspects of chemisorption, and for deciphering UPS data and vibrational-energy-loss data for the chemisorbed state. At times, the similarities are quite striking. 

Heavier Group 13 M—M Multiple Bonding in Reduced Metal Cluster Species... 

Fig. 12. Schematic drawing of the K2Ga4 cluster species K2Ga4(C6H3-2,6-Trip2)2 [66]. H atoms are not shown...

Various homo- or heteronuclear cluster species which contain both a- and 7r-bonded alkynyl groups have been synthesized and characterized, e.g., [Ag5(C=CPh)6]-,278... 

In contrast with formation of three types of bpz-substituted RU3 cluster species, reactions of 2 with pyq induced isolation of monomer 45 and trimer 46 containing 6>rf/ 6>-metallated pyq depending on the reaction conditions [30]. Reduction of the 3+ trimeric complex 46 by addition of aqueous hydrazine gave neutral species 46a. Oxidation of 46a by addition of two equivalents of ferrocenium hexaflu-orophosphate afforded 2+ intercluster heterovalent complex46b containing two Ru30(0Ac)6(py)2II,III,m and one Ru30(OAc)5(py)2II,m,n moieties. 

It has been our goal for some time to run photochemical energy storage reactions without relay molecules or separate catalysts. We have concentrated on the photochemistry of polynuclear metal complexes in homogeneous solutions, because we believe it should be possible to facilitate multielectron transfer processes at the available coordination sites of such cluster species. 

Figure la. Representative dinuclear cluster species of the high- and low-valent... 

Vidal and Walker (17) have observed that Rh(CO)A is in equilibria with Rh5(C0)i5". It is likely that Rh(CO) is also in equilibria with the cluster species in equations (5)-(8) thus, it must also be a part of the benzaldehyde hydrogenation catalyst solution. 

Ford and co-workers (7) have reported a first-order rate dependence on CO pressure in the Ru3(CO)-l2/KOH system and ascribed this effect to CO participation in a rate-limiting elimination of hydrogen from a cluster species. This explanation does not fit our observations, because if loss of H2 were rate-limiting, the use of KOH and NMe3 as bases would be expected to lead to comparable rates for the WGSR. A comparison of activities (Laine (9) 2.3 mol H2 per mol Ru3(CO) 2 Per using KOH/MeOH... 

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