Rhenium carbonyls

SCHEME D Some reactions of rhenium carbonyl chlaide. 

The metal complexes most commonly used in these photoredox systems are manganese and rhenium carbonyls. The proposed mechanism of the photoredox... 

Deposition temperature range is 400-600°C at a pressure of 200 Torr. Rhenium carbonyl is a solid at room temperature and must be vaporized at a temperature > 117°C. It decomposes at 250°C. This reach on is used for the coating of spheres in a fluidized bed. 

Reaction of the manganese and rhenium carbonyls, M2(CO)10, with Ru3(CO)12 or Os3(CO)12 in a 3 1 ratio yields the products [M(CO)5]2M (CO)4, with M = Re or Mn, M = Ru or Os. These are considered to be linear trinuclear metal systems. The only other trinuclear carbonyl derivative isolated is OsCo2(CO)n, obtained as one of a number of compounds from the reaction of Co2(CO)8 with H2Os(CO)4. No structural data are available for this compound (241). 

The existence of the neutral rhenium carbonyl [Re(C0)4] was first claimed in 1965 206 but, although it is easily sublimed, it has not yet been characterized by mass spectrometry and the value of n is still not known. This colourless substance [v (CO) 2055 and 1995 cm-1 in CHC13] has been obtained as a by-product in the synthesis of Re2(CO)i0 starting from Re2S7, copper powder, and carbon monoxide at 85 atm, 200 °C206>. There has also been a report of the compound Re4(CO)10(PPh2Me)6, which can be considered to be a substitution product of the hypothetical species, Re4(CO)i6 it has been obtained by a photochemical reaction between Re2(CO)j0 and PPh2Me194. In both cases, and particularly in the phosphine derivative, a tetrahedral structure seems improbable because of steric constraints. 

Table 13. Enthalpy of formation, AHf (g) and disruption, AH (kj mol x) of alkyl and acyl derivatives of manganese and rhenium carbonyls...

Silicon and germanium hydrides react with cobalt, manganese and rhenium carbonyls affording complexes having a silicon (or germanium)-metal bond. These reactions, described previously for inactive compounds have been used in the synthesis of optically active silyl and germyl-transition metals ... 

In a three-component reaction, a cationic platinum isocyanide complex [(Ph3P)2Pt(CNR)Cl][BF4] is reacted with a /3-bromoamine and butyl lithium to give an imidazoldin-2-ylidene complex.This transformation can be a two-component reaction if the isocyanide ligand contains already the necessary amine functionality. This was shown for chromium, molybdenum, tungsten, and rhenium carbonyls. 

To model the photochemical reaction of Re2(CO)io with silica in the presence of THE, silanolates other than silsesquioxanes [Et3SiOH, PhsSiOH, Ph2Si(OH)2 and (OH)Ph2SiOSiPh2(OH)j with [Re2(CO)8(THE)2] have also been synthesized [148], pointing to the formation of the surface species [((r-=SiO)((r-H)Re2(CO)8j in the above-mentioned reaction with silica. Rhenium carbonyl of the two diol derivatives listed above where both the SiOH have reacted are proposed as models for surface reaction with a vicinal hydroxyl residue, although no direct surface species is reported [148]. 

Various rhenium carbonyl compounds can be prepared on the surface of Si02 or MgO (Scheme 16.1), as described below. 

Early Studies on Rhenium-Carbonyl-Hydride Clusters and Related Species... 

A normal nonbridged rhenium-rhenium linkage was about 3.00 A in length in a rhenium carbonyl cluster. This distance expanded by about 0.15 A... 

Platinum nanoparticles, preparation, 12, 78 Platinum-nitrogen bonds, in platinacycles, 8, 508 Platinum-osmium carbonyl clusters, characteristics, 8, 420 Platinum-oxygen bonds, in platinacycles, 8, 505 Platinum particles, surface reactivity, 12, 542 Platinum-phosphorus bonds, in platinacycles, 8, 508 Platinum-rhenium carbonyl clusters, characteristics, 8, 420 Platinum(II)-ruthenium(II) binary complexes, preparation,... 

Figure 13 illustrates two models used to explain the photochemical properties of rhenium carbonyl complexes. The MLCT absorption band often... 

Rhenium carbonyl complexes were used as probes in biological systems. Photoexcitation of [Re(phen)(CO)3(H83)]+AzM2+ and [Re(phen)(CO)3(H107)] + AzM2+ (Az = Pseudomonas aeruginosa azurin M = Cu or Zn) in the presence of the oxidative quencher, Co(NH3)5C1, resulted in the formation... 

I have always regarded the work of my co-worker H. Schulten (66) on the synthesis of rhenium carbonyl complexes as a landmark in our work. 

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