Platinum complexes infrared spectra

After this we embarked upon a comprehensive study of the infrared spectra of amine complexes of platinum and palladium. By we, I don t just mean Joe, the leader, and myself, but Alan Williams, George Gamlen, Bernard Shaw and last, but far from least, Luigi Venanzi who had the gift of being able to synthesise any compound you could think of which might have an interesting infrared spectrum. Incidentally I remember him not just for his chemical skills but as the most... 

There followed many other exciting adventures involving studies of the infrared spectra of transition-metal complexes, but I will mention just one which I find particularly memorable. This followed the discovery by Bernard Shaw of a remarkably stable volatile platinum complex produced by reduction of [PtCl2(PEt3)2], the spectrum of which had a very strong and sharp absorption band near 2200 cm ... 

On the other hand, the palladium and platinum complexes of pyridine-2-aldoxime, when treated with acetyl chloride in hot chloroform, gave stable chelates containing the acylated ligand. A monoacetylated palladium chelate was isolated in which 1 mole of pyridine-2-aldoxime was replaced by two chloride ions (see reaction XXIV). This compound was identified by its infrared spectrum, which had a strong carbonyl absorption band near 1790 cm-1. The platinum complex of pyridine-2-aldoxime gave a... 

There is no mention in Table 4.2 of structures, either on surfaces or in complexes, wherein two or more of the same type of hydrocarbon molecule are attached to the same metal atom or ion. Because of the wide occurrence of carbonyl complexes, where the M—CO bond is similar to that in the alkene complexes, this is somewhat surprising, but in view of their greater size it is likely that steric repulsion would inhibit their formation except perhaps at atoms of low CN. Somewhat unstable complexes of the form " E2M (M=Pt, Pd) are known, that with platinum being the more stable, and a number of complexes denoted as " E2M and " E3M (M=Co, Rh, Ni, Pd, Pt and Cu) have been formed by matrix isolation in a solid Group 0 element at very low temperature, as well as " EM species. The infrared spectrum of " EPd closely resembles that of the adsorbed structure 2, but there are additional bands that, because of the metal-surface selection rule, are not visible for the adsorbed species. Moreover the measurement of UV-visible spectra is possible. This fascinating area of -complex chemistry, which has produced several prophetic insights into catalytic mechanisms, has been sadly neglected for many years it merits renewed attention. 

All of the physical measurments point to the equivalence of all the platinum atoms (in a noninteger oxidation state) in a chain. The results of the numerous measurements on K2Pt(CN)4Bro.3(H20)s, demonstrates this system to be a one-dimensional metal undergoing a metal-insulator transition as the temperature is lowered. The far infrared and optical measurements show that the electronic excitation spectrum is not that of a simple one-dimensional metal but has a complex behavior at low frequencies. The available data from many diverse types of experiments have been analyzed in terms of numerous models. This system is currently best characterized in terms of a one-dimensional metal undergoing a Peierls transition to a semiconductor at low temperatures, with evidence for the presence of a pinned charge density wave. Further careful measurements of the partially oxidized tetracyanoplatinates are necessary to fully understand the applicability of various one-dimensional models to this class of materials. 

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