Nachweis und Darstellung gemischter Fluoro‐Chloro‐Komplexe von Platin(IV) und Iridium(IV)

Abstract

Alle Komplexe der Reihen [MFnCl6−n]2−; M = Pt, Ir; n = 1–5 lassen sich mit Hilfe der Ionophorese qualitativ nachweisen [PtFCl5]2− und fac‐[PtF3Cl3]2− werden in reiner Form isoliert und IR‐spektroskopisch untersucht. Die Bedeutung wirksamer Trennmethoden für die Darstellung chemisch sehr ähnlicher Gemischtligandkomplexe wird kritisch diskutiert.

Preparation and Spectroscopic Investigations of Mixed Octahedral Complexes and Clusters

“…A more common type of oxidative ligand exchange is the preparation of fluoro-mixed complexes utilizing BrF 3 . The postulated stereospecific formation of fac -K 2 [PtF 3 Cl 3 ] as the sole oxidation product of K 2 [PtCl 6 ] with BrF 3 has never been verified. , Depending on the reaction conditions, other mixed species [PtF n Cl 6 - n ] 2- have been detected; however, for n = 2, 3, 4, only the cis/fac isomers have been present . Corresponding fluorochloro complexes are known for Re(IV,V), Os(IV,V), and Ir(IV,V). − Octahedral complexes containing the heavier halides, Br or I, together with F are rare, but are known for Pt(IV) and Os(IV), ,, and most notably Re(IV), for which there are many examples of 3-fold mixed species …”

“…The other approach to the problems presented by the case of mixed-hexahalogeno metalates, the direct preparation of pure species, is burdened with difficulties, and any reports of such must be considered with severe scepticism. 19 Not only in early publications, [20][21][22][23][24] but even recently, 25 there have been many reports of direct synthesis of unique mixed complexes that are actually mixtures of several components, regardless of a correct gross analytic composition, which implies the presence of only the desired species. The fundamental error is the supposition that by the reaction of educts in distinct molar ratios, distinct substances of defined composition are obtainable.…”

“…The postulated stereospecific formation of fac-K 2 [PtF 3 Cl 3 ] 53 as the sole oxidation product of K 2 -[PtCl 6 ] with BrF 3 has never been verified. 19,54 Depending on the reaction conditions, other mixed species [PtF n Cl 6-n ] 2have been detected; however, for n ) 2, 3, 4, only the cis/fac isomers have been present. 55 Corresponding fluorochloro complexes are known for Re(IV,V), Os(IV,V), and Ir(IV,V).…”

“…In the early 1960s NMR spectrometers, operating in the continous wave mode at 1.4 T ) 60 MHz for 1 H and 56.4 MHz for 19 F, became commercially available. Consequently, the first investigations on mixed-ligand compounds focused on 19 F NMR spectroscopy taking into account the central importance of fluorine in the field of coordination chemistry. [186][187][188] Because of this low magnetic field, only the most sensitive and 100% abundant spin 1 / 2 nuclei 1 H and 31 P beside 19 F were initially investigated.…”

Darstellung und Schwingungsspektren von Fluoro-Chloro-Osmaten(IV) einschließlich der Stereoisomeren/ Preparation and Vibrational Spectra of Fluoro-Chloro-Osmates(IV) Including Stereoisomers

“…Zwar ist der Nachweis aller G lieder der Reihe [WF"C16_"] und vieler F-haltiger Spezies von Sn(IV) durch NM R-M essungen in Gleichgewichtslösungen bereits vor längerer Zeit geführt worden [5,6], die Isolie rung reiner Verbindungen beschränkt sich aber auf einzelne kinetisch stabile Fluorohalogenokom plexe der schwereren Platinelem ente [7][8][9], Von diesen sind durch Ligandensubstitution in organischen Solventien jedoch nur die niedrig fluorierten Spezies zu gänglich [10,11].…”