Transition metal complexes silver

Monomeric transition metal complexes (silver and rhodium) of these Janus bis-carbenes were synthesised by standard procedures, either with reaction of the bis-imidazolium salt with silver(l) oxide or by preparing the free carbene by proton abstraction with LDA and subsequent reaction with [Rh(cod)Cl]2 [379] (see Figure 3.121). If the wingtip group is... 

The preparation of a series of transition metal complexes (Co. Ni. Pd. Pt, Ir. Au. Cu. Ag) with ambident anion (70) and phosphines as ligands has been reported recently (885). According to the infrared and NMR spectra the thiazoline-2-thione anion is bounded through the exocyclic sulfur atom to the metal. The copper and silver complexes have been found to be dimeric. 

Although trialkyl- and triarylbismuthines are much weaker donors than the corresponding phosphoms, arsenic, and antimony compounds, they have nevertheless been employed to a considerable extent as ligands in transition metal complexes. The metals coordinated to the bismuth in these complexes include chromium (72—77), cobalt (78,79), iridium (80), iron (77,81,82), manganese (83,84), molybdenum (72,75—77,85—89), nickel (75,79,90,91), niobium (92), rhodium (93,94), silver (95—97), tungsten (72,75—77,87,89), uranium (98), and vanadium (99). The coordination compounds formed from tertiary bismuthines are less stable than those formed from tertiary phosphines, arsines, or stibines. 

In 2007, Fernandez et al. demonstrated that transition-metal complexes with heterobidentate S/C ligands based on imidazopyridin-3-ylidene and thioether functionalities could be readily prepared from the corresponding azolium salts by reaction with Ag20 and transmetalation of the resulting silver carbenes with appropriate metal sources. The cationic Pd(allyl)(carbene-S) complexes have proven to be active catalysts in the test reaction, reaching enantioselectivities of... 

Trost exploited the annulation of electron rich phenols and alkynoates to obtain coumarins in the presence of transition metal complexes. Ethyl propiolate and 3,4,5-trimethoxyphenol were coupled in formic acid in the presence of a palladium complex and sodium acetate to give 5,6,7-trimethoxycoumarin via a net C-H insertion in acceptable yield (4.42.). The coupling, characteristic of electron rich phenols, was also catalyzed by other transition metals, such as platinum or silver.56... 

The reactions of chlorosilicon and chlorogermanium transition metal complexes with silver hexafluoroantimonate, as well as with silver tetrafluoroborate or silver hexafluorophosphate. 

The complexing capacity of hydroxamic acids was predicted by Werner in 1908, who also indicated the metals most likely to form stable complexes.288 Since then, the formation of poorly soluble and intensely coloured hydroxamates has been used for analytical determinations for a number of metal ions, such as Fe3+, Mos+, Vs+ etc. A recent general review of transition metal complexes of hydroxamic adds included the few known examples of silver(I) complexes.289... 

Transition metal complexes were known to facilitate the addition of silylene to acetylenes from a variety of different sources.60,61,90,91 These conditions, however, often required heating, and the initially formed silacyclopropene often incorporated a second molecule of the acetylene to afford a silole.92,93 With their discovery of low-temperature silver-mediated di-ferf-butylsilylene transfer conditions from cyclohexene silacyclopropane 58 to olefins, Woerpel and coworkers set out to investigate the... 

Transition metal complexes containing catecholate and semiquinone ligands have been reviewed by Pierpont and Buchanan.336 The syntheses of catecholate adducts of platinum group metals by oxidative addition of benzoquinone (BQ) have been reported (reaction 92).337 The coordinated catechol can then be oxidized to the semiquinone with silver ion (reaction 93). In reactions (92) and (93), L M = lr(Cl)(CO)(PPh3)2] and the benzoquinones (BQ) are shown in (146). The oxidative addition of phenanthrenequinone to [Ir(Cl)(CO)(PPh3)2] has also been cited.338... 

Pyrazine derivatives were again popular as ligands in crystallographic studies of transition metal complexes. These complexes included silver(I) alkylpyrazine sulfonates 83 <07IC7299>, tetrakis[3-(pyrazin-2-yloxy)pyridinc-AiVJdithiocyanatomanganese <07AX(E)m441>,... 

One of the most generally used methods to prepare a NHC transition metal complex is the reaction of an azolium salt with silver oxide to form the silver carbene complex [24,25,72], It is so general that it has its own name, the silver(I) oxide (Ag O) method... 

Although the main emphasis with imino functionalised carbene hgands is on their silver complexes, as carbene transfer agents, and on late transition metal complexes - palladium. 

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