Mono complexes ruthenium

Terpyridine moieties have been introduced as a terminal unit of macromolecules. In a subsequent procedure the two-step self-assembly process based on Rum/Run chemistry was used for polymers end-capped with the 2,2/ 6/,2 -terpyridine ligand. More precisely, the terpyridine-functionalized polymers were complexed with RUCI3 to selectively form a mono-complex. In a further step, this mono-complex was reacted under reducing conditions with other uncomplexed 2,2/ 6/,2/-terpyridine-terminated polymer blocks in order to form an asymmetrical AB ruthenium(II) frzs-complex. 

The mono-pincer ruthenium(ll) complex was successfully employed in the transfer hydrogenation of ketones (acetophenone, benzophenone, cyclohexanone) with isopropyl alcohol as the hydrogen source. 

The mono-pincer ruthenium(II) complex was successfuUy employed in the oxidative cleavage of olefins to aldehydes, dialdehydes or keto-aldehydes. 

The overall process, schematically represented in Figure 5, comprises two interconnected catalytic cycles a photochemical one involving [Ru(bpy)3]2+ and a thermal one involving the bis-bpy or mono-bpy ruthenium(II) complex. The reduced [Ru(bpy)3] complex was photogenerated by reductive quenching of the photosensitizer excited state by TEOA (eq. 5), with a rate constant of 1.7 10 M s. ... 

Imidazole is characterized mainly by the T) (N) coordination mode, where N is the nitrogen atom of the pyridine type. The rare coordination modes are T) - (jt-) realized in the ruthenium complexes, I-ti (C,N)- in organoruthenium and organoosmium chemistry. Imidazolium salts and stable 1,3-disubsti-tuted imidazol-2-ylidenes give a vast group of mono-, bis-, and tris-carbene complexes characterized by stability and prominent catalytic activity. Benzimidazole follows the same trends. Biimidazoles and bibenzimidazoles are ligands as the neutral molecules, mono- and dianions. A variety of the coordination situations is, therefore, broad, but there are practically no deviations from the expected classical trends for the mono-, di-, and polynuclear A -complexes. 

A versatile route to 3-benzoheteropines has been reported starting from o-phthalaldehyde, including the first preparations of 3-benzarsepines and the parent 3-benzothiepin and 3-benzoselenepins <96CC2183>. l,7-Dihydro-l//-dibenzo[c,c]tellurepin has been prepared from 2,2 -bis(bromomethyl)biphenyl and potassium tellurocyanate and its complexes with palladium and ruthenium species have been studied, a number of mono- and binuclear complexes are formed <96RTC427>. 

The bulky ruthenium TMP complex Ru(TMP) is very electron deficient in the absence of any coordinating ligand, and a tt-complex with benzene has been proposed. In fact, it readily coordinates dinitrogen, forming the mono- and bis-N adducts Ru(TMP)(N2)(THF) and Ru(TMP)(N2)2, - As a result, the use of the TMP ligand for careful stereochemical control of the chemistry at the metal center, which has been very successful for the isolation of elusive rhodium porphyrin complexes, is less useful for ruthenium (and osmium) because of the requirement to exclude all potential ligands, including even N2,... 

The bifunctional amine-tethered ruthenium(II) arene complexes [Ru(r6 ti1-C6H5CH2(CH2)i1NH2)C12] (n = 1,2) (13a,b) show two consecutive hydrolysis steps to yield the mono- and bis-aqua complexes (64). At extracellular chloride concentrations, the majority of the complexes could be expected to be present as the mono-aqua adduct. Equilibrium constants were determined for both steps (for 13b, Ki = 145 mM K2 = 5.4 mM) and found to be considerably higher than those of cisplatin, which also has two reactive sites available. 

The iron subgroup exhibits a plethora of nonclassical M H Si interactions both for mono- and dinuclear complexes. Iron in the high formal oxidation states IV and ruthenium in the high formal oxidation states IV-VI are particularly prone to form such species. Some of them having three or more hydrides will be discussed in Section IV. 

A special type of reaction is observed with the platinum(IV) complex [PtI(Me)3] which cleaves the Af,N,Af, A -tetraphenyltetraaminoethylene under reduction to form the dimeric cyclometallated mono(NHC) complex of platinum(II) iodide [Eq. (31)]. Cyclometallation with the same ligand is also observed for ruthe-nium. Additional cyclometallations with various substituents of NHCs have been reported for ruthenium(II), rhodium(III), iridium(I), palladium(II), " and platinum(II). In the case of iridium, alkyl groups can be activated twice. In rare cases like for nickel(II) /x-bridging NHCs have been obtained. ... 

Fig. 5 Typical half-sandwich ruthenium fragments used in the preparation of allenylidene complexes. Ancillary ligands include CO, mono- and bidentate phosphines or N-heterocyclic carbenes...

The formation of other mono- [27-29] or even bis[alkoxy(alkenyl)allenylidene[ ruthenium complexes [28, 30] from the corresponding ruthenium chlorides and 5,5 -diphenyl-penta-1,3 -diynyl alcohol or trimethylsilyl ether in the presence of methanol (Scheme 3.13) and of the allenylidene complex 18 in the absence of methanol (Scheme 3.13) [30, 31] was also suggested to proceed via pentatetraenylidene intermediates. Neither one of these pentatetraenylidene complexes could be isolated or spectroscopically detected although their formation as an intermediate was very likely. 

Other recent reports have also indicated that mixed-metal systems, particularly those containing combinations of ruthenium and rhodium complexes, can provide effective catalysts for the production of ethylene glycol or its carboxylic acid esters (5 9). However, the systems described in this paper are the first in which it has been demonstrated that composite ruthenium-rhodium catalysts, in which rhodium comprises only a minor proportion of the total metallic component, can match, in terms of both activity and selectivity, the previously documented behavior (J ) of mono-metallic rhodium catalysts containing significantly higher concentrations of rhodium. Some details of the chemistry of these bimetallic promoted catalysts are described here. 

If cycloalkene-yne 65 having an o -alkynyl substituent at an olefinic position in a cycloalkene is treated with a ruthenium catalyst, what kinds of products are produced. In this reaction, ruthenium mono-substituted carbene complex XVII is anticipated to be formed from a highly strained ruthenacyclobutane intermediate. If it then reacts with ethylene, triene 67 should be formed, but if XVII reacts with an alkene part intramolecularly, bicyclic compound 66 should be formed via ruthenacyclobutane (Scheme 23). 

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