Monomeric complexes, transition metal

The elimination of an alkane from an amido alkyl complex has also formed imido complexes in many cases (Equations 13.57 and 13.58), ° and reactions of a metal polyha-Ude with a silylamine has generated metal-imido complexes. Deprotonation of a cationic amido complex has been used as a route to a monomeric, late transition metal terminal... 

B. Monomerization of Transition Metal Dimer Complexes in Reactions with Polymers... 

Unlike nitric oxide, NO, the monomeric radical sulfur nitride, NS, is only known as a short-lived intermediate in the gas phase. Nevertheless the properties of this important diatomic molecule have been thoroughly investigated by a variety of spectroscopic and other physical techniques (Section 5.2.1). The NS molecule is stabilized by coordination to a transition metal and a large number of complexes, primarily with metals from Groups 6, 7, 8 and 9, are known. Several detailed reviews of the topic have been published. ... 

Monomeric thiazyl halides NSX (X = F, Cl Br) have been characterized in the gas phase, but oligomerization to cyclic species, e.g., (NSX)3 (X = F, Cl) and (NSF)4, occurs in the condensed phase (Section 8.7). These ligands can be stabilized, however, by coordination to a transition metal. The NSF complexes are conveniently prepared in SO2 (Eq. 1.6) The monomeric fluoride NSF is conveniently generated in situ by thermal decomposition of FC(0)NSF2 or Hg(NSp2)2 (Section 8.2). 

Monomeric thiazyl halides can be stabilized by coordination to transition metals and a large number of such complexes are known (Section 7.5). In addition, NSX monomers undergo several types of reactions that can be classified as follows (a) reactions involving the n-system of the N=S bond (b) reactions at the nitrogen centre (c) nucleophilic substitution reactions (d) halide abstraction, and (e) halide addition. Examples of each type of behaviour are illustrated below. 

The heterocycles can be cleaved by reaction with 4-(dimethylamino)pyri-dine, yielding Lewis base-stabilized monomeric compounds of the type dmap—M(R2)E(Tms)2 (M = Al, Ga E = P, As, Sb, Bi). This general reaction now offers the possibility to synthesize electronically rather than kinetically stabilized monomeric group 13/15 compounds. These can be used for further complexation reactions with transition metal complexes, leading to bimetallic complexes of the type dmap—M(Me2)E(Tms)2—M (CO) (M = Al, Ga E = P, As, Sb M = Ni, Gr, Ee). 

The six-membered 1,4-diborines (1,4-diaboracyclohexadienes) are prepared by cocondensing alkynes with monomeric BF or by the tin route . They form a series of transition-metal complexes VIII-XIV by reaction with various complex... 

With the exception of a brief report of a dimethylaluminum complex [5], the coordination chemistry of the monomeric anion in (4) has not been investigated. By contrast, Stahl and co-workers have carried out extensive studies of both main group element and transition-metal complexes of the chelating dianion in the cube (7), which have been summarized in a recent review [9]. A noteworthy feature of the ligand behaviour of this N,N chelating dianion is the additional in-... 

Coordination chemistry of ER The monomeric fragments E-R are isolobal to carbon monoxide, and many complexes analogous to transition metal carbonyls have been synthesized (41 to 43, see Figure 2.3-7) [68], In most cases these reactions started with those clusters which have a high tendency to dissociate and to form monomers, such as pentamethylcyclopentadienylaluminum(I) or the alkylgal-lium(I) or alkylindium(I) derivatives. Often the products are isostructural to the respective metal carbonyls, but exceptions are the gallium compounds 44 and 45. 

The oxidation rates of XOH were measured for the PVP complexes of the transition metal ions of the 4th series, i.e., Cr, Mn, Fe, Co, Ni, Cu and Zn ion. As can be seen in Fig. 2 (a), the Cu complexes exhibit the highest activity and the activity of the PVP-Cu catalyst is higher than that of the monomeric pyridine-Cu catalyst. To this Cu complex, equivalent amount of the second metal component was added i.e., the PVP-Cu, secondary metal ion mixed complexes were prepared. The activities of these mixed complexes are summarized in Fig. 2 (b). One notices that Mn ion increases the catalytic activity of the Cu ion although Cr and Fe ion inhibit the catalytic activity. Another important result in Fig. 2 (b) is that the effect of secondary metal ion is more clearly observed in the PVP system, comparing to the monomeric pyridine catalysts. 

Since photolysis of monomeric di- and polyhydride transition metal complexes often leads to elimination of H2 as the... 

Catalytic hydrogenation of alkynes by a monomeric transition metal complex was thought to yield exclusively the Z-alkene. However, Bargon and coworkers [213, 214], who have been active in PHIP research, observed the formation of -alkenes using [RuCp (alkene)[ as catalyst. Figure 1.36 shows the NMR spectrum after... 

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