Indium complex, transition metal,

Transition-metal complexes of indium and indium adducts are available.Structures, bonding, reactivity, and their materials-related applications are of current interest in the early 2000s. 

Oxidative addition at electron-rich transition metal centers has been exploited as an alternative route to transition metal complexes of Group 13 ligands. Sources of the highly reactive 14-electron species [Pt(dcype)] react with gallium and indium trialkyls MR3 (M = Ga, In R = CH2 Bu, CH2SiMej) via oxidative addition of a M-C bond to give species of the form (dcype)Pt(R)(MR2) (43-46, Scheme 13.4) [219]. 

Although in this chapter we shall be restricting coverage to reactions of transition-metal complexes, the phenomenon of oxidative addition is not confined to this type of compound. Such reactions are also well established for non-transition metals—a recently reported example concerns the oxidative addition of methyl bromide to indium(i) bromide to give InBr2Me— and for non-metals, as in the reaction of phosphorus trichloride with chlorine, to cite a very familiar example. Likewise, reductive eliminations are known and studied outside the area of transition-metal complexes. One example has been mentioned in Chapter 1 of Part II of this volume, namely the elimination of alkyl halides from the thallium(iii) compounds TlRXa. ... 

The cyclotrimerization of alkynes catalyzed by transition metals is a general method for building substituted benzenes from aliphatic precursors. Multiple bonds are formed in these reactions in a single operation. Although the reaction of thermal trimerization relates to allowed electro-cyclic processes, it is catalyzed by several transition metals, such as Co, Ni, Rh, Pd, Rh, and Ru [38]. Most recent publications show promise for the participation of transition metal complexes in [2+2+2] cycloaddition reactions based on zirconium, titanium, and indium [9]. This reaction has synthetic potential for using metallocyclopentadienes as intermediates in the cyclotrimerization of alkynes. The reaction mechanism is shown in Scheme 2.1 [3, 38]. Two alkyne molecules coordinated to the metal, that is, complex 2.1, couple to form cyclopentadiene 2.2. Next there is either addition of the alkyne to the metallocycle 2.3 to form the metallocycle... 

Indium and gallium coordination compounds containing phosphine ligands have recently aroused interest for their widespread application as intermediates in the preparation of the Group 13 - Group 14 semiconductors [4], Since the early reports about compounds with transition metal-indium bonds [51, relatively little research has been reported in this field. However there is a growing interest in the coordination chemistry and structural features of heterometallic indium [6] and gallium complexes [7] which are also attractive as potential precursors of new materials with particular properties. 

Two classes of promoter have been identified for iridium catalysed carbonylation (i) transition metal carbonyls or halocarbonyls (ri) simple group 12 and 13 iodides. Increased rates of catalysis are achieved on addition of 1-10 mole equivalents (per Ir) of the promoter. An example from each class was chosen for spectroscopic study. An Inis promoter provides a relatively simple system since the main group metal does not tend to form carbonyl complexes which can interfere with the observation of iridium species by IR. In situ HP IR studies showed that an indium promoter (Inl3 Ir = 2 1) did not greatly affect the iridium speciation, with [MeIr(CO)2l3] being converted into [Ir(CO)2l4] as the batch reaction progressed, as in the absence of promoter. 

Finally, we note a report of the synthesis and structure of a mixed transition metal-indium complex containing iron and manganese derived from the reaction between [Hg Mn(CO)5 2], [Fe(CO)5], and indium metal, viz. [ Fe(CO)4 2 /i-InMn(CO)5 2], 16 (27) (see Fig. 5). This complex is structurally similar to the manganese-indium complex 11 with each Mn(CO)4 fragment replaced in 16 by an Fe(CO)4 moiety. The increase in the electron count by two has been assumed to account for the absence of a Fe—Fe bond in 16 in contrast to the suggested presence of a corresponding Mn—Mn... 

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