Trinuclear compound

The second type of trinuclear compounds containing (M302(02CR)(,(H20)3] and obtained by the reaction of M(CO)6 (M = Mo, W) with carboxylic acids, features a similar triangle of M-M bonded metal atoms but this time capped on both sides by hj-O atoms (Fig, 23.8d). Complexes m which either one or both of these capping atoms arc replaced by /iy-CR, alkylidene. 

The first cyclic trinuclear compound of gold(I) was reported by Vaughan in 1970 [44], The complex [p,-N, C -pyAu]3 was obtained in a very good yield by adding triphenylarsine gold(I) chloride to a THF solution of 2-pyridyllithium at —40°C, Figure 1.32. 

The dinuclear 2 3 species have been characterized in [Ag20u-dppm)3](OTf)2 and [Ag2(p-dppm)3](N03)2 (92), with the silver centers three coordinate by three phosphorus atoms of different dppm ligands.761,768 A tetranuclear species [Ag2(p-02CMe-0,0 )(p-02CMe-0)(p-dppm)]2 has been obtained by reaction of dppm with two equivalents of AgOAc. 762 The reaction of [Ag(Mes)]4 with dppm gives a trinuclear compound [Ag3(dppm-H)3] (93) in which the dppm ligand has been deprotonated with the formation of mesithylene. In the structure, two of the silver centers are three coordinate to three different phosphorus atoms and the other silver atoms is bonded to two carbon atoms.291,292... 

A trimeric species was formed with one equivalent of a bis(benzimidazole) ligand in the presence of benzylthiolates (59) (Figure 10). Zinc-zinc distances were in the range 3.069-3.958(2) A.126 Other zinc-thiolate trinuclear compounds include Zn3(CH2SiMe3)3(SC6H2iPr3)3 and Zn3(o-phen)2(toluene-3,4-dithiolate)3 but have little structural similarity.81,525... 

A tridentate N02 donor set complex was formed from 2-pyridinecarboxaldehyde N-oxide and 2-aminophenol and gave mononuclear and trinuclear compounds. The trinuclear zinc complex was structurally characterized and revealed bridging acetate groups, [ZnLZn(OAc)4ZnL].865... 

A further example illustrating the importance of lattice effects on the SCO behaviour of these trinuclear compounds is given by [Fe3(iptrz)f,(H20)6] (CF3S03)6 (iptrz = 4-(isopropyl)-1,2,4-triazole). A strong influence of the ST of the central Fe(II) ion on both external Fe(II) ions has been found by Mossbauer spectroscopy, as detected by the perturbation of their quadru-pole interactions [15]. The nature of this phenomenon has been proposed to... 

A further condensation occurs on reaction of the pure trinuclear compounds with CO ... 

A novel tridentate coordination mode for the carbonato-nickel(II) system was reported by Escuer and co-workers (61). The trinuclear compound [Ni2(p-C03)(dmpd)4(H20)][Ni(dmpd)2(H20)2](C104)4 H20 was obtained from the reaction of basic solutions of nickel(II) perchlorate and 2,2-dimethylpropane-1,3-diamine (dmpd) with atmospheric C02. The three nickel atoms show octahedral coordination with three different environments, №( 0 -0,0 )(dmpd)2, №( 0 -0 ) (dmpd)2(H20) and Ni(dmpd)2(H20)2. The carbonate anion acts as a bridge between two nickel ions whereas the [Ni(dmpd)2(H20)2]2 + subunit is linked by hydrogen bonds to the dinuclear group (Fig. 7). The dinuclear [Ni2(p-C03)(dmpd)4(H20)]2 + subunit shows a moderately weak antiferromagnetic coupling with a J value of —7.8 cm-1. 

The bridge-forming proclivity of the neutral cobalt (III) complex, CoL3, has also been demonstrated (6). Two trinuclear compounds of the formula [M(CoL3)]Xn, where M is Ni(II) or Co (III), have been isolated in pure form. Detailed study of these substances indicates that the complex CoL3 forms three mercaptide bridges to the third metal ion, thus providing octahedral coordination of the six sulfur atoms about that ion. Data on these unusual compounds are also included in Tables I and II. 

A trinuclear compound [ Nb(02CH)(Cp) 3(0H)2(0)2] was isolated from the reaction between [Nb(CO)3PPh3)(Cp)f and HCOOH, which involves decarboxylation of the formate... 

Halogenation reactions of Os3(CO) 2 have already been described (78-81). Initially trinuclear compounds are formed, but easy breakdown to mono- and dinuclear compounds occurs with an excess of halogen (81,300). Hydrogenation of Os3(CO)12 at atmospheric pressure gives good yields of... 

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