Binuclear coordination compounds

Theory of bridge bonding and the structure of binuclear coordination compounds. B. Jezowska-Trzebiatowska and W. Wojciechowski, Transition Met. Chem. (N.Y.), 1970,6,1-58 (203). 

Dehydration/anation reactions yielding binuclear coordination compounds... 

BINUCLEAR COORDINATION COMPOUNDS WITH POLYDENTATE LIGANDS... 

Binuclear coordination compounds with polydentate ligands 517... 

However, binuclear coordination compounds of lanthanides with H2LI702 are... 

The advent of pulsed methods has allowed the development of dynamic studies of electron transfer in the nanosecond, the picosecond and now the subpicosecond range. In principle, by using an unsymmetrical binuclear complex, it should be possible to study dynamic electron transfer after triggering by an optical excitation. This would allow the connexion with the study of spontaneous electron transfer. However, this kind of experiment has proved to be particularly difficult with binuclear coordination compounds. The first report has been made by Creutz, Netzel, Sutin et al on the unsymmetrical system ... 

There are few reported coordination compounds of Ir°. Monomeric Ir° species are paramagnetic (id9 electronic configuration), and binuclear compounds are diamagnetic with a metal-metal bond. 

Until recently, the information on the coordination compounds of 2-substituted tetrazoles 6 was very poor. It has been shown that reaction of mono- and binuclear 2-substituted tetrazoles with zinc(ll) perchlorate and copper(n) chloride in organic solvents gives coordination polymers 280 containing as a ligand 2H-monosubstituted tetrazole ring (Equation 50) <2002ICA(340)215, 2005ICA3949>. 

The compounds, similar to 549 [for example, CpW(C0)3(B02C6H4)], were found to cause C — H activation with the elimination of R — B02C6H4. Coordination compound 550 [942,946] is close in its nature to compound 545. Binuclear complexes of types 546, for instance 551, were characterized by x-ray dilfraction [942,947] ... 

The phosphines with one P-donor atom reveal properties close to those of amines and form mononuclear coordination compounds 574 or binuclear structures 239 (Sec. 2.2.4.3) and 575 (3.14) ... 

Among molecular complexes recently obtained by the ligand-exchange method we emphasize the coordination compounds of diorganoditellurides. Thus, the interaction (3.128) of molybdenum hexacarbonyl with diphenyltelluride in THF leads to the formation of a binuclear complex 705 [272] ... 

Further, numerous similar coordination compounds have been obtained. The results of these investigations have been generalized in reviews [53,438] and a monograph [91], In this respect, we note the results of some studies. Thus, fe(salicylal)ethylene-diiminates 752 react with metal carbonyls in THF, forming binuclear complexes 753 (3.203) [439] ... 

The vast majority of the coordination compounds of Os that have been prepared are in the oxidation states 11 and III. Moreover, many of these compounds show reversible or well defined Os / couples in which the electronic and redox properties at the metal are controlled by the a-donor, 7r-acceptor, and r-donor properties of the ligands. Indeed, the study of the redox behavior in Os / and Ru / species, metal ions in which octahedral coordination is almost universally retained in both redox partners, has been central in recent developments to parameterize metal centered redox processes as a function of ligand donor and acceptor capacity. The chemistries of Os and Os are, therefore, intimately linked, and have been extended to studies of important mixed valence Os / binuclear and polynuclear species (see Mixed Valence Compounds). For the purposes of brevity and convenience, this section will deal with Os and Os complexes together. The extensive literature on Os / complexes has been developed with a very wide range of donor ligands a comprehensive assessment of this work is beyond the scope of this article, and the reader is directed to published comprehensive reviews. " ... 

The reaction products of 2,2 -bipyrimidine (bpm), P-diketones, and lanthanide ions demonstrated the diverse nuclearity and dimensionality. As stated in the last section, dinuclear eight-coordinate [Ln2(P-diketonate)6(bpm)] could be formed [78, 79]. Zucchi et al. [26a] reacted Nd(N03)3 with bpm to afford the mononuclear nine-coordinate adduct [Nd(N03)3(bpm)(Me0H)2], while reactions of hydrated NdCb and various P-diketonates in the presence of bpm gave the binuclear nine-coordinate compounds [ Nd(L )3(THF) 2([JL-bpm)] (see Figure 2.46) and [ Nd(L )3(MeOH) 2([r-bpm)]-bpm (see Figure 2.47) and the one-dimensional coordination polymer [Nd(L )3(p,-bpm)-MeOH]oo (4-MeOH) (see Figures 2.48 and 2.49). Other groups have also reported the one-dimensional arrays [Ln(L )3(p.-bpm)]co (Ln = Eu [80], Gd, and Nd [75]. 

There are many structural studies of copper coordination compounds with azide ligands, mainly of mononuclear and binuclear copper complexes but a few also of trinuclear copper complexes. A comprehensive... 

Diorgano ditellurium compounds react with transition metal salts and carbonyl complexes to form coordination compounds (Table 5, p. 283). Complexes with the following transition metals have been reported Ti, Cr, Mo, W, Mn, Re, Fe, Ir, Ni, Pd, Pt, Cu, Ag, Cd, Hg, Yb, and U. In many of these complexes, the organyltelluro group bridges the metal atoms in binuclear complexes. The Te —Te bond seems to remain intact upon complexation to mercury halides, rhenium carbonyls, and uranium pentachloride. For details on tellurolatO bridged complexes see p. 212. Complexes with SnCl are also known. Diphenyl ditellurium and bis[4-ethoxyphenyl] ditellurium formed charge-transfer complexes when equimolar amounts of the ditellurium compound and tetracyano-p-quinodime-thane were refluxed in acetonitrile. ... 

The reaction of urea with cobalt sulfate in aqueous solution gives the coordination compound [Co2(NH2)2(S04)2(H20)2] which is binuclear and includes two bridging sulfate groups [72] ... 

Magnetic Studies of Coordination Compounds Binuclear Copper Derivatives of Diphenyl-Methylarsine. 

The binuclear tungsten(II) and molybdenum(II) compounds react with phosphorous and nitrogen atom donor ligands and after chloride bridge splitting give mononuclear seven-coordinate compounds. 

The reactivity of molybdenum carbonyls in reaction with Lewis acids is comparable to the reactivity of tungsten carbonyls. The treatment of a nitrile carbonyl compound with an equimolar amount of tetrachlorotin in dichloromethane gives the oxidative-addition product, a mononuclear seven-coordinate compound [MoCl(SnCl3)(CO)3(NCMe)2], in good yield [36, 40]. The same compound was isolated from the reaction of a binuclear compound and acetonitrile. The crystal structure of the reaction product is similar to that... 

The seven-coordinate compounds react rapidly at room temperature with an excess of terminal alkyne, such as PA or r-BA, to give an unsaturated polymer in high yield. All binuclear compounds of tungsten(II) polymerise PA at comparable rates that are qualitatively very fast (Table 1). 

Seven-coordinate bimetallic compounds are also active unicomponent catalysts in the ring-opening metathesis polymerisation (ROMP) of cyclic olefins. The first step in this reaction is the coordination of olefin to metal. However, only in the reaction with a chelating ligand such as norbornadiene (NBD) was it possible to isolate and characterise the reaction product. In the reaction with NBD chloride bridge splitting in the binuclear compound of tungsten(II) by a diene molecule occurs very easily and monomeric seven-coordinate compounds are formed (Eq. 6) [48]. 

A similar binuclear product can be obtained by transmetallation of the La compoimd with L649, but the reaction time must be increased [23]. Thus coordination compounds of the rare earth elements with macrocyclic ligands based on pyridine-2,6-dicarbonyl compounds and lower diaminoalkanes, being... 

Metal bipyridine complexes are classical mononuclear coordination compounds of photophysical interest [13]. Related binuclear (Fig. 11) and polynuclear species can be designed using a "double-bipyridine" ligand, obtained by linking together two bipyridine-type ligands via a short polymethylene chain [78-81]. 

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