Dinuclear silver complexes

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

Other polydentate ligands are polyamines and related ligands. Stability constants of silver(I) complexes with polyamines in dimethyl sulfoxide,419 A-methyl-substituted 4-methyldiethylene-triamines,420 or ethylene- or N- or C-methylated ethylenediamine in aqueous solution have been reported.421 The structure of the silver 1,3-diaminopropane complex, [Ag NH2(CH2)3NH2 ]-C104,422 and complex formation with 1,4-diaminobutane and 1,5-diaminopentane have been reported.423 A dinuclear silver(I) compound with ethylenediamine [(enH)Ag(en)Ag(enH)2]4+ has... 

Similarly, by Schiff-base condensation reactions have been used to generate free cryptands from triamines and dicarbonyls in [2+3] condensation mode. These ligands react with silver(I) compounds to give dinuclear or trinuclear macrocyclic compounds where Ag Ag interactions may be present. Thus, with a small azacryptand a dinuclear complex with a short Ag- Ag distance (55) is found.498 With bigger azacryptand ligands also dinuclear complexes as (56) are achieved but without silver-silver interaction. 65,499-501 A heterobinuclear Ag1—Cu1 cryptate has also been... 

In view of the versatility of A-heterocyclic carbenes as ligands and their structural diversity in silver(i) coordination chemistry, an extension of the work to ligands with two or more carbene moieties was reported. A dinuclear silver(i) complex 52 (Figure 21) with an o-phenylenedimethylene-bridged bis(carbene) ligand has been synthesized in 66% yield from silver(i) oxide and the bis(imidazolium) salt.88 The reaction to synthesize 52 has to be carried out in... 

A homoleptic methylene-bridged bis(carbene) dinuclear silver(i) complex, 55, was isolated in 81% yield from a two-step reaction, as shown in Scheme 13.100 The structure of 55 reveals a boat conformation with the two methylene groups protruding away from the Ag2 core in one direction. The Ag-C distances of 2.081(2)-2.095(2) A were in the normal range for silver(i) TV-heterocyclic carbene complexes, while an uncommonly short intramolecular Ag-Ag contact of 3.2039(3) A was observed in the homoleptic silver(i) carbene complexes. 

The stabilized versions of (99)-(101) have easily been obtained from the silver derivative (103), shown in Scheme 31 [212], Treatment of (103) with ClAu(tht) gives (104), which can be oxidized to give the dinuclear complexes (105) and (106) [213], Interestingly, treatment of (103) with Pd precursors gives complexes in which the bis-yUde is always behaving as a chelate [214],... 

The first descriptions of heteronuclear luminescent supramolecular complexes were given by Fackler et al. in 1988 and 1989. In these studies, one gold-thallium and one gold-lead complex were reported. As in the case of the gold-silver dinuclear systems, the extended systems appeared as a result of the unidirectional polymerization of dinuclear or trinuclear units through metal-metal interactions. These were prepared by reaction of the gold precursor [PPN][Au(MTP)2] (PPN = N(PPh3)2 ... 

At the end of 2007, Widenhoefer et al. reported the first examples of the dynamic kinetic enantioselective hydroamination of axially chiral allenes, catalyzed by a dinuclear complex of gold (Figure 8.1) and silver perchlorate [46, 47]. 

H and 13C NMR spectroscopy have been used to study successive formation of mononuclear and dinuclear complexes with [SJcryptands.483 A heteronudear (Ag+,Pb2+) complex of (77) was described. In the 13C spectra, significant differences were observed for the carbon atoms adjacent to the bridgehead nitrogen atoms, such that the dinuclear silver complex and dinuclear lead complex could be readily distinguished from the heteronudear spedes. The fact... 

ESR spectra obtained from magnetically dilute samples of the silver(U) complexes doped into the corresponding dimeric zinc complex could be attributed to both homo- (Ag,Ag) and hetero- (Ag,Zn) dinuclear species. In the Ag,Ag dimer the g values were almost equal to those for the Ag,Zn dimer however, the hyperfine coupling constants A were only about half. From this it was concluded that the structures of these two species were very similar.542... 

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