Di-and trinuclear complexes

Photocleavage activity was also reported for tetra-anionic diplatinum(II) complexes with pyrophosphito ligands. The photocleavage proceeds via hydrogen atom abstraction, which occurs on collision between an excited state of complex and DNA, and is strongly enhanced by magnesium ion, probably due to screening of the electrostatic repulsion between the two reactants [88], 

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Isolation and characterization of stereoisomers in di- and trinuclear complexes with N-heterocyclic ligands 98CSR185. 

Platination of the N3 position in 1-substituted uracil and thymine derivatives requires proton abstraction and usually occurs only at high pH, but the Pt-N3 bond, once formed, is thermodynamically stable (log K 9.6) [7]. Platinum binding to N3 increases the basicity of 04, which becomes an additional binding site leading to di- and trinuclear complexes. A list of X-ray structurally characterized species is given by Lippert [7]. Pt complexes of uracil and thymine can form intensely colored adducts (e.g. platinum pyrimidine blues), which show anticar-cinogenic activity analogously to the monomeric species [7]. 

Species functionalized at boron, such as 50-53, have also been prepared from the corresponding MC2B4 closo clusters via the removal of the apex BH unit (decapitation) with I M Kl)A.54 57 The same approach has been employed to link CoC2B3 units to benzene or other arenes 5 As shown in the following subsection, di- and trinuclear complexes such as 53 and 54 are easily converted to multi-triple-decker sandwich systems. 

Reaction of four equivalents of Ni(II) with 3 resulted in a mixture of di- and trinuclear complexes, [Ni2(3)](C104)4 and [Ni3(3)(OH2)6](C104)6, which were separated by cation exchange chromatography. A tetranuclear complex, [Ni4(3)(OH2)i2](C104)8, was also obtained when the reaction mixture contained a fifty-fold excess of Ni(II). 

A range of di- and trinuclear complexes containing Tp MoOCl fragments connected by bis-or tris-phenolato bridging ligands has been studied by McCleverty, Ward, and co-workers. The... 

The donor and acceptor properties of the heterocycles 1,4-diboracyclo-hexadiene (1), 1,4-diboracyclohexene (1H2), 1,4-dihydro-1,4-dibora-naphthalene (2), 9,10-dihydro-9,10-diboraanthracene (3), as well as the five-membered heterocycles 2,3-dihydro- 1,3-diborol (4) and the 1,3-dihydro-1,3-diborafulvenes (5 and 6), allow the formation of mono-, di-, and trinuclear complexes. Usually the metals are anti-facially coordinated to... 

The di- and trinuclear complexes [Mn(CO)3(CymTp)] (Fig. 1.27), [Mn(CO)3(CymBp(OH))], and [Zn(CymTp)2] have been also reported.194 The structure of [Mn(CO)3(CymTp)], exhibiting a cyclopentadienyl ring together with a scorpionate moiety in the same molecule, indicates that both ligand types (Cp and Tp) exert a very similar electronic influence on the respective Mn(CO)3 fragment. [Mn(CO)3(CymBp(OH))] is obtained when the reaction between... 

Earlier, Herrmann et al. (1976 a, 1976 b) found that the mononuclear (pentacar-bonyl)(hydrido)manganese complex 10.74 forms a 10 1 mixture of the di- and trinuclear complexes 10.75 and 10.76 with diazomethane, if the reagents are mixed in THF at - 85 °C and the system is allowed to reach room temperature (10-34). In the same reaction with the analogous rhenium complex, only the binuclear complex... 

A combination of the two techniques was shown to be a useful method for the determination of solution structures of weakly coupled dicopper(II) complexes (Figure 10.5) [219]. The solution structure of a tris-macrocyclic ligand tricopper(II) complex has recently been studied by a combination of MM-EPR and DFT [410]. The spin Hamiltonian parameters were determined by EPR and DFT for the mononuclear complex and then used, in conjunction vhth computed structural data of the di- and trinuclear complexes, for the EPR spectra simulation. From this, by comparison with experimental spectra, a structural assignment of the solution structure was possible (MM-DFT-EPR) [410]. 

R. Cacciapaglia, A. Casnati, L. Mandolini, D. N. Reinhoudt, R. Salvio, A. Sartori, R. Ungaro, Di- and trinuclear complexes of calix[4]arene based ligands as catalysts of acyl and phos-phoryl transfer reactions, J. Org. Chem., 2005, 70, 624-630,... 

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