Formulae dinuclear species

Recently. quite different products were claimed to be formed when Cu(OH)2 reacted with molten 4-XpzH. A brown powder having the empirical formula [Cu2(OH)(4-Xpz)3(4-XpzH)2] (X = Cl or Br) was isolated with excess molten pyrazole, while the dinuclear species [Cu2(OH)(4-Xpz)3] (X = H, Me, Cl, and Br) formed when a stoichiometric amount of 4-XpzH was used (39). 

Related oxo-bridged complexes of formulas [ZrCl3(MeOCH2CH2OMe)2]2(/r-0)301 and [ZiC13(TT I F)2]2(/i-0)302 have also been synthesized and characterized. These dinuclear species were obtained only in low yields as the source of the oxo-bridge was inferred to be adventitious 02. 

Complexes of general formula [RuGp ( 7 -arene)][X] can be prepared through several routes. The most common precursor is the dinuclear species [ Ru(yU-OMe)Cp 2] 46 which can be easily protonated with triflic acid to generate in situ the [RuCp ][OTf] fragment. When a free arene is present, the desired [RuCp (77 -arene)][OTf] complex is directly formed. The following examples have been prepared using this synthetic approach ... 

We have previously seen examples of the carbon-like formulas of mononuclear and dinuclear osmium compounds, namely the methane-like tetrahydride (4.50c), ethylene-like H20s=CH2 (4.51c) and H2Os = OsH2 (Table 4.15), acetylenelike HOs = CH (4.54c) and HOs = OsH (Table 4.15), allene-like H2C = Os = CH2 (4.55a), and so forth. While the coordination numbers and Lewis-like formulas are formally analogous, the actual structures of Os and C species may be quite similar (e.g., the Td structures of OsfL and CH4) or dissimilar (e.g the strongly bent Cs structure of H20s = CH2 [Fig. 4.13(c)] versus the planar D2h structure of H2C = CH2). 

The solute used was [Cr(bpy)2(H2O)2](NO3)3 i H2O5. A saturated solution of barium nitrate was used as solvent. A weighed sample of [Cr(bpy)2(H2O)2](NO3)3 I H2O was dissolved in the saturated barium nitrate solution and neutralized stepwise by the addition of weighed portions of Ba(OH)2 8 H2O. v was determined after the addition of each portion of barium hydroxide. Since both the nitrate counterion of the chromic species and the barium ion added in the form of barium hydroxide were common to solute and solvent, they did not affect v, which was exclusively dependent on the chromic species. If dimerization of [Cr(dpy)2H2O(OH)] occurred, the initial v of the diaqua salt solution should be reduced by the addition of barium hydroxide and reach its minimum value after 1 equiv of barium hydroxide was added. The results, presented in Fig. 6 confirm this expectation. Addition of more than 1 equiv of OH converts the dinuclear hydroxoaqua ion to the mononuclear dihydroxo ion and raises v as expected. However, dimerization is not complete at a molality of 0.24 m (formula weights of the... 

Neutral metal carbonyls usually undergo one- or two-electron reductions by several reducing agents. The reduced species normally obey the next inert gas rule and the formulas can be easily predicted accordingly. Dinuclear metal carbonyls on reduction give mononuclear anionic species mononuclear metal carbonyls may become doubly charged with loss of CO or undergo a one-electron reduction with formation of dinuclear anions (equations 36-38). 

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