Complexes, cationic and anionic

Selig, H., and Holloway, J. H. Cationic and Anionic Complexes of the Noble Gases, 124, 33-90... 

FIGURE 16.21 The compounds in parts (a) and ib) are coordination isomers. In these compounds, a ligand has been exchanged between the cationic and anionic complexes. 

In the second cluster, the two Ru6 octahedra are linked through two palladium atoms. The third cluster contains two additional palladium atoms. The Pd4 skeleton adopts the form of a bent square. The two Ru6 octahedra have local structures similar to those in the second cluster, but their relative orientation is now twisted. Apparently, formation of these heterometallic cluster complexes does not result from a simple combination reaction between cationic and anionic complexes but is accompanied by partial redox reactions.900... 

Amines (am) react with these bridged complexes to give mononuclear complexes of the type [RhX(am)(diene)] a similar complex is formed by triphenylphosphine, but not by triphenylarsine or diphenylsulphide. Cationic and anionic complexes of the type [Rh(diamine) (diene)]+ and [RhCl2(diene)] are readily formed. The stable acetate (XXVII X = OAc) is prepared from the corresponding chloride and potassium acetate its infrared spectrum indicates that each acetate group is symmetrically bound... 

Indium nitrate can be prepared from InCl3 and N205 158,159 the dissolution of indium metal in cone, nitric acid yields In(N03) xH20 (x = 3, 4, 5),7 which has been used as the source of cationic and anionic complexes.64 Salts of [In(N03)4] have been reported,64160 and Raman studies161,162 have demonstrated the presence of In/NOj complexes in solution the stability constant results have been reviewed.9... 

FIGURE 16.26 Coordination isomers. In this compound, ligands have been exchanged between the cation and anion complexes. 

Hydroxyl groups in partially substituted compounds may be transformed into halo, amino, oxo, deoxy, and other functional groups. Free 1,6-anhydrohexopyranoses199,200 and their aminodeoxy201,202 derivatives tend to form cationic and anionic complexes, in particular with l,6-anhydro-/J-D-allopyranose, which has a vicinal triol system in axial-equatorial-axial arrangement.200... 

The chemical properties of indium are typical of those of Group 13 of the Periodic Table. Most of indium s oxides, salts, and compounds involve the +3 oxidation state (e.g., In203, In[N03]3> and InCl3) many of these compounds are electron-pair acceptors, forming addition compounds with donor molecules (e.g., InBr3 py, py = pyridine). Neutral, cationic, and anionic complexes are also known. Several interesting compounds are derived from the +1 and +2 oxidation states of the element. 

Hydrogen bonds are only rarely an issue in the modeling of small metal complexes. There are, however, some cases where hydrogen bonds are particularly important. For example, when diamineplatinum(II) complexes bind to DNA, hydrogen bonds form between the H(amine) atoms and oxygen atoms on the DNA, and these interactions may be very important in determining the sequence specificity of Pt/DNA interactions[140]. Also, interactions between cationic and anionic complexes will inevitably involve hydrogen bonds and these terms will probably determine whether there is substantial stereoselectivity in the interactions. 

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