Surface-located inner coordination

Direct Photolysis of Surface-Located Inner Coordination Sphere Complexes. In the presence of a strong metal binding ligand, the underlying central metal ion in the surface layer of a metal oxide can exchange its structural OH" ions for the ligand. Thus, the association of citrate with an iron oxyhydroxide surface may be represented ... 

The high resolution X-ray structural studies of the native enzyme, the enzyme-ADPR binary complex, and the enzyme-o-phenanthroline binary complex (47) have revealed that the active site zinc ion is located some 20 A below the surface of the protein at the point of convergence of two deep clefts (see the schematic representation in Fig. 6). One of these clefts has been identified as the coenzyme binding cleft (47). This cleft extends from the surface of the subunit to the zinc ion. If a model of NADH is fit to the coordinates of the ADPR binding site, then the nicotinamide ring can be oriented in such a way that it fits into a pocket adjacent to the zinc ion (47). The second deep cleft, or channel, also extends from the surface of the subunit down to the zinc ion. The inner surface of this cleft is made up of nonpolar amino acid residues contributed by both subunits. 

The surface effects occur when the size of bulk materials is reduced to a nanometer scale, so that they come to possess more and more surface atoms instead of inner atoms. In this case, the properties of the new material are influenced by the characteristics of surface atoms (Issa et al. 2013). When the size of the newly obtained material decreases, the atoms on the surface of a bulky crystalline solid, which are located on the basal planes, are all transformed into edge and comer atoms. In this context, the surface properties of nanosized metals differ from those of the bulky metals. Compared with the atoms from the basal planes, the edge and corner atoms have a very low coordination number, which makes them highly chemically reactive, supercatalytically active, and highly polarizable. In addition, the quantic effects cause particular new properties, induced by... 

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