A brief review on formation of (H2O)n clusters in supramolecular proton transfer compounds and their complexes

Abstract

Water clusters", group of water molecules held together by hydrogen bonds, have been the subject of a number of intense experimental and theoretical investigations because of their importance in understanding cloud and ice formation, solution chemistry, and a large number of biochemical processes. "Water clusters" can play an important role in the stabilization of supramolecular systems both in solution and in the solid state and there is clearly a need for chemists a better understanding of how such aggregates influence the overall structure of their surroundings. The present brief review deals with (H 2 O) n clusters, identified/observed crystallographically upon 170 crystal structures of synthesized coordination compounds based upon proton transfer compounds by Hossein Aghabozorg's research groups since 2000. The structural details of water clusters, (H 2 O) n , n = 2, 3,4,5,6,7,8,9,15,16 and are described systematically.

Investigation of regioselectivity on the reaction of 5-bromo-2,4-dichloro-6-methylpyrimidine with ammonia

“…2). In fact, the presence of water molecules is important in establishing hydrogen bonds contributions to the total lattice energy, and is significant in the stability of the hydrated crystal structure (Aghabozorg et al, 2010). Water is of fundamental importance for human life and plays an important role in many biological and chemical systems.…”

Two Novel Chiral Inorganic–Organic Hybrid Materials Containing Preyssler and Wells–Dawson Heteropolyoxometallates with Valine (val), Glycine (gly), and Proline (pro) Amino acids: (Hval)2(Hgly)(H3O)6K5[Na(H2O)P5W30O110]·19.5H2O and (Hpro)6[P2W18O62]·8H2O

“…Electrostatic forces, van der Waals force and a lot of hydrogen bonds exist between these networks. A careful survey of the structure indicates that water molecules link the anionic and cationic fragments to each other with hydrogen bonds, that is, the water molecules act as a ''glue'' to assemble the supramolecular structure [34].…”

Crystal structure of 4,4'-bipyridinium bis(pyridine-2,6- dicarboxylato)mercurate(II) — diaquabis(6-carboxypyridine- 2-carboxylato)mercury(II)— water (2:1:12), [C10H10N2]2[Hg(C7H3NO4)2]2 · Hg(H2O)2(C7H4NO4)2 · 12H2O

“…Indeed, there are weak p-p stacking between pyridine-pyridine rings of pydc 2-and pyridinepyridine rings of pydc 2-and bipyridinium counter-ion with acentroid-to-centroid distances of 3.710 Å and 3.682 Å,respectively. Also the crystal structure of the title compound contains (H 2O)∞ cluster that may lead to the further stabilization of corresponding crystalline network [5]. (5) 0.00893(6) −0.00117(6) O (7) 8f …”