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Microsphere Assemblies via Phosphonate Monoester Coordination Chemistry
Author(s) -
Bladek Kamila J.,
Reid Margaret E.,
Nishihara Hirotomo,
Akhtar Farid,
Gelfand Benjamin S.,
Shimizu George K. H.
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705985
Subject(s) - phosphonate , coordination sphere , cobalt , ligand (biochemistry) , chemistry , hydrolysis , coordination complex , template , metal , nanoindentation , crystallography , polymer chemistry , organic chemistry , nanotechnology , materials science , metallurgy , biochemistry , receptor
Abstract By complexing a bent phosphonate monoester ligand with cobalt(II), coupled with in situ ester hydrolysis, coordination microspheres (CALS=CALgary Sphere) are formed whereas the use of the phosphonic acid directly resulted in a sheet‐like structure. Manipulation of the synthetic conditions gave spheres with different sizes, mechanical stabilities, and porosities. Time‐dependent studies determined that the sphere formation likely occurred through the formation of a Co 2+ and ligand chain that propagates in three dimensions through different sets of interactions. The relative rates of these assembly processes versus annealing by ester hydrolysis and metal dehydration determine the growth of the microspheres. Hardness testing by nanoindentation is carried out on the spheres and sheets. Notably, no templates or capping agents are employed, the growth of the spheres is intrinsic to the ligand geometry and the coordination chemistry of cobalt(II) and the phosphonate monoester.