Materials Chemistry and Physics, Vol.153, 54-62, 2015
Homo- and heterodinuclear coordination polymers based on a tritopic cyclam bis-terpyridine unit: Structure and rheological properties
An innovative coordination polymer based on a tritopic ligand having the bis-terpyridine cyclam (CHIT) unit is explored. Homo- or heteronuclear 1D coordination polymers can be formed with bivalent metal ions such as Co(II) and Ni(II) in solvent DMF. Creep-recovery curves of the (Co-II)(2)CHTT gels formed from 1D coordination polymers were analyzed with the Burgers model and demonstrated an original self-healing property, unusual in the class of molecular gels. The influence of the metal type was studied through the structural features using small-angle neutron scattering (SANS) experiments. In gels, the corresponding network involves genuine fibers (R approximate to 35 angstrom), bundles of these fibers and also a fraction of finite size aggregates (rods with aspect ratio f approximate to 3-5). We found that the distribution of these latter structural components is sensitive to the metal ions type. Such tritopic 1D coordination polymers exhibit a range of original structural features and a facile control of the developed structures in solutions and gels by tuning their thermodynamic parameters. The versatility associated to the intrinsic dynamic ability of the systems should pave the way to original properties for molecular devices. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Polymers;Creep;Mechanical properties;Small-angle scattering;Neutron scattering and diffraction