Welding Molecular Crystals : A "première"

26 January 2016

The design and fabrication of complex crystalline systems as networks of crystals displaying task specific properties is a step towards new smart materials. Both for fundamental and applied sciences, the design of complex molecular systems in the crystalline phase with strict control of order and periodicity at both microscopic and macroscopic levels is of prime importance for developments of new solid state materials and devices. Researchers of the Molecular Tectonics Laboratory (C. Adolf, S. Ferlay, N. Kyritsakas and M. W. Hosseini) have recently reported (J. Am. Chem. Soc. 2015, 137, 15390−15393) an unprecedented strategy based on 3D epitaxial growth to weld in solution crystals under mild conditions (25 °C). Isostructural (same space group and crystalline system) and almost isometric (close cell dimensions) molecular crystals displaying different colours were used not only to fabricate core-shell crystals (Fig. 1a) but to weld them into networks of crystals as multidomain single crystalline entities (Fig. 1b). Welding of crystals by self-assembly processes into macroscopic networks of crystals is a powerful strategy for the design of hierarchically organised periodic complex architectures composed of different subdomains displaying targeted characteristics. Crystal welding, may be regarded as a first step towards the design of new hierarchically organized complex crystalline systems (Fig. 2).


These investigations have been supported by the Labex "Chemistry of Complex Systems", International Centre for Frontier Research in Chemistry (icFRC) and by the CNRS.



Figure 1: Schematic representations of the formation of core-shell crystals resulting from epitaxial growth of a crystalline shell B and a core crystal A (a) and homo- and hetero-welding (b) of crystals into single crystalline entities by 3D epitaxial growth in solution under mild conditions (25 °C).

Des cristaux (a, d, g) ont étaient coupés et placés et orientés (b, e, h) puis sont soudés (homo- (c) et hétéro- (f, i) en monocristaux par croissance épitaxiale en solution sous conditions douces

Figure 2: Initial crystals a, d, g), cut into two parts (b, e, h), homo (c) and hetero- (f, i) welded into single crystalline entities by 3D epitaxial growth in solution under mild conditions (25 °C).