2021-03-16, Moradi, Mina, Lengweiler, Nadia, Housecroft, Catherine, Tulli, Ludovico, Stahlberg, Henning, Jung, Thomas, Shahgaldian, Patrick

We report on monolayer-to-bilayer transitions in 2D metal–organic networks (MONs) from amphiphiles supported at the water–air interface. Functionalized calix[4]arenes are assembled through the coordination of selected transition metal ions to yield monomolecular 2D crystalline layers. In the presence of Ni(II) ions, interfacial self-assembly and coordination yields stable monolayers. Cu(II) promotes 2D coordination of a monolayer which is then diffusively reorganizing, nucleates, and grows a progressive amount of second layer islands. Atomic force microscopic data of these layers after transfer onto solid substrates reveal crystalline packing geometries with submolecular resolution as they are varying in function of the building blocks and the kinetics of the assembly. We assign this monolayer-to-bilayer transition to a diffusive reorganization of the initial monolayers owing to chemical vacancies of the predominant coordination motif formed by Cu2+ ions. Our results introduce a new dimension into the controlled monolayer-to-multilayer architecturing of 2D metal–organic networks.

2015, Tulli, Ludovico, Wang, Wenjie, Lindemann, William R., Kuzmenko, Ivan, Meier, Wolfgang, Vaknin, David, Shahgaldian, Patrick

2017-11-13, Moradi, Mina, Tulli, Ludovico, Nowakowski, Jan, Jung, Thomas A, Shahgaldian, Patrick, Baljozovic, Milos

A flexible and versatile method to fabricate two-dimensional metal–organic coordination networks (MOCNs) by bottom-up self-assembly is described. 2D crystalline layers were formed at the air–water interface, coordinated by ions from the liquid phase, and transferred onto a solid substrate with their crystallinity preserved. By using an inherently three-dimensional amphiphile, namely 25,26,27,28-tetrapropoxycalix[4]arene-5,11,17,23-tetracarboxylic acid, and a copper metal node, large and monocrystalline dendritic MOCN domains were formed. The method described allows for the fabrication of monolayers of tunable crystallinity on liquid and solid substrates. It can be applied to a large range of differently functionalized organic building blocks, also beyond macrocycles, which can be interconnected by diverse metal nodes.

2016, Tulli, Ludovico, Wang, Wenjie, Rullaud, Vanessa, Lindemann, William R., Kuzmenko, Ivan, Vaknin, David, Shahgaldian, Patrick

Two amphiphilic calix[4]​arenes bearing four dodecyl chains at the lower rim and two amino functions (vicinal and distal) at the para-​phenolic positions have been synthesized. Surface-​pressure vs. mol.-​area isotherms reveal that Langmuir monolayers of the two regioisomers show considerably distinct self-​assembly behaviors at the air-​water interface. Compression isotherms, Brewster angle microscopy and synchrotron-​based X-​ray near-​total-​reflection fluorescence, X-​ray reflectivity and grazing incidence X-​ray diffraction reveal that the monolayers of the two diamino calix[4]​arene derivs. and those of their structural analogs bearing four amino moieties in para positions exhibit significant differences in their binding properties towards HgCl2 despite the structural and functional similarity among the macrocycles.