Small molecule single crystal X-ray diffraction studies at the MX2 beamline of the LNLS: crystal engineering of organic molecules and coordination compounds with relevance to material science

FLORENCIA DI SALVO; FEDERICO MOVILLA; JUAN MANUEL REY; HUCK-IRIART, CRISTIÁN

Campinas

Congreso; 29th RAU/Anual Users Meeting LNLS/CNPEM; 2019

lABORATORIO NACIONAL DE LUZ DE SINCROTRON

Crystal engineering is a discipline that has as main interests the design and synthesis of crystalline solids with a particular purpose and specific properties [1]. Thus, as a starting point, it is essential to perform high quality single crystal X-ray diffraction studies that conduct successfully to the determination of the molecular and supramolecular structure of the studied systems. The instrumental limitations of laboratory single crystal X-ray diffractometers restrict significantly the projects related with crystal engineering and structural chemistry. Data collection at a storage-ring synchrotron source opened new possibilities for crystal structure determinations bringing enormous advantages for fields related to small molecules building blocks, like crystal engineering, as well as chemical and materials science areas in general [2]. In this work we will present the single crystal X-ray diffraction structural studies of several small molecule systems performed by the data obtained using the MX2 beamline of the LNLS. We were able to successfully determine the structure of several members of the following systems: a) organic molecules which are able to act as building blocks for the construction of different materials such as, supramolecular gels and mesocrystals; b) mononuclear and polynuclear coordination compounds and c) coordination polymers (CP). The coordination systems included in b) and c) were mainly synthetized using the molecules mentioned in a), as ligands. In all cases the information obtained contributed to unequivocally confirm their molecular structure and study their supramolecular characteristics and properties. These results were also fundamental to analyse the role of the structural features and intermolecular interactions in the crystal packing and also, in the physical and chemical properties. Regarding the compounds included in system a), new chiral molecules derived from amino acids and platforms like aldehydes were synthesized in our group for the development of different type of materials such as, supramolecular gels [3] and mesocrystals, a fascinating class of crystalline nanostructured materials [4]. With the data obtained from the MX2 beamline, it was possible to study the single crystals of several amino acid derivatives and successfully determine their structure with excellent resolution. These results contributed to the understanding of the mechanism related to the gel formation and mesocrystals aggregation. On the other hand, some of these molecules were used as ligands for the synthesis of coordination compounds ?systems b) and c)?, exhibiting different physical and chemical properties. For instance, with the data collected at the LNLS it was possible to determine the X-ray diffraction structure of a trinuclear Ni(II) complex based on a L-Tyrosine derivative, several mononuclear amino-acid based Cu(II) monocuclear complexes and 1D Cd(II) and Co(II) coordination polymers. Finally, some of the physical and chemical properties of these coordination compounds are also discussed in term of their structural features.