From Tin(II) to Tin(IV): Following Solid‐liquid Reactions by Microscopy

Abstract In order to study the formation of complexes independently from stoichiometry we developed a microscale experiment that allows us to monitor the reaction progress by light microscopy In the present study, the complex formation between SnF 2 and 1,10‐phenanthroline (phen) with N , N ‐dimethylformamide as solvent was investigated over a period of some weeks. By use of this setup, the formation of three different crystals has been observed, whose compositions and structures were determined by single crystal X‐ray diffraction: 3SnF 2 ⋅ phen, 1 , 2SnF 2 ⋅ SnF 4 ⋅ phen, 2 , SnF 4 ⋅ phen, 3 . While the octahedral fluorine environment of the tin(IV) atoms of 2 and 3 is very regular, the coordination of the tin(II) atoms in 1 and 2 is irregular. Assuming a non‐bonding 5 s electron pair, classical 2c–2e‐ and symmetrical and asymmetrical, hypervalent 3c–4e‐bonds – all based on the orthogonal p atomic orbitals of Sn – an approach to analyze and describe these coordinations in a simple comprehensive way is presented.