Synthesis and structure of tin tetrachloride adducts with crown ether: Crystal structure of [Sn(H2O)2Cl4] · 18C6 and [Sn(H2O)2Cl4] · 18C6 · 2H2O

Tin coordination compounds [Sn(H2O)2Cl4] · 18C6 (I) and [Sn(H2O)2Cl4] · 18C6 · 2H2O (II) were synthesized and identified by IR spectroscopy, CH analysis, and X-ray powder diffraction. The crystal structures of compounds I and II were determined. The crystals of I and II are orthorhombic; a = 16.871(1) Å, b = 7.7305(7) Å, c = 16.939(1) Å, Z = 4, space group Cmca for I; a = 14.206(2) Å, b = 20.376(3) Å, c = 8.319(1) A, Z = 4, space group Pna21 for II. The structural units of I and II are [Sn(H2O)2Cl4] · 18C6 complex molecules (in II, also water molecules of crystallization). The coordinated water molecules in I are trans and those in II are cis to each other. The structural units in the crystals of I and II are combined only by hydrogen bonds between water molecules and the crown-ether oxygen atoms with the formation of the chain structure. Complex I was tested as the precursor of tin dioxide in a chemical vapor deposition (CVD) process. The morphology of the obtained film was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and the composition was studied by laser mass spectrometry for elemental analysis.