Hydrogen-Bonding Patterns in Oxime/Oximato Platinum(II) Species Providing the Formation of One-Dimensional Chains, Two-Dimensional Networks, and Cages

Heating cis -[PtCl 2 (Me 2 C OH) 2 ] in molten 2-propanone oxime affords the cationic complex [PtCl(Me 2 C NOH) 3 ]Cl. This compound reacts with 1 equiv of NaOH to give the neutral complex cis -[PtCl(Me 2 C NO)(Me 2 C NOH) 2 ] ( 1 ). Further, the reaction of [PtCl(Me 2 C NOH) 3 ]Cl with 2 equiv of AgNO 3 and successive addition of excess oxime and NaSbF 6 afford the chloride-free cationic complex [Pt(Me 2 C NO)(Me 2 C NOH) 3 ](SbF 6 ). When a solution of NaOH, instead of NaSbF 6, was added to the reaction mixture, the neutral compound [Pt(Me 2 C NO) 2 (Me 2 C NOH) 2 ]·2H 2 O ( 2 ) was isolated. The homoleptic complex [Pt(Me 2 C NOH) 4 ]Cl 2 ( 3 ) was prepared both by addition of excess HCl to [Pt(Me 2 C NO) 2 (Me 2 C NOH) 2 ] (87% yield) and by prolonged heating of [PtCl(Me 2 C NOH) 3 ]Cl and excess 2-propanone oxime, although in the latter case the conversion of the starting complex did not exceed 5−10%. 1 − 3 were characterized by X-ray diffraction. All three compounds display interesting hydrogen-bonding modes. In 1, two crystallographically independent molecules of cis -[PtCl(Me 2 C NO)(Me 2 C NOH) 2 ] form the repeat unit for a novel type of self-assembly that produces infinite one-dimensional polymeric chains held by strong H-bonds. 2, as compared to vic -dioxime Pt(II) complexes, displays stronger intramolecular hydrogen bonds and shows the absence of columnar stacking. In addition, the solvation H 2 O molecules connect the Pt(II) building elements by intermolecular H-bonds to form a layered two-dimensional network. In 3, the counterion is involved in (μ 4 -Cl - )· cis -[(···H−O−) 2 (···H−CH 2 −) 2 ] hydrogen bonding, thus forming the caged complex. Another interesting structural feature of 3 is the interaction between methyl hydrogens and platinum.