N-Functionalized Ferrocenes: Subvalent Group XIV Element Chlorides and tert-Butyllithium-Induced C-C Bond Cleavage under Mild Conditions

Intramolecularly O,N,O-Coordinated Tin(II) Salts: Syntheses, Structures, Cyclization, and Transition Metal Complexation

We report the syntheses of tin(II) salts of the types [L1SnX]SnX3 [L1=2,6-{(i-PrO)2(O)P}2C5H3N: 1, X=Cl; 2, X=Br], [L2SnCl]SnCl3 [L2=2-{(i-PrO)Ph(O)P}-6-{(i-PrO)2(O)P}C5H3N: 3], [L3SnX]SnX3 [L3=2,6-{MeO(O)C}2C5H3N: 4, X=Cl; 5, X=Br], [L4SnX]SnX3 [L4=2,6-{Et2N(O)C}2C5H3N: 6, X=Cl; 7, X=Br]. These compounds were obtained by addition of SnX2 to the corresponding ligand inducing autoionization of the respective tin(II) halide. The thermal stability of 1, 3, and 4 was elucidated, giving, under ester cleavage and cyclisation, the tin(II) derivatives 8-12. The reaction of [L1SnCl]SnCl3 (1) with W(CO)4(thf)2 afforded the tungsten tetracarbonyl complex [{L1SnCl}{SnCl3}W(CO)4] (13), representing the first example in which a tin(II) stannate anion and a tin(II) stannylium cation simultaneously coordinate to a transition metal centre. The compounds were characterized by single crystal X-ray diffraction analyses and in part by elemental analyses, IR and NMR spectroscopy, electrospray ionization mass spectrometry. DFT calculations accompany the experimental work.

Crystal structures of [(N,N-di-methyl-amino)-meth-yl]ferrocene and (R p,R p)-bis-{2-[(di-methyl-amino)-meth-yl]ferrocen-yl}di-methyl-silane

The title compound [(N,N-di-methyl-amino)-meth-yl]ferrocene, [Fe(C5H5)(C8H12N)], (1), is an inter-esting starting material for the synthesis of planar chiral 1,2-disubstituted ferrocenes, as demonstrated by the preparation of (R p,R p)-bis-{2-[(di-methyl-amino)-meth-yl]ferrocen-yl}di-methyl-silane, [Fe2(C5H5)2(C18H18N2Si)], (2), from the li-thia-ted derivative of 1. The configuration of the lithium compound is unchanged after the substitution reaction and the chirality is preserved in space group P212121. In both compounds, the Cp rings adopt eclipsed conformations. Hirshfeld surface analysis was used to investigate the inter-molecular inter-actions, and showed that H⋯H (van der Waals) inter-actions dominate in both structures with contact percentages of 83.9 and 88.4% for 1 and 2, respectively.