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

Abstract

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.