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The series of organotin(IV) complexes L 1-3 SnPh n Cl 3-n , where L 1-3 are O,C,O-chelating ligands (called the pincer ligands), 2,6-bis(alkoxymethyl)phenyl-, 2,6-, have been synthesized and characterized by 1 H, 13 C, and 119 Sn NMR spectroscopy, MS-ESI spectrometry, and elemental analysis. The structure of selected compounds L 1 SnPh 3 (1), L 1 SnPh 2 Cl (2), L 1 SnPhCl 2 (3), L 1 SnCl 3 (4), L 2 SnPhCl 2 (7), and L 3 SnPhCl 2 (11) was studied by X-ray crystallography and 119 Sn CP/ MAS NMR spectroscopy in the solid state. The determination of crystal structures reveals the similarity of all the shapes of coordination polyhedra. The deformations of the shapes of coordination polyhedra depend on the degree of donor-acceptor Sn-O interaction (from very weak (interatomic distance Sn-O 2.963(1) Å) to medium-strong (2.475(1) Å)), which increases with increasing Lewis acidity of the tin atom in the L 1-3 SnPh n Cl 3-n entities and decreases with increasing steric demands of substituents R (from Me to t-Bu). NMR spectroscopy indicates a similar structural arrangement of the studied compounds in solution.

119Sn, 15N, 13C, and 1H NMR spectra were studied for [2-(dimethylaminomethyl)phenyl]stannanes, R1R2R3R4Sn or R1R2R24Sn, where R1, R2, and R3 are 1-butyl, Cl or Br, the same or different, and R4 is 2-(dimethylaminomethyl)phenyl. The occurrence of intramolecular interaction between the nitrogen and tin atoms was demonstrated based on changes in the characteristic values of the NMR parameters of these nuclides (δ(15N), δ(119Sn), J(119Sn,15N), and their interrelations, as well as on the relatively high values of the coupling constants 3J(119Sn,13C(CH2)).

Eight organoantimony and organobismuth dihalides, containing two types of O,C,O-chelating (so-called pincer) ligands, 2,6-(ROCH2)C6H3 - (R = Me, L1; R = t Bu, L2; L1SbCl2 (1), L2SbCl2 (2), L1SbI2 (3), L2SbI2 (4), L1BiCl2 (5), L2BiCl2 (6), L1BiI2 (7), L2BiI2 (8)) were prepared and characterized with the help of elemental analysis, electrospray ionization mass spectrometry, 1H and 13C NMR spectroscopy, and X-ray diffraction techniques. Except for 5, which exists as a centrosymmetric dimer, all studied compounds are monomeric in the solid state and the coordination polyhedra of the central atoms are distorted square-pyramidal. Both oxygen donor atoms are coordinated to the central metal through moderately strong or strong intramolecular interactions (range of Sb−O distances 2.279(2)−2.6912(14) Å and Bi−O distances 2.379(3)−2.460(4) Å), both in cis fashion for 1 and 2 (angles O−Sb−O 116.65(5)° and 116.73(4)°) and trans fashion for 3, 4, and 6−8 (range of angles O−M−O; M = Sb or Bi, 142.26(12)−148.28(8)°). In noncoordinating solvents (CDCl3, toluene-d 8) 1−8 display structures similar to those found in the solid state based on variable-temperature 1H NMR measurements.

The dimeric organoantimony(III) oxide (ArSbO) 2 (Ar ) NCN chelating ligand, C 6 H 3 -2,6-(CH 2 NMe 2 ) 2 ) was obtained by the reaction of the parent ArSbCl 2 compound with KOH. This oxide is able to bind carbon dioxide with formation of the monomeric, air-stable carbonate ArSbCO 3 . In turn, carbon dioxide can be easily eliminated from this carbonate by prolonged heating to 130 °C to recoVer (ArSbO) 2 .