73296-25-0Relevant articles and documents
Oxy and thio phosphorus acid derivatives of tin. 8. Tin(II) bis(dithiophosphate) esters and their bipyridyl adducts. X-ray crystal and molecular structure of bis(O,O′-diphenyl dithiophosphato)tin(II), a bicyclic dimer held together by three-coordinated sulfur atoms and by η6-C6H5 interactions binding tin(II) lone pairs to phenoxy ester groups
Lefferts,Molloy,Hossain,Van Der Helm,Zuckerman
, p. 1410 - 1416 (2008/10/08)
Four tin(II) dithiophosphate esters, Sn[S2P(OR)2]2, where R = CH3, C2H5, i-C3H7, or C6H5, are synthesized in high yield by the action of the O,O′-diorganodithiophosphoric acids on dimethoxytin(II) in benzene to release methanol. The R = C2H5 product is a pale yellow oil, but the others are colorless crystalline solids soluble in nonpolar organic solvents. The 2,2′-bipyridyl adducts of the parent esters form immediately upon mixing. NMR coupling is observed from the ester groups to phosphorus, as |3J(31P-O-C-1H)| = 15.5 Hz in the R = CH3 derivative. Infrared spectral assignments can be made for the vasym(PS2) (660-627 cm-1), vsym(PS2) (525-505 cm-1), v[(P)O-C] (1190-1150 cm-1), v[P-O(C)] (1030-1010 cm-1), and v(SnS) (355-332 cm-1) modes. In the mass spectra parent molecular ions are found for all the species, but the fragments resulting from the loss of one ligand moiety are more abundant. The chief pathway for the decomposition is the successive loss of ligand moieties. Ditin-bearing ions are detected in the spectrum of the R = C2H5 derivative. The mass spectra of the bipyridyl adducts are the superposition of those of the parent tin(II) esters and of bipyridyl. The tin-119m M?ssbauer isomer shifts (IS = 3.66-3.78 mm s-1) confirm the presence of tin(II), and the barely resolvable quadrupole splittings (QS = 0.97-1.06 mm s-1) do not increase on complexation by bipyridyl (1.03-1.15 mm s-1), suggesting that the parent tin(II) esters themselves have higher coordination number in the solid state. Bis(O,O′-diphenyl dithiophosphato)tin(II), C24-H20O4S4P2Sn, crystallizes in the triclinic space group P1 with a = 10.499 (5) ?, b = 13.948 (7) ?, c = 9.291 (4) ?, α = 99.18 (6)°, β = 95.71 (5)°, and γ = 91.80 (5)°, at 138 ± 2 K. The structure was determined by Patterson and Fourier techniques from 5517 reflections measured at 138 ± 2 K on an automatic diffractometer with monochromatic Mo Kα radiation and refined to a final R value of 0.029 for all data. The centrosymmetric dimer contains one ligand bridging two tin atoms intermolecularly, while simultaneously chelating one tin atom in an extremely anisobidentate fashion via a bifurcated, three-coordinated sulfur atom [S(4)]. A second ligand is involved in normal chelation. Completing the coordination sphere at the tin(II) atom and contributing to the formation of the dimer is an η6-C6H5 interaction between the phenoxy ester group of the bridging ligand of the second molecular unit and the tin(II) lone pair to produce a ψ-6-coordinated metal center. A planar Sn2S2 ring is demanded by crystallographic symmetry and is seen to be circumscribed by an eight-membered [SnSPS]2 ring in a chair conformation. The ester P(1)-S(1)-Sn(1) and P(2)-S(3)-Sn(1) systems are distinguished from the double-bonded, dative P(1)=S(2)→Sn(1), P(2)=S(4)→Sn(1), and P(2′)=S(4′)→Sn(1) systems on the basis of their P-S and S-Sn internuclear distances. The tin atom is 0.46 ? out of the plane formed by the S(1), S(2), S(4), and S(4′) atoms and is away from the S(3) atom, with the ester-bound sulfur atoms cis oriented [∠S(1)-Sn(1)-S(3) = 87.41°]. The smallest angle in the plane is formed by the terminally chelating sulfur atoms [∠S(1)-Sn(1)-S(2) = 74.28°]. Atom S(3) is opposite the expected direction of the tin(II)-lone-pair vector, which if extended strikes a perpendicularly oriented phenoxy group with tin to carbon distances at 3.457-4.317 ?. The distances to the center of the ring and to the plane of the ring are 3.66 and 3.46 ?, respectively. The ordering of the angles at the phosphorus atoms obeys the expected isovalent hybridization predictions: ∠S-P-S > ∠S-P-O > ∠O-P-O. The stability of the phenoxy ester to air oxidation is rationalized in terms of the additional η6-C6H5 bonding contribution and by the steric blocking of the tin(II) lone pair by the phenoxy group.
