Far-infrared and tin-119m Moessbauer study of complexes of phosphorus- and arsenic-containing ligands with tin(IV) halides

Abstract

Twenty-five complexes of the type SnX4B2, where X = C1, Br, or I, B = &PO (R = C Z H~, C4H9, C&), (C6H6)3As0, (CH3)zS0, (CeH5)3As, RIP (R = C4H9, CeH6, CSHl?), or COHS(CH~)ZP, and BZ = O-[(COH~)ZP]CSH~, U -( C H~)~N ( C~H~) P -(C&)Z, or [u-(CH3)~N(C6H4)]2P(C6H5), fifteen of them previously unreported, have been synthesized and studied by llgmSnMossbauer and far-infrared techniques. Cis and trans isomers have been distinguished by the number of v(Sn-X) and G(Sn-X) bands they exhibit; those assigned trans on this basis are found t o exhibit Mossbauer quadrupole splittings of ca. 1 mm/sec. The point-charge model predicts that the QS for cis isomers should be half that for the trans, and the QS for these isomers is barely resolvable as expected. In one case, S~C L .~P ( C !~H S )~, the infrared and Mossbauer evidence leads to opposite stereochemical assignments. In general, the oxygen donor ligands give cis complexes while all the fifthgroup donor ligands but triphenylarsine give the trans isomers except when bidentate These differences are rationalized on steric arguments.Dithiocarboxylates (L = CeH6-CSS-= dtb-, P-CH3-CeHa-CSS-= dtt-, CHa-CSS-= dta-, ceH&H~-cSs-= dtpa-) react with both VOz+ ion and V(II1) to give stable VL4 complexes. Magnetic measurements, infrared spectra, and molecular weight measurements in solution are consistent with eight-coordinated V(1V). Epr and preliminary X-ray results demonstrate an approximate Dzd geometry for the VSS chromophores. Electronic spectra are discussed.

Tin(IV) Fluoride Complexes with Tertiary Phosphane Ligands – A Comparison of Hard and Soft Donor Ligands

“…570 cm -1 , and usually some MeCN or THF. 3 there was little evidence for coordination to SnF 4 . In contrast, arsane complexes of SnX 4 (X = Cl, Br or I) form readily, [9] and indeed [SnI 4 {o-C 6 H 4 (AsMe 2 ) 2 }] is one of the very small number of structurally characterised neutral ligand adducts of SnI 4 .…”

“…In the course of this work the [SnX 4 {MeC(CH 2 AsMe 2 ) 3 }] (X = Cl or Br) were prepared from the appropriate SnX 4 and triarsane in CH 2 Cl 2 and their 1 H NMR spectra show the triarsane bound as a bidentate to a six-coordinate tin centre. The 119 Sn NMR chemical shifts of δ = -696 and -1290 ppm (Table 6) are typical of SnX 4 As 2 donor sets.…”

“…The majority of these ligands have hard O or N donor atoms, but examples with softer P, As, S, Se or Te donors have also been characterised. [3][4][5][6][7][8][9][10] In marked contrast little is known about adducts of SnF 4 with neutral ligands. Some examples were reported in the period , often as part of larger surveys including the heavier tin(IV) halides, but little data were provided and only a single complex, [SnF 4 (2,2Ј-bipy)], was structurally characterised.…”

“…[18] The latter complexes show no dissociation in solution, which is indicative of stronger binding of the phosphane oxide ligands compared to the ethers. The differences in the distances Sn- [9] [SnCl 4 {Ph 2 P(CH 2 ) 2 PPh 2 }] -18.8 -5.5 -626 (t) 890 [9] [SnCl 4 {o-C 6 H 4 (PPh 2 ) 2 }] -13.9 -1 -607.5 (t) 890 [9] [SnCl 4 {o-C 6 H 4 (AsMe 2 ) 2 }] ---675 (s) - [9] [SnBr 4 {o-C 6 H 4 (AsMe 2 ) 2 }] ---1354 (s) - [9] [SnCl 4 {MeC(CH 2 AsMe 2 ) 3 may be compared with that of [SnCl 4 (1,10-phenanthroline)], [24] which possess Sn-N = 2.234 (7) [16,25,26] The 2,2Ј-bipyridyl series shows the longest Sn-N bonds in the iodide and the shortest in the fluoride, with the chloride and bromide less clearly discriminated, support for the fluoride being the strongest Lewis acid of the four halides. …”

Structure and pseudosymmetry of tetrabromobis(dimethyl sulfoxide)tin(IV)

“…In the case of tin(IV) bromide complexes, few experimental data are available and more crystallographic and Mrssbauer measurements are necessary before a similar relationship can be searched for. The IR spectrum of [SnBr4 (Me2SO)2] suggests a cis-octahedral molecular structure with the Me2SO ligands coordinated to tin through the O atom (Harrison, Lane & Zuckerman, 1972), and its Mrssbauer quadrupole splitting agrees within experimental error with those of [cis-SnBr2C12(Me2SO)2] (Tudela, Fernfindez, Tornero & Vegas, 1986) and (Tudela, Fernfindez & Tornero, 1985) whose crystal structures have been recently reported (Tudela et al, 1986;Kisenyi, Willey & Drew, 1985 Kisenyi et al (1985) and Tudela et al (1986). Scattering factors and dispersion corrections for neutral atoms from Cromer & Waber (1965) and Cromer & Liberman (1970).…”