Di-n-butyltin Methyl- and Phenylphosphonates

Abstract

The structure of [Bu 2 Sn(HO 3 PMe) 2 ] 2 (1), as determined by single-crystal X-ray diffraction, is based on a dimer containing bridging and terminal hydrogenophosphonate ligands. The tin atoms are formally five-coordinate, but exhibit also two additional remote contacts, d(Sn-O) ≈ 3.14 Å, which results in a "5+2" type coordination. This crystalline compound and the three other amorphous compounds, Bu 2 Sn(O 3 PMe) (2), Bu 2 Sn(HO 3 PPh) 2 (3), and Bu 2 -Sn(O 3 PPh) (4), have been characterized by solid state 31 P and 119 Sn MAS NMR. Compound 1 exhibits a very well resolved 31 P MAS NMR spectrum in which three different 2 J-( 31 P-119/117 Sn) iso scalar couplings can be measured. 31 P and 119 Sn NMR, 31 P-19 Sn HMQC spectroscopy, and various other 2D NMR techniques at variable temperatures were used to unravel the basic structural unit of compounds 2 and 4 in solution, which is proposed to be based on a trigonal bipyramid of the type R 2 SnO 3 with two apical and one equatorial oxygen atom. Compound 1, in solution, displays a similar local geometry at tin and the same dimeric unit as in the crystalline state. In contrast with 2 and 4, however, compounds 1 and 3 display an extremely high degree of stereochemical fluxionality based on fast exchange of the bridging and terminal hydrogenophosphonate ligands.

Structural Diversity in Organotin Compounds Derived from Bulky Monoaryl Phosphates: Dimeric, Tetrameric, and Polymeric Tin Phosphate Complexes

“…Moreover, since the X-ray diffrac- tion studies suggest that the molecule should exhibit a three line spectrum (with a 2:1:1 ratio for dipp-H, dipp-H 2 and dipp ligands, respectively), a variable temperature 31 P NMR study was carried out in the temperature range 300-243 K. The spectral pattern, however, remained the same. Thus, the presence of only two 31 P NMR signals over the entire temperature range studied suggests that the only two types of dipp-H phosphate ligands exist in the molecule in solution as has been reported for the di-n-butyltin methylphosphonate complex by Ribot et al [15] These observations have further been supported by the presence of a single broad multiplet centered at -258.7 ppm in the 119 Sn NMR spectrum of 4.…”

“…[6] After a dormant period in between, Chandrasekhar et al [7] and others [8][9][10] showed in recent years that newer and more interesting tin aggregates and polymers could be synthesized by employing a variety of exotic and suitably designed carboxylic acids, phosphinic acids, sulfonic acids, and other acidic proton-containing main group ligands. Thus, while the interaction of both phosphinic [11][12][13] and phosphonic acids [11,[14][15][16][17] with organotin precursors in the assembly of organostannoxane cages has been a subject of intense investigation for sometime now, the use of phosphate esters for this purpose has been limited to a few sporadic reports. [18] Owing to the important role played by bulky substituents in main group chemistry in recent times, 2 ] n ·nH 2 O (3).…”

The Isoelectronic Replacement of E = P+ and Si in the Trinuclear Organotin−Oxo Clusters [Ph2E(OSntBu2)2O·tBu2Sn(OH)2]

“…[20] 4 . The solid-state NMR spectra were measured using the same instrument equipped with a 4 mm MAS probe.…”

“…The solid-state NMR spectra were measured using the same instrument equipped with a 4 mm MAS probe. Crystalline NH 4 H 2 PO 4 (δ ϭ 0.95 ppm) and c-Hex 4 Sn (δ ϭ Ϫ97.35 ppm) were used as secondary references. The 119 Sn MAS NMR spectra were obtained using cross polarization (contact time 5 ms, recycle delay 10s).…”

Synthesis, Characterization, and Hydrolytic Behavior of Diorganotin(IV) Coordination Polymers with Layered Structural Motifs

“…Jambor et al have demonstrated that the intramolecular coordination of N,C,N-type chelating ligands to the tin center is a useful strategy for the isolation of molecular diorganotin phosphonates featuring [-Sn-O-P-O-] 2 eightmembered cyclic rings. [7] The contribution of phosphonate groups in both monoanionic and dianionic forms has been exemplified in several one-dimensional di-and triorganotin phosphonates, [8][9][10] and a layered structural motif is observed in Me 2 Sn(O 3 PPh). [11] The structure is composed of fused 12-membered tritin macrocyclic rings through bridging bidentate coordination of the phosphonate groups, and the third oxygen atom of each phosphonate provides a layered connectivity.…”