Solid state and solution structural investigation of homoleptic tin(IV) alkoxide compounds. Part I. Sn(O—t-Bu)₄ and [Sn(O—i-Pr)₄•HO—i-Pr]₂

Abstract

. Can. J. Chem. 69, 121 (1991).The crystal and molecular structures of s n ( % t -B~)~ and [Sn(&i-Pr)4.H&i-Pr]2 have been determined by single-crystal X-ray diffracti9n. Sn(&t-Bu)40crystallizes in the monoclinic crystal system with space group C2/c, where a = 17.382(6) A, [Sn(&i-Pr)4.H&i-Pr]2 exhibits an edge-shared, bi-octahedral structure in the solid state that is distorted due to the presence of asymmetric hydrogen bonding between axially coordinated alcohol ligands and an isopropoxide ligand. I3C NMR and IR spectroscopic data have been recorded for Sn(&t-Bu)4 and S n ( & t -B~-d~)~ to establish criteria for unambiguous identification of solution structures of tin(1V) alkoxides. It is demonstrated that the two-bond 2~~j C -&~~9 s n coupling constant is larger for terminal alkoxide ligands than for k2-alkoxide bridges, and the v(Sn-0) stretching frequency has been assigned. The dynamic solution behaviour of [Sn(&i-Pr)4.H&i-Pr]2 has been studied using variable temperature 'H and I3C NMR spectroscopy. The data obtained are consistent with a process that involves rapid reversible dissociation of isopropanol at room temperature. Upon cooling, the equilibrium concentration of the species with coordinated alcohol increases, and the molecule undergoes rapid intramolecular proton transfer (AG* < 11.9 kcal mol-I). Upon further cooling, the I3C NMR data are consistent with a solution structure analogous to that found in the solid state.Key words: tin, alkoxide, NMR, dynamic, structure. travers deux liaisons 2~~lC-&ttssn, est plus grande pour les ligands alcoolates terminaux que pour les ponts alcoolates-k2; de plus, on a attribut la frtquence de,. Faisant appel a la rmn du 'H et du I3c, a temperature variable, on a ttudit le comportement dynamique du [Sn(%i-Pr).HO--i-Pr] en solution. Les donntes obtenues sont en accord avec un processus qui implique une dissociation reversible rapide de l'isopropanol, a la temptrature ambiante. Par refroidissement, la concentration de l'espkce avec de I'alcool isopropylique augmente et la moltcule subit un transfert intramoltculaire rapide de proton (AG* < 1 1,9 kcal mol-I). Si on continue le refroidissement, les donntes de la rmn du I3c obtenues sont en accord avec une structure en solution qui serait analogue a celle qui est trouvte a l'ttait solide.

Tin Nanoparticles in Carbon/Silica Hybrid Materials by the Use of Twin Polymerization

“…2-(Hydroxymethyl)-4-methoxyphenol and 2-(hydroxymethyl)-5-methoxyphenol were prepared from 4-methoxyphenol and 5-methoxyphenol, respectively, using a published procedure. [27] Tin(IV) tert-butoxide, [24] tin(II) n-butoxide, [28] tin(II) acetate, [29] tin(IV) acetate, [30] tin(II) methoxide, [28] 2,2'-spirobi[4H-1,3,2-benzodioxasiline], [15,17] 2,2'-spirobi[4H-1,3,2-benzodioxastannine] (A), [13] 2,2'-spirobi[6-methyl-4H-1,3,2-benzodioxastannine] (B), [13] and 2,2'-spirobi[6-methoxy-4H-1,3,2-benzodioxastannine] (C) [13] were prepared according to literature procedures. Solid-state NMR measurements were performed at 9.4 T on a Bruker Avance 400 spectrometer equipped with double-tuned probes capable of magic angle spinning.…”

“…[24][25][26] This assumption is reinforced by comparison of the solid-state 119 Sn NMR data of the tetracoordinated tin atom in Sn(OtBu) 4 (d = À371 ppm) with the hexacoordinated tin atom in [Sn(OiPr) 4 ·HOiPr] 2 (d = À648 ppm). [24] HAADF-STEM analyses of the hybrid materials 6-8 show the typical morphology of twin polymers with 2 nm sized domains (Figure 7). [14][15][16] In addition to Sn-(OtBu) 4 the tin additives Sn-(OnBu) 2 and the tin carboxylates Sn(OAc) 2 and Sn(OAc) 4 were tested for their potential in the synthesis of Sn/C/SiO 2 materials (Scheme 3).…”

“…The solid-state 119 Sn NMR spectra show broad signals at d = À638 (8), À659 (6 s), À658 (6), and À650 ppm (7), which points to an incorporation of hexacoordinated tin species Sn(OR) 4Àx (OtBu) x ·n tBuOH (R = H, OAr) in the polymer matrix ( Figure 6). [24][25][26] This assumption is reinforced by comparison of the solid-state 119 Sn NMR data of the tetracoordinated tin atom in Sn(OtBu) 4 (d = À371 ppm) with the hexacoordinated tin atom in [Sn(OiPr) 4 ·HOiPr] 2 (d = À648 ppm). [24] HAADF-STEM analyses of the hybrid materials 6-8 show the typical morphology of twin polymers with 2 nm sized domains (Figure 7).…”

Size‐Dependent Photoconductance in SnO2 Nanowires

“…The alkoxide precursor, [Sn(O t Bu) 4 ], was synthesized by a reported procedure 17. All experimental manipulations were performed in a modified Schlenk‐type vacuum assembly, taking stringent precautions against atmospheric moisture.…”

Chemistry of a Novel Family of Tridentate Alkoxy Tin(II) Clusters

“…The modification of 1 therefore is not as surprising as originally appeared since these molecules are fluctional in solution. The 117-119 Sn 2 J-coupling normally associated with Sn-O-Sn linkages, and that typically range from 223 19,66 to 420-440 31,65,67 to 610 Hz, 65 was not observed for any of these compounds. This phenomenon was also previously reported for the similar Sn 6 O 4 (OSiMe 3 ) 4 compound 68 and attributed to rapid ligand exchange.…”