Tin(ii) amide/alkoxide coordination compounds for production of Sn-based nanowires for lithium ion battery anode materials

Abstract

A series of tin(II) amide alkoxides ([(OR)Sn(NMe(2))](n)) and tin(II) alkoxides ([Sn(OR)(2)](n)) were investigated as precursors for the production of tin oxide (SnO(x)) nanowires. The precursors were synthesized from the metathesis of tin dimethylamide ([Sn(NMe(2))(2)](2)) and a series of aryl alcohols {H-OAr = H-OC(6)H(4)(R)-2: R = CH(3) (H-oMP), CH(CH(3))(2) (H-oPP), C(CH(3))(3) (H-oBP)] or [H-OC(6)H(3)(R)(2)-2,6: R = CH(3) (H-DMP), CH(CH(3))(2) (H-DIP), C(CH(3))(3) (H-DBP)]}. The 1:1 products were all identified as the dinuclear species [(OAr)Sn(μ-NMe(2))](2) where OAr = oMP (1), oPP (2), oBP (3), DMP (4), DIP (5), DBP (6). The 1:2 products were identified as either a polymer ([Sn(μ-OAr)(2)](∞) (where OAr = oMP (7), oPP (8)), dinuclear [(OAr)Sn(μ-OAr)](2) (where OAr = oBP (9), DMP (10) or DIP/HNMe(2) (11)), or mononuclear [Sn(DBP)(2)] (12) complexes. These novel families of compounds (heteroleptic 1-6, and homoleptic 7-12) were evaluated for the production of SnO(x) nanowires using solution precipitation (SPPT; oleylamine/octadecene solvent system) or electrospinning (ES; THF solvent) processing conditions. The SPPT route that employed the heteroleptic precursors yielded mixed phases of Sn(o):romarchite [1 (100:0); 2 (80:20); 3 (68:32); 4 (86:14); 5 (66:35); 6 (88:12)], with a variety of spherical sized particles [1 (350-900 nm); 2 (150-1200 nm); 3 (250-950 nm); 4 (20-180 nm); 5 (80-400 nm); 6 (40-200 nm)]. For the homoleptic precursors, similar phased [7 (80:20); 8 (23:77); 9 (15:85); 10 (34:66); 11 (77:23); 12 (77:23)] spherical nanodots were isolated [7 (50-300 nm); 8: (irregular); 10 (200-800 nm); 11 (50-150 nm); 12 (50-450 nm)], except for 9 which formed polycrystalline rods [Sn(o):romarchite (15:85)] with aspect ratios >100. From ES routes, the heteroleptic species were found to form 'tadpole-shaped' materials whereas the homoleptic species formed electrosprayed nanodots. The one exception noted was for 7, where, without use of a polymer matrix, nanowires of Sn(o), decorated with micron sized 'balls' were observed. Due to the small amount of material generated, PXRD patterns were inconclusive to the identity of the generated material; however, cyclic voltammetry on select samples was used to tentatively identify the final Sn(o) (from 7) with the other sample identified as SnO(x) (from 1).

Novel Heteroleptic Tin(II) Complexes Capable of Forming SnO and SnO2 Thin Films Depending on Conditions Using Chemical Solution Deposition

“…These 119 Sn{ 1 H} NMR spectra for complexes 4 – 6 are consistent with previously reported complexes. 35 , 36 …”

“…These 119 Sn{ 1 H} NMR spectra for complexes 4− 6 are consistent with previously reported complexes. 35,36 Crystal Structures. X-ray quality crystals were obtained by slow evaporation of a saturated THF solution for complexes 1−3 and saturated hexane for complexes 4−5.…”

Perfluorinated tert‐Butoxides of Tin(II): The Dimeric Alkoxide and Its Monomeric Ate Complex

“…First NMR experiments of these alkoxides together with Sn(O n Bu) 2 were published a few years later , . Numerous other tin(II) alkoxides were structurally characterized yielding monomeric, dimeric,, , , or polymeric, , structures and depending on the bulk of the alkoxy group or additional interactions as in Sn(OCH 2 CH 2 NMe 2 ) 2 (Figure ).…”

Characterization of core-shell microstructure and self-healing performance of electrospun fiber coatings

“…ES typically produces nonwoven fibers in the diameter range of 10 nm to 10 µm [15,16]. Moreover, a wide range of materials can be processed using this method, including polymers, ceramics, and inorganics [15][16][17][18][19][20][21][22][23]. The versatility of ES allows for tailoring to specific applications by strategic selection of starting materials.…”