Oxidation Reactions of the N‐Heterocyclic Stannylenes [o‐C₆H₄(NSitBuMe₂)₂]Sn and [{Fe(η⁵‐C₅H₄‐NSitBuMe₂)₂}Sn] with Sulfur, Selenium, and Diphenyl Diselenide

Abstract

The N‐heterocyclic stannylenes [{Fe(η5‐C5H4‐NSitBuMe2)2}Sn] (1) and [o‐C6H4(NSitBuMe2)2]Sn (2) were prepared in one‐pot reactions from SnCl2, LiN(SiMe3)2, and the corresponding diamine, viz. [Fe(η5‐C5H4‐NHSitBuMe2)2] and o‐C6H4(NSiHtBuMe2)2, respectively. Oxidative addition reactions of 1 and 2 with S8 and Se8, respectively, afforded the corresponding 1,3,2,4‐dithiadistannetanes ((1S)2, (2S)2), and 1,3,2,4‐diselenadistannetanes [(1Se)2, (2Se)2]. The reactions of 1 and 2 with PhSeSePh respectively furnished 1(SePh)2 and 2(SePh)2. The crystal structures of o‐C6H4(NSiHtBuMe2)2, 1, 2, (1S)2, (2S)2, (1Se)2, (2Se)2, 1(SePh)2, and 2(SePh)2 were determined by single‐crystal X‐ray diffraction. Stannylene 2 shows a chain‐like aggregation in the solid state due to intermolecular Sn···arene interactions. A short intramolecular CH···Se contact compatible with a hydrogen bond was observed for (1Se)2.

Reactions of Mesityl Azide with Ferrocene‐Based N‐Heterocyclic Germylenes, Stannylenes and Plumbylenes, Including PPh2‐Functionalised Congeners

“…107.1(2)° [30] . This is in line with previous observations that the 1,1’‐ferrocenylene backbone of N‐heterocyclic carbenes and their heavier analogues [{Fe(η 5 −C 5 H 4 −NR) 2 }E] (E=C–Pb) gives rise to large bond angles at the divalent tetrel atom close to those of corresponding acyclic congeners [27–29,31,32] . The Sn−N bonds of stannylene 16 are longer than the Ge−N bonds of germylene 17 by ca.…”

“…(18) 18 (E = Sn) [b] 2.035( Chemistry-A European Journal E] (E = C-Pb) gives rise to large bond angles at the divalent tetrel atom close to those of corresponding acyclic congeners. [27][28][29]31,32] The SnÀ N bonds of stannylene 16 are longer than the GeÀ N bonds of germylene 17 by ca. 0.2 Å, which is in accord with the difference of the covalent radii of tin (1.39 Å) and germanium (1.20 Å).…”

“…The N‐heterocyclic germylene [{Fe(η 5 −C 5 H 4 −NSi t BuMe 2 ) 2 }Ge] ( 17 ) was conveniently prepared analogous to the stannylene [{Fe(η 5 −C 5 H 4 −NSi t BuMe 2 ) 2 }Sn] ( 16 ) [28] by reacting LiN(SiMe 3 ) 2 , [GeCl 2 (1,4‐dioxane)] and [Fe(η 5 −C 5 H 4 −NHSi t BuMe 2 ) 2 ] in a 2 : 1 : 1 molar ratio in THF. The product was obtained in 92 % yield and was structurally characterised by single‐crystal X‐ray diffraction (XRD).…”

“…Starting materials were procured from standard commercial sources and used as received. [Fe(η 5 −C 5 H 4 −NHSi t BuMe 2 ) 2 ], [59] [GeCl 2 (1,4‐dioxane)], [60] 12 – 14 , [23] 15 , [27] 16 [28] and MesN 3 [61] were synthesised by adapted versions of the published procedures. NMR spectra were recorded at ambient temperature with Varian NMRS‐500 and MR‐400 spectrometers operating at 500 and 400 MHz, respectively, for 1 H. Elemental analyses were carried out with a HEKAtech Euro EA‐CHNS elemental analyser at the Institute of Chemistry, University of Kassel, Germany.…”

“…We selected MesN 3 , which is a readily available aryl azide considered particularly safe for use (C/N atom number ratio not lower than 3) [26] . We were interested in the influence of the Lewis pair nature of the donor‐functionalised N‐heterocyclic tetrylenes 12 – 14 in this context and therefore included the unfunctionalised congeners [{Fe(η 5 −C 5 H 4 −NSi t BuMe 2 ) 2 }E] [E=Pb ( 15 ), [27] Sn ( 16 ), [28] Ge ( 17 ); Figure 1, bottom] in our study. The Si t BuMe 2 substituent was chosen instead of the SiMe 3 substituent present in 12 – 14 , because all three unfunctionalised tetrylenes are stable and can be isolated in pure form, whereas the trimethylsilyl‐substituted plumbylene [{Fe(η 5 −C 5 H 4 −NSiMe 3 ) 2 }Pb] is unstable [27] .…”