Neutral penta-coordinate derivatives of bis(O-dioxophenylene) silicon—crystal structure of Si(O2C6H4)2(OPPh3) and Si(O2C6H4)2{OP(NC5H10)3} · CH2Cl2

Bis(perchlorocatecholato)silan – eine neutrale Silicium‐Lewis‐Supersäure

“…[11] Verglichen mit SiF 4 (310 kJ mol À1 )e rhçht sich die FIA erheblich mit der Anwesenheit von Perfluoraryl-(SiF(C 6 F 5 ) 3 ,3 61 kJ mol À1 )o der Perfluoralkylgruppen (SiF(C 2 F 5 ) 3 ,4 43 kJ mol À1 ). [8,16] Reaktionen von HSiCl 3 mit Perchlorcatechol in Anwesenheit von Et 2 Oo der die Verdrängung von Acetonitril aus 1-(CH 3 [17] und zeigen eher ¾hnlichkeit zu Ether-Addukten von Silyliumkationen. Bisher untersuchtes tarke, neutrale Silicium-Lewis-Säuren und die in dieser Arbeit präsentierte Lewis-Supersäure 1.…”

Complexation of tris(pentafluorophenyl)silanes with neutral Lewis bases

“…24 [12][13][14][15]. Almost the same value for Si-O-P angle is observed in neutral complexes with square-pyramidal Si atom containing O@P(N(CH 2 ) 4 ) 3 and O@PPh 3 (144.3°and 143.2°, respectively) [11]. The cationic complex 3a containing two HMPA molecules is presented in Fig.…”

“…The Si(1)-O(1A) and Si(1)-O(1B) bonds differ by 0.04 Å which can be explained by the influence of crystal packing. Similar to 1a,b, in 3a the molecules of HMPA and Si(C 6 F 5 ) 3 moiety are arranged in eclipsed conformation (the pseudotorsional angles N(1A)P(1A)Si(1)C (11) and N(2B)P(2B)Si(1)C(11) are equal to 0.73°and À57°, respectively), and the Si-O-P angles are close to linear (169.1°a nd 177.3°). In the crystal of 3a the triflate anion does not have any influence on the geometry of the cation, since the shortest SiÁ Á ÁOTf distance of 6.22 Å is far beyond the sum of the Van der Waals radii (3.5 Å ).…”

“…The structures of starting TPFS-F and TPFS-Cl were also determined for comparison (Table 1). It should be pointed out, that in the literature only two compounds containing pentacoordinate complexes of silanes with phosphine oxides are described [11]. There are also several tetracoordinate structures containing Si-HMPA fragment, in which silicon atom is a part of metal silylene moiety [12][13][14][15].…”

“…Such a fact is surprising taking into account the high steric crowding of silicon coordination center. Indeed, the HMPA and Si(C 6 F 5 ) 3 moieties in 1a,b are in unfavorable eclipsed conformation (pseudotorsional angles N(3)P(1)Si(1)C (21) and N(2)P(1)Si(1)C (11) are equal to 4.1°and 4.7°in 1a and 1b, respectively).…”