Preparation, molecular structure, and photolysis of a new ring system, peralkyl-1-germa-2,3,4-trisilacyclobutanes

An Isolable Radical Anion and Dianion of a Cyclotetrasilane: Synthesis and Structure of [Si{1,2‐(NEt)2C6H4}]4−. and [Si{1,2‐(NEt)2C6H4}]42−

“…2.372 ) [12] or for tetrasilacyclobutanes (2.363-2.445 ). [13] Even further reduction of the Si1ÀSi2 bond length is found for complex 2 (2.284(2) ), which is close to the range of SiÀSi double bonds (2.138-2.261 ) [12] and may also be compared to the Si = Si bonds in a Z-diaminodisilyldisilene (the tetramer of C; 2.289 ) [8] or cyclotetrasilenes (2.174, 2.257 ). [14,15] The substantial shortening of the SiÀSi bond in 1 and 2 can be attributed to the additional one or two electrons, respectively, which are delocalized in the Si 4 ring.…”

MOLECULAR STRUCTURE OF ORGANOSILICON COMPOUNDS WITH Si-M (M = Ge, Sn, Pb, Ti, Zr, Hf) BONDS

“…The four-membered GeSi 2 0 ring of germadisilaoxetane 21 [35] has an almost planar structure in contrast with the folded structures of germatrisilacyclobutanes 22 (R-Pr, 'BUCH 2 ) [39], with puckering angles of 24 and 36 respectively. The germadisilaoxetane heterocycle is somewhat deformed with the following bond distances and endocyclic angles: Si-Ge 2.…”

Synthesis and Structure of an Azatrisilacyclobutane and Its Precursor, a Novel Lithium Enamide Having a Tricyclic (LiNSiO)2 Skeleton

“…[3] It has a rhomboidal, planar (LiN) 2 core (the endocyclic angles at the Li atoms are wider than those at the N [5] [4] The other geometric parameters are unexceptional (cf., ref. [3]).…”

“…[5] The endocyclic SiÀN bond lengths are slightly longer than those within the silylene moiety. The internal angles of the Si 3 N ring range from 75.39(3)8 at the central silicon atom Si3 to 110.46(9)8 at the N atom.…”

“…[8,9] No structural information is available for the azatrisilacyclobutanes (Me 2 Si) 3 NM(N 3 )[CH(SiMe 3 ) 2 ] 2 (M Ge and Sn), which were obtained by treatment of M[CH(SiMe 3 ) 2 ] 2 with N 3 (SiMe 2 ) 3 N 3 . [10,11] Only a few other X-ray-characterized compounds with Si 3 X (X=Si) ring structures have been described (Cambridge data base); X C, [12±15] X N, [7] X Ge, [5,16] X O, [17,18] and X Te. [19] The pathway leading to the lithium compound 1 (first step in Scheme 1) is likely to be similar to that described for the conversion of Li[CH(SiMe 3 ) 2 ] and tBuCN into the h 3 -1-azaallyllithium compound I.…”