Structural studies of pentacoordinate silicon. I. Phenyl-(2,2',2''-nitrilotriethoxy)silane

Abstract

The crystal structure of (CeH5)Si(OCH2CH2)3N has been determined by three-dimensional X-ray diffraction methods and confirms the predicted pentacoordination of silicon in this compound. The distorted trigonal bipyramid coordination geometry of the silicon has the three equatorial oxygens bent away from the phenyl group toward the nitrogen as shown by the average C-Si-O angle of 97.1 °and the average O-Si-O angle of 118.5°. Bond distances to the silicon are Si-O(l) 1.638 Á, Si-0(2) 1.664 Á, Si-0(3) 1.665 A, Si-C 1.882 Á, and Si-N 2.193 A. The space group is Pbca with a = 13.220 A, b = 18.524 Á, c = 10.050 A and eight molecules per unit cell. The structure was solved by iterative application of Sayre's method in three dimensions using a visual data set. Refinement was by full matrix least squares to a final reliability index of 10.8%. Data Collection. Crystals of phenyl-(2,2',2"-nitrilotriethoxy)silane are colorless with a lath-like habit and a melting point of 207-(12) R.

Crystal and molecular structure of β-1-phenylsilatrane, C12H17NSi

“…1 shows the ORTEP diagram of the molecule. The molecular geometry is a distorted trigonal bipyramid similar to that in the 0c form (Turley & Boer, 1968). The length of the transannular Si-<--N dative bond Other bond lengths and angles are comparable to the values found in the a modification.…”

“…The crystal structure of 0c-l-phenylsilatrane, C6HsSi(OCH2CH2)aN, was determined by Turley & Boer (1968). The structure is disordered.…”

Silatranes and Their Tricyclic Analogs

“…Attempts to obtain disilatranylmethane (n D 1) failed because of unfavorable steric effects 47 . However, germatranylmethylsilatrane, N(CH 2 CH 2 O) 3 GeCH 2 Si(OCH 2 CH 2 ) 3 N, is formed in moderate yield (30%) under the same conditions 47 …”

“…RSSi(OCH 2 CH 2 ) 3 N RSSi(OMe) 3 (13) Organyltrialkoxysilanes can be converted to the corresponding silatranes by a onepot reaction with bis(2-hydroxyalkyl)amines and epoxides 52,69 . According to Frye and coworkers 69 the procedure involves in situ formation of trialkanolamine.…”

Structures cristallines du [2.2.2]paracyclophane (I) (C24H24) et de son complexe avec le perchlorate d'argent (II) (C24H24.AgClO4)

“…The large difference in the Ti-O(non-bridging) and Ti-N bond lengths, 1.87 vs 2.33 A, in the (nitrilotriethanolato)titanium moiety does not seem unusual when compared with similar bonds in nitrilotriethanolate complexes of other metals. Ge(C2Hs)-[N(CH2CH20)3] (Atovmyan, Bleidelis, Kemme & Shibaeva, 1970) and Si(C6Hs)[N(CH2CH20)3] (Turley & Boer, 1968), for example, have bond lengths with even larger M--O and M-N differences: Ge-O, 2.24;1.66;2.19 A. No other structures containing a (2,2',2"-nitriloethanolato)titanium(IV) moiety have been reported. Titanium complexes with nitrilotriacetate, a similar tetradentate with a central nitrogen atom and three oxygen atoms, have much longer Ti-O(non-bridging) bonds, 1.96-2.08 ,/~ (Wieghardt, Quilitzsch, Weiss & Nuber, 1980;Schwarzenbach & Girgis, 1975); the ethanolate group,-C H2C H20-, clearly forms a stronger bond because the negative charge on the oxygen atom is not diluted by resonance as it is within the acetate group, -CH2COO-.…”