title: Syntheses, Characterization, and Molecular Mechanics Calculations of Optically Active Silatrane Derivatives.
abstract: A series of optically active silatrane derivatives, [Si{N(CHRCH(2)O)(CH(2)CH(2)O)(2)}X] (R = Me, i-Pr; X = Ph, OMe) has been synthesized by the reaction of optically active triethanolamine derivatives with XSi(OMe)(3), and characterized by (1)H NMR, (13)C NMR, (29)Si NMR, and mass spectroscopy, and the structures of six compounds have been determined by X-ray analysis. Molecular mechanics methods have also been employed to obtain the energy-minimized structures. The (29)Si NMR chemical shifts and the lengths of Si-N determined by X-ray analysis are sensitive to the bulkiness of the substituent (R). The Si-X bond lengths (X: trans position to nitrogen) do not appreciably differ from one another. The MM2 calculations indicated that the substituent exists in the equatorial position, and the results are in agreement with those of X-ray analysis and (1)H NMR spectroscopy. Crystallographic data: [R = H; X = OMe], C(7)H(15)NO(4)Si, orthorhombic, Pna2(1), a = 13.407(1) Å, b = 8.761(2) Å, c = 8.191(1) Å, Z = 4; [R = Me; X = OMe], C(8)H(17)NO(4)Si, orthorhombic, P2(1)2(1)2(1), a = 10.110(3) Å, b = 11.083(2) Å, c = 9.474(2) Å, Z = 4; [R = i-Pr; X = OMe], C(10)H(21)NO(4)Si, monoclinic, P2(1), a = 8.481(1) Å, b = 7.805(1) Å, c = 10.218(2) Å, beta = 111.31(1) degrees, Z = 2; [R = Me; X = Ph], C(13)H(19)NO(3)Si, orthorhombic, P2(1)2(1)2(1), a = 8.813(1) Å, b = 11.137(2) Å, c = 13.757(1) Å, Z = 4; [R = i-Pr; X = Ph], C(15)H(23)NO(3)Si, orthorhombic, P2(1)2(1)2(1), a = 8.365(1) Å, b = 13.538(2) Å, c = 13.841(2) Å, Z = 4.
authors.affiliation: Coordination Chemistry Laboratories, Institute for Molecular Science, Myodaiji, Okazaki 444, Japan.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Tasaka
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hirotsu
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kojima
authors.forename: Shunji
authors.initials: S
authors.lastname: Utsuno
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Yoshikawa