Monomeric Three- and Four-Coordinate Magnesium Amides.
Treatment of bis(bis(trimethylsilyl)amido)bis(tetrahydrofuran)magnesium with 2 equiv of 2,3,5-collidine, 2-picoline, 4-picoline, or 3,5-lutidine in benzene at room temperature for 18 h afforded bis(bis(trimethylsilyl)amido)bis(2,3,5-collidine)magnesium (80%), bis(bis(trimethylsilyl)amido)bis(2-picoline)magnesium (70%), bis(bis(trimethylsilyl)amido)bis(4-picoline)magnesium (48%), or bis(bis(trimethylsilyl)amido)bis(3,5-lutidine)magnesium (58%), respectively. Sublimation of bis(bis(trimethylsilyl)amido)bis(2,3,5-collidine)magnesium (90 degrees C, 0.1 mmHg) and bis(bis(trimethylsilyl)amido)bis(2-picoline)magnesium (115 degrees C, 0.1 mmHg) afforded colorless crystals of bis(bis(trimethylsilyl)amido)(2,3,5-collidine)magnesium (53%) and bis(bis(trimethylsilyl)amido)(2-picoline)magnesium (46%), respectively. Treatment of bis(bis(trimethylsilyl)amido)bis(tetrahydrofuran)magnesium with 1 equiv of 2,6-lutidine in benzene at room temperature for 18 h afforded bis(bis(trimethylsilyl)amido)(2,6-lutidine)magnesium (56%). The X-ray crystal structures of bis(bis(trimethylsilyl)amido)bis(2,3,5-collidine)magnesium, bis(bis(trimethylsilyl)amido)bis(4-picoline)magnesium, bis(bis(trimethylsilyl)amido)(2-picoline)magnesium, and bis(bis(trimethylsilyl)amido)(2,6-lutidine)magnesium were determined. Bis(bis(trimethylsilyl)amido)bis(2,3,5-collidine)magnesium crystallizes in the monoclinic space group C2/c with a = 11.8410(7) Å, b = 20.5413(13) Å, c = 15.5746(10) Å, beta = 93.072(2) degrees, V = 3782.8(4) Å(3), and Z = 4. Bis(bis(trimethylsilyl)amido)bis(4-picoline)magnesium crystallizes in the triclinic space group P&onemacr; with a = 10.4914(6) Å, b = 11.8504(6) Å, c = 15.4546(9) Å, alpha = 99.3180(10) degrees, beta = 98.4180(10) degrees, gamma = 111.5320(10) degrees, V = 1718.8(2) Å(3), and Z = 2. Bis(bis(trimethylsilyl)amido)(2-picoline)magnesium crystallizes in the orthorhombic space group Pbca with a = 18.4536(14) Å, b = 15.2326(9) Å, c = 20.614(2) Å, V = 5794.6(7) Å(3), and Z = 8. Bis(bis(trimethylsilyl)amido)(2,6-lutidine)magnesium crystallizes in the orthorombic space group Pbca with a = 18.6221(13) Å, b = 15.3236(9) Å, c = 20.9085(14) Å, V = 5966.4(7) Å(3), and Z = 8. Application of the these complexes as source compounds in chemical vapor deposition processes is discussed.
Sebestl
Jennifer L.
JL
Department of Chemistry, Wayne State University, Detroit, Michigan 48202.
Nadasdi
T. Timothy
TT
Heeg
Mary Jane
MJ
Winter
Charles H.
CH