Monomeric Three- and Four-Coordinate Magnesium Amides

Abstract

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.