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.

Magnesium-doped semiconductors have existing and anticipated applications in the fabrication of blue and green light-emitting diodes, blue and green laser diodes, and in microelectronics devices. At present, the area is limited by the precursor characteristics of bis(cyclopentadienyl)magnesium and substituted derivatives. We will describe our efforts to identify new magnesium source compounds that are potentially superior to magnesocenes and can be used in chemical vapor deposition processes. Monomeric three- and four-coordinate amides have been synthesized and totally characterized. These complexes are low-melting solids and are significantly more volatile than magnesocene derivatives. We will also describe the synthesis and characterization of several other classes of volatile magnesium compounds that might be useful in chemical vapor deposition processes.