Syntheses and Crystal Structures of Intramolecularly Stabilized Organogallium Compounds Containing an o-Carboranyl C,N-Chelating Ligand System

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• 作者：Jong-Dae Lee ; Cheol-Ki Baek ; Jaejung Ko ; Kwonil Park ; Sungil Cho ; Suk-Ki Min ; and Sang Ook Kang
• 刊名：Organometallics
• 出版年：1999
• 出版时间：May 24, 1999
• 年：1999
• 卷：18
• 期：11
• 页码：2189 - 2197
• 全文大小：182K
• 年卷期：v.18,no.11(May 24, 1999)
• ISSN：1520-6041

文摘

The reaction of HCab^N (1; HCab^N = closo-1-[(dimethylamino)methyl]-o-carborane) withGaCl₃ yielded the simple Lewis acid-base adduct complex HCab^N·GaCl₃ (3). The reactionof LiCab^N (2; LiCab^N = closo-1-[(dimethylamino)methyl]-2-lithio-o-carborane) with GaCl₃in a 1:1 ratio produced the four-coordinated metallacyclic organogallium compound Cab^NGaCl₂ (4), in which the gallium atom was stabilized via intramolecular C,N-coordination. Asimilar intramolecularly base-stabilized four-coordinated gallane, Cab^NGaMe₂ (5), wassynthesized from the reaction of 2 with Me₂GaCl. Complex 5 was also formed upon reactionof the complex 4 with 2 equiv of LiMe. The X-ray structural studies of complexes 4 and 5indicate that the gallium atom is located in the center of a distorted tetrahedron. The Lewisacid 4 added the base pyridine to yield the adduct Cab^NGaCl₂·NC₅H₅ (6). The trigonal-bipyramidal coordination of the metal center was proven by the single-crystal X-raydetermination of the complex 6. The reaction of LiCab^N (2) with GaCl₃ in a 2:1 ratio affordedthe bis[((dimethylamino)methyl)-o-carboranyl]gallium compound (Cab^N)₂GaCl (7). The NMRspectra revealed that intramolecular Ga-N coordination occurs in solution, resulting in apentacoordinate (Cab^N)₂GaCl structure. Crystals of (Cab^N)₂GaCl(H₂O) (8) were obtained whilerecrystallizing 7 in toluene over a period of several days. X-ray analysis of this complex 8provides support for the assignment of the water-coordinated bis[((dimethylamino)methyl)-o-carboranyl]gallane structure.