Synthesis and Structural Characterization of Copper Complexes Containing "R-Substituted" Bis-7-Azaindolyl Borate Ligands.

The coordination chemistry of scorpionate ligands based on borates containing the 7-azaindole heterocycle is relatively unexplored. Thus, there is a requirement to further understand their coordination chemistry. This article outlines the synthesis and characterization of a family of complexes containing anionic flexible scorpionate ligands of the type [(R)(bis-7-azaindolyl)borohydride] - ([ R Bai ] - ), where R = Me, Ph or naphthyl. The three ligands were coordinated to a series of copper(I) complexes containing a phosphine co-ligand to form the complexes, [Cu( Me Bai )(PPh 3 )] ( 1 ), [Cu( Ph Bai )(PPh 3 )] ( 2 ), [Cu( Naphth Bai )(PPh 3 )] ( 3 ), [Cu( Me Bai )(PCy 3 )] ( 4 ), [Cu( Ph Bai )(PCy 3 )] ( 5 ) and [Cu( Naphth Bai )(PCy 3 )] ( 6 ). Additional copper(II) complexes, namely, [Cu( Me Bai ) 2 ] ( 7 ) and [Cu( Ph Bai ) 2 ] ( 8 ), were obtained during attempts to obtain single crystals from complexes 4 and 2 , respectively. Complexes 7 and 8 were also prepared independently from CuCl 2 and two equivalents of the corresponding Li[ R Bai ] salt alongside an additional complex, namely, [Cu( Naphth Bai ) 2 ] ( 9 ). The copper(I) and copper(II) complexes were characterized using spectroscopic and analytical methods. Furthermore, a crystal structure was obtained for eight of the nine complexes. In all cases, the boron-based ligand was found to bind to the metal centers via a κ 3 - N , N , H coordination mode.