For 2, a total of 3529 reflections in the range of 2.24 < 2θ < 27.53, and −23 < h < 16, −14 < k < 14, −16 < l < 18 were collected, of which 3025 reflections were accepted. The final R1 is 0.0293. The structures were all solved by direct methods and refined by the full-matrix least squares on F2 using the SHELXTL-97 program. All non-hydrogen atoms were refined with anisotropic displacement parameters. Hydrogen atoms were assigned by searching the q peaks located in the electron density map and refined normally.