1. College of Materials Science and Engineering Huaqiao University Xiamen 361021 P. R. China
2. School of Chemistry and Chemical Engineering State Key Laboratory of Crystal Materials Shandong University Jinan 250100 P. R. China
3. Department of Chemistry College of Science King Saud University P. O. Box 2455 Riyadh 11451 Saudi Arabia
4. Department of Chemistry Southern Methodist University 3215 Daniel Avenue Dallas TX 75275-0314 USA