1. School of Chemistry; Institute of Science; Suranaree University of Technology; Nakhon Ratchasima 30000 Thailand
2. Department of Chemistry; Colorado State University; Fort Collins CO 80523 USA
3. College of Industrial Technology; King Mongkut's University of Technology North Bangkok; Bangkok 10800 Thailand
4. Department of Chemistry and Biochemistry; New Mexico State University; Las Cruces NM 88003 USA