1. MICROWAVE SPECTRUM AND AB INITIO CALCULATIONS OF meta-CHLOROBENZALDEHYDE Sean Arnold, Jessica Garrett, & Dr. Gordon Brown Department of Science and Mathematics Coker College 300 E College Ave. Hartsville, SC 29550 RK15

2.  Its Schiff base is known to have antifungal properties  Used in the synthesis of amino alcohols  Common starting material in organic synthesis Applications of m-chlorobenzaldehyde

3. meta-chlorobenzaldehyde trans-meta-chlorobenzaldehyde cis-meta-chlorobenzaldehyde

4. Coker CP-FTMW 240 MHz

5. 240 MHz Chirped Pulse before power amplifier Chirped Pulse Fourier Transform

6. Double Sideband Measurement 16 5 12 17 4 13 2 0 2 3 -1 3 5 1 5 4 1 4 v 0 = 12300MHz white spectrum v 0 = 12304 MHz gold spectrum For 2 0 2 3 -1 3 : 12300 – 121.4 = 12178.6 MHz 12304 – 125.4 = 12178.6 MHz

7. Coker CP-FTMW

8. Results : Conditions: Nozzle heated to 150 degrees Celsius Backing pressure set to 50 psi 10,000 signal averages (~40 hours measurement time )

9. Analysis using JB95 to help determine experimental rotational constants.

10. Results : cis 35 Clcis 37 Cltrans 35 Cltrans 37 Cl A (MHz) 2345.808 ± 0.002 2327.419 ± 0.0013172.65 ± 0.093153.90 ± 0.08 B (MHz) 959.439 ± 0.001 937.520 ± 0.002813.009 ± 0.001794.127 ± 0.002 C (MHz) 680.9698 ± 0.0008 668.3451 ± 0.0008647.232 ± 0.001634.478 ± 0.002 Xaa -37.38 ± 0.05 -30.58 ± 0.05-52.1 ± 0.5-42 ± 1 Xbb 4.2± 0.1 4.45 ± 0.0918.5 ± 0.514.9 ± 0.8 Xcc 33.1836 26.125433.582027.0369 DJ 2 x10 -5 ± 5 x10 -6 1.4 x10 -5 ± 9 x10 -6 1.0 x10 -5 ± 6 x10 -6 7 x10 -6 ± 4 x10 -6 DJK ———— DK ——4 x10 -2 ± 2 x10 -2 — omc (MHz) 0.0710.0580.0310.045 number of lines 2101267256

11. Comparison to ab initio Conformation of Chlorobenzaldhyde Rotational Constants (MHz) ConstantRHFMP2MO52XB3LYPExperimental Trans-meta- chlorobenzaldehyde ( 35 Cl species) A 3201.5873152.38123200.29403163.36423172.65± 0.09 B 818.4013808.3755815.6633807.0433813.009 ± 0.001 C 651.7888643.3891649.9976642.9173647.232 ± 0.001 X aa -51.9044-51.0553-50.8394-52.1 ± 0.5 X bb 19.422217.886719.157418.5 ± 0.5 X cc 32.482233.168631.682133.6 Cis-meta- chlorobenzaldehyde ( 35 Cl species) A 2376.46242328.29892355.90002340.0462345.808 ± 0.002 B 962.39351955.1133965.3409951.0559959.439 ± 0.001 C 685.2671677.2800684.7581676.2217680.9698 ± 0.0008 X aa -36.9161-37.072-36.5835-37.38 ± 0.05 X bb 4.89914.11085.14324.2± 0.1 X cc 32.016932.961231.440233.18

12.  Measured 8-18.5 GHz spectrum of meta-chlorobenzaldehyde  Determined experimental rotational, distortion, and quadrupole coupling constants.  Compared constants to ab-initio calculations Conclusions : trans-meta-chlorobenzaldehydecis-meta-chlorobenzaldehyde

13. Acknowledgements  American Chemical Society-Petroleum Research Fund  (PRF #50746-UN16)  Coker College  National Science Foundation (CHE-1213560)