1. Growth and Spectroscopic Studies on Vitamin ‘C’ Crystal S.N.Saravanamoorthy, Assistant Professor, Devanga Arts College (Autonomous), Aruppukottai – 626 101. Website : http://saravanamoorthy-physics.blogspot.com

2. Crystal * A crystal is a solid that has regularly repeating internal structure (arrangement of atoms). * The basic “building block” in a crystal is called the unit cell. * Most of the living beings form crystals. When the body fluids get supersaturated with minerals, crystallization takes place. * These crystals have both beneficial as well as pathological effects on humans.

3. Chemical Bonding in Solids

4. Importance of Crystals * Crystals find an important role in modern science and present day technology. * Crystals are used in transducers, strain gauges, lasers and in polarizer etc. * Crystalline films are used for microelectronic and computer technology. * Crystals are a boon for the modern scientific development. * In the recent years, direct visualization of nucleic acid and variety of proteins with which it interacts is possible by growing single crystals.

5. Methods of Growing Crystals The main categories of crystal growth methods are 1. Solid Growth 2. Melt Growth 3. Vapour Growth 4. Solution Growth 5. Gel Growth etc.,

6. Solution Growth * Crystal growth from solution occurs well below the melting point of the solid, thus minimizing the risk of thermal decomposition and giving low strain and dislocation content. * The solution growth is feasible, whenever suitable solvent is available. * The main disadvantage of this method is the incorporation of solvent into the crystals.

7. Solution Growth Low temperature High temperature Slow cooling Slow evaporation Temperature gradient Flux growth Hydrothermal growth

8. Present Work * Vitamin ‘C’ crystal was grown by the slow evaporation method. * The lattice parameters related to the grown crystal have been calculated using X-ray single crystal diffraction data. * FT-IR spectra of the Vitamin ‘C’ compound has been recorded.

9. Vitamins *Vitamins are all organic chemicals. * Vitamins are essential because the organism cannot synthesize these compounds, which are necessary for life. * There are about 25 vitamins which have been arbitrarily classified into two types: 1) Fat soluble 2) Water soluble

10. Vitamin ‘C’ * The original name was hexuronic acid, but this was changed to L(+)-ascorbic acid or vitamin ‘C’ because of its healing effect on scurvy. * The chemical constitution was determined by Herbet, Hirst, Percival, Reynolds & Smith in 1933. * It is closely related to the hexoses in structure and is conveniently synthesized from glucose. * It is not a typical organic acid in that it has no free carboxyl group; actually a lactone structure is present.

11. Structure of Vitamin ‘C’ compound

12. Experimental Procedure * L-ascorbic acid was weighed to 1.7614 gm and transferred into 50 ml beaker and 10 ml of distilled water was added to it and made it completely dissolved. It was transferred into Petri dish. * The crystals were grown at room temperature by slow evaporation technique. * The density of the crystal was measured by using Sink an Swim method (measured by flotation in a mixture of CCl4 & bromoform). * Three dimensional intensity data were collected using Nonius Sealed tube MACH3 diffractometer.

13. Crystallographic data, intensity data collection and structure refinement parameters for the title compound

15. Bond lengths (Å) between various non-hydrogen atoms in the title compound

17. Bond angle (Å) between various non-hydrogen atoms in the title compound

19. Hydrogen bond lengths (Å) and angles (  ) in the title compound

21. Spectroscopy * Spectroscopy is the measurement and interpretation of absorption and emission of electromagnetic radiation when atoms or molecules or ions move from one energy level to another. * There are various types of spectroscopic methods to analyze the molecular structures. * Here, we have to use FT-IR spectroscopic methods to analyze the structure of Vitamin ‘C’ crystal.

22. FT-IR Spectroscopy *FT-IR spectroscopy first developed by astronomers in the early 1950 to study the IR spectra of distant stars. * It is a measurement technique that allows one to record IR spectra. * Infrared light is guided through an interferometer and further across the sample. * The recorded signal is an interferogram that includes two contributions. One from the instrument itself, and another one due variations in “optical path difference” introduced by the sample.

23. *Performing a Fourier transform on these two sets of data (one with sample inserted, one without) results in spectra comparable to those obtained from a conventional (dispersive) infrared spectrometer. * The effect due to the sample can be isolated by calculating the ratio or the difference of the two spectra. * The measurement is faster in FTIR technique because the information at all frequencies is collected simultaneously. * Virtually all modern infrared spectrometers are FTIR instruments.

24. Uses of FT-IR Spectroscopy * Widely used in both research and industry. * It is of especial use in forensic analysis in both criminal and civil cases, enabling identification of polymer degradation. * Highly for applications in both organic and inorganic chemistry. * It has been successfully utilized in the field of semiconductor microelectronics. * FTIR is Used to study the events that occur at the blood- biomaterial interface. * FTIR is now extensively used in areas such as toxicology, mutagenesis and general cellular research.

26. Spectral data (cm-1) and band assignments * v, very; w, weak; m, medium; s, strong; sh, shoulder; b, broad.

27. Conclusion *The investigation of the Vitamin ‘C’ compound is important one because it acts as an electron donor for 11 enzymes and probably all of its biochemical and molecular roles can be accounted for by this function. * The compound crystallites is the monoclinic space group P21. * The molecular structure consists of intramolecular hydrogen bonds of type O-H…O. * The wavenumber assignments have been made for the functional groups, viz. C=O, C=C, C-H, O-H, C-C, C-O, C-O-C, C-O-H, C-C(=O)-O.