تاریخچه x-Ray

1. تاریخچه x-Ray

2. در 1895 رونتگن به جای اشعه کاتدی اشعه x تولید کرد( نوبل 1901) • 1896 Thomson نشان داد که پرتوهای کاتدی دراتی با بار منفی و جرم 1/1800 برابر جرم اتم دارد و توسط شیشه جذب می شوند. • 1905 Barkla وابستگی اشعه x به فلز را نشان داد( نوبل 1917) • 1900 رونتگن- سامرفلد و دبای به همراهGroth یک گروه تحقیقاتی تشکیل دادند • 1909 love و Ewald که شاگردان ماکس پلانک و سامرفلد بودند که نتایج بررسی پراش بلور را بدست اوردند نتایج آنها در 1912 منتشر و در 1914 نوبل گرفتند • 1913 اوالد کره کریستالوگرافی ارائه داد • در همین سال Bragg که پدر و پسر بودند که ارتباط بین شدت و انرژی را بدست اوردند و در 1915 نوبل گرفتند

3. Diffraction Basics: What You Really Need To Know! Published in The New Yorker December 28, 1987

4. X-ray Diffraction Nobel Prizes • 1901 W. C. Roentgen discovery of x-rays. • 1914 M. von Laue x-ray diffraction from crystals. • 1915 W. H. Bragg and W. L. Bragg crystal structure • derived from x-ray diffraction. • 1917 C. G. Barkla radiation of elements. • 1924 K. M. G. Siegbahn x-ray spectroscopy. • 1927 A. H. Compton scattering of x-rays by electrons. • 1936 P. Debye diffraction of x-rays and electrons in gases. • 1937 C.J. Davisson and G.P. Thomson diffraction of • x-rays by electrons. • 1954 L. Pauling the chemical bond and structures of • complex substances. • 1962 J. Watson, M. Wilkins, F. Crick structure of DNA. • 1964 D. Hodgkin structure of important biomolecules. • 1976 B. Lipscomb structure of boron hydrides. • 1979 A.M. Cormack and G.N. Hounsfield axial • tomography. • 1981 K. M. Siegbahn electron spectroscopy. • 1982 A. Klug structures of nucleic acid-protein complexes. • 1985 H. Hauptman, J. Karle direct methods. • 1987 J. Deisenhofer, R. Huber, M. Michel structural • evidence of a photosynthetic reaction center. • 1988 J. Deisenhofer, R. Huber, Michel proteins. • 1997 B. Brockhouse, C. Shull neutron diffraction Sir William Henry Bragg pioneered the determination of crystal structure by X-ray diffraction methods (1915) Clinton J. Davisson (with George P. Thomson) discovered that electrons can be diffracted like light waves (1937)

5. The Process: An Overview Crystal growth (0.5 hr to) Crystal selection and mounting (15 to 60 min.) Data collection (4 hours to 1 week) Structure solution and refinement (0.5 hr to)

6. X-ray Crystallography and Protein Structures R. Franklin – X-ray data L. Pauling – Triple helix J. Watson/F. Crick – Double helix (1962) Concepts of Genetics, Prentice Hall 2000. Sir William Henry Bragg pioneered the determination of crystal structure by X-ray diffraction methods (1915) Clinton J. Davisson (with George P. Thomson) discovered that electrons can be diffracted like light waves (1937)

7. X-ray Crystallography and Protein Structures R. Franklin – X-ray data L. Pauling – Triple helix J. Watson/F. Crick – Double helix (1962) Concepts of Genetics, Prentice Hall 2000. • HIV - Dana-Farber Cancer Institute (1998) • Crystallize an important protein involved in the HIV viral invasion process. • Protein GP120 demonstrates a two lock mechanism. • GP120 has an identical region found in all HIV variants. • Indicated the cavity in all HIV variants were potentially susceptible to highly specific drug regimes.

8. X-ray Crystallography and Protein Structures R. Franklin – X-ray data L. Pauling – Triple helix J. Watson/F. Crick – Double helix (1957) Concepts of Genetics, Prentice Hall 2000. EBOLA X-ray crystallographic analysis indicates Ebo-74, a protein found on the outer membrane of the Ebola virus, is similar to other structures found in HIV, SIV (HIV for monkeys) and Influenza.

9. X-ray Crystallography and Small Molecules • PSEUDOEPHEDRINE STUDIES • Pseudoephedrine is the active ingredient found in over-the-counter antihistamines such as Sudafed and Nyquil. • The X-ray structures of this system provide detailed conformational information. • The larger the R group, the more distorted the angle of the carbonyls becomes. Knowing such structural details helps to predict the properties, including potential drug characteristics, and the mechanism for synthesizing other similar molecules. • J. Org. Chem. 67 (2002) 8871-8876.

10. Clinton J. Davisson (with George P. Thomson) discovered that electrons can be diffracted like light waves (1937)

11. X-ray Crystallography vs. NMR • X-ray: • must crystallize • molecules may be large • better resolution • structure modified by crystal packing • oxidation states of metals, etc., may be difficult to determine • In principle, the structure can be determined in the absence of any additional information • NMR: • must be soluble • limitations to molecular size • less accurate • can capture motion • spin of the nucleus • complex structure determination difficult.

12. بلور شناسی • حل ساختار یعنی اندازه گیری و تعیین دقیق ارایش فضایی همه اتمهای یک ترکیب شیمیایی در حالت بلوری است • نتیجه حل ساختار: • وضعیت اتصال اتمها • ارایش بندی در فضا • زوایای پیوند • طول پیوند • استوکیومتری • دانسیته • تقارن • جورچین اتمها در سه بعد

13. چرا از اشعه x استفاده می کنیم • اندازه اتمها و فواصل آنها باید با طول موج تابانیده شده هماهنگی داشته باشد • در کریستالوگرافی نوع برهم کنش پراکندگی و پراش است • برای detect از چشم نمیتوان استفاده کرد • از لنز هم نمیتوان استفاده کرد بلکه فقط الگوی پراش را خواهیم دید

14. بجز اشعه x از اشعه دیگری هم میتوان استفاده کرد • 1- پراش الکترونها • 2- پراش نوترونی • 3- پراش گاما

15. Crystal structure determination • y=A sin(ωt+θ0) • Iα A2 • X- Ray→10-18 • Vib→10-14

16. Simple Diffraction

20. 13,500 lines/inch ~660 nm

22. The New Yorker February 25, 1991 The New Yorker November 4, 2002

23. Unit Cell Constants a, b, c a =  (b – 0 – c) b =  (a – 0 – c) g =  (a – 0 – b) c 0 a b Molecular Crystals Unit Cells – reproducible space in a crystal

24. Unit Cells

25. Unit Cells

29. b c

30. Conditions For Diffraction Clinton J. Davisson (with George P. Thomson) discovered that electrons can be diffracted like light waves (1937) Changing Wavelength ()

31. Conditions For Diffraction Changing Distance (d)

32. Conditions For Diffraction Changing Theta

33. Bragg’s Law For Diffraction • The difference between the length of wave 1 and 2 = CB + BD • Constructive interference (diffraction) will only occur if CB + BD = 2CB = n sin = CB/d CB = n/2 sin = (n/2)/d Bragg’s Law 2dsin = n sin  1/d (reciprocal space)

34. Consequences of sin  1/d (Reciprocal Space) 1 size of crystal lattice  size of diffraction pattern http://www.uni-wuerzburg.de/mineralogie/crystal/teaching/

35. Consequences of sin  1/d (Reciprocal Space) Square Lattice Atomic (x,y,z) Coordinates Reflection (h,k,l) http://www.uni-wuerzburg.de/mineralogie/crystal/teaching/

36. Consequences of sin  1/d (Reciprocal Space) Rectangular Lattice http://www.uni-wuerzburg.de/mineralogie/crystal/teaching/

37. Consequences of sin  1/d (Reciprocal Space) Oblique Lattice http://www.uni-wuerzburg.de/mineralogie/crystal/teaching/

38. Consequences of sin  1/d (Reciprocal Space) Oblique Lattice Crystal Translation http://www.uni-wuerzburg.de/mineralogie/crystal/teaching/

39. RECIPROCAL LATTICE - a set of imaginary points constructed in such a way that the direction of a vector from one point to another coincides with the direction of a normal to the real space planes and the separation of those points (absolute value of the vector) is equal to the reciprocal of the real interplanar distance. Crystal Lattice Reciprocal Lattice (Imaginary) 0 2 2 2 -2 2 2 0 -2 0 -2 -2 2 -2 0 -2

40. Crystal Lattice Reciprocal Lattice g = 2/d N d 0 2 2 2 -2 2 2 0 -2 0 g -2 -2 2 -2 0 -2

41. Crystal Lattice Reciprocal Lattice g = 2/d d N 0 2 2 2 -2 2 g 2 0 -2 0 -2 -2 2 -2 0 -2

42. Crystal Lattice Reciprocal Lattice g = 2/d d N 0 2 2 2 -2 2 g 2 0 -2 0 -2 -2 2 -2 0 -2

43. Crystal Lattice Reciprocal Lattice g = 2/d d N 0 2 2 2 -2 2 0 2 2 2 -2 2 g 2 0 -2 0 2 0 -2 0 -2 -2 2 -2 -2 -2 2 -2 0 -2 0 -2

44. Crystal Lattice Reciprocal Lattice g = 2/d 0 2 0 2 2 2 2 2 -2 2 -2 2 N d g 2 0 -2 0 2 0 -2 0 -2 -2 -2 -2 2 -2 2 -2 0 -2 0 -2

45. Crystal Lattice Reciprocal Lattice Reciprocal unit cell c* Real unit cell c c* b b* c b* b a* a a a* Real unit cell Reciprocal unit cell

46. http://phillips-lab.biochem.wisc.edu/software.html

47. From Diffraction Patterns to Crystal Structures (or visa versa) X-ray diffraction data (h,k,l) Fourier Series Electron Density Structure Factor Complete description of a diffracted ray recorded as reflection hkl (a wave equation) Frequency Amplitude Phase Contour map of electron density (x,y,z) X-ray Source  (Intensity)1/2 unknown

48. Conclusions – X-ray diffraction is not magic It is 2dsin = n (Bragg’s Law) Reciprocal space 2dsin = n (Bragg’s Law) Reciprocal space Waves (x-rays) interacting with the atomic periodicity in the crystal Waves (x-rays) interacting with the atomic periodicity in the crystal Each atom of a molecule contributing to every reflection Each atom of a molecule contributing to every reflection Predictable, calculable and useful for decoding structural details of crystals Predictable, calculable and useful for decoding structural details of crystals X-rays diffracting via electrons X-rays diffracting via electrons

50. کریستال را از چند جنبه بررسی می کنیم • 1- کیفیت کریستال، رشد کریستال • وضعیت ساختار کریستالی مثل شبکه و سلول واحد، گروه فضایی، شبکه براوه • کریستال: یک ماده جامد است که بصورت یک الگوی پایهBasic pattern در سه بعد فضا تکرار می شود.