/
(X-Ray Crystallography) (X-Ray Crystallography)

(X-Ray Crystallography) - PowerPoint Presentation

liane-varnes
liane-varnes . @liane-varnes
Follow
507 views
Uploaded On 2016-03-12

(X-Ray Crystallography) - PPT Presentation

XRay Diffraction I XRay Diffraction Uses XRays to identify the arrangement of atoms molecules or ions within a crystalline solid Quantitative and qualitative Ooi L Principles of Xray Crystallography ID: 253285

crystal crystallography 2006 ray crystallography crystal ray 2006 clear rhodes 3rd 2010 diffraction ooi principles structure atoms crystalline diffracted

Share:

Link:

Embed:

Download Presentation from below link

Download Presentation The PPT/PDF document "(X-Ray Crystallography)" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.


Presentation Transcript

Slide1

(X-Ray Crystallography)

X-Ray DiffractionSlide2

I. X-Ray Diffraction

Uses X-Rays to identify the arrangement of atoms, molecules, or ions within a crystalline solid

Quantitative and qualitative

Ooi

, L.

Principles of X-ray Crystallography

(2010)Slide3

A. X-Rays

0.1 – 100 Angstroms (

Å)Useful Range: 0.5 – 2.5 ÅSlide4

B. Amorphous Substances

1. Gases and Liquids

Extremely difficult

2. Non-crystalline Solids

Atoms are not regularly arranged or regularly shapedInterferenceFiber DiffractionSlide5

Atoms

are

regularly arranged

“The Unit Cell” – a cookie cutter

C

.

Crystalline Solids

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd

ed.

(2006)Slide6

II. X-Ray C

rystallography

A. Small-molecule crystallography

Up to ~100 atomsOrganic molecules, catalysts, newly synthesized drugs, etc.

Identify each atomB. Macromolecular (protein) crystallography Large biological molecules – nucleic acids and proteinsIdentify 2° structureNote: must show that the crystal structure (asymmetric unit) is comparable to structure in solution (biological unit) Slide7

III. X-Ray

Diffractometer

Ooi

, L. Principles of X-ray Crystallography

(2010)Slide8

A. X-Ray Source

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd ed. (2006)

1. X-Ray Tube (a)2. Rotating Anode (b) Slide9

3. Particle Storage Ring (Synchrotron Radiation)

Particle Accelerator

Ooi

, L.

Principles of X-ray Crystallography

(2010)Slide10

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd

ed.

(2006)

National Synchrotron Light Source at Brookhaven National Lab (Long Island)

Slide11

B. Collimator

Narrow metal tube that selects and reflects the X-Rays into parallel paths

Ooi, L. Principles of X-ray Crystallography (2010)Slide12

C. Crystal (Sample)

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd ed. (2006)

1. Growth – Screens Crystal vs. useless blob2. OptimizationQuantity3. Crystal QualityPurity

4. Mount for Data Collection

Cryocrystallography

Note:

Diffracted in “mother liquor”Slide13

D. Camera

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd ed. (2006)

Goniometer

Goniostat

Slide14

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd

ed.

(2006)Slide15

E. Detector

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd ed. (2006)

1. Charged Couple Device (CCD)2. Image Plate (IP) Slide16

IV. Data Analysis

Measure intensity and position of diffracted

X-Rays

Intensity: strength of diffracted beamPosition:

direction in which beam was diffracted by the crystal

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd

ed.

(2006)Slide17

Ooi

, L.

Principles of X-ray Crystallography

(2010)

Computer calculates this data from the diffraction

patternSlide18

A. Fournier Sum

Based on simple waves

f(x) = F

cos 2π

(hx + α)

F = f

0

+ f

1

+ f

2

+ …Rhodes, G. Crystallography Made Crystal Clear, 3rd ed. (2006)Slide19

B. Bragg’s Law

States: diffraction spots occur when 2

d sin θ = n

λ

Rhodes, G.

Crystallography Made Crystal Clear, 3

rd

ed.

(2006)Slide20
Slide21
Slide22

Molecular structure in solid crystalline state with extreme certainty

Direct inference of data

Provides limitless info.

CrystalsSlow

HydrogenStill just a modelBenefits

Downfalls