1 Mass Spec - Fragmentation An extremely useful result of EI ionization in particular is a phenomenon known as fragmentation. The radical cation that is produced when an electron is knocked out of a neutral closed-shell molecule in EIMS initially possesses a lot of energy. Energy sufficient to break chemical bonds: radical cation will usually break into a neutral radical and a cation. It is also possible for a neutral closed shell fragment (such as water) to fall off. H 3 C H 1 electron H 3 C H 2 electrons H 3 C H CH 2 H H H 3 C H CH 3 H
2 Predicting Fragmentation A considerable volume of literature regarding the fragmentation reactions of certain molecules is available. Using this knowledge, we can predict how a given molecule might fragment. But first a few conventions.
3 Conventions It is always best to localize the cation and radical, obeying the rules of Lewis structures (i.e. don t put more than 8 electrons on carbon). For example, for the three structures above, A is discouraged in favour of B or C. This convention is not always possible to obey (alkanes).
4 More on Conventions When a molecule is ionized by EIMS, must decide which electron to remove. Always best to remove an electron from a π-bond, or from a heteroatom lone pair. It will become more clear which is the better choice when we look at individual examples. The bond breaking can be done either by homolytic or heterolytic cleavage. H 3 C CH 2 R H 3 C CH 2 Br 1 e EI CH 3 CH 2 R EI CH 3 CH 2 Br 2 e CH 3 H 2 C R CH 3 CH 2 Br Homolytic Heterolytic
5 Fragmentation Notes - Most fragments are even-electron cations. These split to make more even-electron cations. - The probability of cleaving a given bond is related to the bond strength, and to the stability of the fragments formed. In particular, cations like to rearrange or decay into more stable cations. - Remember that for a ring system, at least 2 bonds must break for the ring to fragment. In addition, there are 10 general rules to keep in mind when predicting the most likely ions to be formed for a given molecule.
6 Fragmentation Guidelines 1. The relative height of the M peak is greatest for straightchain molecules and decreases as the branching increases. 2. The relative height of the M peak decreases with chain length for a homologous series. 3. Cleavage is favoured at alkyl-substituted carbons, with the probability of cleavage increasing as the substitution increases. These rules mostly arise from the fact that carbocation and radical stability show the following trend: Most Stable Benzylic > Allylic > Tertiary > Secondary >> Primary Least Stable Stevenson s Rule At the point of breakage, the larger fragment usually takes the radical to leave the smaller cation.
7 Fragmentation Guidelines 4. Double bonds, cyclic structures, and especially aromatic rings will stabilize the molecular ion and increase its probability of appearance. 5. Double bonds favor allylic cleavage to give a resonance stabilized allylic carbocation, especially for cycloalkenes. EI 6. For saturated rings (like cyclohexanes), the side chains tend to cleave first leaving the positive charge with the ring. R R
8 Fragmentation Guidelines 7. Unsaturated rings can also undergo retro-diels-alder reactions to eliminate a neutral alkene. EI 8. Aromatic compounds tend to cleave to give benzylic cations, or more likely tropylium cations. R R EI m/z 91
9 Fragmentation Guidelines 9. C-C bonds next to heteroatoms often break leaving the positive charge on the carbon with the heteroatom. 10. Cleavage is often favoured if it can expel small stable molecules like water, C, NH 3, H 2 S, etc. In addition to bond fragmentation, various intramolecular rearrangements can take place to give sometimes unexpected ions.
10 Rearrangements ne common type of rearrangement in MS is the McLafferty rearrangement which takes place in compounds that contain a carbonyl group. Y H H Many other rearrangements are possible, even some that are not well understood and are considered random. H 3 C CH 3 CH 3 CH 3 CH 2 CH 3
11 Chem 325 Mass Spectra of Various Classes of rganic Compounds
12 1. Saturated Hydrocarbons General rules 1-3 apply well to hydrocarbons. Rearrangements are common but usually do not give intense peaks. The M peak of a straight-chain hydrocarbon is always visible, but decreases in intensity as the molecule gets larger. The fragmentation pattern is characterized by peaks separated by 14 mass units (a CH 2 group). The most intense peaks are the C 3 C 5 fragments.
13 Branched Hydrocarbons The MS for branched saturated hydrocarbons are similar, except certain fragments become more prominent.
14 CI-MS For some types of compounds the M peak is very weak or not observable at all! Due to EI ionization being a hard ionization : so much internal energy is given to the molecular ion that extensive fragmentation immediately results. How to measure the molecular mass?? Chemical Ionization (CI).
15 Chemical Ionization Ion source filled with relatively high pressure reagent gas, example isobutane i-c 4 H 10, ammonia, or methane CH 4 Electron impact ionizes the CH 4, high pressure ensures many ion-molecule collisions and reactions to produce CH 5, which acts as a protonating agent when it collides with sample molecule M e CH 4 CH 5 CH 5 M MH CH 4 (MC 2 H 5 ), (MC 3 H 5 ) Can also use i-c 4 H 10, NH 3, etc. soft ionization : much less fragmentation, can see molecular ion
17 Cyclic Hydrocarbons Cyclic hydrocarbons show a much more intense M ion (Rule 4) Two bonds must break to form fragments.
18 2. Alkenes It is usually easy to see the M peak of alkenes in EIMS. In acyclic alkenes, the double bond freely migrates in the fragments, so it can be difficult to determine the double bond location, but for cyclic alkenes it is easier. Cleavage usually happens at allylic bonds (Rule 5).
19 3. Aromatic Hydrocarbons Aromatic hydrocarbons usually show strong M peaks (Rule 4). Aromatic rings are stable and have a lower tendency to fragment. Alkyl substituted benzenes often give a strong peak at m/z 91 due to benzylic cleavage (Rule 8).
20 MS of n-butylbenzene m/z 91
21 4. Alcohols Alcohols fragment very easily secondary and primary alcohols show very weak M peaks, and tertiary alcohols often do not show M at all. MW is often determined by derivatization or CI-MS. The C-C bond nearest the H is frequently the first bond to break. Thus primary alcohols often show a prominent peak at 31 m/z. H H H m/z = 60 m/z = 31
22 Secondary Alcohols Secondary alcohols cleave in the same way, often showing a prominent CHR-H peak. H m/z = 74 H m/z = 45 H H m/z = 74 m/z = 59
23 Alcohols Sometimes the hydrogen R 2 CH-H in 1 and 2 alcohols cleaves rather than an alkyl group. The result is an M-1 peak. H H H M m/z = 74 M-1 m/z = 73
24 Tertiary Alcohols Tertiary alcohols cleave in a similar fashion to give CRR-H fragments. A H B m/z = 116 (not observed) A B H m/z = 59 H m/z = 101
25 More on Alcohols Alcohols can lose a molecule of water to show a sometimes prominent M-18 peak. It is especially noticeable for primary alcohols. H H H H M m/z = 102 M-18 m/z = 84
26 Benzylic Alcohols Benzylic alcohols fragment much differently from aliphatic alcohols. Benzylic cleavage happens as expected (Rule 8). Benzyl alcohol fragments via the following pathway: H H -H -C H m/z = 108 m/z = 107 m/z = 79 m/z = 77 H H H H H H
27 Benzylic Alcohols Benzylic alcohols will usually lose water (M-18). The M-18 peak is especially strong for molecules for which loss of water is mechanistically straightforward. H H m/z = 122 m/z = 104
28 Phenols Phenols often show peaks at 77 m/z resulting from formation of phenyl cation, and peaks resulting from loss of C (M-28) and CH (M-29) are usually found in phenols. H 94 M-29 M-28
29 Phenols If alternative attractive cleavage pathways are available for phenols, the molecule will often take that path. Molecular ions will fragment along the path of least resistance!
30 Example: ctane m/z = 114
31 Example: 4-methyl-2-hexene m/z = 98
32 Example: 3-methyl-1-pentanol m/z = 102 H
33 Example: 4-methyl-2-pentanol H m/z = 102
34 Example: 2-phenylethanol m/z = 122 H
35 Example: 1-phenylethanol H m/z = 122
36 5. Ethers Cleavage happens in two main ways: 1. Breakage of the C-C bond next to (like alcohols) CH 3 A CH 3 B m/z = 88 A B m/z = 73 CH 3 or m/z = 59 m/z = 29
37 Ethers Cleavage happens in two main ways: 2. C- bond cleavage with the charge on the C fragment. CH 3 CH 3 m/z = 88 m/z = 57
38 Aromatic Ethers M is usually strong. MS is similar to phenols both form phenoxyl cation (m/z 93) and associated daughters.
39 6. Ketones Ketones usually give strong M peaks. A major fragmentation pathway involves α-cleavage to give an acylium ion. A A m/z = 71 B m/z = 100 B m/z = 57
40 6. Ketones The carbonyl-containing fragment can also take the radical. A B A m/z = 29 m/z = 100 B m/z = 43
41 6. Ketones For ketones with longer chains, the McLafferty rearrangement often leads to strong peaks. H H m/z = 128 m/z = 58
42 6. Aromatic Ketones M is evident. Primary cleavage is α to the carbonyl to give a strong ArC peak (m/z 105 when Ar = Ph). This will lose C to give the phenyl cation (m/z 77).
43 7. Aldehydes Aldehydes show weak but discernable M peaks. Major pathways are α-cleavage and McLafferty Rearrangement. H H A B A M-1 m/z = 85 H C M m/z = 86 H H B M-R m/z = 29 H m/z = 44 C
44 7. Aromatic Aldehydes are similar to aromatic ketones. M is strong, and M-1 (αcleavage to carbonyl) is also strong to give the ArC ion (m/z 105 for Ar = Ph). Loss of C from this ion is common to give m/z77 phenyl cation. H -C M m/z = 106 M-1 m/z = 105 m/z = 77
45 8. Carboxylic Acids (Aliphatic) M is weak, and not always visible. A characteristic m/z 60 peak is often present due to the McLafferty Rearrangement. Bonds α to carbonyl also frequently break to give M-H and M-C 2 H peaks. H M m/z = 88 m/z = 71 m/z = 43 H H m/z = 60
46 Aromatic Acids M is very prominent. Common peaks are loss of H (M-17) and loss of C 2 H (M-45). H 3 C H H 3 C H 3 C M m/z = 136 M-17 m/z = 119 M-45 m/z = 91
47 Aromatic Acids If an ortho hydrogen-bearing group is present, loss of water (M-18) is visible as well. H H H H 2 H 2 M m/z = 136 M-18 m/z = 118
48 9. Aliphatic Esters M is usually distinct. The most characteristic peak is due to the McLafferty rearrangement. H H M m/z = 144 m/z = 88
49 Aromatic Esters M is usually prominent, unless R chain is long. The base peak is loss of R. m/z = 164 m/z = 105 C m/z = 77
50 Aromatic Esters The McLafferty rearrangement give the corresponding acid. A more complicated rearrangement often gives a prominent acid1 peak. H H m/z = 164 m/z = 122 H H m/z = 123
51 10. Amines Aliphatic monoamines have odd numbered and weak M peaks. Most important cleavage is usually breakage of the C-C bond next to the C-N bond. NH 2 3 H m/z = 73 NH 2 NH 2 NH 2 m/z = 72 m/z = 58 m/z = 44
52 10. Amines The base peak in nearly all primary amines comes at 30 m/z. m/z = 101 NH 2 NH 2 m/z = 30
53 Aromatic Amines M is intense (why?). An NH bond can be broken to give a moderately intense M-1 peak. H N H - H N H m/z = 93 m/z = 92
54 Aromatic Amines A common fragmentation is loss of HCN and H 2 CN to give peaks at 65 and 66 m/z. H N H m/z = 93
55 Aromatic Amines Alkyl substituted aromatic amines typically show breakage of the C-C bond next to the C-N to give a strong peak at 106 when Ar = Ph. H N H N m/z = 121 m/z = 106
56 11. Amides Primary amides give a strong peak at m/z 44 due to breakage of the R-CNH 2 bond. NH 2 NH 2 m/z = 115 m/z = 44
57 11. Amides Aliphatic amides M is weak but discernible. For straightchain amides more than 3 carbons, McLafferty gives the base peak at m/z 59. H H m/z = 115 NH 2 m/z = 59 NH 2
58 Any familiar features? Aromatic Amides
59 Aromatic Amides M is strong. Loss of NH 2 to make PhC (105) followed by loss of C to make the phenyl cation (77). NH 2 m/z = 121 m/z = 105 m/z = 77
60 12. Nitriles M are weak or absent for aliphatic nitriles. Loss of the α- hydrogen can give a weak M-1 peak. C N C N H m/z = 69 m/z = 68
61 Nitriles Base peak is usually 41 due to a rearrangement like the McLafferty. This has limited diagnostic value since (C 3 H 5 ) has the same mass. H H H N C NH C CH 2 m/z = 69 m/z = 41
62 13. Nitro compounds Aliphatic nitro compounds have weak odd M. The main peaks are hydrocarbon fragments up to M-N 2. m/z = 29 N 2 m/z = 131 m/z = 43 m/z = 57 m/z = 71 m/z = 85
63 Aromatic Nitro Compounds M is strong. Prominent peaks result from loss of N 2 radical to give an M-46 peak. Also prominent is M-30 from loss of N. N - 2 m/z = 123 M-46 m/z = 77 N M-30 m/z = 93
Chapter : rganic Compounds with xygen Alcohols, Ethers Alcohols An alcohol contains a hydroxyl group ( H) attached to a carbon chain. A phenol contains a hydroxyl group ( H) attached to a benzene ring.
BACKGROUND INFORMATION Infrared Spectroscopy Before introducing the subject of IR spectroscopy, we must first review some aspects of the electromagnetic spectrum. The electromagnetic spectrum is composed
Ch14_PT MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Compounds with the -OH group attached to a saturated alkane-like carbon are known as A)
Chapter 12 Organic Compounds with Oxygen and Sulfur 1 Alcohols An alcohol contains a hydroxyl group ( OH) that replaces a hydrogen atom in a hydrocarbon. A phenol contains a hydroxyl group ( OH) attached
CHEM 3311 Exam #1 Name Dr. Minger June 8, 2015 Please read and sign the Honor Code statement below: I pledge that on my honor, as a University of Colorado at Boulder student, I have neither given nor received
1. Which is the structural formula of methane? 6. Which hydrocarbon is a member of the alkane series? 7. How many carbon atoms are contained in an ethyl group? 1 3 2 4 2. In the alkane series, each molecule
hemical Bonds and Groups - Part 1 ARB SKELETS arbon has a unique role in the cell because of its ability to form strong covalent bonds with other carbon atoms. Thus carbon atoms can join to form chains.
Biochemistry - I Prof. S. Dasgupta Department of Chemistry Indian Institute of Technology, Kharagpur Lecture-11 Enzyme Mechanisms II In the last class we studied the enzyme mechanisms of ribonuclease A
Southeastern Louisiana University Dual Enrollment Program--Chemistry The Southeastern Dual Enrollment Chemistry Program is a program whereby high school students are given the opportunity to take college
INTDUCTIN T LEWIS ACID-BASE CEMISTY DEINITINS Lewis acids and bases are defined in terms of electron pair transfers. A Lewis base is an electron pair donor, and a Lewis acid is an electron pair acceptor.
Bioremediation A technology that encourages growth and reproduction of indigenous microorganisms (bacteria and fungi) to enhance biodegradation of organic constituents in the saturated zone Can effectively
Today s Topics Polar Covalent Bonds ydrogen bonding Properties of water p Water C bonds are Nonpolar Will these molecules dissolve in water? Start Macromolecules Carbohydrates & Lipids Sept 4, 05 Why are
INTERMOLECULAR FORCES Intermolecular forces- forces of attraction and repulsion between molecules that hold molecules, ions, and atoms together. Intramolecular - forces of chemical bonds within a molecule
Electrospray mass spectrometry of human hair wax esters methods Mark Fitzgerald and Robert C. Murphy 1 Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Aurora, CO
Amino Acids 20 common amino acids there are others found naturally but much less frequently Common structure for amino acid COOH, -NH 2, H and R functional groups all attached to the a carbon Ionization
Problem 1. (12 points total, 4 points each) The molecular weight of an unspecified protein, at physiological conditions, is 70,000 Dalton, as determined by sedimentation equilibrium measurements and by
Non-Covalent Bonds (Weak Bond) Weak bonds are those forces of attraction that, in biological situations, do not take a large amount of energy to break. For example, hydrogen bonds are broken by energies
Double Bonds What do we do with double bonds? We do addition reactions. In an addition reaction, something is added to both carbons involved in a double bond (or not involved in the double bond, in the
Georgia Perimeter College - Dunwoody Campus Chemistry 1152-200 Fall 2011 Course Syllabus(revised) Course Title: Survey of Chemistry II, TR 1000 1115 Room NE-1260 Instructor: Dr. Jerry L. Poteat, Associate
Study of the Surface Morphology of Methyl 4-nitrobenzoate Template Thin-film Molecularly Imprinted Polymers Gary Kaganas Dartmouth College and Center for Nanomaterials Research at Dartmouth, Hanover NH
Peptide Bond Peptide Bond Amino acids are linked together by peptide bonds to form polypepetide chain. + H 2 O 2 Peptide bonds are strong and not broken by conditions that denature proteins, such as heating.
18.2 Protein Structure and Function: An Overview Protein: A large biological molecule made of many amino acids linked together through peptide bonds. Alpha-amino acid: Compound with an amino group bonded
Chemical Bonds 1. Which of the following is NOT a true compound? a. pure substance b. composed of combinations of atoms c. held together by chemical bonds d. substance that cannot be broken down into simpler
John E. McMurry www.cengage.com/chemistry/mcmurry Chapter 2 Polar Covalent Bonds: Acids and Bases Modified by Dr. Daniela R. Radu Why This Chapter? Description of basic ways chemists account for chemical
arbonyl hemistry (12 Lectures) Aim of ourse Professor Donna G. Blackmond firstname.lastname@example.org tel. 41193 oom 639 1 To build upon elements of Dr E.. Smith s and Dr. D.. Braddocks s course. To introduce
The CHROMacademy Essential Guide Understanding GC-MS Analysis Part 1 Speakers John Hinshaw GC Dept. Dean CHROMacademy Tony Taylor Technical Director Crawford Scientific Moderator M ( g ) e M ( g ) 2e Peter
Addition eactions of arbon-arbon Pi Bonds - Part 1 3 δ+ 2 δ 3 3 3 + 2 3 2 3 What Is an Addition eaction? Addition reaction: Atoms or groups are added to opposite ends of a pi bond. X Y Why should I study
EXPERIMENT 9 Dot Structures and Geometries of Molecules INTRODUCTION Lewis dot structures are our first tier in drawing molecules and representing bonds between the atoms. The method was first published
Supplementary Information for Multi-generation gas-phase oxidation, equilibrium partitioning, and the formation and evolution of secondary organic aerosol Christopher D. Cappa 1, Kevin R. Wilson  [Department
Prentice Hall Chemistry (Wilbraham) 2008, National Student Edition - South Carolina Teacher s Edition High School C O R R E L A T E D T O High School C-1.1 Apply established rules for significant digits,
VOL. 18, 1932 CEMISTRY: L. PA ULING 293 INTERATOMIC DISTANCES IN COVALENT AMOLECULES ANAD RESONANCE BETWEEN TWO OR MORE LEWIS ELECTRONIC STR UCTUR.8S BY LINuS PAULING GATES CEMICAL LABORATORY, CALIFORNIA
John E. McMurry www.cengage.com/chemistry/mcmurry Chapter 26 Biomolecules: Amino Acids, Peptides, and Proteins Proteins Amides from Amino Acids Amino acids contain a basic amino group and an acidic carboxyl
PART 4 rganic Qualitative Analysis rganic chemists must regularly identify the compounds that are formed in chemical reactions or isolated from natural sources. Discovering the identity of an unknown organic
Questions- Proteins & Enzymes A. A peptide with 12 amino acids has the following amino acid composition: 2 Met, 1 Tyr, 1 Trp, 2 Glu, 1 Lys, 1 Arg, 1 Thr, 1 Asn, 1 Ile, 1 Cys Reaction of the intact peptide
This class deals with the fundamental structural features of proteins, which one can understand from the structure of amino acids, and how they are put together. 1 A more detailed view of a single protein
Acids and Bases Chapter 16 The Arrhenius Model An acid is any substance that produces hydrogen ions, H +, in an aqueous solution. Example: when hydrogen chloride gas is dissolved in water, the following
Bonds hapter 8 Bonding: General oncepts Forces that hold groups of atoms together and make them function as a unit. Bond Energy Bond Length It is the energy required to break a bond. The distance where
Role of Hydrogen Bonding on Protein Secondary Structure Introduction The function and chemical properties of proteins are determined by its three-dimensional structure. The final architecture of the protein
Peptides: Synthesis and Biological Interest Therapeutic Agents Therapeutic peptides approved by the FDA (2009-2011) 3 Proteins Biopolymers of α-amino acids. Amino acids are joined by peptide bond. They
Lecture 1 Introduction, Noncovalent Bonds, and Properties of Water Reading: Berg, Tymoczko & Stryer: Chapter 1 problems in textbook: chapter 1, pp. 23-24, #1,2,3,6,7,8,9, 10,11; practice problems at end
Ch. 9 - Electron Organization The Bohr Model [9.4] Orbitals [9.5, 9.6] Counting Electrons, configurations [9.7] Predicting ion charges from electron configurations. CHEM 100 F07 1 Organization of Electrons
Name: Class: Date: Unit 11 Practice Multiple Choice Identify the choice that best completes the statement or answers the question. 1) Crystalline solids. A) have their particles arranged randomly B) have
General Considerations The Strategy of Peptide Synthesis Making peptide bonds between amino acids is not difficult. The challenge is connecting amino acids in the correct sequence. andom peptide bond formation
82 Chapter 6 Acid-ase and Donor-Acceptor Chemistry CATER 6: ACID-ASE AD DR-ACCETR CEMISTRY 6.1 Acid ase Definition a. Alr 3 r Lewis b. Cl 4 C 3 C Lewis, rønsted-lowry c. i 2+ 3 Lewis d. Cl 3 Lewis e. S
SUBJECT OUTLINE Subject Name: Chemistry and Biochemistry SECTION 1 GENERAL INFORMATION Subject Code: BIOB111 Award/s: Total course credit points: Level: Bachelor of Health Science (Naturopathy) 128 Core
SUBJECT OUTLINE Subject Name: Chemistry and Biochemistry SECTION 1 GENERAL INFORMATION Subject Code: BIOB111 Award/s: Total course credit points: Level: Bachelor of Health Science (Naturopathy) 128 Core
AS/A Level GCE GCE Chemistry A OCR Advanced Subsidiary GCE in Chemistry A H034 OCR Advanced GCE in Chemistry A H434 version 4 September 2013 QAN 500/2425/5 QAN 500/2347/0 Contents 1 About these Qualifications
Lesson Objectives Students will: Create a physical representation of the autoionization of water using the water kit. Describe and produce a physical representation of the dissociation of a strong acid
Combinatorial Biochemistry and Phage Display Prof. Valery A. Petrenko Director - Valery Petrenko Instructors Galina Kouzmitcheva and I-Hsuan Chen Auburn 2006, Spring semester COMBINATORIAL BIOCHEMISTRY
Type of Chemical Bonds Covalent bond Polar Covalent bond Ionic bond Hydrogen bond Metallic bond Van der Waals bonds. Covalent Bonds Covalent bond: bond in which one or more pairs of electrons are shared
IV. -Amino Acids: carboxyl and amino groups bonded to -Carbon A. Acid/Base properties 1. carboxyl group is proton donor! weak acid 2. amino group is proton acceptor! weak base 3. At physiological ph: H
Exam 4 Outline CH 105 Spring 2012 You need to bring a pencil and your ACT card. Chapter 24: Lipids 1. Describe the properties and types of lipids a. All are hydrophobic b. Fatty acid-based typically contain
Amino Acids & Proteins Shu-Ping Lin, Ph.D. Institute te of Biomedical Engineering ing E-mail: email@example.com Website: http://web.nchu.edu.tw/pweb/users/splin/ edu tw/pweb/users/splin/ Date: 10.13.2010
BERGEN COMMUNITY COLLEGE DIVISION OF MATHEMATICS, SCIENCE AND TECHNOLOGY DEPARTMENT OF PHYSICAL SCIENCES STUDENT COURSE OUTLINE Course Title: Prerequisites: Course Description: Textbook: CHM 212 Organic
an ABC Laboratories white paper Correlation of the Mass Spectrometric Analysis of Heat-Treated Glutaraldehyde Preparations to Their 235nm / 280 nm UV Absorbance Ratio A. Sen, R. Dunphy, L. Rosik Analytical
Biological Molecules I won t lie. This is probably the most boring topic you have ever done in any science. It s pretty much as simple as this: learn the material deal with it. Enjoy don t say I didn t
Prof. Dr. Burkhard König, Institut für rganische Chemie, Uni Regensburg 1 1. Some Basics Enolate Chemistry In most cases the equilibrium lies almost completely on the side of the ketone. The ketone tautomer
CHAPTER 3 THE CHEMISTRY OF ORGANIC MOLECULES 3.1 Organic Molecules The chemistry of carbon accounts for the diversity of organic molecules found in living things. Carbon has six electrons, four of which
Elements in Cells The living substance of cells is made up of cytoplasm and the structures within it. About 96% of cytoplasm and its included structures are composed of the elements carbon, hydrogen, oxygen,
Candidate Style Answer Chemistry A Unit F321 Atoms, Bonds and Groups High banded response This Support Material booklet is designed to accompany the OCR GCE Chemistry A Specimen Paper F321 for teaching
SOLID SUPPORTS AND CATALYSTS IN ORGANIC SYNTHESIS Editor Professor K. SMITH, M.SC,PhD. Head of Department of Chemistry University College of Swansea Wales ELLIS HORWOOD PTR PRENTICE HALL NEW YORK LONDON
7512 J. Org. Chem. 1997, 62, 7512-7515 NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities Hugo E. Gottlieb,* Vadim Kotlyar, and Abraham Nudelman* Department of Chemistry, Bar-Ilan University,
Topics to be Covered Elements of Step-Growth Polymerization Branching Network Formation Chapters 1 & 2 in CD (Polymer Science and Engineering) Dawn of Understanding "I am inclined to think that the development
The Physics and Chemistry of Water 1 The water molecule and hydrogen bonds in water Stoichiometric composition H 2 O the average lifetime of a molecule is 1 ms due to proton exchange (catalysed by acids
Using NIST Search with Agilent MassHunter Qualitative Analysis Software James Little, Eastman Chemical Company Sept 20, 2012 Introduction Screen captures in this document were taken from MassHunter B.05.00
CHEM Degrees: A.S. A.S. Chemical Technology Certificate of Achievement: Chemical Technology Associate in Science Degree Program Information is the study of the properties, composition, and transformations
Chemistry 201 Lecture 15 Practical aspects of buffers NC State University The everyday ph scale To review what ph means in practice, we consider the ph of everyday substances that we know from experience.
Chemical Sputtering von Kohlenstoff durch Wasserstoff W. Jacob Centre for Interdisciplinary Plasma Science Max-Planck-Institut für Plasmaphysik, 85748 Garching Content: Definitions: Chemical erosion, physical
Essential rganic Chemistry Chapter 16 The rganic Chemistry of Amino Acids, Peptides, and Proteins Amino Acids a-amino carboxylic acids. The building blocks from which proteins are made. H 2 N C 2 H Note:
Structure of proteins Primary structure: is amino acids sequence or the covalent structure (50-2500) amino acids M.Wt. of amino acid=110 Dalton (56 110=5610 Dalton). Single chain or more than one polypeptide
Green Organic Chemistry @ Mt. SAC Mt. San Antonio College Walnut, California Iraj B. Nejad firstname.lastname@example.org 210 th 2YC3 Conference Chemistry for a Sustainable Future Kaneohe, Hawaii May 22-23, 2015 Mt.
Short Peptide Synthesis Keith ó Proinsias 8 th February 2010 Introduction Amide bond and basic amide synthesis Solution phase peptide synthesis Protecting groups required for peptide synthesis Coupling
ABSTRACT A. 'Hypersensitive' peptide bonds and autodegradation of proteins Several pure proteins, which gave a single band on electrophoretic analysis, when stored for a long time, were found to be partially
Name Class: Partner, if any: INTRODUCTION TO PROTEIN STRUCTURE PRIMARY STRUCTURE: 1. Write the complete structural formula of the tripeptide shown (frame 10). Circle and label the three sidechains which
Acid-Base (Proton-Transfer) Reactions Chapter 17 An example of equilibrium: Acid base chemistry What are acids and bases? Every day descriptions Chemical description of acidic and basic solutions by Arrhenius
Safe Storage of Chemicals Proper storage of chemicals within a laboratory is a difficult and continuing problem. Some experts have stated that the majority of laboratory accidents are related to improper
CHAPTER 10: INTERMOLECULAR FORCES: THE UNIQUENESS OF WATER Problems: 10.2, 10.6,10.15-10.33, 10.35-10.40, 10.56-10.60, 10.101-10.102 10.1 INTERACTIONS BETWEEN IONS Ion-ion Interactions and Lattice Energy
Users Manual for the Emissions Speciation Database Files and Programs William P. L. Carter College of Engineering Center for Environmental Research and Technology University of California, Riverside, CA
VOL. 37, 1951 CHEMISTR Y: PA ULING AND COREY 251 THE PLEATED SHEET, A NEW LAYER CONFIGURATION OF POL YPEPTIDE CHAINS BY LINUS PAULING AND ROBERT B. COREY GATES AND CRELLIN LABORATORIES OF CHEMISTRY,* CALIFORNIA
Part B 2 Allow a total of 15 credits for this part. The student must answer all questions in this part. 51  Allow 1 credit for 3 Mg(s) N 2 (g) Mg 3 N 2 (s). Allow credit even if the coefficient 1 is