Download Chemistry 3211 - Inorganic Chemistry of the Transition Metals

Chemistry 3211 - Inorganic Chemistry of the Transition Metals
Instructor: Dr. C. M. Kozak
Office: C2018 ext. 8082
E-mail: [email protected]
Research Labs: C5006 (ext. 4784) and C5007
URL: http://www.chem.mun.ca/zfac/cmk.php
Course Subject: The properties, reactions and structures of the transition metals.
Lectures: Monday, Wednesday, Friday 9:00 – 9:50, Room C4002
Labs: Tuesday, 9:00 to 12:00 and 14:00 to 17:00, Room C5001
Office hours: Drop-in visits are OK, but make an appointment if you need more than just a quick
comment. E-mail Dr. K to arrange a time (include “Chem 3211” in subject lines of e-mails)
Prerequisites: Chemistry 2210 and 2300
Recommended Resources:
• “Shriver and Atkins’ Inorganic Chemistry” 5th Ed. by Atkins, Overton, Rourke, Weller, Armstrong,
Hagerman (Freeman 2010) and the optional Solutions Manual are sold in the bookstore and is the
required text for this course. This is the same text used in Chemistry 2210 and 3210.
Other Useful References are in the Library. It is your friend. Visit it once in a while. The call
numbers for inorganic chemistry generally start with QD 151. Go for a browse!
• “Inorganic Chemistry” 2nd or 3rd Ed. by Housecroft and Sharpe (H & S) Pearson – Prentice Hall
2008. 2nd Ed. is not as thorough as S & A, but is decent. 3rd Ed. is much expanded.
• “Inorganic Chemistry” 2nd or 3rd Ed. by Miessler and Tarr (M & T) Pearson – Prentice Hall.
Focuses on good explanation but the figures aren’t as good.
• “Inorganic Chemistry: Principles of structure and reactivity”, 4th Ed. by Huheey & Keiter, 1993.
An old text, but a real classic. Very thorough and excellent for understanding MO theory.
• “Basic Inorganic Chemistry”, 3rd Ed. by Cotton, Wilkinson, and Gauss, 1995.
• “Descriptive Inorganic Chemistry”, 4th Ed. by Rayner-Canham and Overton, 2006.
• All potentially serious inorganic chemists should at some time read “Advanced Inorganic
Chemistry” 6th Ed. by Cotton, Wilkinson, Murillo and Bochmann; and “Chemistry of the Elements”
2nd Ed. by Greenwood and Earnshaw.
The “Oxford Chemistry Primers” series is an affordable and very useful source for understanding the
basics of chemistry and is published in small soft cover volumes. The following are recommended for
this course. They are not available in the bookstore, but may be in the library or can be purchased:
Ø “d-Block Chemistry” by M. J. Winter
Ø “Chemistry of the First-row Transition Metals” by Jon McCleverty.
Ø “Inorganic Spectroscopic Methods” by A. K. Brisdon. Useful if you have not taken Chem 3500.
The grading scheme for the course is as follows:
1 Midterm (Wednesday Feb 13th)
Laboratory (all labs must be completed and submitted in order to pass)
4 Assignments (due Jan 21st, Feb 8th, Mar 8th, Mar 27th)
Final Examination (held during regular exam period)
20%
20%
20%
40%
The lecture and laboratory components must both be passed to pass the course. All experiments must
be performed and submitted before the end of the course in order to pass.
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Course Outline
Chem 3211 comprises three lectures and one lab per week. In addition to the four Assignments, which
will be graded, students will be assigned small problem sets (one or two questions) roughly every week
and this material will be discussed in a tutorial session during a regular lecture. No marks for these
problem sets will be assigned, but class participation will be taken into account.
The general breakdown of the course and its relevant chapters in S & A are listed below. Of course,
you are encouraged to consult the other resources mentioned above as well.
Subjects covered in Chem 3211 (Chapters refer to S & A, 5th edn):
1.
Background information is found in Chapter 2. You should already know about Lewis structures,
VSEPR theory, Valence-bond/Hybrid Orbital theory. You should already know most of what is
covered in Sections 2.1 to 2.10. Molecular orbital theory of homo- and heteronuclear diatomics
was covered in Chem 2210, but I will review this in class as required. I will teach MOs of
polyatomic molecules, since this helps understand MOs of coordination complexe.
2.
Symmetry (Ch 6) – You should re-familiarize yourselves with the simple symmetry operations
and how to assign point groups (Sections 6.1 and 6.2). Applications of Symmetry (Sections 6.3 to
6.10) will be briefly covered.
3.
Introduction to Coordination Compounds (Ch 7) – The Periodic Table and the transition
elements; Alfred Werner and the historical development of the ideas of coordination chemistry;
coordination complexes and structures; isomerism; types of ligands and introduction to
nomenclature.
4.
d-Block Elements (Ch 19) – Trends (Sections 19.3 to 19.6); Representative compounds, metalmetal bonding (Sections 19.7 to 19.11).
5.
d-Metal Complexes: Electronic Structure and Properties (Ch 20) – Bonding Theories; crystal
field and ligand field theories; magnetism; molecular orbital theories; orbital overlap interactions;
Beer-Lambert laws; quantum numbers of multielectron atoms and spin-orbit coupling; the
electronic structure of transition metal atoms in the gas phase; the electronic structure of derived
ions in the gas phase; electronic spectra of atoms and complexes; term symbols and relations to
spectroscopy.
6.
Coordination Chemistry: Reactions of Complexes (Ch 21) – Reaction mechanisms of d-block
complexes; substitution (inert vs. labile) and redox reactions; photochemical reactions.
7.
d-Metal Organometallic Chemistry (Ch 22) – Introduction to organometallics; effective atomic
numbers; catalytic reactions of organometallic species (parts of Ch 26).
8.
Selected topics including structure determination in inorganic chemistry; biological inorganic
chemistry; medicinal inorganic chemistry; descriptive chemistry of the 1st row transition metals
will be scattered throughout the lectures where applicable.
The above course breakdown should only be treated as a guide. We may change the order of the
lectures, or spend more time on a specific topic, if the need arises.
One final reminder: It is extremely important, as in any course, to keep up with the required reading.
One can become lost very quickly, and the pace of this course, combined with the fact that many of the
topics discussed rely heavily on a firm knowledge of the prior material, can leave you behind and
frustrated.
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Detailed Course Contents
General Foundation Topics:
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Definitions of coordination chemistry, ligands, complexes, atomic structure and orbital description of
transition metals, quantum numbers and the evolution of the periodic table.
Physical properties and abundances/ occurrence, effective nuclear charge, general periodic trends (oxidation
states, atomic & ionic radii, electron affinity, ionization energy, electronegativity).
Coordination Complexes:
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History and early ideas (Alfred Werner vs. C. W. Blomstrand), IUPAC nomenclature, coordination numbers,
geometry and oxidation states.
X-ray crystallography and structure determination.
Ligand classes (monodentate, bidentate, tridentate); isomers including geometric (cis, trans, fac, mer),
optical rotation and chirality, isomerization in 4, 5 and 6 coordinate complexes.
Symmetry:
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Review of symmetry elements and point groups.
Introduction to character tables and group theory, Mullikan symbols.
Bonding:
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Thermodynamics including equilibrium, chelate and macrocyclic effects; magnetic susceptibility and
magnetic moment.
Valence Bond and Crystal field theories; Recall of MO diagrams for simple main group di- and triatomics
(N2, O2, CO, NH3).
Ligand field and Linear Combination of Atomic Orbital – Molecular Orbital (LCAO-MO) theory; Crystal
Field & Ligand Field Stabilization Energies (CFSE/LFSE).
Crystal field splitting diagrams for octahedral, tetrahedral and other geometries; crystal field splitting
energies (Δo, Δt) and the spectrochemical series.
High spin vs. low spin complexes; Jahn-Teller theory and geometric distortions.
Electronic Spectra of Transition Metal Complexes:
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UV-visible absorption spectra; interpreting transitions from spectroscopic data.
Tanabe Sugano Diagrams, microstates, term symbols, ground state terms, Racah parameters, high spin – low
spin transitions, nephelauxetic effect.
Selection rules, intensities of transitions, forbidden transitions & Laporte selection rules, charge transfer
(MLCT & LMCT) bands, solvatochromism.
Characterization of Inorganic Complexes:
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Crystallography and diffraction methods
Reaction Mechanisms:
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Substitution reactions, Inert and Labile complexes, kinetics, classes of mechanism (A, D, Ia, Id), trans effect
Electron transfer reactions, inner and outer sphere mechanisms, reactions of coordinated ligands.
Organometallic Chemistry and Catalysis:
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Nature of the metal-carbon bond, bioorganometallics (vitamin B12), effective atomic number and electron
counting, 18-electron rule, oxidation states
Carbonyl complexes and bonding modes (although this will be introduced in “Bonding Theories”)
Sigma and pi bonding in organic ligands; cyclopentadienyl ligands and bonding in ferrocene
Alkyl, alkylidene and alkylidyne ligands (Schrock & Fisher carbenes)
Characterization of organometallics, NMR, IR, fluxionality (time permitting)
Principles of catalysis and simple catalytic mechanisms (time permitting).
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APPLICATIONS AND RESEARCH AREAS RELATING TO CHEM 3211
In 3211 you will learn about molecules and solids that contain transition metals. They have a variety of
uses and an overview of their applications is presented below.
Catalysis – A wide variety of both soluble and insoluble transition metal compounds are effective as
catalysts. A catalyst is a chemical that is able to promote a particular reaction but is not used up itself.
Therefore, a tiny amount of catalyst can be used to make a huge amount of product, often using less
energy intensive processes. Some catalysts are used to make small amounts of research chemicals in
the lab, others are used to make chemicals such as pharmaceuticals on a multi-ton scale, and others are
used to make widely used chemicals and materials on a huge scale. For example, Ti and Zr are used as
olefin polymerization catalysts. Rh containing molecules are used to make millions of tones of acetic
acid and aldehydes every year. Fe and V are used to make > 120 million tons of NH3 and SO3 every
year, and precious metals such as Pt and Rh are used in catalytic converters in our cars. Catalysis is
therefore an important part of the emerging field of Green Chemistry.
Green Chemistry – Research in this area includes the use of transition metal complexes to produce
biodegradable polymers, to remove sulfur containing organic impurities from oil and gas, or to harvest
solar energy. Many researchers are also involved in the development of catalysts that use O2 as an
oxidant instead of stoichiometric, toxic metal oxidants such as dichromate. Other catalytic research
involves reactions in water or room temperature ionic liquids instead of volatile organic solvents. These
techniques and others allow catalysts to be recycled more easily. New catalysts are being developed
that will allow reactions to run at lower temperatures and pressures (making them more energy
efficient), or are based on less toxic and more abundant metals (e.g. iron), produce fewer unwanted byproducts, or catalysts that are required in even smaller amounts to promote a particular reaction.
Metal Extraction, Mining and Industrial Waste Treatment – The ability to selectively complex one
metal and not another is of huge importance in this area. Also, new technologies to clean up waste
streams of these industries and to monitor water, etc. are being developed by inorganic chemists and
engineers.
Electronics and Magnetic Materials – Transition metals are used extensively in the microelectronics
industry, and the type of metal containing molecules that we learn about in 3211 are often used to
deposit uniform thin films of metals or metal compounds (e.g. for circuit wiring or as insulation in
memory and logic chips). This technique is called chemical vapour deposition (CVD). As with much of
inorganic chemistry, this work is typically carried out under strictly air-free conditions. Many materials
with important magnetic properties incorporate transition metals, ranging from the magnets in your
stereo speakers to superconducting magnets (e.g. NMR and MRI instruments). Of course, the role of
main group metals and non-metals (e.g. Si) should not be overlooked in this area.
Biology, Biochemistry and Medicine – Transition metals (in particular Mn, Fe, Co, Ni, Cu and Zn)
play a very important role in organisms (e.g. iron in hemoglobin in our blood, cobalt in Vitamin B12,
manganese in antioxidant enzymes). As with many other areas of biological chemistry, there is a lot of
research currently ongoing and new roles for metals in life are being discovered. In addition, both
transition metals and the lanthanides are also used extensively in biotechnology – for example, to bind
with a new protein that has been prepared and separate it from impurities, or as fluorescent tags for
biological molecules. In medicine, platinum complexes are used as anti-cancer drugs (e.g. cisplatin =
[cis-PtCl2(NH3)2]). Gold complexes are used as drugs for arthritis (e.g. Auranofin). Radioactive
technicium and rhenium is used in radiopharmaceuticals. Various transition metals are used to
construct medical implants (e.g. titanium, vanadium) or medical devices (e.g. shape memory Ni-Ti
alloys for use as anchors for tendon fixation, stents or orthodontic wires).
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Lasers and Nonlinear Optical Materials – Many lasers rely on the optical transitions that occur in 1st
row transition metal compounds – e.g. Cr3+ or Ti3+ replacing some Al3+ ions in Al2O3 (ruby or sapphire
lasers). Metals are also found in many nonlinear optical materials that can be used to manipulate the
frequency of light and are particularly important in the telecommunications industry. A familiar
product that relies on nonlinear optical frequency doubling is the green laser pointer: laser light at a
wavelength of 1064 nm is generated using a Nd:YVO4 crystal, and this is passed through a nonlinear
optical crystal of KTiOPO4 which doubles the frequency to produce 532 nm green laser light.
Other Uses (by no means exhaustive) – Batteries, paints (TiO2, blue cobalt compounds etc.), fuel
additives [e.g. Fe(η-C5H5)2], corrosion resistant coatings (especially Cr and Zn), alloys for various uses
(bronze = Cu/Sn, brass = Cu/Zn, Monel = Cu/Ni), nuclear control rods (e.g. Hf or Ag/In/Cd), nuclear
fuel rod coatings (e.g. Zr), structural metals (stainless steel is typically iron with 10-25% chromium and
0-10% nickel), basic electrical metals (copper and gold wires), metals for jewelry (e.g. Au, Pt, Rh, Ag)
etc.
A vast amount of research involving transition metal chemistry is currently going on worldwide. Some
of this research is directed towards improving/extending existing applications and developing new
applications. Other research is directed towards increasing our understanding of transition metal
chemistry and advancing the complexity of the structures that chemists are able to make. This more
fundamental or exploratory work provides the basic platform of knowledge that allows the
development of the future technologies.
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