Thione-thiol tautomerism

1
Thione-thiol tautomerism

• Safety
• Aqueous Co2 complexes dispose in liquid waste
  bottle.
• Wear gloves when working with MIMT
• Ligands for complexes (A) Co(MIMT)4(NO3)2 and
  (B) Co(MIMT)2 (NO3)2

MIMT Methimazole 2-Mercapto-1-methylimidazole
Nitrate ion
1-Methyl-1,3-dihydroimidazole-2-thione
2
Keto-enol and thione-thiol tautomerism
3
MIMT is used for treating hyperthyroidism
Uridine (Uracil deoxyribose)
MIMT
Propylthiouracil
4
Characterization of products

• UV-VIS spectroscopy
• probes crystal field gap
• IR spectroscopy
• probes atomic motion

DO
DT
Co2
C S
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Characterization of products

• UV-VIS spectroscopy
• probes crystal field gap
• IR spectroscopy
• probes atomic motion
• Effect of modifying bond is to

Co2
C S
6
Characterization of products

• IR spectroscopy
• probes atomic motion
• Increase electron density in bond
• increases k, increases v
• Decrease electron density in bond
• decreases k, decreases v

7
Colors for lab 6
8
Color of solutions

• Additive mixing Subtractive mixing

9
Lab report writing
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Lab report writing

• Scientists read for content, not for pleasure
• Content should be accessible, not obscured
• People estimate quality of science from quality
  of writing
• If you want your work to be read, make sure you
  are writing well
• No work achieves its full potential without major
  revising
• Generally needs external input

11
Academic integrity

• Electronically duplicated responses are
  UNACCEPTABLE

12
Why keep a laboratory notebook?

• In scientific research (industry)
• The lab notebook is like a notarized document.
  If your work is not recorded in a signed lab
  notebook, it DID NOT HAPPEN, from a legal point
  of view.
• This has important legal ramifications when
  patents are issued, especially when priority is
  at stake and billions of dollars are on the line.
• Since many synthetic procedures are not out of a
  book, it will also provide a record of the steps
  necessary to make a product and to verify its
  nature, both for yourself and for your colleagues
  (should your actions ever be questioned).

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Why keep a laboratory notebook?

• In this lab
• Useful data is kept handy (MWs, mps/bps,
  hazards, etc.)
• Chance to envision the experiment in advance
• Should have a schematic flow chart, not a 50-step
  procedure
• Chance to consider what variables are crucial to
  success
• Record of work actually performed
• Value of your observations may only be obvious in
  hindsight
• This way we know that you are not changing
  results to fit model

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Laboratory notebook

• Should be clear on tense
• Flow chart
• Add 350mg of Co complex and 140mL of en to MeOH
  soln.
• Record
• 352 mg of CoCl3.6H2O (green powder, Aldrich, 98
  purity) were added
• Should include variables crucial to
  success/failure
• 352 mg of CoCl3.6H2O (green powder, Aldrich, 98
  purity) were added en masse to 5.0 ml of MeOH in
  a 25ml RB flask. 140. mL of en (Sigma, 99.5)
  were added dropwise over 2 minutes, causing a
  little bubbling, and turning the solution from
  dark green to a medium purple. 4 chunks of a
  dull gray mossy zinc (TW 117 mg, Alfa, 98) were
  cleaned by swirling in 6N HCl for 1 min,
  followed by three water rinses, one MeOH rinse,
  and air jet drying. No change in the color of
  the Zn was observed during the cleaning process.
  The Zn and a stirbar were added to the reaction
  mixture. The solution was refluxed over a sand
  bath (setting 40) with the RB flask in contact
  with the sand with slow stirring (unable to
  create stable vortex at higher spin settings). A
  yellow solid began to appear at the top of the RB
  flask (outside of the liquid) after 40 min.
  After a total of 65 minutes of heating, the
  solution was directly quenched into an ice bath,
  allowed to cool for 7 min, and filtered through a
  12 mm piece of filter paper (Fisher brand, pore
  size 6). A fine purple powder was obtained no
  yellow solid was found in the filtrate, even
  after washing with cold 100 EtOH. The Zn chunks
  had a pitted look and a duller luster after the
  reaction.

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Title / Abstract / Introduction

• Used to judge if full article will be read or not
• Title
• Specifies system and what is interesting
• Should make people want to read your article /
  report
• Introduction
• Should answer question of why work was done
• Should discuss the question being posed, and
  value of answer
• May need to provide background information
• Abstract
• Needs to be comprehensive in scope
• Should only include the most essential results
  and conclusions
• You have been asked to write an Introduction, not
  an Abstract

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Title Specifies system and what is interesting

• Homochiral Coordination Polymer with Infinite
  Double-Stranded Helices
• Photochemical Production of a Highly Reactive
  Porphyrin-Iron-Oxo Species
• An Unusual 1D Manganese Azido Complex with Novel
  EO/EO/EO/EE Coordination Mode Synthesis,
  Structure, and Magnetic Properties
• Low-Temperature Spectral Observation of the First
  Six-Coordinate Nitrosyl Complexes of Cobalt(II)
  meso-Tetratolylporphyrin with Trans Nitrogen Base
  Ligands
• Cyanide-Bridged WV-CoII Double-Zigzag Chain Based
  on an Octacoordinated W Precursor Metamagnetism
  and Spin Canting
• Deliberate Design of a 3D Homochiral
  CuII/L-met/AgI Coordination Network Based on the
  Distinct Soft-Hard Recognition Principle