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

Keto-enol and thione-thiol tautomerism

MIMT is used for treating hyperthyroidism

“MIMT” Propylthiouracil

Uridine

(Uracil + deoxyribose)

Characterization of products

• UV-VIS spectroscopy– probes crystal field gap

• IR spectroscopy– probes atomic motion C S

Co2+

Characterization of products

• UV-VIS spectroscopy– probes crystal field gap

• IR spectroscopy– probes atomic motion

Effect of modifying bond is to:

vhchc

hvE ~

m

kv

kxF

C S

Co2+

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

m

kvkxF and

C S

Edonor

C S

Eacceptor

C S

Co2+

Colors for lab 6

Color of solutions

Additive mixing Subtractive mixing

Lab report writing

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

Academic integrity

• Electronically duplicated responses are UNACCEPTABLE

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).

Why keep a laboratory notebook?

• In this lab

Useful data is kept handy (MWs, mp’s/bp’s, 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

Laboratory notebook

• Should be clear on tense– Flow chart:

Add 350mg of Co complex and 140L 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. L 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.

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

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