Lab 1 procedure Tin4 iodide | Lab Reports Inorganic Chemistry

Laboratory Experiments for Inorganic Chemistry (Stockton University, Updated for Fall 2023)

S.E. Kalman

The Synthesis and Characterization of a Hypervalent Tin(IV) Compound

Learning Goals

1) Gain experience synthesizing main group inorganic compounds

2) Have the opportunity to learn and use melting point determination and infrared spectroscopy

3) Assess how structure can influence reactivity of inorganic compounds

4) Apply lecture material on VSEPR to a hypervalent tin compound

Background

Tin is a main group metal in the same group as carbon on the periodic table. While elements in the

same group often have similar properties, this is not always the case. For instance, in organic

chemistry we often think of carbon as being happy with four bonds based on its valence orbitals.

Tin, on the other hand, can form more than four bonds, in part, due to its larger size.1,2 Rather than

involving “low energy d orbitals,” there is potentially more evidence that a main group hypervalent

compound involves both covalent and ionic bonding.3 Interestingly, the reactivity between tin

compounds with four bonds versus those with six bonds can be quite different.2 In this laboratory

experiment, you will be investigating one such case.

Furthermore, tin compounds also have very important uses. A variety of tin compounds are used

in organic synthesis (see the Stille Reaction) and also have biological applications. Additionally,

there has been work studying tin compounds, like the ones you are synthesizing for this project,

as semiconductors.4

In the first week of the experiment you will be synthesizing and characterizing tin(IV) iodide by a

combination of quantitative and qualitative techniques. In the following week, you will treat your

SnI4 product with triphenylphosphine oxide to produce a hypervalent tin(IV) compound.

Hazards

The products, iodine, triphenylphosphine oxide, and chloroform are harmful. Toluene and

chloroform are flammable. All work should be performed in a fume hood while wearing gloves

and safety goggles. If chemicals get on your glove, immediately wash your hands and use new

gloves. Dispose of all waste in the provided container.

Procedure5

Make sure that all of your glassware has been thoroughly cleaned.

Synthesis of Tin(IV) Iodide

Weigh 0.500 g of tin metal and 1.250 g of iodine into a 10 mL round-bottom flask equipped with

a stir bar. Add ~5 mL of toluene to the round-bottom flask and commence stirring. Fix a condenser

to the round-bottom flask and begin heating using a heating mantle and variac. Be sure that your

Partial preview of the text

Download Lab 1 procedure Tin4 iodide and more Lab Reports Inorganic Chemistry in PDF only on Docsity!

Laboratory Experiments for Inorganic Chemistry (Stockton University, Updated for Fall 20 23 ) The Synthesis and Characterization of a Hypervalent Tin(IV) Compound Learning Goals

Gain experience synthesizing main group inorganic compounds
Have the opportunity to learn and use melting point determination and infrared spectroscopy
Assess how structure can influence reactivity of inorganic compounds
Apply lecture material on VSEPR to a hypervalent tin compound Background Tin is a main group metal in the same group as carbon on the periodic table. While elements in the same group often have similar properties, this is not always the case. For instance, in organic chemistry we often think of carbon as being happy with four bonds based on its valence orbitals. Tin, on the other hand, can form more than four bonds, in part, due to its larger size.1,2^ Rather than involving “low energy d orbitals,” there is potentially more evidence that a main group hypervalent compound involves both covalent and ionic bonding.^3 Interestingly, the reactivity between tin compounds with four bonds versus those with six bonds can be quite different.^2 In this laboratory experiment, you will be investigating one such case. Furthermore, tin compounds also have very important uses. A variety of tin compounds are used in organic synthesis (see the Stille Reaction) and also have biological applications. Additionally, there has been work studying tin compounds, like the ones you are synthesizing for this project, as semiconductors.^4 In the first week of the experiment you will be synthesizing and characterizing tin(IV) iodide by a combination of quantitative and qualitative techniques. In the following week, you will treat your SnI 4 product with triphenylphosphine oxide to produce a hypervalent tin(IV) compound. Hazards The products, iodine, triphenylphosphine oxide, and chloroform are harmful. Toluene and chloroform are flammable. All work should be performed in a fume hood while wearing gloves and safety goggles. If chemicals get on your glove, immediately wash your hands and use new gloves. Dispose of all waste in the provided container. Procedure^5 Make sure that all of your glassware has been thoroughly cleaned. Synthesis of Tin(IV) Iodide Weigh 0.500 g of tin metal and 1.250 g of iodine into a 10 mL round-bottom flask equipped with a stir bar. Add ~5 mL of toluene to the round-bottom flask and commence stirring. Fix a condenser to the round-bottom flask and begin heating using a heating mantle and variac. Be sure that your

Laboratory Experiments for Inorganic Chemistry (Stockton University, Updated for Fall 20 23 ) round-bottom flask is securely clamped. Start by setting the variac to 40 – 45 V until you begin to see purple vapor condensing at the top of the round-bottom flask or in the condenser. At this point, turn down the variac to approximately half the voltage and allow the reaction to continue heating for approximately 30 min. You should notice a color change during this time period. Be sure to record all observations in your notebook. After 30 min, turn off the variac and allow the reaction to cool slightly until it can be comfortably handled. If after a couple minutes, the round-bottom is still too warm, see the instructor. While the reaction mixture is still warm, decant the solution from the remaining tin metal and the stir bar by pouring it into another vessel, preferably a beaker or Erlenmeyer flask 50 mL or smaller (make sure it can hold the necessary volume). To the decanted solution, add ~5 mL of hexanes. Allow the mixture to cool to room temperature and then move it to an ice-water bath to cool for several minutes to maximize precipitation/crystallization. Collect the resulting orange solid over a Hirsch funnel (with vacuum) using another 5 mL of cold hexanes to rinse. Air dry the final product. Transfer the product into a tared vial and calculate the percent yield. Characterize the product using melting point determination and infrared spectroscopy. Furthermore, perform the following qualitative tests. To two separate test tubes, add a small amount of your product (the tip of a spatula is sufficient). To one of the test tubes, add some silver nitrate (the tip of a spatula). To both test tubes add 1 – 2 mL of DI water and shake/swirl. Record your observations. Here you are investigating the stability of the product toward water as well as determining whether iodide is present in your product. Synthesis of tetraiodobis(triphenylphosphine oxide)tin(IV) To a vial weigh 300 mg of SnI 4 and dissolve it in ~3 mL of chloroform. To this solution, add 275 mg of triphenylphosphine oxide as a solid. Briefly swirl or stir the contents until everything is mixed well. Allow the reaction mixture to sit undisturbed for 20 – 30 minutes. Red crystals should begin to form. If not, see your instructor. Collect the product over a Hirsch funnel (with vacuum). Wash the product with ~1 mL of CHCl 3 and ~1 mL of hexanes. Allow the solid to air dry. Transfer the product into a tared vial and calculate the percent yield. Characterize the product using melting point determination and infrared spectroscopy. The product will decompose before it melts. Set the power on the Mel-Temp to a power setting of 6 to observe this (it should darken). Record the temperature at which this occurs. Repeat the hydrolysis experiment for this product. Add a small amount of product to a test tube and add 1 – 2 mL of DI water. Note: If time allows, you may want to weigh out Mo(CO) 6 for next week. See your instructor. Report You should write a formal lab report for this experiment as outlined in the lab manual. You should use the general lab report rubric as you write your report in addition to the “Hints” provided below.

Laboratory Experiments for Inorganic Chemistry (Stockton University, Updated for Fall 20 23 ) (2) Smellie, I. A.; Woolins, J. D. Tetraiodiotin(IV) and its Triphenylphosphine Oxide Complex. In Inorganic Chemistry Experiments; Woolins, J. D., Ed.; Wiley-VCH: Weinheim, 2010; pp 73 – 74. (3) Gillepsie, R. J.; Silvi, B. Coordination Chemistry Reviews 2002 , 233 - 234 , 53-62. (4) Wlazlak, E.; Macyk, W.; Nitek, W.; Szacilowski, K. Inorganic Chemistry 2016 , 55 , 5935

(5) This procedure was adapted from reference 2. (6) For IR characterization of the product see: J. Inorg. Nucl. Chem. 1977 , 39 , 377 – 379. Due to the age of this paper, a copy will be posted on Blackboard for your convenience.

Lab 1 procedure Tin4 iodide, Lab Reports of Inorganic Chemistry

Related documents

Partial preview of the text

Download Lab 1 procedure Tin4 iodide and more Lab Reports Inorganic Chemistry in PDF only on Docsity!