Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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Question
please solve only question 3 in the red box, 3. Which complex shows lower C-O stretching frequency, [Ni(acac)2(H2O2 or [Ni(acac)2]? Explain.
![[Ni(acac)2(H₂O₂], [Ni(acac)2(Py)2] and [Ni(acac)2]
Purpose
Preparation of bis(acetylacetonato)diaquanickel(II), anhydrous bis(acetylacetonato)nickel(II), and
bis(acetylacetonato)dipyridinenickel(II) complexes.
Reagent Required
Acetylacetone, 11 mL
Sodium hydroxide, 4.0 g
95% ethanol, 250 mL.
Nickel sulfate hexahydrate, 13.0 g
Pyridine, 5.0 mL
Experimental Procedures:
A) Bis(acetylacetonato)diaquanickel(II)
1. Dissolve acetylacetone (11 mL) in 1.0 M sodium hydroxide solution (4.0 g NaOH in 100 ml
water). Add further acetylacetone drop by drop until a drop remains undissolved, and then just
add enough ethanol to dissolve it. Add to this solution, with stirring, nickel sulfate hexahydrate
(13 g) in water (50 mL).
2. Filter the precipitate on Büchner funnel, dry it in air (not in the oven) and recrystallize it from
hot ethanol (~200 mL). The product crystallizes in light blue-green needles.
3. Dry the product in air or in an oven at temperature less than 80°C. Weigh the product and
calculate the percentage yield.
4. Record the melting pint of the compound, its visible spectrum in ethanol, its I.R. spectrum
and its magnetic properties, measure the conductance of the of the compound in ethanol and
determine its molecular weight by freezing point depression method (as in expl).
B) Anhydrous bis(acetylacetonato)nickel(II)
Weigh precisely about 2 grams of the prepared bis(acetylacetonato)diaquanickel(II) in a
preweighed dry sample tube 100°C and under vacuum for one hour, allow to cool to room
temperature and weigh the sample tube containing the sample and calculate the mass loss.
The anhydrous nickel(II) complex is dark green. Record the melting pint of the compound, its
I.R. spectrum and its magnetic properties.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F358e2f4d-bfd7-4a31-b907-9d166b0a50a3%2F58b7d31f-6011-4ae6-ad0a-b985e7ae43c8%2F802dr78_processed.jpeg&w=3840&q=75)
Transcribed Image Text:[Ni(acac)2(H₂O₂], [Ni(acac)2(Py)2] and [Ni(acac)2]
Purpose
Preparation of bis(acetylacetonato)diaquanickel(II), anhydrous bis(acetylacetonato)nickel(II), and
bis(acetylacetonato)dipyridinenickel(II) complexes.
Reagent Required
Acetylacetone, 11 mL
Sodium hydroxide, 4.0 g
95% ethanol, 250 mL.
Nickel sulfate hexahydrate, 13.0 g
Pyridine, 5.0 mL
Experimental Procedures:
A) Bis(acetylacetonato)diaquanickel(II)
1. Dissolve acetylacetone (11 mL) in 1.0 M sodium hydroxide solution (4.0 g NaOH in 100 ml
water). Add further acetylacetone drop by drop until a drop remains undissolved, and then just
add enough ethanol to dissolve it. Add to this solution, with stirring, nickel sulfate hexahydrate
(13 g) in water (50 mL).
2. Filter the precipitate on Büchner funnel, dry it in air (not in the oven) and recrystallize it from
hot ethanol (~200 mL). The product crystallizes in light blue-green needles.
3. Dry the product in air or in an oven at temperature less than 80°C. Weigh the product and
calculate the percentage yield.
4. Record the melting pint of the compound, its visible spectrum in ethanol, its I.R. spectrum
and its magnetic properties, measure the conductance of the of the compound in ethanol and
determine its molecular weight by freezing point depression method (as in expl).
B) Anhydrous bis(acetylacetonato)nickel(II)
Weigh precisely about 2 grams of the prepared bis(acetylacetonato)diaquanickel(II) in a
preweighed dry sample tube 100°C and under vacuum for one hour, allow to cool to room
temperature and weigh the sample tube containing the sample and calculate the mass loss.
The anhydrous nickel(II) complex is dark green. Record the melting pint of the compound, its
I.R. spectrum and its magnetic properties.
![C) Bis(acetylacetonato) bis(pyridine)nickel(II)
1. Heat 3.0 grams of bis(acetylacetonato)diaquanickel(II) with a mixture of pyridine (5mL) and
ethanol (10 mL). Upon cooling the solution, blue crystals of
bis(acetylacetonato)bis(pyridine)nickel(II) appear. Filter the crystals on Buchner funnel, wash
2. Record the melting pint of the compound, its visible spectrum in ethanol, its I.R. spectrum
and its magnetic properties, measure the conductance of the of the compound
in ethanol and determine its molecular weight by freezing point depression method (as in expl).
Questions
1. Explain the spectra of both the diaqua and the bispyridine complexes.
Explain any difference. Which of the two has higher ligand field splitting? Explain. Do you
observe any distortion? Explain the presence of extra bands in the spectra.
2. Suggest the structures of the three complexes. Can the I.R. spectra or the magnetic moments be=
used for the assignment of the structures.
3. Which complex shows lower C-O stretching frequency, [Ni(acac)2(H₂O2 or [Ni(acac)2]?
Explain.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F358e2f4d-bfd7-4a31-b907-9d166b0a50a3%2F58b7d31f-6011-4ae6-ad0a-b985e7ae43c8%2F04batw_processed.jpeg&w=3840&q=75)
Transcribed Image Text:C) Bis(acetylacetonato) bis(pyridine)nickel(II)
1. Heat 3.0 grams of bis(acetylacetonato)diaquanickel(II) with a mixture of pyridine (5mL) and
ethanol (10 mL). Upon cooling the solution, blue crystals of
bis(acetylacetonato)bis(pyridine)nickel(II) appear. Filter the crystals on Buchner funnel, wash
2. Record the melting pint of the compound, its visible spectrum in ethanol, its I.R. spectrum
and its magnetic properties, measure the conductance of the of the compound
in ethanol and determine its molecular weight by freezing point depression method (as in expl).
Questions
1. Explain the spectra of both the diaqua and the bispyridine complexes.
Explain any difference. Which of the two has higher ligand field splitting? Explain. Do you
observe any distortion? Explain the presence of extra bands in the spectra.
2. Suggest the structures of the three complexes. Can the I.R. spectra or the magnetic moments be=
used for the assignment of the structures.
3. Which complex shows lower C-O stretching frequency, [Ni(acac)2(H₂O2 or [Ni(acac)2]?
Explain.
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