Final Exam (105 Pts)

Chem.451 (Spring, 2007)

Final Exam (105 pts)

Name: ------, Student Clid #: ------, May 11, 2007

LAST, First

Circle the alphabet segment of your Last Name: A-G H-L M-P Q-Z

Please answer the following questions:

Part I: Multiple Choices(18 pts: 6 @ 3 pts). Please circle the ONE best answer:

Which of the following complexes one would expect to be labile?

I:K2[MnI6]II:cis-Pt(NH3)2Cl2III:K3[Fe(CN)6]IV: (NH4)2[Cr(O)Cl5]

a)III and IVb) I and III

c) Only IVd) I and IV

2.Which of the following complexes are chiral?

I: [Ru(en)3]2-II: [Pt(dien)Cl]+III: cis-[Cr(C2O4)2Cl2]3-IV: trans-[Cr(C2O4)2Cl2]3-

a)Only IIIb) II and IV

c) I and IIId) II and III

3. Which of the following species belong to the point group C2v?

I: [CoCl2Br2]2-II: [PdCl4]2-III: trans-Pt(NH3)2Cl2IV: [NiBr4]2-

a) Only III b) Only I

c) Iand IIId) II and IV

What is the point group of trans-difluorobis(ethylenediamine)cobalt(III) ion?

a) D4h b) Td

c) C2vd) Oh

5. Which of the following compounds is expected to be paramagnetic with a magnetic moment, μ

close to 3.9 BM?

a) K3[Fe(CN)6]b) (NH4)2[Cr(O)Cl5]

c) K2[VCl4]d) K2[MnI6]

On the basis of the 18-e rule, identify the most likely second row transition metal for the complexes?

I: (η5-C5H5)M(η2-C2H4)(PMe3)II: [(η5-Cp)(CO)2M-M(η5-Cp)(CO)2]

III: M(CO)(PMe3)2Cl (square planar)IV: (η5-C5H5)2M(CO)2

a) Rh, Ru, Pd and Zr respectively.b) Ru, Rh, Pd and Zr respectively.

c) Co, Fe, Ni and Ti respectively.d) Rh, Ru, Pd and Mo respectively.

Part II.(34 pts) Coordination Chemistry

(14 pts) Explain the electron configuration in the following diamagnetic complexes

a) (7 pts) [Co(NH3)6]3+ on the basis of VBT, MOT and CFT (Include a diagram showing the

molecular geometry and d-orbital energy levels for the complex as part of your answer)

b) (3 pts) trans-[Co(NH3)4F2]+ on the basis of CFT(Include diagram showing the molecular

geometry and d-orbital energy levels for the complex as part of your answer)

c) (4 pts) [PdCl2(PPh3)2] on the basis of VBT and CFT (Include diagram showing the molecular

geometry and d-orbital energy levels for the complex as part of your answer)

2. (6 pts) Sketch all possible geometrical isomers and then indicate which of these complexes would exhibit optical activity. Also identify each complex by name

a) [Fe(C2O4)2Cl2]+ ion (C2O42- = oxalate ion),

b) [PdCl2(PPh3)2] (diamagnetic)

3. (14 pts) Rationalize for the following observations:

a) (6 pts) Solutions of the complexes [Co(NH3)6]3+, [Co(OH2)6]2-and [CoCl4]2- are colored. One is pink, another is yellow-orange and the third is blue. Assign each color to one of the complexes and explain the basis of your assignment.

b) (4 pts) [FeF6]3- is colorless whereas [CoF6]3- is colored and exhibits only a single band in the visible region.

d) (4 pts) Solutions of [Cr(OH2)6]3+ are pale blue-green but the chromate ion CrO42- is an intense yellow.

Part III. (18 pts) Organometallic Compounds

(6 pts) Determine the metal-metal bond order consistent with the 18-electron rule for the following;

a) [(η5-C5H5)Mo(CO)3]2 b) [(η5-C5H5)Mo(CO)2]2 c) [(η5-C5H5)Mo(CO)]22-

2. (6 pts) Show how CH3CHO can be prepared by the oxidation of CH2=CH2 using [PdCl4]2-as a catalyst by Wacker process.

3. (6 pts) Rationalize the following observations:

a)On going from Fe(CO)5 to Fe(CO)3(PPh3)2, absorptions in the IR spectrum at 2025 cm-1 are

replaced by bands at 1944, 1886 and 1881 cm-1.

b) The complex ion [Co(CO)3(PPh3)2]+ has a single carbonyl stretching frequency whereas Mo(CO)3(NC-C2H5)3 has two bands. Account for the structural changes.

Part IV. (18 pts) Bioinorganic Chemistry:

1. (10 pts) a) What prevents simple iron porphyrins from functioning as O2-carrier?

b) How these problem were overcome in synthesizing successful models for iron porphyrins

c) Briefly explain the role of the peptide portion of hemoglobin in preventing the irreversible oxidation of Fe2+?

2. (6 pts) To counteract these effects, second generation of Pt-drugs, such as those shown above have been developed that show similar therapeutic activities but at a lower dosages. What structure and chemical characteristics of these molecules can be used to rationalize their enhanced therapeutic properties?

______

Part V. (18 pts) Transition Metals

(9 pts) Compare and contrast (similarities and dissimilarity) between the general properties of transition metals, lanthanides and actinides.

2. (9 pts) Predict the probable structure (bond order & electron configuration and magnetic properties) for the followingmetal-metal bonded tetragonal-prismatic complexes:

a) [Cu2(μ-O2CMe)4] b) [Mo2(μ-O2CMe)4] c)[Cr2(μO2CC2H5)4]

You will have 140 minutes to complete this exam.

The exam has 9 pagesplus Periodic Table

When you are told to do so, tear off the Periodic Table cover sheet and use as required during exam.

Ligand abbreviations:

en = ethylenediamine, H2N-CH2CH2-NH2

dien = diethylenetriamine, H2N-CH2CH2-NH-CH2CH2-NH2

OX = oxalate dianion, -OOC-COO-

1 / 1
H
1.01 / Periodic Table of the Elements / 2
He
4.00
2 / 3
Li
6.94 / 4
Be
9.01 / 5
B
10.81 / 6
C
12.01 / 7
N
14.01 / 8
O
16.00 / 9
F
19.00 / 10
Ne
20.18
3 / 11
Na
22.99 / 12
Mg
24.30 / 13
Al
26.98 / 14
Si
28.08 / 15
P
30.97 / 16
S
32.06 / 17
Cl
35.45 / 18
Ar
39.95
4 / 19
K
39.1 / 20
Ca
40.08 / 21
Sc
44.96 / 22
Ti
47.88 / 23
V
50.94 / 24
Cr
52.00 / 25
Mn
54.94 / 26
Fe
55.85 / 27
Co
58.93 / 28
Ni
58.69 / 29
Cu
63.55 / 30
Zn
65.38 / 31
Ga
69.72 / 32
Ge
72.59 / 33
As
74.92 / 34
Se
78.96 / 35
Br
79.90 / 36
Kr
83.80
5 / 37
Rb
85.47 / 38
Sr
87.62 / 39
Y
88.91 / 40
Zr
91.22 / 41
Nb
92.91 / 42
Mo
95.94 / 43
Tc
(98) / 44
Ru
101.1 / 45
Rh
102.9 / 46
Pd
106.4 / 47
Ag
107.9 / 48
Cd
112.4 / 49
In
114.8 / 50
Sn
118.7 / 51
Sb
121.8 / 52
Te
127.6 / 53
I
126.9 / 54
Xe
131.1
6 / 55
Cs
132.9 / 56
Ba
137.3 / 57
La
138.9 / 72
Hf
178.5 / 73
Ta
181.0 / 74
W
183.8 / 75
Re
186.2 / 76
Os
190.2 / 77
Ir
192.2 / 78
Pt
195.1 / 79
Au
197.0 / 80
Hg
200.6 / 81
Tl
204.4 / 82
Pb
207.2 / 83
Bi
209.0 / 84
Po
(209) / 85
At
(210) / 86
Rn
(222)
7 / 87
Fr
(223) / 88
Ra
226.0 / 89
Ac
227.0 / 104
Rf
(261) / 105
Db
(262) / 106
Sg
(263) / 107
Bh
(262) / 108
Hs
(265) / 109
Mt
(266) / 110
Uun
(269) / 111
Uuu
(272) / 112
Uub
(277)
58
Ce
140.1 / 59
Pr
140.9 / 60
Nd
144.2 / 61
Pm
(145) / 62
Sm
150.4 / 63
Eu
152.0 / 64
Gd
157.2 / 65
Tb
158.9 / 66
Dy
162.5 / 67
Ho
164.9 / 68
Er
167.3 / 69
Tm
168.9 / 70
Yb
173.0 / 71
Lu
175.0
90
Th
232.0 / 91
Pa
231.0 / 92
U
238.0 / 93
Np
237.0 / 94
Pu
(244) / 95
Am
(243) / 96
Cm
(247) / 97
Bk
(247) / 98
Cf
(251) / 99
Es
(252) / 100
Fm
(257) / 101
Md
(258) / 102
No
(259) / 103
Lr
(260)