Chapter 9 Coordination Chemistry I: Structures and Isomers
123
CHAPTER 9: COORDINATION CHEMISTRY I: STRUCTURES AND ISOMERS 9.1
Hexagonal:
C2v
C2v
D2h
Hexagonal pyramidal:
Cs
Cs
C2v
Trigonal prismatic:
Cs
C2v
C2
Trigonal antiprismatic:
Cs
C2
C2h
The structures with C2 symmetry would be optically active. 9.2
a.
dicyanotetrakis(methylisocyano)iron(II) or dicyanotetrakis(methylisocyano)iron(0)
b.
rubidium tetrafluoroargentate(III) or rubidium tetrafluoroargentate(1–)
c. cis- and trans-carbonylchlorobis(triphenylphosphine)iridium(I) or cis- and transcarbon ylchlorobis(triphenylphospine)iridium(0)
9.3
d.
pentaammineazidocobalt(III) sulfate or pentaammineazidocobalt(2+) sulfate
e.
diamminesilver(I) tetrafluoroborate(III) or diamminesilver(1+) tetrafluoroborate(1–) – (The BF4 ion is commonly called “tetrafluoroborate.”)
a.
tris(oxalato)vanadate(III) or tris(oxalato)vanadate(3–)
b.
sodium tetrachloroaluminate(III) or sodium tetrachloroaluminate(1–)
c. carbonatobis(ethylenediamine)cobalt(III) chloride or carbonatobis(ethy lenediamine)cobalt(1+) chloride
9.4
d.
tris(2,2-bipyridine)nickel(II) nitrate or tris(2,2-bipyridine)nickel(2+) nitrate (The IUPAC name of the bidentate ligand, 2,2-bipyridyl may also be used; this ligand is most familiarly called “bipy.”)
e.
hexacarbonylmolybdenum(0) (also commonly called “molybdenum hexacarbonyl”). The (0) is often omitted.
a.
tetraamminecopper(II) or tetraamminecopper(2+)
b.
tetrachloroplatinate(II) or tetrachloroplatinate(2–)
c.
tris(dimethyldithiocarbamato)iron(III) or tris(dimethyldithiocarbamato)iron(0)
d.
hexacyanomanganate(II) or hexacyanomanganate(4–)
e.
nonahydridorhenate(VII) or nonahydridorhenate(2–) (This ion is commonly called “enneahydridorhenate.”)
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124 9.5
Chapter 9 Coordination Chemistry I: Structures and Isomers a.
triamminetrichloroplatinum(IV) or triamminetrichloroplatinum(1+)
b.
diamminediaquadichlorocobalt(III) or diamminediaquadichlorocobalt(1+)
c.
diamminediaquabromochlorocobalt(III) or diamminediaquabromochlorocobalt(1+)
d.
triaquabromochloroiodochromium(III) or triaquabromochloroiodochromium(0)
e. or
dichlorobis(ethylenediamine)platinum(IV) or dichlorobis(ethylenediamine)platinum(2+) dichlorobis(1,2-ethanediamine)platinum(IV) or dichlorobis(1,2ethanediamine)platinum(2+)
f. diamminedichloro(o-phenanthroline)chromium(III) or diamminedichloro(ophenanthroline)chro mium(1+) or diamminedichloro(1,10-phenanthroline)chromium(III) or diamminedichloro(1,10-phenanthroline)chromium(1+) g. or
bis(2,2-bipyridine)bromochloroplatinum(IV) or bis(2,2bypyridine)bromochloroplatinum(2+) bis(2,2-bipyridyl)bromochloroplatinum(IV) or bis(2,2bipyridyl)bromochloroplatinum(2+)
h. dibromo[o-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(II) or dibrom o[o-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(0) or dibrom o[1,2-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(II) or dibrom o[1,2-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(0) i. dibromochlorodiethylenetriaminerhenium(III) or dibrom ochlorodiethylenetriaminerhenium(0) or dibromochloro(2,2diam inodiethylamine)rhenium(III) or dibromochloro(2,2diam inodiethylamine)rhenium(0) 9.6
9.7
a.
dicarbonylbis(dimethyldithiocarbamato)ruthenium(III) or dicarbonylbis(dimethyldithiocarbamato)ruthenium(1+)
b.
trisoxalatocobaltate(III) or trisoxalatocobaltate(3–)
c.
tris(ethylenediamine)ruthenium(II) or tris(ethylenediamine)ruthenium(2+)
d.
bis(2,2-bipyridine)dichloronickel(II) or bis(2,2-bipyridine)dichloronickel(2+)
a.
Bis(en)Co(III)-µ-amido-µ-hydroxobis(en)Co(III)
N N
Co N
4+
N
N H2 N O H
Co
N N
N
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Chapter 9 Coordination Chemistry I: Structures and Isomers b.
125
Diaquadiiododinitritopalladium(IV) I ONO
H2O
Pd
H2O
ONO
ONO
ONO
H 2O
I
I
I OH2
ONO
OH2
H 2O
OH2 I
ONO I
I I
I
Pd
ONO
ONO
Pd
I
H 2O
I
Pd
I
Pd
ONO
OH2
ONO
ONO
OH2
Pd
ONO
OH2
H2O
enantiomers
c.
Fe(dtc)3
S S S
S
Fe
S
S
S
S
Fe
S S
S
S =
C
–
N
S S
S
CH3
H
S
At low temperature, restricted rotation about the C—N bond can lead to additional isomers as a consequence of the different substituents on the nitrogen. These isomers can be observed by NMR.
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126 9.8
Chapter 9 Coordination Chemistry I: Structures and Isomers a.
triammineaquadichlorocobalt(III) chloride +
H2O H3N H 3N
Co
Isomers are of the cation: +
Cl
Cl
H3N
NH3
H3N
Co
OH2
H2O
NH3
Cl
Co Cl
Cl
Cl
cis
trans mer
b.
H3N
O
Cr
NH3
H3N
4+
NH3
H3N H3N
H3N
c.
fac
-oxo-bis(pentammine-chromium(III)) ion
Cr NH3
NH3 NH3
potassium diaquabis(oxalato)manganate(III) –
O O H2O
Mn
O
O
O
O
H2O
Mn
Isomers are of the anion:
–
O
–
H2O
O
O
OH2
O
OH2
O
H2O
trans
Cl
a.
O
Mn
cis enantiomers
9.9
NH3
cis-diamminebromochloroplatinum(II)
Pt Br
NH3 I
b.
diaquadiiododinitritopalladium(IV)
H2O
Pt
ONO
ONO OH2
I
c.
tri--carbonylbis(tricarbonyliron(0))
O C
O O C C Fe OC
+
NH3
O C CO Fe
CC O O
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CO
NH3 NH3
Chapter 9 Coordination Chemistry I: Structures and Isomers O
9.10 C
CH2
O –
H2 N O N
= N
O
O
M
O
N
N
O
O
N
M
N
N
O
O
N
N
M
N
N
N
O
O
N
O
mer
M(AB)3 B A
B
M
B
A
A
B
B
A
M
A
A
B
B
A
A
M
A
A
A
B
B
A
B
mer
[Pt(NH3)3Cl3]+
a.
B
M
B
fac
9.12
O
M
O
fac
9.11
127
+
NH 3 Cl
Pt
Cl
+
Cl
NH3
H3N
NH3
Cl
NH3
Pt
NH3
Cl
Cl
fac
mer
[Co(NH3)2(H2O)2Cl2]+
b.
+
NH3 H 2O Cl
Co
+
Cl
NH3
H 2O
OH2
H 2O
Cl
Co
NH3
Cl
NH3
Cl
+
OH2
Cl
Co
Co
Cl
OH2
H2 O
NH3
H 3N
NH3
H3N
Cl
Co
Co NH3
+
H 2O OH2 Cl
Cl
enantiomers
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+
NH3
OH2
NH3
Cl
H 2O
+
NH3
OH2 Cl
128
Chapter 9 Coordination Chemistry I: Structures and Isomers [Co(NH3)2(H2O)2BrCl]+
c.
+
OH2 H 3N H 3N
Co
Br
H 2O
Cl
H 2O
Co
OH2
+
Br
Co
NH3
Br
NH3
Cl
Co
+
H 3N
NH3
H 3N
Cl
OH2
Cl
OH2
H2 O
H2 O
Co
Cl
Br
+ NH3
H3 N
NH3
H3N
+ OH2
Co
Cl
Br
enantiomers
d.
Br
H2O
Br
Cl
OH2
Co NH3
OH2
OH2
Co
+
NH3
NH3
H2O
NH3
+
NH3
Br
OH2 H 2O
+
Cl
enantiomers
Cr(H2O)3BrClI OH2 H2 O
H2O OH2
Cr
Cl
H2 O
I
OH2
Cr
I
Br
Cl
Br
enantiomers
Cl H2 O
Cr
OH2
I H 2O
Br
Cr
OH2
Cl
Br
H2 O
OH2
Cr
I
Br
Cl
I
e.
OH2
OH2
OH2
[Pt(en)2Cl2]2+ 2+
N N Cl
Pt
2+
N
N
N
N
N
Cl
Pt
N Cl
Cl
cis enantiomers
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2+
Cl N N
Pt Cl
trans
N N
Chapter 9 Coordination Chemistry I: Structures and Isomers [Cr(o-phen)(NH3)2Cl2]+
f.
+
N Cl
NH3
H 3N
NH3
H3N
N
N
Cr
N
trans NH3 ligands
2+ 2+
Br
2+
N
N
N
N
N
N
Pt
Cl
Cl
Cl
trans Cl ligands
[Pt(bipy)2BrCl]2+
Pt
H3N
NH3
NH3
Cr
NH3
enantiomers
N
N
Cl
Cr
Cl
Cl
Cl
Cl
N
N
N
Cr
+
+
+
N
g.
129
Br
Br
Cl
Cl
N
Pt
N N
N
enantiomers
h.
Re(arphos)2Br2
Abbreviating the bidentate ligands As P :
Br P As
Re
Br P
P
As
As
Re
Br
Br
Re
As
Br
P
Br
Br
P
P
P
P
Re
Re
P As
As
As
As
P
As
As Br
P
Br
Br
Br
Br
P
As
As
Re
As
As
P
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Re
P As
P As
Re P
Br Br
Br Br
130
Chapter 9 Coordination Chemistry I: Structures and Isomers i.
Re(dien)Br2Cl Cl N
Re
N
Br
Cl Br
Br
Br
Br
Re
N
N
N
N
N
Br
N
Cl
Re
Cl
N
N
N
Br
Re
Br
9.13
Br
N
N
N
Cl
Re
N
Br
a. M(ABA)(CDC) C A
A
M
B
D
C
A
D
B
M
C
B
C
A
D
C
B
M
A
A
A
A
M
C
C
b. M(ABA)(CDE) C A B
M
D
C
A
D
E
C D
C D
A
A M
B
B
A
A
M
E
E
B
B
M
A
A
A
A
M
E
E
A
A
M E
A
A
B
B
M E
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C D
C D
C D
C D
Chapter 9 Coordination Chemistry I: Structures and Isomers
131
9.14 A
A C B
M
B
A
C
B
M
B
A B
9.15
B
C
C
M
B
B
C
C
A B
C
A
A M
B
C
A
A
A
C
M
A
A
B
B
C
M
A
A
B
B
M
C
C
C
C
B
B
B
B
M
C
C
A
B
M
A
A
B
B
M
C
C
A
A
C
C
M
C
A B
A B
C
a. The “softer” phosphorus atom bonds preferentially to the soft metal Pd (see Section 6.6.1). b, c. Abbreviating the bidentate ligands N P : Cl P N
Ni
Cl P
P
N
N
Ni
Cl
Cl
Ni
N
Cl
P
Cl
Cl
N Cl
P
P
P
P
Ni
N
N
N
N
P
N P
Ni
P
Cl
Cl
Cl
Cl
Ni
P
N
N
Ni
N
N
P
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P
P
N
N
Ni P
Cl Cl
Cl Cl
132
9.16
Chapter 9 Coordination Chemistry I: Structures and Isomers
a, b.
Abbreviating the bidentate ligands N P and O S : Cl S O
N Cl Cl
M
P
P
O
O
Cl
P
S
N
O
M
Cl
Cl
N
P
M
Cl
Cl
Cl
Cl
M
N P
P N
N
O
O
M
S
S
N
N
P
P
S
Cl
M
Cl
M
P
P
S
S
M
S
Cl
Cl
Cl
Cl
M
N
N
S
S
M
O
O
O
O
Cl Cl
Cl Cl
–
N
9.17
The single C–N stretching frequency indicates a trans structure for the cyanides (the symmetric stretch of the C—N bonds is not IR active), while the two C–O bonds indicate a cis structure for the carbonyls (both the symmetric and antisymmetric C–O stretches are IR active). As a result, the bromo ligands are also cis.
C O
C Br
Co C N
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O
C Br
Chapter 9 Coordination Chemistry I: Structures and Isomers 9.18
There are 18 isomers overall, six with the chelating ligand in a mer geometry and 12 with the chelating ligand in a fac geometry. All are enantiomers. They are all shown below, with dashed lines separating the enantiomers. N P
M
As
P
P
Br
Br
OH2
H2O
N
N P
M
P
As
M
As
Br
Br
NH3
H 3N
N P
M
N
N
N
N
N
OH2 Br
H2O
P
M
Br
P
As
As
H3 N
NH3
M
Br
Br
P
M
As
H 2O
NH3
H3N
M
OH2
Br
Br
NH3
NH3
OH2
OH2
NH3
NH3
N OH2
N
P
M
H2O
P
As
Br
N
N
M
As
1. Mo
O
2.
O
S
Mo
OH2
Cs
S Mo
S
O
S Mo
O
Mo
Cr W
Mo
Mo
O Cr
C1
O
Se
C1
O S
O
Mo
S
S
Mo
O
W
Cr W
Se
C1
O Mo
Cr W
S
Se
Se
O
Mo
C1
O O
W
Mo
Cr
C1
Se
W
Cs
C1
S
O
O
W
Mo
Mo
Mo
O
Cr Se
O
Mo
S
Mo
Mo
Mo
Se Cr
O Se
O W
C1
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O
Mo Cr
W
C1
M OH2
S Mo
W
N Br
O W
Mo
Mo
3.
Mo
O
N Br
Mo
O
O
M
As
O
Cs C3v
S
S Mo
W
d.
Mo
O
Mo
c.
P
As
Br
Br
b.
P
M
H3N
NH3
a, b.
As
OH2
OH2
9.22
M
NH3
20b 20c top ring: , bottom ring:
P
NH3
9.21
M
N
All are chiral if the ring in b does not switch conformations.
H2 O
Br
9.20
H3N
Br
a.
NH 3 OH2
OH2
9.19
M
As
OH2
Br
P
As
N
NH3
M
As
N
NH3
M
As
133
S
P As
P As
P As
134
Chapter 9 Coordination Chemistry I: Structures and Isomers
S Mo
Mo Mo
Cr
9.23
S
Se O
Mo Se
W
W O O Cs Cs
O
c.
Yes, provided the structure has no symmetry or only Cn axes. Examples are the structures with C1 symmetry in part a.
Cr
The 19F doublet is from the two axial fluorines (split by the equatorial fluorine). The 19F triplet is from the equatorial fluorine (split by the two axial fluorines). The two doubly bonded oxygens are equatorial, as expected from VSEPR considerations. Point group: C2v
9.24
+
F O O
Os
F
F
Examples include both cations and anions: –
–
–
–
–
[Cu(CN)2] , [Cu2(CN)3] , [Cu3(CN)4] , [Cu4(CN)5] , [Cu5(CN)6]
[Cu2(CN)]+, [Cu3(CN)2]+, [Cu4(CN)3]+, [Cu5(CN)4]+, [Cu6(CN)5]+ Based primarily on calculations (rather than experimental data), Dance et al. proposed linear structures such as the following: –
[Cu(CN)2] :
NC—Cu—CN
–
NC—Cu—CN—Cu—CN
–
NC—Cu—CN—Cu—CN—Cu—CN
[Cu2(CN)3] : [Cu3(CN)4] : +
[Cu2(CN)] :
Cu—CN—Cu
+
Cu—CN—Cu—CN—Cu
+
Cu—CN—Cu—NC—Cu—CN—Cu
[Cu3(CN)2] : [Cu4(CN)3] :
Where 2-coordinate copper appears in these ions, the geometry around the Cu is linear, as expected from VSEPR. 9.25
The bulky mesityl groups cause sufficient crowding that the phosphine ligands can show HC chirality (C3 symmetry) and can be considered as similar to left-handed (PL) and right-handed (PR) propellers. If two P(mesityl)3 phosphines are attached in a linear arrangement to a gold atom, three isomers are possible: 3
PL—Au—PL
PR—Au—PR
PL—Au—PR
H 3C
mesityl
(PR—Au—PL is equivalent to PL—Au—PR, as can best be seen with models.) NMR data at low temperature support the presence of these isomers, which interconvert at higher temperatures.
Copyright © 2014 Pearson Education, Inc.
CH3
Chapter 9 Coordination Chemistry I: Structures and Isomers 9.26
The point group is D3h. A representation based on the nine 1s orbitals of the hydride ligands is: D3h A1 E A2 E
E 9 1 2 1 2
2C3 0 1 –1 1 –1
3C2 1 1 0 –1 0
2S3 0 1 –1 –1 1
h 3 1 2 –1 –2
3v 3 0 0 1 0
Re
z2 (x, y), (x2–y2, xy) z (xz, yz)
135
= H
The representation reduces to 2 A1 + 2 E + A2 + ECollectively these representations match all the functions for s (totally symmetric, matching A1), p, and d orbitals of Re, so all the s, p, and d orbitals of the metal have suitable symmetry for interaction. (The strength of these interactions will also depend on the match in energies between the rhenium orbitals and the 1s orbital of hydrogen.) 9.27 NN
NN
NN
O Cr O
O Cr O
O Cr O
O Mn O O O
OO
OO
OO
OO
O Mn O O O O O
OO
OO
OO O Mn O O O O O
O O Mn O
OO
O
O Cr O
O Cr O
O Cr O
NN
NN
NN
9.28
N
N N
N N O O
O O
N
N
N
N
N
O
N
N N
Co O O
N Co
N
O O
Co O
O O N
N
N
N N O O N
Co
N O
O O
N
N
O
O O N
N
N
N
N
N
Co O O
N
N Co
O O N
N
N
N
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136 9.29
9.30
Chapter 9 Coordination Chemistry I: Structures and Isomers a.
Cu(acacCN)2: D2h
b.
C6
tpt: C2v
All four metal-organic frameworks studied (MOF-177, Co(BDP), Cu-BTTri, Mg 2 (dobdc) ) are significantly more effective at adsorbing carbon dioxide relative to adsorbing hydrogen. This is attributed, in part, to the higher polarizability of CO 2 relative to that of H 2 . The formation of an induced dipole in these gases by exposed cations within MOFs is an important prerequisite for adsorption. The two MOF properties that most strongly correlate with CO 2 adsorption capacity are MOF surface area and MOF accessible pore volume. As these values (tabulated below) increase, the CO 2 adsorption capacity increases. MOF
Surface Area ( m2 g )
Accessible Pore Volume ( cm3 g )
MOF-177
4690
1.59
Co(BDP)
2030
0.93
Cu-BTTri
1750
0.713
Mg 2 (dobdc)
1800
0.573
The graphs in Figure 1 of the reference clearly indicate that Mg 2 (dobdc) adsorbs the most CO 2 at 5 bar. The arrangement and concentration of open Mg 2+ cation sites on the Mg 2 (dobdc)
surface is hypothesized to render this MOF more susceptible to CO 2 adsorption. This MOF, along with Cu-BTTri, which also features exposed metal sites, are identified as the best prospects for CO 2 H 2 separation. 9.31
The synthesis and application of amine-functionalized MOFs for CO 2 adsorption is the general
topic of the reference. While the M 2 (dobdc) series of MOFs were proposed as excellent candidates for this functionalization (on the basis of their relatively large concentration of exposed metal cation sites), their amine-functionalization proved difficult. This was attributed to the relatively narrow MOF channels that may hinder amine diffusion into M 2 (dobdc) .
One hypothesized solution was to prepare a MOF with the M 2 (dobdc) structure-type, but with larger pores. The wider linker dobpdc (below, along with dobdc for comparison) was used in the hope of obtaining MOFs with larger pores. O
O O
O
O O
O
O O
O
O
O dobdc
dobpdc
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Chapter 9 Coordination Chemistry I: Structures and Isomers
137
Amine-functionalized Mg 2 (dobpdc) was prepared by mixing H 4 (dobpdc) , magnesium bromide, and a small solvent volume (a mixture of N,N’-diethylformamide and ethanol) in a Pyrex container. The mixture was heated in a microwave reactor, and the M 2 (dobpdc) collected by
filtration after cooling. Dried samples of Mg 2 (dobpdc) were then heated for roughly one hour at
420 °C under dynamic vacuum. After this “activation” step, Mg 2 (dobpdc) was stirred with an excess of N,N’-dimethylethylenediamine (mmen) in hexanes for one day. Subsequent heating under vacuum resulted in removal of residual solvents to afford mmen-functionalized Mg 2 (dobpdc) . The “activation” step was found necessary to completely remove residual N,N’diethylformamide from the Mg 2+ coordination sites. 9.32
This reference discusses application of porphyrin-containing MOFs where the porphyrin provides a binding site for Fe(III) and Cu(II). The precursor to the porphyrin linker (TCPP) is provided below; the resulting carboxylates of this linker permit its incorporation into the MOF. HOOC
COOH
N H N
N H N
HOOC
COOH
The metallation options include premetallation and postmetallation. In premetallation, H 4 -TCPP-Cu and H 4 -TCPP-FeCl , respectively, are used as reactants for the MOF synthesis. In this case, the porphyrin linker and its bound metal ion are installed simultaneously into the MOF. This general approach afforded MOF-525-Cu, MOF-545-Fe, and MOF-545-Cu. MOF-525-Fe could not be obtained via this strategy. For this MOF, postmetallation was employed, via the reaction of MOF-525 with Fe(III) chloride; Fe(III) ions were introduced into the MOF-525 porphyrin linkers via this method. In terms of similarities and differences, MOF-545 can be metallated with both Fe(III) and Cu(II) via a premetallation strategy, while MOF-525 requires alternate procedures for incorporation of Cu(II) (premetallation) and Fe(III) (postmetallation), respectively.
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