Coordination Chemistry Flashcards
1
Q
Transition metals
A
- found in nature
- Rocks and Minerals
- Gem stone colour
- Biomolecules
2
Q
Rubies are — due to —
A
red; Cr
3
Q
Sapphire are — due to presences of — & —
A
blue; Fe; Ti
4
Q
Many biomolecules contain transition metals that are involved in the functions of these biomolecules
A
- Vitamin B12 contains Co
- Hemoglobin, myoglobin, and cytochrome C contain Fe
5
Q
useful applications for Transition metals and their compounds
A
- Fe -> used to make steel & stainless steel
- Ti -> used to make lightweight alloys
- used as pigments
- Used in many industrial processes
6
Q
TiO2 pigment
A
White
7
Q
PbCrO4 pigment
A
yellow
8
Q
Fe4[Fe(CN)6]3
A
Prussians blue = blue
9
Q
e- in partially filled d sublevel
A
absorbs visible light
moves to slightly higher energy d orbital
10
Q
Properties of transition metals
A
- Has metallic properties
- Not as reactive as Grp. 1A, 2A metals
- Has high MP’s, high BP’s, high density, are hard and strong
- Has 1 or 2 s electrons in valence shell
- Differ in # d electrons in n-1 energy level
- Exhibit multiple oxidation states
11
Q
[Ar]3d14s2
A
Sc
12
Q
[Ar]3d24s2
A
Ti
13
Q
[Ar]3d34s2
A
V
14
Q
[Ar]3d54s1
A
Cr
15
Q
[Ar]3d54s2
A
Mn
16
Q
[Ar] 3d64s2
A
Fe
17
Q
[Ar] 3d74s2
A
Co
18
Q
[Ar] 3d84s2
A
Ni
19
Q
[Ar]3d104s1
A
Cu
20
Q
[Ar]3d104s2
A
Zn
21
Q
Characteristics due to d electrons
A
- Exhibit multiple oxidation states
- Compounds typically have color
- Exhibit interesting magnetic properties {paramagnetism
and ferromagnetism}
22
Q
Transition metals act as —- acids
A
Lewis
23
Q
Form complexes/complex ions
A
{lewis acid} Fe3+(aq) + {lewis base} 6CN-(aq) → {complex ion} Fe(CN)63-(aq)
24
Q
{lewis acid} Ni2+(aq) + {lewis base} 6NH3(aq) →
A
Ni(NH3)62+(aq) {complex ion}
25
Complex contains
central metal ion bonded to one or more molecules or anions
Lewis acid = metal = center of coordination
Lewis base = ligand = molecules/ions covalently bonded to metal in complex
26
Complex with a net charge =
Complex ion
27
Complexes have ----- properties
distinct
28
Coordination compound
Compound that contains 1 or more complexes
29
Coordination compound examples
[Co(NH3)6]Cl3
[Cu(NH3)4][PtCl4]
[Pt(NH3)2Cl2]
30
Coordination sphere
Metal and ligands bound to it
31
Coordination number
number of donor atoms bonded to the central metal atom or ion in the complex
Most common = 4, 6
Determined by ligands
Larger ligands and those that transfer substantial negative charge to metal favor lower coordination numbers
32
Coordination Compound consists of
complex ion and necessary counter ions
33
Complex ion: [Co(NH3)5Cl]2+
Counter ions: 2 Cl-
34
with the knowledge of the charge on a complex ion and the charge on each ligand, one can determine
the oxidation number for the metal.
35
With knowledge of the oxidation number on the metal and the charges on the ligands
one can calculate the charge on the complex ion.
36
Complex ion
Species where transition metal ion is surrounded by a certain number of ligands
37
Transition metal ion are
Lewis Acid
38
Ligands are
Lewis bases
39
Ligands
Molecule or ion having a lone electron pair that can be used to form a bond to a metal ion
(Lewis base)
consists of;
- Coordinate covalent bond
- Monodentate
- Bidentate
- Polydentate
40
coordinate covalent bond
metal-ligand bond
41
monodentate
one bond to metal ion
42
bidentate
two bond to metal ion
43
polydentate
more than two bonds to a metal ion possible
44
Complex charge =
sum of charges on the metal and the ligands
45
Neutral charge of coordination compound =
sum of charges on metal, ligands, and counterbalancing ions
46
[Co(NH3)6]Cl2
neutral compound
47
Ligands are classified according to;
the number of donor atoms
48
Chelating agents
Bidentate - Polydentate
2 or more donor atom
49
Monodentate
1 donor atom
Examples:
H2O, CN-, NH3, NO2-, SCN-, OH-, X- (halides), CO, O2-
Example Complexes
[Co(NH3)6]3+
[Fe(SCN)6]3-
50
Bidentate
2 donor atom
Examples
oxalate ion = C2O42-
ethylenediamine (en) = NH2CH2CH2NH2
ortho-phenanthroline (o-phen)
Example Complexes
[Co(en)3]3+
[Cr(C2O4)3]3-
[Fe(NH3)4(o-phen)]3+
51
Hexadentate
6 donor atoms
ethylenediaminetetraacetate (EDTA) = (O2CCH2)2N(CH2)2N(CH2CO2)24-
Example Complexes
[Fe(EDTA)]-1
[Co(EDTA)]-1
52
Common geometries of complex
- Linear
- Tetrahedral
- Square planar
- Octahedral
53
Coordination # 2
Example: [Ag(NH3)2]+
Linear
54
Coordination # 4
Examples: [Zn(NH3)4]2+, [FeCl4]-
tetrahedral
55
characteristic of metal ions with 8 d e-’s
Example: [Ni(CN)4]2-
Square planar
56
Coordination # 6
Examples: [Co(CN)6]3-, [Fe(en)3]3+
Octahedral
57
Myoglobin
a protein that stores O2 in cells
58
Nomenclature of Coordination Compounds: IUPAC Rules
- The cation is named before the anion
1. When naming a complex:
Ligands are named first
- alphabetical order
2. Metal atom/ion is named last
- oxidation state given in Roman numerals follows in parentheses
3. Use no spaces in complex name
4. The names of anionic ligands end with the suffix -o
-ide suffix changed to -o
-ite suffix changed to -ito
-ate suffix changed to -ato
59
bromide, Br-
bromo
60
chloride, Cl-
chloro
61
cyanide, CN-
cyano
62
hydroxide, OH-
hydroxo
63
63
63
64
65
oxide, O2-
oxo
65
fluoride, F-
fluoro
65
oxalate, C2O42-
oxalato
65
sulfate, SO42-
sulfato
65
carbonate, CO32-
carbonato
65
Sulfite, SO32-
sulfito
65
thiocyanate, SCN-
thiocyanato
66
thiosulfate, S2O32-
thiosulfato
67
Neutral ligands
referred to by the usual name for the molecule
Example
ethylenediamine
Exceptions
- water, H2O = aqua
- ammonia, NH3 = ammine
- carbon monoxide, CO = carbonyl
68
Greek prefixes
used to indicate the number of each type of ligand when more than one is present in the complex
di-, 2; tri-, 3; tetra-, 4; penta-, 5; hexa-, 6
69
If the ligand name already contains a Greek prefix, use ---
alternate prefixes:
bis-, 2; tris-, 3; tetrakis-,4; pentakis-, 5; hexakis-, 6
The name of the ligand is placed in parentheses
70
If a complex is an anion
its name ends with the -ate
appended to name of the metal
71
the name of the cation
appears first
72
The anion
is named last
73
Ligands are listed
alphabetically before the metal
74
Prefixes denotes he number of a particular ligand are
ignored when alphabetizing.
75
The names of anionic ligands end
"o"
76
the endings of the names of neutral ligands are
Not charged
77
Prefixes
tells the number of a type of ligand in the complex.
78
If the name of the ligand itself has a prefix
alternatives like bis-, tris-, etc., are used.
79
If the complex is an anion
its ending is changed to -ate
80
The oxidation number of the metal
listed as a Roman numeral in parentheses immediately after the name of the metal.
81
Naming of Coordination Compounds
1. Cation then anion
2. Ligands
- in alphabetical order before metal ion
- neutral: molecule name*
- anionic: -ide → -o
prefix indicates number of each
3. Oxidation state of metal ion in () only if more than one possible
4. If complex ion = anion, metal ending → -ate
82
K2[Co(NH3)2Cl4]
potassium diamminetetrachlorocobaltate(II)
83
[Co(NH3)4Cl2]Cl
tetraamminedichlorocobalt(III) chloride
84
