Unless otherwise stated, all images in this file have been reproduced from:

Blackman, Bottle, Schmid, Mocerino and Wille,     Chemistry, 2007 (John Wiley)

     ISBN: 9 78047081 0866

Slide 2/23

e CHEM1002 [Part 3]

Dr Michela SimoneLecturer

BSc (I Hons), MSc, D.Phil. (Oxon), MRSC, MRACI

Weeks 8 – 13

Office Hours: Monday 3-5, Friday 4-5Room: 412A (or 416)

Phone: 93512830e-mail: michela.simone@sydney.edu.au

Slide 3/23

e

Complexes III

• Transition metal atoms of the first transition series have electron configuration [Ar]4sx3dy where x + y is the group number

• For the cations, the electronic configuration is [Ar]3dz where z = group number – oxidation number

• These electrons occupy the ten d-orbitals and, if this leads to unpaired electrons, the complex is paramagnetic

• Complexes in which the 3d orbitals are not empty, half full or full are coloured due to excitations of the electrons

Summary of Last Lecture

Slide 4/23

e

Lecture 15• Metals in Biological Processes• Essential Elements• Toxic Elements• Medicinal Uses• Blackman Chapter 13

Lecture 16• Chemical Kinetics• Rate of Reaction• Rate Laws• Reaction Order• Blackman Chapter 14, Sections 14.1 - 14.3

Complexes IV

Slide 5/23

e The Biological Periodic Table

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

1HYDROGEN

H1.008

2HELIUM

He4.003

3LITHIUM

Li6.941

4BERYLLIUM

Be9.012

5BORON

B10.81

6CARBON

C12.01

7NITROGEN

N14.01

8OXYGEN

O16.00

9FLUORINE

F19.00

10NEON

Ne20.18

11SODIUM

Na22.99

12MAGNESIUM

Mg24.31

13ALUMINIUM

Al26.98

14SILICON

Si28.09

15PHOSPHORUS

P30.97

16SULFUR

S32.07

17CHLORINE

Cl35.45

18ARGON

Ar39.95

19POTASSIUM

K39.10

20CALCIUM

Ca40.08

21SCANDIUM

Sc44.96

22TITANIUM

Ti47.88

23VANADIUM

V50.94

24CHROMIUM

Cr52.00

25MANGANESE

Mn54.94

26IRON

Fe55.85

27COBALT

Co58.93

28NICKEL

Ni58.69

29COPPER

Cu63.55

30ZINC

Zn65.39

31GALLIUM

Ga69.72

32GERMANIUM

Ge72.59

33ARSENIC

As74.92

34SELENIUM

Se78.96

35BROMINE

Br79.90

36KRYPTON

Kr83.80

37RUBIDIUM

Rb85.47

38STRONTIUM

Sr87.62

39YTTRIUM

Y88.91

40ZIRCONIUM

Zr91.22

41NIOBIUM

Nb92.91

42MOLYBDENUM

Mo95.94

43TECHNETIUM

Tc[98.91]

44RUTHENIUM

Ru101.07

45RHODIUM

Rh102.91

46PALLADIUM

Pd106.4

47SILVER

Ag107.87

48CADMIUM

Cd112.40

49INDIUM

In114.82

50TIN

Sn118.69

51ANTIMONY

Sb121.75

52TELLURIUM

Te127.60

53IODINE

I126.90

54XENON

Xe131.30

55CAESIUM

Cs132.91

56BARIUM

Ba137.34

57-71 72HAFNIUM

Hf178.49

73TANTALUM

Ta180.95

74TUNGSTEN

W183.85

75RHENIUM

Re186.2

76OSMIUM

Os190.2

77IRIDIUM

Ir192.22

78PLATINUM

Pt195.09

79GOLD

Au196.97

80MERCURY

Hg200.59

81THALLIUM

Tl204.37

82LEAD

Pb207.2

83BISMUTH

Bi208.98

84POLONIUM

Po[210.0]

85ASTATINE

At[210.0]

86RADON

Rn[222.0]

87FRANCIUM

Fr[223.0]

88RADIUM

Ra[226.0]

89-103 104RUTHERFORDIUM

Rf[261]

105DUBNIUM

Db[262]

106SEABORGIUM

Sg[266]

107BOHRIUM

Bh[262]

108HASSIUM

Hs[265]

109MEITNERIUM

Mt[266]

LANTHANIDES

57LANTHANUM

La138.91

58CERIUM

Ce140.12

59PRASEODYMIUM

Pr140.91

60NEODYMIUM

Nd144.24

61PROMETHIUM

P.m.[144.9]

62SAMARIUM

Sm150.4

63EUROPIUM

Eu151.96

64GADOLINIUM

Gd157.25

65TERBIUM

Tb158.93

66DYSPROSIUM

Dy162.50

67HOLMIUM

Ho164.93

68ERBIUM

Er167.26

69THULIUM

Tm168.93

70YTTERBIUM

Yb173.04

71LUTETIUM

Lu174.97

ACTINIDES

89ACTINIUM

Ac[227.0]

90THORIUM

Th232.04

91PROTACTINIUM

Pa[231.0]

92URANIUM

U238.03

93NEPTUNIUM

Np[237.0]

94PLUTONIUM

Pu[239.1]

95AMERICIUM

Am[243.1]

96CURIUM

Cm[247.1]

97BERKELLIUM

Bk[247.1]

98CALIFORNIUM

Cf[252.1]

99EINSTEINIUM

Es[252.1]

100FERMIUM

Fm[257.1]

101MENDELEVIUM

Md[256.1]

102NOBELIUM

No[259.1]

103LAWRENCIUM

Lr[260.1]

essential toxic archaeamedicinal

Slide 6/23

e Metal Ions in Biology

• Metal ions in biology fall into three groups:

Essential elements e.g. Na+, K+, Mg2+, Ca2+, Fe2+/3+, Cu+/2+, Zn2+

Toxic elements e.g. Pb2+, Hg2+, Be2+

Elements used in medicine e.g. Li+, Pt2+

Slide 7/23

eNa+ K+ Mg2+ Ca2+

Ionic radius, Å 1.16 1.52 0.86 1.14

Charge/radius ratio 0.86 0.66 2.32 1.75

Coordination number 6 6-8 6 6-8

Preferred donors O O N,O O

Concentration (mmol/kg)

Intracellular 11 92 2.5 0.1

Extracellular 152 5 1.5 2.5

Seawater 460 10 52 10

Essential Elements

Slide 8/23

e Essential Elements - Na+ and K+

Na+, K+ pump

Outer membrane

Inner membrane(inside of the cell)

• Maintaining the Na+ and K+ concentrations requires a pumping system and a lot of energy (ATPase)

Slide 9/23

e Iron – Oxygen Transport/Storage

O

Fe

O

protein

• Oxygen binds reversibly to the free coordination site of Fe

• Square planar coordination of Fe by porphyrin ligand

Slide 10/23

e O2 Transport Complexes

• In humans, transport system (haemoglobin) and storage system (myoglobin) are both Fe(II) complexes:

myoglobin

haemoglobin

muscle lungs

affinity of myoglobin > affinity of haemoglobin

affinity of haemoglobin increases as O2 pressure grows – cooperative effect

Slide 11/23

e Haemoglobin and Myoglobin - Structures

• Haemoglobin consists of 4 haem groups, myoglobin consists of 1 haem group:

N

N N

N

Fe2+ Fe2+

HN

N

HN

N

proximal histidine residue

distal histidine residue

Slide 12/23

e Haemoglobin and Myoglobin - Function

Fe3+

HN

N

HN

N

proximal histidine residue

distal histidine residue

OO

weak H-bond?

Fe2+

HN

N

HN

N

proximal histidine residue

distal histidine residue

CO

enforcedbending

partial prevention of (irreversible) CO attachment

Slide 13/23

e

HN

N

Fe3+ NN

• Unoxygenated protein contain Fe(II) d6:

• Ion has is too large to fit in haemring and actually sits slightly below it

• Oxygenated protein contains smallerFe(III) d5 which fits into ring

Haemoglobin – Cooperative Effect

proximal histidine residue

OO

Fe2+NN

Fe3+ NN

• The motion of the proximal group is transferred through protein structure to the next deoxygenated haem group decreasing its activation energy for O2 attachment

HN

N

Fe2+NN

Slide 14/23

e Carbonic Anhydrase• Zn2+-OH2 is acidic:

N3Zn-OH2 N3Zn-OH + H+

• Metal is bonded to "OH-" which is a good nucleophile

• Binds CO2 reversibly for transfer from muscles to lungs CO2 + OH- CO3

2-

Slide 15/23

e Trace and Toxic Elements

Health

Concentration

Dead

Well

Essential Trace Element

• Lack or shortage of a trace element is damaging to health, as is an excess.

• Low concentrations of toxic metals may be tolerated but at even moderate concentrations they damage health.

Slide 16/23

e

Ca5(PO4)3(OH)(s)

• Pb2+ has approximately the same size and charge as Ca2+ - it can substitute for Ca in biological systems especially bone and teeth.

• Many poisons act due to have the same size/charge ratio as an essential molecule/ion

remove as [Pb(EDTA)]2-

Lead in the Body

PbCa4(PO4)3(OH)(s)

Slide 17/23

e Pt Anti-Cancer Drugs

Slide 18/23

e Two mice with solid Sarcoma-180 tumors

Untreateddied day 21tumor 3 g.

Bottom mouse treated with cis-[PtCl2(NH3)2] on day 8. Tumor completely regressed by day 14. Died of old age 3 years later.

Slide 19/23

e Pt Anti-Cancer Drugs

cis-diamminedichloroplatinum very active

Pt

Cl

NH3

H3N

Cl

PtClH3NClH3N

• All Pt(II) complexes are square planar

trans-diamminedichloroplatinum inactive

Slide 20/23

e Pt Anti-Cancer Drugs

• cis-Pt(NH3)2 bonds to two N-bases in the DNA• causes DNa helix to "kink" preventing it from replicating

• trans-Pt(NH3)2 cannot bind to DNA

Slide 21/23

e Summary: Biological Periodic Table

Learning Outcomes - you should now be able to:

• Identify essential, toxic and medicinal elements• Explain functioning of metals in body• Relate medicinal uses to function of element• Think about consequences for drug design (for

example: why cis-PtCl2(NH3)2 is active but trans form is not)

Next lecture:

• Reaction kinetics

x

Desferal is taken over 8-12 hour periods up to six times per week.A value of logK = 30.6 is associated with the following equilibrium:

Fe3+ + LH3+ FeL+ + 3H+ where LH3

+ = Desferal

Practice Examples

H3N

N

HN

OH

O

O

N

O

NH

HO

O

NHO

O

Desferal

1. Hemochromatosis or “iron overload” is a potentially fatal disorder in which excess iron is deposited in the bodily organs as insoluble hydrated iron(III) oxide. It can be treated by administration of desferioxamine B (Desferal), a natural substance isolated from fungi.

Briefly describe the chemical basis for the use of Desferal in iron overload therapy.

Slide 23/23

x Practice Examples

2. Compounds of d-block elements are frequently paramagnetic. Using the box notation to represent atomic orbitals, account for this property in compounds of Ni2+.

3. Complete the following table.

Formula O.N. CN 3dn Species in water

K3[FeF6]

[Cr(NH3)5(OH2)]Cl3

[Zn(en)Cl2]

en = ethylenediamine = NH2CH2CH2NH2