Transcript LAndmark discoveries p block 2014 july 22

CYL 503: Chemistry of the main group
elements and solids
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Shapes of molecules, symmetry and group theory
Hypervalency and d orbital participation
Space groups
Boron group
Carbon group
http://chemistry.iitd.ac.in/faculty/elias.html
Nitrogen group
Oxygen group
Instructor: Prof. Anil J. Elias
Halogen group
Room: MS 733: IIG1
Rare gases
Evaluation and material
• One quiz on revision of fundamentals (5marks)
10 questions from http://web.iitd.ac.in/~elias/ProblemsinPblock.html
• Minor 1 (25 Marks) (check iitd website for dates)
• MInor2 ( 25 Marks)
• Major ( 45 Marks)
Material: What the instructor teaches!
Lecture Notes/powerpoint slides will be provided from
time to time
Books:
Inorganic chemistry: Huheey, keiter and keiter
Inorganic Chemistry: Housecroft and Sykes
Your duty: Attend Classes and be punctual (8.00.00 AM)
IIT Delhi 2014
Landmark discoveries in the chemistry of
p block Elements
An introductory lecture presentation to main group
chemistry
Instructor: Prof. Anil J. Elias,
Room: MS 733: IIG1
3000 BC
Dancing Girl
a bronze
statuette
dating around
2500 BC, from
the Mohenjodaro site
Zebu Bull from Mohenjo-Daro and Harappa
Pure tin candlestick
Bronze, an alloy of tin and copper was the first alloy to be used around 3000 BC.
After 600 BC pure metallic tin was produced.
~1570 BC
Tyrian purple, a reddish purple organobromine natural dye was used by ancient
Phoenicians. The dye was produced from the secretions of a species of sea snails in the
family, Muricidae. The chemical component (main ingredient: 6, 6’- dibromoindigo) was
discovered in 1909 by Paul Friedlaender.
~800 BC
The three philosophical principles of alchemy:
salt, sulfur and mercury
“Bring sulfur, old nurse, that cleanses all
pollution, and bring me fire that I may purify
the house with sulfur”
Homers’ Odyssey
Fumigating power of sulfur mentioned by Homer. Sulfur is also
mentioned in the Bible as brimstone.
940 AD
Sulfuric acid and alcohol first prepared by the
physician, alchemist and writer from Bagdad, Abu Bekr
Zakariya Razi (Rhazes)
In 1746 in Birmingham, England, John Roebuck began
producing sulfuric acid in lead-lined chambers, which were stronger,
less expensive, and could be made much larger than
the glass containers which had been used previously.
1250
Albertus Magnus, a catholic saint (Albert the Great, 1193–1280) is
believed to have been the first to isolate arsenic by heating soap
together with arsenic trisulfide (orpiment As2S3 along with realgar, As4S4).
1669
The Alchemist Discovering Phosphorus : a painting by Joseph Wright
Hennig Brandt discovers phosphorus from reductive distillation of urine concentrate
by evaporating urine to dryness and distilling the residue with sand.
1694
Boyle rejects the
Aristotelian theory of the
four elements (earth, air,
fire, and water) and also
the three principles (salt,
sulfur, and mercury)
proposed by Paracelsus.
Robert Boyle makes P4O10 by oxidation of yellow phosphorus
and H3PO4 by hydrolysis of P4O10.
1772
J. J. Becher proposed
the phlogiston theory
phlogiston theory is an obsolete scientific theory that
postulated a fire-like element called phlogiston,
contained within combustible bodies, that is released
during combustion.
Daniel Rutherford isolates N2 gas after he removed oxygen and carbon dioxide from
the air mixture. He named the isolated gas as noxious air or phlogisticated air and
believed it was exhaled by the mouse which he used in the experiment to remove
oxygen by breathing.
1772
Scheele isolates oxygen gas by heating manganese dioxide (and later potassium nitrate
and mercuric oxide) but did not publish his findings immediately.
It was also independently discovered by Joseph Priestly by heating and decomposing
mercuric oxide in 1774.
1774, 1777
dephlogisticated
muriatic acid air
Carl Wilhelm Scheele
Schwefelluft”
Carl Wilhelm Scheele discovers chlorine gas from HCl in 1774. He discovered
hydrogen sulphide gas when he treated ferrous sulfide or pyrite (fool’s gold)
with a mineral acid, which released a gas with the smell of rotten eggs. He
referred to this gas as stinkede (stinking) and called it “Schwefelluft” meaning
sulfur air.
1808
Gay Lussac
Red phosphorus
Thenard
Gay Lussac and Thenard discovers PCl3 and also PCl5 by passing a slow
current of chlorine over heated red phosphorus.
1811
Nitrogen compounds as explosives
Dulong
Pierre Louis Dulong prepares nitrogen trichloride, NCl3 and looses two
fingers and an eye in two explosions. An NCl3 explosion also blinded
Humphry Davy (famous for Davies Safety lamp) triggering him to hire
Michael Faraday as a co-worker.
1824
Silicon: a versatile element with myriad aplications
Silicon discovered by Berzelius
fluorosilicate with metallic potassium:
from the reduction of potassium
1831
Contact process for sulphuric acid
Contact process for sulphuric acid patented by the British vinegar merchant
Peregrine Phillips. In addition to being a more economical process for concentrated
sulfuric acid than the previous lead chamber process, the contact process also
produces sulfur trioxide and oleum. Sulfuric acid is the second largest inorganic
chemical produced worldwide (200 million tonnes)
1834
Friedrich Wöhler
Father of Synthetic
Organic Chemistry
Cl
N
Cl
P
Cl
Cl
P
N
N
Cl
0
2 1 0 -2 5 0 C
N
P Cl
Cl
P
n
Cl
RONa
-N a C l
RM
(O rg a n o m e ta llic
a g e n t)
RNH2
R 2 NH
-HCl
OR
N
P
OR
NR
NHR
N
n
or
P
NHR
n
N
R
2
N
P
NR
2
n
P
Cl
n
Wöhler statue at Göttingen
J. Liebig and F. Wöhler prepares the inorganic heterocycle
cyclophosphazene , N3P3Cl6 from the reaction of PCl5 and NH4Cl.
3 Si + 2 N2 → Si3N4 (1857)
1840
Mn2+
C.F. Schoenbein detects and names ozone from its characteristic odour after a
lightning storm
1859
lead–acid battery
The French physicist Gaston Planté discovers the lead–acid battery, the oldest type
of rechargeable battery
1886
Henri Moissan prepared fluorine gas, F2 by the electrolysis of a solution of potassium
hydrogen difluoride in liquid hydrogen fluoride. For this discovery he received the
Nobel prize in 1906.
1890-1894
The Azides: MN3 and RN3
Wislicenus
(1892)
Curtius
1890
The common synthesis method is the "Wislicenus process," which
proceeds in two steps from ammonia. In the first step, ammonia is
converted to sodium amide:
2 Na + 2 NH3 → 2 NaNH2 + H2
The sodium amide is subsequently combined with nitrous oxide:
2 NaNH2 + N2O → NaN3 + NaOH + NH3
Alternatively the salt can be obtained by the reaction of sodium nitrate
with sodium amide.
1904
F. S. Kipping
F. S. Kipping coins the word "silicone"
to describe
polydiphenylsiloxane by analogy of its formula, with the formula
of benzophenone
Silicone Polymers
In 1937 after 30 years of research, Kipping In the Bakrerian lecture of the
Royal Society said “The prospect of any immediate and important advance
in this section of organic chemistry does not seem to be very hopeful."
Me
Me
H 2O
M e 2 S iC l 2
Si
1 2 lit
4 lit
Me
O
O
Si
Si
O
Me
Me
O
Si
Me
Me
+ T rim e r (0 .5 % )
P e n ta m e r (7 % )
H e x a m e r (2 % )
42%
Me
Me
Me
Si
Me
O
O
Si
Si
O
Me
Me
O
M e 3 S iO
Si
O
S iM e 3
a c id o r b a s e c a ta lys t
(e g . c o n c . H 2 S O 4 )
Si
Me
T h e rm a l a n d /o r b y
Me
Me
M e 3 S iO S iM e 3
Me
n
Me
P o ly d im e th yl s ilo x a n e P D M S
Lowest glass transition temperature, Tg = -127 °C
1904
In 1901-1902 Ramsay had been asked to
advise the Indian government on the
founding of a science institute and the
institute was established in Bangalore with
the help of the Government of Mysore
and JN Tata. Ramsay suggested his student
Morris Travers as a possible director for this
institute and in 1906, Travers was appointed
as the director of the new Indian Institute of
Science
Morris M. Travers
(1862-1961)
Sir William Ramsay
Sir William Ramsay discovered neon, krypton, and xenon and received
Nobel Prize in 1904. He also isolated helium which had been observed
in the spectrum of the sun but had not been found on earth till then. In
1910 he also made and characterized radon. (1894 argon with Lord Raleigh)
1907
The first light emitting
diode (LED) made of SiC
Henry Joseph Round
Gallium arsenide (GaAs)
Aluminium gallium arsenide (AlGaAs)
Silicon carbide
Gallium phosphide
Indium gallium nitride etc
To the Editors of Electrical World:
SIRS: – During an investigation of the unsymmetrical passage of current through a contact of carborundum and other
substances a curious phenomenon was noted. On applying a potential of 10 volts between two points on a crystal of
carborundum, the crystal gave out a yellowish light. Only one or two specimens could be found which gave a bright
glow on such a low voltage, but with 110 volts a large number could be found to glow. In some crystals only edges
gave the light and others gave instead of a yellow light green, orange or blue. In all cases tested the glow appears to
come from the negative pole, a bright blue-green spark appearing at the positive pole. In a single crystal, if contact is
made near the center with the negative pole, and the positive pole is put in contact at any other place, only one
section of the crystal will glow and that same section wherever the positive pole is placed.
There seems to be some connection between the above effect and the e.m.f. produced by a junction of carborundum
and another conductor when heated by a direct or alternating current; but the connection may be only secondary as
an obvious explanation of the e.m.f. effect is the thermoelectric one. The writer would be glad of references to any
published account of an investigation of this or any allied phenomena.
New York, N. Y.
H. J. Round
Haber
1909
Bosch
•Fritz Haber reports Haber process for the catalytic synthesis of NH3
which was made into a large scale industrial process along with C. Bosch
in 1913.
• Haber received the Nobel Prize in Chemistry in 1918.
•According to an estimate, nearly 80% of nitrogen present in the human
tissue has had its origins from Haber process.
•The worldwide production of ammonia exceeds 140 million tonnes and
is the third largest inorganic chemical produced in the world.
Alfred Stock- the father of boron hydride chemistry
1912
B. P
B 2 H 6 -9 2 .5 °C
B 4 H 1 0 1 6 °C
B 5H 9
5 8 °C
B 5 H 1 1 6 5 °C
B 6 H 1 0 1 0 8 °C
B 1 0 H 1 4 2 1 3 °C
m .p . 9 9 .7 °C
Alfred Stock prepares a series of boron hydrides including B2H6 and
separates them using the first sophisticated vacuum manifold. Due to their
very high air and moisture sensitivity and flammability, till then they were not
separable. He published his work in 1933.
M g3B 2
+
H 3 P O 4 (a q)
B 2 H 6 + 2N a H 2 P O 4
N aB H 4 + H 3 P O 4
B 2H 6
B 4H 10, B 5H 9, B 6H 10
pyro lysis
+ H2
B 4H 10, B 5H 9, B 5H 11, B 10H 14
Borazine: The Inorganic Benzene
H
H
First reported in 1926 by Alfred Stock and Pohland
H
H
B
N
N
B
B
3 B2H6 + 6 NH3 → 2 B3N3H6 + 12 H2
N
H
H
H
H
B
N
N
B
B
H
An alternative more efficient route begins with lithium borohydride and ammonium
chloride:
3 LiBH4 + 3 NH4Cl → B3N3H6+ 3 LiCl + 9 H2
Borazine is isostructural with benzene. The six B-N bonds have length of 1.436 Å. The carbon-carbon bond in
benzene is shorter length at 1.42 Å. The boron-nitrogen bond length is between that of the B -N (1.51Å ) and
the B=N (1.31 Å). This suggests partial delocalization of nitrogen lone pair.
Probability Distributions for borazine (left) and benzene (right)
Borazine has the same colligative properties as benzene, however the two are very different chemically. The
electron density along the boron-nitrogen bond is not distributed evenly, due to the difference in electro
negativities between the two atoms. Therefore, the molecular orbitals of the system are lumpy in appearance.
This uneven distribution makes borazine makes it prone to addition reactions.
N
H
H
H
1935 H J Taylor
Aerial view of Chernobyl reactor
1938
Roy J. Plunkett
Poly tetrafluoroethylene (Teflon) accidentally discovered by Roy J. Plunkett of
kinetic chemicals (A subsidiary of DuPont) while attempting to make a new CFC
using tetrafluoroethylene. He observed that there was no gas flowing out of a
small cylinder of tetrafluoroethylene whose weight indicated no loss of substance.
On cutting open the cylinder, he observed a waxy white highly slippery solid on its
interior walls whose analysis indicated polymerized tetrafluoroethylene.
Thomas Midgley: A daring inventor
1941
To show that his chlorofluorocarbon (CFC) coolant, Freon,
is nontoxic and nonflammable, Thomas Midgley Jr. takes
the stage at an ACS national meeting, inhales a lungful of
Freon, and blows out a candle.
J.R. McNeill an environmental historian remarked that Midgley had more
impact on the Earth’s atmosphere than any other living organism due to his
inventions: namely, lead gasoline additives and chlorofluorocarbons.
However, Midgley wasn’t killed by these inventions which we now know to
be exceptionally harmful. He met his maker thanks to a bed that he created
after contracting polio and becoming bedridden at the age of 51. The bed
featured a complex system of ropes and pulleys to help Midgley’s attendants
get him out of bed…ropes which eventually strangled him.
In 1941, the American Chemical Society gave Midgley its highest award, the Priestley
Medal This was followed by the Willard Gibbs Award in 1942. He also held two honorary
degrees and was elected to the United States National Academy of Sciences. In 1944, he
was elected president and chairman of the American Chemical Society
Industrial success of Silicones
E.G. Rochow
1954
ITO
resistive
capacitive
G. Rupprecht reports the semi conducting properties of Indium oxide, In2O3.
This was followed by the report by V. A. Williams in 1966 on the potential of
tin doped indium oxide (Indium tin oxide, ITO) as a transparent conducting
material. ITO is a solid solution of indium(III) oxide and tin(IV) oxide, typically
90% In2O3, 10% SnO2 by weight. It is the most widely used transparent
conducting oxide, especially as films
because of
its electrical
conductivity, optical transparency, as well as the ease of depositing as thin
films. Applications include liquid crystal, flat panel and plasma displays, touch screen
technology of mobile phones and ATM’s, electronic ink, light-emitting diodes, solar
cells, antistatic coatings, defrosting aircraft wind shields and infrared reflecting
coatings.
1962
The discovery of the first noble gas reaction
In March of 1962, Bartlett set up a glass apparatus containing PtF6, a red gas in
one container and xenon, a colorless gas in an adjoining container, separated by
a seal. Here's his recollection of the ensuing experiment, which he conducted
while working alone in his laboratory: "Because my co-workers at that time
(March 23, 1962) were still not sufficiently experienced to help me with the
glassblowing and the preparation and purification of PtF6 [platinum
hexafluoride] necessary for the experiment, I was not ready to carry it out until
about 7 p.m. on that Friday. When I broke the seal between the red PtF6 gas and
the colorless xenon gas, there was an immediate interaction, causing an orangeyellow solid to precipitate. At once I tried to find someone with whom to share
the exciting finding, but it appeared that everyone had left for dinner!"
The reaction took place at room temperature "in the twinkling of an eye" and
was "extraordinarily exhilarating," recalls Bartlett. He was certain that the
orange-yellow solid was the world's first noble gas compound. But convincing
others would prove somewhat difficult. The prevailing attitude was that no
scientist could violate one of the basic tenets of chemistry: the inertness of
noble gases. That orange-yellow solid was subsequently identified in laboratory
studies as xenon hexafluoroplatinate (XePtF6), the world's first noble gas
compound.
Metalla
Carboranes
M. F Hawthorne
B 10H 14 + 2 E t2S
1965
(n -P r) 2 O
C2 B10H12 + MeO
-H 2
HC
B 1 0 H 1 2 (E t 2 S ) 2
H 2,
CH
C 2 B 10H 12
E t2 S
[C2 B9H12]2 + H2 + B(OMe)3
+ 2MeOH
85 °C
[C2 B9H12]2 + NaH
n id o 7,8 [C 2 B 9 H 1 1 ] 2 + Fe C l 2
[C2 B9H11]2 + H2 + Na
Fe
5

[7,8 (C 2 B 9 H 1 1 )] 2 F e 2
“olla” metallacarborane
1967
Allen K. Breed
One azido group contributes about 335 kj/mol ( 80 kcal/mol) of
endothermicity to a compound
Allen K. Breed uses sodium azide, NaN3 along with a collision sensor in
automobile airbags (instead of compressed air) and achieves inflation of
the airbag under 30 milliseconds required for collision safety
1971
Wade’s Rules
Ken Wade,
Durham
B 2H 6
+ 2 E t3 N
B 4 H 10 , 1 9 0 °C
2 E t3 N . B H 3
[E t 3 N H ] 2 [B 1 2 H 1 2 ]
For borane and carborane clusters, the structures are based on deltahedra,
which are polyhedra in which every face is triangular. The clusters are classified
as closo-, nido-, arachno- or hypho-, based on whether they represent a
complete (closo-) deltahedron, or a deltahedron that is missing one (nido-), two
(arachno-) or three (hypho) vertices.
Boron hydride
Name
No. of skeletal
electron pairs
Examples
[BnHn]2- or BnHn+2
Closo
n+1
B6H62-, B12H122-
BnHn+4
Nido
n+2
B2H6,B5H9, B10H14
BnHn+6
Arachno
n+3
B4H10
BnHn+8
Hypho
n+4
B5H12
Each BH unit furnishes 2 skeletal bonding electrons
Each additional H· furnishes 1 skeletal bonding electron
Ionic charges must be included in the electron count
1976
Earl R. Stadtman (b. 1919) and
Theresa C. Stadtman (b. 1920)
Selenocysteine is the 21st proteinogenic amino acid. It exists naturally in all
kingdoms of life as a building block of selenoproteins. Selenocysteine is
a cysteine analogue with a selenium-containing selenol group in place of
the sulfur-containing thiol group. It is present in severalenzymes (for
example
glutathione
peroxidases,
tetraiodothyronine
5'
deiodinases, thioredoxin reductases, formate dehydrogenases, glycine
reductases etc). Selenocysteine was discovered by biochemist Theresa
Stadtman, wife of Earl R. Stadtman, at the National Institutes of Health.
1981
“Why do you want to climb mount Everest”?
“Because it‘s there”
George Mallory :British mountaineer, 1886-1924
ROBERT WEST
2.160Å
Robert West makes the first stable silicon–silicon double
bonded compound
1991
Anthony J.
Arduengo, III
Carbene Is Genie In A Bottle
Chemists are particularly drawn to molecules that behave like ferocious cats,
reacting rapidly and often violently and hence cannot seem to resist the
temptation to control them. One such species is the carbene which is
imperative for an entire framework of organic reactions thereby leading
to an altogether a separate branch named---Carbene Chemistry.
Anthony J Arduengo III prepares the first stable carbene
now well known as the NHC or N-Heterocyclic Carbene
1999
Pentazenium, N5+
Karl O. Christe
First N5+ (pentazenium) compound, N5+ AsF6discovered by Karl O. Christe. N5+ cation is a
highly energetic ion with a calculated
endothermicity of 1471.8 kJ/mol.
One azido group contributes about 335
kj/mol (80 kcal/mol) of endothermicity
to a compound
2000
Konrad Seppelt
first metal-xenon
compound
where xenon
acts as a ligand
Konrad Seppelt discovers the first metal-xenon compound
where xenon acts as a ligand achieved by reduction of AuF3
with xenon. The AuXe42+(Sb2F11-)2 complex had a square
planar gold with a Au-Xe bond distance of 274 pm.
Jemmis’ rules
E.D. Jemmis,
I.I.Sc, Bangalore
Jemmis draws together a number of corollaries to Wade's
rules into a single, easily employed general rule,"
Thomas P. Fehlner
Jemmis’ mno rule states that m + n + o skeletal electron pairs are
necessary for a closed macropolyhedral system to be stable
[or (m + n + o + p) for systems having open polyhedra as well].
Fe
H
B
BH
HC
BH
BH
CH
BH
2001
BH
BH
BH
B
H
[(7,8 -C 2 B 9 H 1 1 )Fe (C p)] 1
m + n +o + p = 2+ 17 +1 +1 = 21
s ke le ta l e c o u n t
9 B H = 9 p a irs
Here
m = number of condensed polyhedra
n = number of vertices
o = number of single atom bridges between two polyhedra
p = number of vertices missing for open polyhedra if present.
For example, for nido clusters p = 1 and for arachno clusters p = 2. For a benzene ring or
cyclopentadienyl ring as such p = 2 and if it is already in an 6 or 5 mode, p= 1.
For transition metals, the oxidation state of the metal should be known and the number of
electrons for the electron count should be taken as the same as the number of electrons lost by
the neutral metal atom to reach that oxidation state; for example, Fe3+ gives 3 electrons.
7 C H = 1 0 .5 p a irs
F e 2 + = 1 p a ir
1 - = 0 .5 p a ir
to ta l = 2 1 p a irs
s ta b le
The uniqueness of Jemmis’ mno rules is that they are not only applicable to macropolyhedral
clusters but also applied to polyhedra, metallocenes, and even unsaturated cyclic organic
compounds. Interestingly, Jemmis’ rules get reduced to Wade’s rules when m = 1 and o = 0 (one
polyhedron).
2004
first silicon-silicon triple bond
Akiro Sekiguchi
Akiro Sekiguchi prepares the first silicon-silicon triple bonded
compound
2004
Sir Andre Geim
•Stronger than steel: 200 times
•Thinner than hair: 1 million times
•Worlds most conductive material
•Stretchable, transparent, flexible
permeable
•Worlds first 2D material
Graphene
Geim was awarded the 2010 Nobel Prize in Physics jointly with Novoselov "for
groundbreaking experiments regarding the two-dimensional material graphene".
Graphene consists of one-atom-thick layers of carbon
atoms arranged in two-dimensional hexagons, and is the thinnest
material in the world, as well as one of the strongest and
hardest.The material has many potential applications and is
considered a superior alternative to silicon. Geim's achievements
include the discovery of a simple method for isolating single
atomic layers of graphite, known as graphene. The team
published their findings in October 2004 in Science
2006
Douglas Stephan
Douglas W. Stephan discovers the first example of a frustrated Lewis acid
base pair based on boron and phosphorus. Due to their unquenched reactivity
such molecules are able to heterolytically cleave dihydrogen molecule making
them potential metal free hydrogenation catalysts.
2007-2008
G.M Robinson proposed the first gallium–gallium triple
bonded compound in 1997 which evoked the famous
comment from F.A Cotton that, "That's no more a triple
bond than I'm the Dalai Lama!"
GREG ROBINSON
2007
B=B
2008
Si=Si
(0 state)
2.229Å
2012
K Tamao
K Tamao prepares a stable germanone molecule having a Ge=O
bond. This is the first example of a heavier element ketone
analogue
2012
Holger Braunschweig
First example of a stable diboryne having a BB and stabilized by N-heterocyclic carbenes
prepared by Holger Braunschweig
2014
Borospherene
Lai-Sheng Wang
Lai-Sheng Wang at Brown University in Providence, Rhode Island, and his
colleagues have made a cage-like molecule with 40 boron atoms by vaporizing a
chunk of boron with a laser then freezing it with helium, creating boron clusters.
The team analyzed the energy spectra of these clusters and compared them with
computer models of 10,000 possible arrangements of boron atoms. The matching
configuration revealed they had created the boron ball.
Unlike carbon buckyballs, in which the faces are made of hexagons and pentagons,
the boron buckyball is made from triangles, hexagons and heptagons. As a result, it
is less spherical but still an enclosed structure. Wang has dubbed the molecule
"borospherene". The team is now hunting for a boron analogue of graphene – a
strong sheet of carbon just one atom thick that is often touted as a "wonder"
material because of its unique electrical properties. ( july 12, 2014 Nature
Chemistry )