Intr

oduc

tion

to In

orga

nic

Che

mis

try

Wha

t is

inor

gani

c ch

emis

try?

Inor

gani

c C

hem

istry

Org

anim

etal

licB

ioin

orga

nic

Org

anic

vs

Inor

gani

c

Intr

oduc

tion

to In

orga

nic

Che

mis

try

Org

anic

vs

Inor

gani

c

Intr

oduc

tion

to In

orga

nic

Che

mis

try

Org

anic

vs

Inor

gani

c

Cha

pter

8 A

n In

trod

uctio

n to

Coo

rdin

atio

n C

ompo

unds

8.1

Hig

h co

ordi

natio

n nu

mbe

rs

8.2

Inte

rmed

iate

coo

rdin

atio

n nu

mbe

rs

8.1

Low

coo

rdin

atio

n nu

mbe

rs

8.5

Rep

rese

ntat

ive

ligan

ds

Liga

nds

and

nom

encl

atur

e

8.4

Pol

ymet

allic

com

plex

es

Isom

eris

m a

nd c

hira

lity

8.6

Nom

encl

atur

e

Con

stitu

tion

and

geom

etry

8.7

Squ

are-

plan

ar c

ompl

exes

8.11

Lig

and

chira

lity

8.10

Oct

ahed

ral c

ompl

exes

8.9

Trig

onal

-bip

yram

idal

and

squa

re-p

yram

idal

com

plex

es

8.8

Tetra

hedr

al c

ompl

exes

His

tory

Wha

t is

coor

dina

tion

com

poun

d?C

oord

inat

ion

com

poun

ds in

clud

e co

mpo

und

com

pose

d of

a m

etal

ato

m o

r ion

and

one

or m

ore

ligan

dsth

at fo

rmal

ly d

onat

e el

ectro

ns to

the

met

al.

Mor

e sp

ecifi

cally

, a tr

ansi

tion

met

al s

urro

unde

d by

ne

utra

l mol

ecul

es o

r ani

ons

with

a d

efin

ite g

eom

etry

.

Wha

t is

ligan

d?Li

gand

can

be a

ato

m, i

on, a

nd m

olec

ules

.

His

tory

Wha

t is

coor

dina

tion

com

poun

d?C

oord

inat

ion

com

plex

es w

ere

know

n -a

lthou

gh n

ot u

nder

stoo

d in

any

sen

se -

sinc

e th

e be

ginn

ing

of c

hem

istry

, e.g

. Pru

ssia

n bl

ue, A

ureo

lin,a

nd c

oppe

r vitr

iol.

The

key

brea

kthr

ough

occ

urre

d w

hen

Alfr

ed W

erne

r pro

pose

d,

inte

r alia

, tha

t Co(

III) b

ears

six

liga

nds

in a

n oc

tahe

dral

geo

met

ry.

Prus

sian

blu

e(G

erm

an: P

reuß

isch

blau

or B

erlin

er B

lau,

in E

nglis

hB

erlin

bl

ue) i

s a

dark

blu

epi

gmen

tuse

d in

pai

nts

and

form

erly

in b

luep

rints

. P

russ

ian

blue

was

dis

cove

red

by a

ccid

ent b

y pa

inte

r Hei

nric

h D

iesb

ach

in

Ber

linin

170

4-5,

whi

ch is

why

it is

als

o kn

own

as B

erlin

blu

e. (D

iesb

ach

was

atte

mpt

ing

to c

reat

e a

pain

t with

a re

d hu

e.) I

t has

sev

eral

diffe

rent

ch

emic

al n

ames

, the

se b

eing

iron

(III)

ferr

ocya

nide

, fer

ric fe

rroc

yani

de,

iron(

III) h

exac

yano

ferra

te(II

), an

d fe

rric

hex

acya

nofe

rrat

e. C

omm

only

and

co

nven

ient

ly it

is s

impl

y ca

lled

"PB

.

Aur

eolin

(som

etim

es c

alle

d C

obal

tYel

low

) is

a pi

gmen

t use

d in

oil

and

wat

erco

lor p

aint

ing.

Its

colo

r ind

ex n

ame

is P

Y40

(40t

h en

try o

nlis

t of

yello

w p

igm

ents

). It

was

firs

t mad

e in

185

1 an

d its

che

mic

al c

ompo

sitio

n is

po

tass

ium

cob

altin

itrite

.

Cop

per(

II) s

ulfa

te("

sulp

hate

" in

mos

t Com

mon

wea

lthna

tions

) is

the

chem

ical

com

poun

dw

ith th

e fo

rmul

aC

uSO

4. Th

is s

alt e

xist

s as

a s

erie

s of

co

mpo

unds

that

diff

er in

thei

r deg

ree

of h

ydra

tion.

The

anh

ydro

usfo

rm is

a

pale

gre

en o

r gra

y-w

hite

pow

der,

whi

le th

e pe

ntah

ydra

te, t

he m

ost

com

mon

ly e

ncou

nter

ed s

alt,

is b

right

blu

e. T

his

hydr

ated

cop

per s

ulfa

te

occu

rs in

nat

ure

as th

e m

iner

alca

lled

chal

cant

hite

. The

arc

haic

nam

e fo

r co

pper

(II) s

ulfa

te is

"blu

e vi

triol

" or "

blue

ston

e"

Alfr

ed W

erne

r

In 1

893,

Wer

ner w

as th

e fir

st to

pro

pose

cor

rect

stru

ctur

es fo

r coo

rdin

atio

n co

mpo

unds

con

tain

ing

com

plex

ions

, in

whi

ch a

cen

tral t

rans

ition

met

al

atom

is s

urro

unde

d by

neu

tral o

r ani

onic

liga

nds .

For e

xam

ple,

it w

as k

now

n th

at c

obal

t for

ms

a "c

ompl

ex" w

ith fo

rmul

a C

oCl 3•

6NH

3, bu

t the

nat

ure

of th

e as

soci

atio

n in

dica

ted

by th

e do

t was

m

yste

rious

. Wer

ner p

ropo

sed

the

stru

ctur

e [C

o(N

H3)

6]Cl 3,

with

the

Co3

+ io

n su

rrou

nded

by

six

NH

3at

the

verti

ces

of a

n oc

tahe

dron

. The

thre

e C

l-ar

e di

ssoc

iate

d as

free

ions

, whi

ch h

e co

nfirm

ed b

y m

easu

ring

the

elec

trica

l con

duct

ivity

of th

e co

mpo

und

in a

queo

us s

olut

ion.

Nob

el P

rize

for C

hem

istry

1913

For c

ompl

exes

with

mor

e th

an o

ne ty

pe o

f lig

and,

Wer

ner s

ucce

eded

in

expl

aini

ng th

e nu

mbe

r of i

som

ers

obse

rved

. For

exe

mpl

e, h

e ex

plai

ned

the

exis

tenc

e of

two

isom

ers

of "C

o(N

H3)

4Cl 3"

, one

gre

en a

nd o

ne p

urpl

e.

Wer

ner p

ropo

sed

that

thes

e ar

e tw

o ge

omet

ric is

omer

sof

form

ula

[Co(

NH

3)4C

l 2]C

l, w

ith o

ne C

l-io

n di

ssoc

iate

d as

con

firm

ed b

y co

nduc

tivity

m

easu

rem

ents

. The

Co

atom

is s

urro

unde

d by

four

NH

3an

d tw

o C

llig

ands

at th

e ve

rtice

s of

an

octa

hedr

on. T

he g

reen

isom

er is

"tra

ns" w

ith th

e tw

o C

llig

ands

at o

ppos

ite v

ertic

es, a

nd th

e pu

rple

is "c

is" w

ith th

e tw

o C

lat

adja

cent

ver

tices

.

His

tory

Wha

t is

coor

dina

tion

com

poun

d?C

oord

inat

ion

com

plex

es w

ere

know

n -a

lthou

gh n

ot u

nder

stoo

d in

any

sen

se -

sinc

e th

e be

ginn

ing

of c

hem

istry

, e.g

. Pru

ssia

n bl

ue, A

ureo

lin,a

nd c

oppe

r vitr

iol.

The

key

brea

kthr

ough

occ

urre

d w

hen

Alfr

ed W

erne

r pro

pose

d,

inte

r alia

, tha

t Co(

III) b

ears

six

liga

nds

in a

n oc

tahe

dral

geo

met

ry.

The

theo

ry a

llow

s on

e to

und

erst

and

the

diffe

renc

e be

twee

n co

ordi

nate

d an

d io

nic

chlo

ride

in th

e co

balt

amm

ine

chlo

rides

an

d to

exp

lain

man

y of

the

prev

ious

ly in

expl

icab

le is

omer

s.

He

reso

lved

the

first

coo

rdin

atio

n co

mpl

ex in

to o

ptic

al is

omer

s,ov

erth

row

ing

the

theo

ry th

at c

hira

lity

was

nec

essa

rily

asso

ciat

ed

with

car

bon

com

poun

ds.

His

tory

Wha

t is

ligan

d?In

che

mis

try, a

liga

ndis

an

atom

, ion

, or m

olec

ule

that

gen

eral

ly

dona

tes

one

or m

ore

of it

s el

ectro

nsth

roug

h a

coor

dina

te

cova

lent

bon

dto

one

or m

ore

cent

ral a

tom

s or

ions

(the

se

ligan

dsac

t as

a Le

wis

bas

e ).

The

ligan

dsth

at a

re d

irect

ly b

onde

d to

the

met

al (t

hat i

s, s

hare

el

ectro

ns),

are

calle

d "in

ner s

pher

e " li

gand

s.If

the

inne

r-sph

ere

ligan

dsdo

not

bal

ance

the

char

ge o

f the

ce

ntra

l ato

m, t

his

may

be

done

by

sim

ple

ioni

c bo

ndin

gw

ith

anot

her s

et o

f cou

nter

ions

(the

"out

er-s

pher

e" li

gand

s).

The

com

plex

of t

he m

etal

with

the

inne

r sph

ere

ligan

dsis

then

ca

lled

a co

mpl

ex io

n(w

hich

can

be

eith

er c

atio

nic

or a

nion

ic).

The

com

plex

, alo

ng w

ith it

s co

unte

r ion

s, is

cal

led

a co

ordi

natio

n co

mpo

und.

The

siz

e of

a li

gand

is in

dica

ted

by it

s co

ne a

ngle

.

His

tory O

rgan

omet

allic

Com

poun

d

Org

anom

etal

licch

emis

try

is th

e st

udy

of c

hem

ical

com

poun

dsco

ntai

ning

bon

dsbe

twee

n ca

rbon

and

a m

etal

.

Org

anom

etal

licch

emis

try c

ombi

nes

aspe

cts

of in

orga

nic

chem

istry

and

orga

nic

chem

istry

.

Org

anom

etal

licco

mpo

unds

find

pra

ctic

al u

se in

sto

ichi

omet

rican

d ca

taly

tical

lyac

tive

com

poun

ds.

Ele

ctro

n co

untin

gis

key

in u

nder

stan

ding

org

anom

etal

licch

emis

try. T

he 1

8-el

ectro

n ru

leis

hel

pful

in p

redi

ctin

g th

e st

abili

ties

of o

rgan

omet

allic

com

poun

ds. O

rgan

omet

allic

com

poun

ds w

hich

hav

e 18

ele

ctro

ns (f

illed

s, p

, and

d o

rbita

ls)

are

rela

tivel

y st

able

. Thi

s su

gges

ts th

e co

mpo

und

is is

olab

le, b

ut

it ca

n re

sult

in th

e co

mpo

und

bein

g in

ert.

Nom

encl

atur

e –

Com

mon

Mon

oden

tate

Liga

nds

Cla

ssic

al (o

r "W

erne

rCom

plex

es")

: Lig

ands

in c

lass

ical

co

ordi

natio

n ch

emis

try b

ind

to m

etal

s.

Org

anom

etal

lic: L

igan

dsar

e or

gani

c (a

lken

es, a

lkyn

es, a

lkyl

s) a

s w

ell a

s "o

rgan

ic-li

ke" l

igan

dssu

ch a

s ph

osph

ines

, hyd

ride,

and

C

O.

Bio

inor

gani

c: L

igan

dsar

e th

ose

prov

ided

by

natu

re, e

spec

ially

in

clud

ing

the

side

cha

ins

of a

min

o ac

ids,

and

man

y co

fact

ors

such

as

porp

hyrin

s.

Exa

mpl

e: h

emog

lobi

n

Clu

ster

: Lig

ands

are

all o

f the

abo

ve b

ut a

lso

incl

ude

othe

r m

etal

s as

liga

nds.

E

xam

ple

Ru 3

(CO

) 12

Con

stitu

tion

and

geom

etry

In a

n in

ner-

sphe

re c

ompl

ex, t

he li

gand

sar

e at

tach

ed d

irect

ly to

a

cent

ral m

etal

ion:

the

num

ber o

f lig

ands

depe

nds

on th

e si

ze o

f th

e m

etal

, the

iden

tity

of th

e lig

ands

, and

the

elec

troni

c in

tera

ctio

ns.

Siz

e: li

gand

, cen

tral a

tom

or i

onE

lect

ron

dens

ityM

ultip

le b

ond

{[Mn(

H2O

) 6]2+

SO

42-}

vs[M

n(H

2O) 5

SO

4]

Con

stitu

tion

and

geom

etry

8.1

Low

coo

rdin

atio

n nu

mbe

rs

Coo

rdin

atio

n nu

mbe

r 2; C

u+ , A

g+ , A

u+ ,th

ey o

ften

gain

ad

ditio

nal l

igan

dsto

form

thre

e-or

four

-coo

rdin

ate

com

plex

es.

Coo

rdin

atio

n nu

mbe

r 3: w

ith b

ulky

liga

nds

Pos

ition

of th

ese

com

plex

es in

pe

riodi

c ta

ble.

Con

stitu

tion

and

geom

etry

8.2

Inte

rmed

iate

coo

rdin

atio

n nu

mbe

rs

Coo

rdin

atio

n nu

mbe

r 4, 5

, 6.

They

incl

ude

the

vast

maj

ority

of c

ompl

exes

.

Four

-coo

rdin

atio

n:

Tetr

ahed

ralc

ompl

exes

are

favo

ured

over

hig

her

coor

dina

te c

ompl

exes

if th

e ce

ntra

l ato

m is

sm

all

or th

e lig

ands

larg

e.-l

igan

d-lig

and

repu

lsio

ns o

verr

ide

the

ener

gy

adva

ntag

e of

form

ing

mor

e m

etal

-liga

ndbo

nds

Squa

re-p

lana

rcom

plex

es a

re ty

pica

lly o

bser

ved

for m

etal

s w

ith d

8co

nfig

urat

ions

(Rh+ ,

Ir+ , P

d2+,

Pt2+

, Au3+

).

Con

stitu

tion

and

geom

etry

8.2

Inte

rmed

iate

coo

rdin

atio

n nu

mbe

rs

Geo

met

ric is

omer

ism