TRO3 Lecture 24

8/9/2019 TRO3 Lecture 24

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Chapter 24Transition

Metals andCoordinationCompounds

2007, Prentice Hall

Chemistry: A Molecular Approach , 1 st Ed. Nivaldo Tro

Roy KennedyMassachusetts Bay o!!unity olle"e

#ellesley Hills, M$


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Tro, Chemistry: A Molecular Approach

2

%e!stones

&the colors o' ru(ies and e!eralds are (oth dueto the )resence o' r *+ ions the di''erence liesin the crystal hostin" the ion

-o!e $l *+ ions

in $l 2 * arere)laced (y

r *+

-o!e $l *+ ionsin

Be *$l 2/-i * are re)laced (y

r *+


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Pro)erties and Electron on'i"urationo' Transition Metals

& the )ro)erties o' the transition !etals are si!ilar toeach other

and very di''erent tot he )ro)erties o' the !ain "rou) !etals

hi"h !eltin" )oints, hi"h densities, !oderate to very hard,and very "ood electrical conductors& in "eneral, the transition !etals have t o valence

electrons e are 'illin" the d or(itals in the shell (elo the valence

%rou) 1B and so!e others have 1 valence electron due to3)ro!otion4 o' an electron into the d su(level to 'ill it'or! ions (y losin" the ns electrons 'irst, then the / n 1 d


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$to!ic -i5e

&the ato!ic radii o' allthe transition !etalsare very si!ilar

s!all increase in si5edo n a colu!n


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6oni5ation Ener"y

&the 'irst ioni5ationener"y o' the

transition !etalsslo ly increasesacross a series

&third transition seriessli"htly hi"her 1 st 6E

trend o))osite to!ain "rou) ele!ents


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Electrone"ativity

& the electrone"ativity o'the transition !etalsslo ly increases acrossa series

e ce)t 'or last ele!ent inthe series

&electrone"ativitysli"htly increases do nthe colu!n

trend o))osite to !ain"rou) ele!ents


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idation -tates

&o'ten e hi(it !ulti)le o idation states&vary (y 1&hi"hest o idation state is "rou) nu!(er 'or *B to 7B


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oordination o!)ounds& hen a co!)le ion co!(ines ith counterions to

!a8e a neutral co!)ound it is called a coordinationcompound

& the primary valence is the o idation nu!(er o' the!etal

& the secondary valence is the nu!(er o' li"ands (ondedto the !etal

coordination number

&coordination nu!(er ran"e 'ro! 2 to 12, ith the !ostco!!on (ein" and 9

o l * H2 : ; o/H 2 < l*


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o!)le 6on =or!ation&co!)le ion 'or!ation is a ty)e o' >e is acid?

(ase reaction

&a (ond that 'or!s hen the )air o' electrons isdonated (y one ato! is called a coordinatecovalent bond


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>i"ands ith E tra Teeth

&so!e li"ands can 'or! !ore than one coordinatecovalent (ond ith the !etal ato!lone )airs on di''erent ato!s that are se)arate enou"hso that (oth can reach the !etal

&chelate is a co!)le ion containin" a!ultidentate li"and

li"and is called the chelating agent


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E@T$a Polydentate >i"and


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o!)le 6ons ith Polydentate >i"ands


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%eo!etries in o!)le 6ons


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Na!in" oordination o!)ounds1 deter!ine the na!e o' the nonco!)le ion2 deter!ine the li"and na!es and list the! in

al)ha(etical order

* deter!ine the na!e o' the !etal cation9 na!e the co!)le ion (yA

1 na!e each li"and al)ha(etically, addin" a )re'i in 'ront o'each li"and to indicate the nu!(er 'ound in the co!)le ion

2 'ollo ith the na!e o' the !etal cation

rite the na!e o' the cation 'ollo ed (y the na!e o'the anion


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o!!on >i"ands


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o!!on Metals 'ound in$nionic o!)le 6ons


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6so!ers

&Structural isomers are !olecules that have thesa!e nu!(er and ty)e o' ato!s, (ut they are

attached in a di''erent order &Stereoisomers are !olecules that have the sa!e

nu!(er and ty)e o' ato!s, and that are attached

in the sa!e order, (ut the ato!s or "rou)s o'ato!s )oint in a di''erent s)atial direction


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>in8a"e 6so!ers


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E . 29. @ra the structures and la(el the ty)e'or all iso!ers o' ; o/en

2l

2


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)tical 6so!ers

&optical isomers arestereoiso!ers that are

nonsu)eri!)osa(le !irrori!a"es o' each other

; o/en *


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E 29.7 @eter!ine i' the cis?trans iso!ers o'; o/en

2l

2


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Bondin" in oordination o!)ounds

Dalence Bond Theory

& (ondin" ta8e )lace hen the 'illed ato!ic

or(ital on the li"and overla)s an e!)ty ato!icor(ital on the !etal ion

&e )lain "eo!etries ell, (ut doesn t e )lain

color or !a"netic )ro)erties


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Bondin" in oordination o!)ounds

rystal =ield Theory& (onds 'or! due to the attraction o' the electrons on the

li"and 'or the char"e on the !etal cation&electrons on the li"ands repel electrons in the

unhy(ridi5ed d or(itals o' the !etal ion& the result is the ener"ies o' or(itals the d su(level are

s)lit& the di''erence in ener"y de)ends the co!)le and 8inds

o' li"andscrystal 'ield s)littin" ener"ystron" 'ield s)littin" and ea8 'ield s)littin"


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-)littin" o' d r(ital Ener"ies due to

>i"ands in a ctahedral o!)le


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-tron" and #ea8 =ield -)littin"


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o!)le 6on olor

&the o(served color is the co!)li!entary color o'the one that is a(sor(ed


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o!)le 6on olor and

rystal =ield -tren"th&the colors o' co!)le ions are due to electronic

transitions (et een the s)lit d su(level or(itals

&the avelen"th o' !a i!u! a(sor(ance can (eused to deter!ine the si5e o' the ener"y "a)

(et een the s)lit d su(level or(itals

E )hoton : h : hcF :


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>i"and and

rystal =ield -tren"th&the stren"th o' the crystal 'ield de)ends in lar"e

)art on the li"andsstron" 'ield li"ands includeA N G N 2 G en NH *

ea8 'ield li"ands include H 2 H G = G l G Br G 6 G

&crystal 'ield stren"th increases as the char"e onthe !etal cation increases


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Ma"netic Pro)erties and

rystal =ield -tren"th& the electron con'i"uration o' the !etal ion ith s)lit d

or(itals de)ends on the stren"th o' the crystal 'ield

& the 9th

and th

electrons ill "o into the hi"her ener"y d x2- y2 and d z2 i' the 'ield is ea8 and the ener"y "a) is s!all leadin" to un)aired electrons and a )ara!a"neticco!)le

& the 9th

thru th

electrons ill )air the electrons in the d xy ,d yz and d xz i' the 'ield is stron" and the ener"y "a) is lar"e leadin" to )aired electrons and a dia!a"netic co!)le


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>o -)in I Hi"h -)in o!)le es

)ara!a"netic

hi"h?s)in co!)le

dia!a"neticlo ?s)in co!)le

only electron con'i"urations d 9, d , d , or d 7 can have lo or hi"h s)in


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Tetrahedral %eo!etry andrystal =ield -)littin"

& (ecause the li"and a))roach interacts !orestron"ly ith the )lanar or(itals in thetetrahedral "eo!etry, their ener"ies are raised

&!ost hi"h?s)in co!)le es


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Tro, Chemistry: A Molecular Approach 37

-Cuare Planar %eo!etry andrystal =ield -)littin"

&d J !etals&the !ost co!)le s)littin" )attern&!ost are lo ?s)in co!)le es


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$))lications o'

oordination o!)ounds&co!!ercial colorin" a"ents

)russian (lue : !i ture o' he acyano=e/66 and =e/666

in8s, (lue)rintin", cos!etics, )aints& (io!olecules

)or)hyrin rin"cytochro!e he!o"lo(inchlor)hyll

chloro)hyll


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$))lications o'

oordination o!)ounds&car(onic anhydrase

cataly5es the reaction (et een ater and 2

contains tetrahedrally co!)le ed n 2+


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$))lications o'

oordination o!)ounds&@ru"s and Thera)eutic $"ents

cis)latin

anticancer dru"

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TRO3 Lecture 24