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1、Copyright Cengage Learning.All rights reserved,2,Transition Metals,Show great similarities within a given period as well as within a given vertical group.,Copyright Cengage Learning.All rights reserved,3,The Position of the Transition Elements on the Periodic Table,Copyright Cengage Learning.All rig
2、hts reserved,4,Forming Ionic Compounds,More than one oxidation state is often found.Cations are often complex ions species where the transition metal ion is surrounded by a certain number of ligands(Lewis bases).,Copyright Cengage Learning.All rights reserved,5,The Complex Ion Co(NH3)63+,Copyright C
3、engage Learning.All rights reserved,6,Ionic Compounds with Transition Metals,Most compounds are colored because the transition metal ion in the complex ion can absorb visible light of specific wavelengths.Many compounds are paramagnetic.,Copyright Cengage Learning.All rights reserved,7,Electron Conf
4、igurations,ExampleV:Ar4s23d3Exceptions:Cr and CuCr:Ar4s13d5Cu:Ar4s13d10,Copyright Cengage Learning.All rights reserved,8,Electron Configurations,First-row transition metal ions do not have 4s electrons.Energy of the 3d orbitals is significantly less than that of the 4s orbital.Ti:Ar4s23d2Ti3+:Ar3d1,
5、Copyright Cengage Learning.All rights reserved,9,What is the expected electron configuration of Sc+?Explain.Ar3d2,CONCEPT CHECK!,Copyright Cengage Learning.All rights reserved,10,Plots of the First(Red Dots)and Third(Blue Dots)Ionization Energies for the First-Row Transition Metals,Copyright Cengage
6、 Learning.All rights reserved,11,Atomic Radii of the 3d,4d,and 5d Transition Series,3d transition metalsScandium chemistry strongly resembles lanthanidesTitanium excellent structural material(light weight)Vanadium mostly in alloys with other metalsChromium important industrial materialManganese prod
7、uction of hard steelIron most abundant heavy metalCobalt alloys with other metalsNickel plating more active metals;alloysCopper plumbing and electrical applicationsZinc galvanizing steel,Copyright Cengage Learning.All rights reserved,12,Oxidation States and Species for Vanadium in Aqueous Solution,C
8、opyright Cengage Learning.All rights reserved,13,Typical Chromium Compounds,Copyright Cengage Learning.All rights reserved,14,Some Compounds of Manganese in Its Most Common Oxidation States,Copyright Cengage Learning.All rights reserved,15,Typical Compounds of Iron,Typical Compounds of Cobalt,Typica
9、l Compounds of Nickel,Copyright Cengage Learning.All rights reserved,18,Typical Compounds of Copper,Alloys Containing Copper,Copyright Cengage Learning.All rights reserved,20,A Coordination Compound,Typically consists of a complex ion and counterions(anions or cations as needed to produce a neutral
10、compound):Co(NH3)5ClCl2Fe(en)2(NO2)22SO4K3Fe(CN)6,Copyright Cengage Learning.All rights reserved,21,Coordination Number,Number of bonds formed between the metal ion and the ligands in the complex ion.6 and 4(most common)2 and 8(least common),Copyright Cengage Learning.All rights reserved,22,Ligands,
11、Neutral molecule or ion having a lone electron pair that can be used to form a bond to a metal ion.Monodentate ligand one bond to a metal ionBidentate ligand(chelate)two bonds to a metal ionPolydentate ligand more than two bonds to a metal ion,Copyright Cengage Learning.All rights reserved,23,Coordi
12、nate Covalent Bond,Bond resulting from the interaction between a Lewis base(the ligand)and a Lewis acid(the metal ion).,Copyright Cengage Learning.All rights reserved,24,The Bidentate Ligand Ethylenediamine and the Monodentate Ligand Ammonia,The Coordination of EDTA with a 2+Metal Ion,ethylenediamin
13、etetraacetate,Copyright Cengage Learning.All rights reserved,26,Rules for Naming Coordination Compounds,Cation is named before the anion.“chloride”goes last(the counterion)Ligands are named before the metal ion.ammonia(ammine)and chlorine(chloro)named before cobalt,Co(NH3)5ClCl2,Rules for Naming Coo
14、rdination Compounds,For negatively charged ligands,an“o”is added to the root name of an anion(such as fluoro,bromo,chloro,etc.).The prefixes mono-,di-,tri-,etc.,are used to denote the number of simple ligands.penta ammine,Copyright Cengage Learning.All rights reserved,28,Co(NH3)5ClCl2,Rules for Nami
15、ng Coordination Compounds,The oxidation state of the central metal ion is designated by a Roman numeral:cobalt(III)When more than one type of ligand is present,they are named alphabetically:pentaamminechloro,Copyright Cengage Learning.All rights reserved,29,Co(NH3)5ClCl2,Rules for Naming Coordinatio
16、n Compounds,If the complex ion has a negative charge,the suffix“ate”is added to the name of the metal.The correct name is:pentaamminechlorocobalt(III)chloride,Copyright Cengage Learning.All rights reserved,30,Co(NH3)5ClCl2,Name the following coordination compounds.Co(H2O)6Br3Na2PtCl4,Copyright Cenga
17、ge Learning.All rights reserved,31,hexaaquacobalt(III)bromidesodiumtetrachloro-platinate(II),EXERCISE!,Some Classes of Isomers,Structural Isomerism,Coordination Isomerism:Composition of the complex ion varies.Cr(NH3)5SO4Br and Cr(NH3)5BrSO4 Linkage Isomerism:Composition of the complex ion is the sam
18、e,but the point of attachment of at least one of the ligands differs.,Copyright Cengage Learning.All rights reserved,33,Linkage Isomerism of NO2,Stereoisomerism,Geometrical Isomerism(cis-trans):Atoms or groups of atoms can assume different positions around a rigid ring or bond.Cis same side(next to
19、each other)Trans opposite sides(across from each other),Copyright Cengage Learning.All rights reserved,35,Geometrical(cis-trans)Isomerism for a Square Planar Compounda)cis isomerb)trans isomer,Geometrical(cis-trans)Isomerism for an Octahedral Complex Ion,Copyright Cengage Learning.All rights reserve
20、d,37,Stereoisomerism,Optical Isomerism:Isomers have opposite effects on plane-polarized light.,Copyright Cengage Learning.All rights reserved,38,Unpolarized Light Consists of Waves Vibrating in Many Different Planes,Copyright Cengage Learning.All rights reserved,39,The Rotation of the Plane of Polar
21、ized Light by an Optically Active Substance,Copyright Cengage Learning.All rights reserved,40,Optical Activity,Exhibited by molecules that have nonsuperimposable mirror images(chiral molecules).Enantiomers isomers of nonsuperimposable mirror images.,Copyright Cengage Learning.All rights reserved,41,
22、A Human Hand Exhibits a Nonsuperimposable Mirror Image,Copyright Cengage Learning.All rights reserved,42,Does Co(en)2Cl2Cl exhibit geometrical isomerism?YesDoes it exhibit optical isomerism?Trans form NoCis form YesExplain.,Copyright Cengage Learning.All rights reserved,43,CONCEPT CHECK!,Bonding in
23、Complex Ions,The VSEPR model for predicting structure generally does not work for complex ions.However,assume a complex ion with a coordination number of 6 will have an octahedral arrangement of ligands.And,assume complexes with two ligands will be linear.But,complexes with a coordination number of
24、4 can be either tetrahedral or square planar.,Copyright Cengage Learning.All rights reserved,44,Bonding in Complex Ions,2.The interaction between a metal ion and a ligand can be viewed as a Lewis acidbase reaction with the ligand donating a lone pair of electrons to an empty orbital of the metal ion
25、 to form a coordinate covalent bond.,Copyright Cengage Learning.All rights reserved,45,The Interaction Between a Metal Ion and a Ligand Can Be Viewed as a Lewis Acid-Base Reaction,Copyright Cengage Learning.All rights reserved,46,Hybrid Orbitals on Co3+Can Accept an Electron Pair from Each NH3 Ligan
26、d,The Hybrid Orbitals Required for Tetrahedral,Square Planar,and Linear Complex Ions,Focuses on the energies of the d orbitals.AssumptionsLigands are negative point charges.Metalligand bonding is entirely ionic:strong-field(lowspin):large splitting of d orbitalsweak-field(highspin):small splitting o
27、f d orbitalsThe Interactions between metal orbitals and the negative point charges of the ligand are repulsion,Copyright Cengage Learning.All rights reserved,49,Octahedral Complexes,point their lobes directly at the point-charge ligands.point their lobes between the point charges.,Copyright Cengage
28、Learning.All rights reserved,51,An Octahedral Arrangement of Point-Charge Ligands and the Orientation of the 3d Orbitals,Copyright Cengage Learning.All rights reserved,52,The five d-orbitals in an octahedral field of ligands,Bonding in Coordination Compounds,Spherical Fieldtransition metalatom,Bonde
29、dtransition metalatom,Crystal field splitting(D)is the energy difference between two sets of d orbitals in a metal atom when ligands are present,Possible Electron Arrangements in the Split 3d Orbitals in an Octahedral Complex of Co3+,Magnetic Properties,Strongfield(lowspin):Yields the minimum number
30、 of unpaired electrons.Weakfield(highspin):Gives the maximum number of unpaired electrons.Hunds rule still applies.,Copyright Cengage Learning.All rights reserved,58,Spectrochemical Series,Strongfield ligands to weakfield ligands.(large split)(small split)CN NO2 en NH3 H2O OH F Cl Br IMagnitude of s
31、plit for a given ligand increases as the charge on the metal ion increases.,Complex Ion Colors,When a substance absorbs certain wavelengths of light in the visible region,the color of the substance is determined by the wavelengths of visible light that remain.Substance exhibits the color complementa
32、ry to those absorbed.,Copyright Cengage Learning.All rights reserved,60,Bonding in Coordination Compounds:Crystal Field Theory,ColorAs with reflected light,transmitted light of selected wavelengths is responsible for color.The color of observed light is the complementary color to the light absorbed.
33、,Bonding in Coordination Compounds:Crystal Field Theory,The process of photoabsorption:,An absorption spectrum of Ti(H2O)63+The energy of the incoming photon is equal to the crystal field splitting.,Complex Ion Colors,The ligands coordinated to a given metal ion determine the size of the dorbital sp
34、litting,thus the color changes as the ligands are changed.A change in splitting means a change in the wavelength of light needed to transfer electrons between the t2g and eg orbitals.,Copyright Cengage Learning.All rights reserved,64,Absorbtion of Visible Light by the Complex Ion Ti(H2O)63+,Copyrigh
35、t Cengage Learning.All rights reserved,65,Which of the following are expected to form colorless octahedral compounds?Zn2+Fe2+Mn2+Cu+Cr3+Ti4+Ag+Fe3+Cu2+Ni2+,CONCEPT CHECK!,Tetrahedral Arrangement,None of the 3d orbitals“point at the ligands”.Difference in energy between the split d orbitals is signif
36、icantly less.dorbital splitting will be opposite to that for the octahedral arrangement.Weakfield case(highspin)always applies.,Copyright Cengage Learning.All rights reserved,67,Splitting of d-orbital energies by a tetrahedral field and a square planar field of ligands,tetrahedral,square planar,The
37、d Orbitals in a Tetrahedral Arrangement of Point Charges,Copyright Cengage Learning.All rights reserved,70,t=4/9 o,The Crystal Field Diagrams for Octahedral and Tetrahedral Complexes,Copyright Cengage Learning.All rights reserved,73,Consider the Crystal Field Model(CFM).Which is lower in energy,dorb
38、ital lobes pointing toward ligands or between?Why?The electrons in the dorbitals are they from the metal or the ligands?,Copyright Cengage Learning.All rights reserved,74,CONCEPT CHECK!,Consider the Crystal Field Model(CFM).Why would electrons choose to pair up in dorbitals instead of being in separ
39、ate orbitals?Why is the predicted splitting in tetrahedral complexes smaller than in octahedral complexes?,Copyright Cengage Learning.All rights reserved,75,CONCEPT CHECK!,Using the Crystal Field Model,sketch possible electron arrangements for the following.Label one sketch as strong field and one s
40、ketch as weak field.Ni(NH3)62+Fe(CN)63 Co(NH3)63+,Copyright Cengage Learning.All rights reserved,76,CONCEPT CHECK!,A metal ion in a highspin octahedral complex has 2 more unpaired electrons than the same ion does in a lowspin octahedral complex.What are some possible metal ions for which this would
41、be true?Metal ions would need to be d4 or d7 ions.Examples include Mn3+,Co2+,and Cr2+.,Copyright Cengage Learning.All rights reserved,77,CONCEPT CHECK!,Between Mn(CN)63 and Mn(CN)64 which is more likely to be high spin?Why?,Copyright Cengage Learning.All rights reserved,78,CONCEPT CHECK!,The d Energ
42、y Diagrams for Square Planar Complexes,Copyright Cengage Learning.All rights reserved,79,The d Energy Diagrams for Linear Complexes Where the Ligands Lie Along the z Axis,Copyright Cengage Learning.All rights reserved,80,MO,Electronic Spectra,Lambert-Beer Law,Relaxation of Selection Rules,Octahedral
43、 complexes:centrosymmetric Laporte rule relaxed by vibronic coupling,Tetrahedral complexes:non-centrosymmetric Laporte rule relaxed by orbital mixing,Selection Rules,Spin Selection Rule,DS=0,There must be no change in spin multiplicity during an electronic transition,Laporte Selection Rule,D l=1,The
44、re must be a change in parity during an electronic transition,d5 complexes:vibronic coupling and Spin-orbit coupling,Selection Rules,TransitionecomplexesSpin forbidden10-3 1Many d5 Oh cxsLaporte forbidden Mn(OH2)62+Spin allowedLaporte forbidden1 10Many Oh cxsNi(OH2)62+10 100 Some square planar cxs P
45、dCl42-100 10006-coordinate complexes of low symmetry,many square planar cxs particularly with organic ligandsSpin allowed102 103Some MLCT bands in cxs with unsaturated ligandsLaporte allowed102 104Acentric complexes with ligands such as acac,or with P donor atoms103 106 Many CT bands,transitions in
46、organic species,CHARGE-TRANSFER SPECTRA,Jahn Teller Effects,For a non-linear molecule that is in an electronically degenerate state,distortion must occur to lower the symmetry,remove the degeneracy,and lower the energy.,Jahn-Teller effects do not predict which distortion will occur other than that t
47、he center of symmetry will remain.The distortion by the unsymmetrical distribution of electrons in eg orbital is stronger than that of t2g.,Jahn-Teller Theorem If the ground electronic configuration of a nonlinear molecule is degenerate,the molecule will distort so as to remove a degeneracy and achi
48、eve a lower energy.,e.g.Octahedral Cu(II)complexes(d9)Two degenerate ground electronic configurations:,d8 d9 d10,The geometry of some six-coordinatedCu(II)complexes is tetragonal instead of octahedral.Solid-state structure of Cu(NH3)62+,Elongation of the two axial bonds leads to stabilization of z2
49、and destabilization of x2-y2.Overall,the tetragonal geometry is more stable than the octahedral analogue by(21 1)or 0.5 1N.B.Distortion by either elongation or compression of the axial bonds will remove the degeneracy and results in stabilizationJ-T theorem cannot predict which way it will take,Tetr
50、agonal geometry for 6-coordinated Cu(II)complexes Broadening of absorption band for Ti(H2O)63+(splitting into two peaks)Small K5 and K6 for CuL6e.g.Cu2+(aq)+xs NH3(aq)deep blue soln,Metal ion complexes are used in humans for the transport and storage of oxygen,as electron-transfer agents,as catalyst
