普通化學配合物雜化理論

1、Chapter3CoordinationCompounds配位化合物Definition 定義配位化合物是中心原子與一定數(shù)量的分子或離子形成的具有一定的空間結(jié)構(gòu)的配離子或分子，以前稱絡(luò)合物。一、配合物的組成 內(nèi)界（配離子或配合分子）與外界以離子鍵結(jié)合 內(nèi)界：中心形成體與配體NH3®M¬NH3n+,Mn+配離子配離子電荷：中心形成體和配位體總電荷配合物的組成配體：與中心形成體以配位鍵結(jié)合.NH3, Cl-配位原子：配體中提供孤對的原子N、O、C、S、P、As、X配位數(shù)：直接與中心元素配合的配位原子常見2、4、6、8數(shù)。配位數(shù)與配位體數(shù)？多嚙配體與螯合物配體中，若有多個配位原子

2、，稱為多嚙配體.與多嚙配體形成的配合物，稱為螯合物。Forexample,Cu(en)22+,二乙二胺合銅(II)en:NH2CH2CH2NH2,ethylenediamine乙二胺.Chelate螯合物H2N Cu2+H2NNH2CHH2C2CH2H2CNH2Some Common Ligands常見配體Cu(en)22+的配位數(shù)為4。單嚙配體: H2O, NH3,Cl-, Br-, I-, CN-,SCN-, CO. 雙嚙配體: CO32-, C2O 2-, en:4 多嚙配體: EDTABidentate and Polydentate LigandsOOCCOONNOxalato 草酸

3、根2,2-bipyridine 聯(lián)吡啶H2CHOOCCH2COOHNCH2CH2NCH2COOHHOOCH2CEDTA, 乙二胺四乙酸二、 配合物命名先命名陰離子，再陽離子（不管配離子是陰還是陽離子）內(nèi)界（ 在配離子中，先命名配體，再命名金屬。）名稱“合”配體個數(shù)中心形成體（化合價）name the ligands alphabetically按字母順序命名配體. Negative ligands(anions) have names formed by adding “o” to the stem name of the group.For example, O2- oxo, NO3- ni

4、trato.use the numeric prefix to indicate the number of ligands present. 用數(shù)字前綴表示配體數(shù)量。2: di 或 bis；3: tri 或 tris；4: tetra 或 tetrakis etc.Examples of the Names of Complexes配合物命名范例K3Ag(S2O3)potassium bis(thiosulfato)argentate(I). 二硫代硫酸根合銀(I)酸鉀。Co(en)(NO2)Cl2-dichloroethylenediaminenitrocobaltate(III).二氯二

5、硝基乙二胺合鈷(III)配離子。Cu(NH3)4SO4tetraamminecopper(II) sulfate 硫酸四氨合銅(II)Co2(CO)8octacarbonyl dicobalt(0) 八羰基合二鈷。配位化合物的化學鍵理論 1930年P(guān)auling提出雜化軌道理論，并應(yīng)用到配合物中，后人、補充，逐漸形成了配合物的價鍵理論。Valence Bond Theory價鍵理論 配位鍵本質(zhì)上是共價鍵。 配體提供對與金屬離子共享。對占據(jù)了金屬離子的某個雜化軌道。形成條件 M必須有空的價層軌道 L中的配位原子至少含有一對孤對配位鍵形成的過程 為了增強成鍵能力，中心形成體提供的空軌道，必須首先進

6、行雜化 雜化軌道分別與配位原子的孤對電子所占據(jù)的軌道發(fā)生重疊，形成配位鍵。 雜化方式?jīng)Q定了空間構(gòu)型。配合物的空間構(gòu)型空間構(gòu)型直線型平面三角形正四面體 平面正方形三角雙錐八面體八面體配位數(shù)23445雜化方式舉例spsp2 sp3 dsp2dsp3-2Ag(NH3)2+, Cu(CN)HgCl3-Zn(CN)42-, FeCl4- Ni(CN)42-, Cu(NH3)42+Fe(CO)5Co(NH3)62+, Fe(CN)63-FeF63-d2sp3sp3d266為了減少配體間的靜電排斥作用（或成鍵對間斥力），配位體要盡量遠離，在中心形成體周圍采取對稱分布狀態(tài)二配位+Cu(NH3)23d10+Ag

7、(NH3)24d10-Au(CN)25d10The Complexes of d10 Metal IonExample: in Ag(NH3)2+, Ag+ ion has the valence configurationof 4d10.NH3 molecules donate two pair electrons.sp hybridization5s, 5p orbitalsSilver, 3d10Coordination num. 2Linear 線型.sp hybridization四配位2+Zn(NH3)43d102+Ni(NH3)43d82-Ni(CN)4Tetrahedral a

8、nd planar square2+2-NH3NCCNNiNiNH3 NH3CNH3NNC四氨合鎳(II)配離子合鎳(II)配離子四The Complexes of d8 Metal Ion(Tetrahedron) in Ni(NH3)42+, Ni2+ ion has the valence configuration of 3d8. Ammonia molecules donatefourpair electrons.sp3hybridization4s, 4p orbitalsel, 3d8Coordination num. 4 tetrahedron 四面體. outer orbit

9、al complexThe Complexes of d8 Metal Ion(Planar Square) in Ni(CN)42-, Ni2+ ion has the valence configurationof 3d8.Cyanide ions donate four pair electrons.4s, 4p orbitalsdsp 2 hybridizationel, 3d8Coordination num. 4 planar square 正方形. Inner orbital complexdsp2 hybridization發(fā)生重排的 與配位體的強弱有關(guān)（或與配位原子的電負性有

10、關(guān)） 配位原子電負性小，容易給出孤對的配體六配位：八面體 Fe(CN)63- FeF63-The Complexes of d57 Metal Ions(Octahedron) in FeF63-, Fe3+ ion has the valence configurationof 3d5. Fluoride ions donate six pair electrons.配位數(shù)64d orbitals4s, 4p orbitalsIron, 3d5hybridizationsp3d2sp3d2 hybridizationOctahedron 八面體The Complexes of d57 Met

11、al Ions(Octahedron) in Fe(CN)63-, Fe3+ ion has the valence configuration of 3d5. Cyanide ions donate six pair electrons.4d orbitals4s, 4p orbitalsIron, 3d5d2sp3 hybridizationCoordination num. 6d2sp3 hybridizationInner Orbital Complexes andOuter Orbital Complexesinner orbital complex 內(nèi)軌型配合物, (低自旋配合物)

12、中心離子有內(nèi)層d軌道與外層s、p軌道雜化，形成雜化軌道。Outer orbital complex 外軌型配合物, (旋配合物)中心離子全部用最外層軌道參加雜化并與配位體結(jié)合Octahedral complexesNi2+3d8Ni(NH3)42+sp3數(shù)：2成單Ni(CN)42- 成單數(shù)：0dsp2配合物的磁性：擁有未成對的分子是順磁性分子；若沒有未成對，稱為逆磁性分子。數(shù)n有關(guān)磁矩與未成對m=m) Bn +2n(形成內(nèi)軌型配合物磁矩低于原中心離子形成外軌型配合物磁矩不變FeF63- 5.88 Fe(CN)63- 2.00n=5n=1內(nèi)軌型：，鍵能大，磁矩小，在水中不易離解；外軌型：不，鍵能

13、小，磁矩大，在水中易解離。中心離子是形成內(nèi)、外軌的決定因素，且與配體強弱有關(guān)。(n-1)d10(n-1)dx(n-1)dx外軌x<55-8次外層有空軌道，形成內(nèi)軌型可內(nèi)可外時，與配位體強弱有關(guān)F- ,H2O,OH-多外軌CN-,CO多內(nèi)軌NH3,Cl-配位原子電負性居 中，可內(nèi)可外。價鍵理論局限性優(yōu)點：空間構(gòu)型，磁性，離子配位數(shù)性，中心缺點：不能定量說明配合物性質(zhì)，對激發(fā)態(tài)為力，在解釋配合物顏色、吸收光譜時遇到。：只看到配位體提供的孤對占據(jù)中心離子空軌道，未看到配位體對中心離子d軌道的能量產(chǎn)生影響，使d軌道-晶體場理論發(fā)生Crystal Field Theory晶體場理論d Orbita

14、ls in Octahedral Fieldd 22x- yd2zdyzdxzdxySplit Energy D,能As ligands approach the metal to form bonds, there are repulsion between the electrons of the metal and ligands. This repulsion between the positive metal ion and negative ligand lone pair areelectrostatic. Thus, the degenerate dorbitals of a

15、atom or ion are split.配體靠近中心離子成鍵時，配體中的孤對與中心離子的d互相排斥，引起簡并的d軌道發(fā)生。Split Energy in Octahedral Fieldd 2x,d 2called eg orbitalsz- y2D, splitting energyd orbitalsdxy, dxz, dyz. called t2g orbitalsIt is assigned that D能= 10Dq, soEeg - Et2g = D = 10Dq；2Eeg + 3Et2g =0；the energy of t2g orbital = -4Dq；that of

16、eg orbital = 6DqThe Magnitude of Split Energy能的大小The split energy, D,depends upon能取決于the nature of the ligands; 配體性質(zhì)Different ligands have the different split energy. the charge on the metal ion; 金屬離子的電荷the more positive the charge is, the greater split energy.whether the metal is in the first, seco

17、nd or thirdrow of transition elements.金屬原子的周期數(shù)the 2nd or 3rd metal ions have larger split energy.Weak Field Ligands and StrongField Ligands弱場配體和強場配體Ligands which cause only a small degreeof crystal field splitting are termed weakfield ligands 導(dǎo)致晶體場能小的配體，稱為弱場配體, otherwise are strong fieldligands 導(dǎo)致晶體

18、場場配體.能大的配體，稱為強Spectrochemical Series光化學序列2-weak field 弱場配體: I- < Br- < S2- < Cl- < NO3< F< OH- < EtOH < oxalate < H2O < EDTA < NH3、-pyridine < ethylenediammine < NO2 < CN < CO.Strong field ligands. 強場配體H2O: borderline. 強場配體與弱場配體的分界線Weak Field and Strong F

19、ieldd 22x - y, d 2zd 22x - y, d 2zeg orbitalsStrong fieldWeak fieldd orbitalsdxy, dxz, dyz. t2g orbitalsdxy, dxz, dyz. t2g orbitalsExamples:Fe(CN)63-, Co(NH3)63+Examples:FeF63-, Co(H2O)63+5.9mB,5.0mB.2.3mB,0 mB.The Split Energies of 1st Series of Transition Metal Ions the magnitude of D increases as

20、 the charge on themetal ion increases. 中心離子的電荷愈高，能愈大。Oxidation stateTiVCrMnFeCoNiCu(II) elec. config.d2d3d4d5d6d7d8d9Din cm-112600139007800104009300850012600(III) elec. config.d1d2d3d4d5d6Din cm-1203001890017830210001370018600 the magnitude of D increases as the metal ion downs a group of transition

21、 elements. 同一族，自上而下，D大High-spin and Low-spin Complexes旋、低自旋配合物d 2x,deg2orbitalsd,d2eg orbitals- y2z22- yxzStrong fieldWeak fielddxy, dxz, dyz. t2g orbitalsExamples: Mn(H2O)62+dxy, dxz, dyz. t2g orbitalsFe(CN)63-Mn2+, Fe3+ : d5Electron Pairing Energy andSplit Energy成對能和能According to Hunds rule, it re

22、quires theelectron pairing energy Punpaired electrons in Mn2+成對能 when theion are forced tobe paired. 根據(jù)成對，就引入Mn2+的規(guī)則，是否成對能這一物理量。Thus, the complex is high spin if D is lessthan the P, the weak field complex, D < P, 弱場配合物,旋配合物, and the complex is lowspin if D is greater than the P, the strong field

23、complex. D > P, 強場配合物, 低自旋配合物Crystal Field StabilizationEnergy 晶體場化能(CFSE)d 2x,d e2 g orbitalsd,d2eg orbitals- y2z22- yxzStrong fieldWeak fielddxy, dxz, dyz. t2g orbitalsFe(H2O)62+dxy, dxz, dyz. t2g orbitalsFe(CN)64-Fe2+ : d6CFSEs of Complexes配合物的晶體場化能In Fe(H2O)62+,CFSE = 4Et2g + 2Eeg = 4´(-

24、4Dq)+ 2´6Dq = -4Dq In Fe(CN)64-,CFSE = 6Et2g = 6´(-4Dq) = -24Dq, more stable.CFSE in octahedral complexesdnd0d1d2d3d4d5d6d7d8d9d10weak0-4-8-12-60-4-8-12-60strong 0-4-8-12 -16 -20-24-18-12-60Magnetic Moments of Complexes配合物的磁距Molecules such as O2 and ions Fe(H2O)62+ that contain unpaired el

25、ectrons are paramagnetic 順磁性. Whereas compounds having no unpaired electronsare diamagnetic 逆磁性.擁有未成對的分子是，稱為逆磁順磁性分子；分子中若沒有未成對性分子。The size of the magnetic moment of a system containing unpaired electrons is related directly tothe number of such electrons. 分子磁距的大小與未成對數(shù)成正比。Paramagnetic and Diamagnetic順

26、磁性和逆磁性mB: Bohr magneton玻爾磁子md 22x - yn ( n + 2 ) meg orbitals=, d 2zBd 22x - y, d 2zeg orbitalsLow spin,strong fieldHigh spin,weak fielddxy, dxz, dyz. t2g orbitalsdxy, dxz, dyz. t2g orbitals Fe(CN)64-diamagneticFe(H2O)62+ParamagneticFe2+ : d6How to Use Crystal Field theory?The color of complexes配合物的

27、顏色Enthalpies change of hydration for M2+ions, in kJ×mol-1. 二價金屬離子的水合能Color of Complexes color of complexese.g. Ti(H2O)63+, purple the complex absorbs theblue-cyan component light 藍綠色光, owing to d-d transition d-d躍遷.The absorption peak at490.2 nm,D= c ¸ l = 107 ¸ 490.2 = 20400 cm-1,lig

28、htD = 20400´1.986´10-23 J/cm-1= 4.03 ´10-19 J.d-d transition of Ti(H2O)63+Purple blue cyan greenyellow orange redComplementary Color Theory顏色互補理論When an object absorbs some component color light of sunlight, we see thecomplementary colors 互補色 of the object. 物體吸收太陽光中的某一組分光后，其顏色與吸收的組分光成互補。For example, the blue color of the Cu(NH3)42+ ion results because this ion absorbs orange and red light, leaving thecomplementary colors of blue. 如Cu(NH3)42+離子吸收橙紅色后，顯橙紅色的互補色藍色。Color CircleIn Fe(CN)64-, because of greater D,