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  • 2Chng 1

    GII THIU V PHC CHT

  • 31. KHI NIM PHC CHT

    - Cc nguyn t kt hp vi nhau cc hp cht n gin (hp

    cht bc nht), chng hn: Na2O, CaO, NaCl, CuCl2...

    - Cc hp cht n gin c th kt hp vi nhau to thnh hp

    cht phn t (hp cht bc cao), gi l phc cht.

    Chng hn: K2[HgI4] (HgI2.2KI),

    [Ag(NH3)2](NO3) (AgNO3.2NH3),

    K4[Fe(CN)6] (Fe(CN)2.4KCN)...

    (Gi l hp cht phn t nhm nhn mnh: chng khng phi l

    cc nguyn t, cc gc m l cc phn t kt hp vi nhau).

    - Vn t ra l hp cht phn t no th c gi l phc

    cht?

  • 4- A. Werner: phc cht l hp cht phn t no bn trong dung

    dch nc, khng phn hu hoc ch phn hu rt t ra cc hp

    phn to thnh to thnh hp cht .

    VD: Trong dung dch, phc cht [Ag(NH3)2](NO3) in ly:

    [Ag(NH3)2](NO3) = [Ag(NH3)2]+ + NO3

    -

    - A. Grinbe: phc cht l nhng hp cht phn t xc nh, khi

    kt hp cc hp phn ca chng li th to thnh cc ion phc

    tp tch in dng hay m, c kh nng tn ti dng tinh th

    cng nh trong dung dch. Trong trng hp ring, in tch

    ca ion phc tp c th bng 0.

  • 5- K. B. Iaximirxki: phc cht l nhng hp cht to c cc

    nhm ring bit t cc nguyn t, ion hoc phn t vi nhng

    c trng:

    + c mt s phi tr

    + khng phn ly hon ton trong dung dch

    + c thnh phn phc tp, s phi tr v s ho tr khng trng

    nhau

  • 6Tng qut:

    Phc cht l hp cht to thnh gia ion hay nguyn t kim loi

    M vi cc phi t A l cc phn t hay ion khc. Phn t hoc

    ion phc tng i bn trong dung dch. S lin kt to thnh

    gia M vi A nhiu hn ha tr thng thng ca M.

    V d: [AgCl2]-, [Ag(NH3)2]

    +, [Co(NH3)6]3+, [Fe(CO)5]

    Cng thc chung ca phc cht: [MAa]

    - Hu ht cc ion kim loi trong nc tn ti dng phc

    hydrat: [M(H2O)n]x+ vi n thng bng 6.

  • 7Hin tng xy ra khi cho t t dung dch NH3 vo dungdch CuCl2

  • 8Hin tng xy ra khi cho thuc th K4[Fe(CN)6] vo dungdch FeCl3

  • 92. Cu to phc cht

    Cng thc chung ca phc cht: [MAa]

    M: ion trung tm

    A: phi t

    a: s phi tr

    V d:

    [Ag(NH3)2]2SO4

    phi tion trung tm s phi tr

    cu ngoicu ni

  • 10

  • 11

    1.2.1. Ion trung tm v phi t

    - Ion hay nguyn t kim loi M c gi l ion trung

    tm. M l axit Lewis v c cc orbital ha tr ang cn trng,

    c th nhn cc cp electron ca cc phn t hay ion khc.

    - Phi t A l baz Lewis. A c cc cp electron t do

    cho M. V d: Cl-, CN-, H2O, NH3...

  • 12

    1.2.2. Cu ni, cu ngoi

    - Du mc vung [ ] c dng ch cc nguyn t

    lin kt vi nhau bng lin kt cng ha tr, cc nguyn t

    c gi chung l cu phi tr, cu ni hay ion phc.

    - Nu cu ni mang in th cn kt hp thm cc ion

    tri du to hp cht trung ha in, cc ion c gi l

    cu ngoi.

    V d: [Ag(NH3)2]Cl, Na[AgCl2]

    Nh vy nu cu ni khng mang in th khng c cu

    ngoi. V vy, t phc cht thng dng ch cu ni.

  • 13

    Phc cht trung ha l cht in ly trong nc. Lc :

    - Ion phc v cu ngoi tch khi nhau (in ly hon ton)

    - Ion phc in ly rt yu, c th b qua s in ly ca ion

    phc.

    V d: [Ag(NH3)2]Cl = [Ag(NH3)2]+ + Cl-

    Nu quan tm n s in ly ca ion phc, ta c cn bng:

    MAa M + a A

    Phc cht cng bn, hng s = cng ln.

    c gi l hng s bn ca phc cht MAa.

    a

    a

    ]A][M[

    ]MA[

  • 14

    1.2.3. S phi tr

    S phi tr ca M l s lin kt m ion trung tm M to

    c vi cc phi t.

    S phi tr quan h mt thit vi cu trc hnh hc ca

    phc cht (Bng 1.1)

  • 15

    SPTCu trc hnh hc ca

    phc chtV d

    2 Thng [CuCl2]

    -, [Ag(NH3)2]+,

    [AuCl2]-

    4

    Vung phng

    [Ni(CN)4]2-, [PdCl4]

    2-, [Pt(NH3)4]

    2+

    T din[Cu(NH3)4]

    2+, [Zn(NH3)4]2+,

    [MnCl4]2-

    6 Bt din [Cr(H2O)6]

    3+, [V(CN)6]4-,

    [Cu(NH3)4Cl2]+, [Co(En)3]

    3+

  • 16

    1.2.4. Phi t n rng, a rng

    - Phi t n rng l phi t ch cho M mt cp

    electron t do, mc d n c th c nhiu cp electron t do.

    V d: X- , OH-, CN-, SCN-, NH3, H2O...

  • 17Triclo triammin coban (III)

  • 18

    - Phi t a rng l phi t c th cho M t hai cp electron

    tr ln.

    V d:

    + Phi t 2 rng: en (etylendiamin: NH2-CH2-CH2-NH2),

    cacbonat, oxalat, bpy (bipyridin), o-phenanthrolin...

  • 19

  • 20

    [CoCl(en)2NO]2+

  • 21

    [Co(C2O4)3]3-

  • 22

    [Co(en)3]3+

  • 23

    + Phi t 6 rng: EDTA4- (etylen diamin tetraaxetat)

    Phi t a rng c gi l phi t chelat. Chela ting Hy lp

    ngha l con cua. Phc ch cha cc phi t a rng c gi

    l phc vng cng hay chelat.

  • 24

  • 25

    3. VAI TR CA PHC CHT

    3.1. Trong ho hc phn tch

    Phc cht ng mt vai tr quan trng trong vic pht

    trin cc phng php phn tch nh tnh v nh lng.

    - Trong phn tch nh tnh: thuc th to vi cc ion kim loi

    cc phc cht c mu c trng, thng c dng nhn

    bit ion kim loi.

    V d:

    + Thuc th Na3[Co(NO2)6] kt hp vi M+ (K+, Cs+, Ag+, Tl+,

    NH4+) cho phc rn c mu:

    2M+ + Na3[Co(NO2)6] M2Na[Co(NO2)6] + 2Na+

  • 26

    + Thuc th Nestler K2[HgI4] trong mi trng kim to phc

    vi NH4+ c mu vng rt c trng:

    NH4+ + 2[HgI4]

    2- + 2OH- [NH2(HgI)2]I + 5I- + 2H2O

    + Thuc th K4[Fe(CN)6] trong mi trng axit to phc vi

    Fe3+ c mu xanh berlin c trng:

    4Fe3+ + 3[Fe(CN)6]4- Fe4[Fe(CN)6]3

    + Thuc th K3[Fe(CN)6] trong mi trng axit to phc vi

    Fe2+ c mu xanh tuabin c trng:

    3Fe2+ + 2[Fe(CN)6]3- Fe3[Fe(CN)6]2

  • 27

    - Nhng phc cht tan c mu m thng c dng trong

    phng php so mu xc nh nng ion kim loi.

    V d:

    + xc nh nng Cu2+ ngi ta to phc vi NH3 to

    thnh dung dch [Cu(NH3)4]2+ c mu xanh c trng:

    Cu2+ + 4NH3 [Cu(NH3)4]2+

    + xc nh nng Ti(IV), ngi ta to phc vi H2O2 to

    thnh dung dch [TiO(H2O2)2]2+ c mu vng c trng:

    TiOSO4 + 2H2O2 [TiO(H2O2)2]SO4

  • 28

    - Trong phn tch nh lng, s dng EDTA (Na2H2Y) to

    phc bn vi cc cation kim loi. Phn ng ca EDTA vi cc

    cation kim loi xy ra theo t l hp thc ng lng nghim

    ngt:

    Na2H2Y 2Na+ + H2Y

    2-

    Me2+ + H2Y2- MeY2- + 2H+

    Me2+ l: Ca2+, Mg2+, Ba2+, Co2+, Ni2+, Cu2+, ...

    Me3+ + H2Y2- MeY- + 2H+

    Me3+ l: Al3+, Fe3+, In3+, ...

    Me4+ + H2Y2- MeY + 2H+

    Me4+ l: Th4+, Ce4+, ...

  • 29

    - Trong phn tch th tch, dng s to phc che cc ion l

    (v d: xc nh Cu2+ khi c mt Fe3+ ngi ta dng F-

    che Fe3+) hoc dng lm thuc th chun cc ion kim

    loi, hoc lm cht ch th ca cc phn ng oxi ho kh.

  • 30

    3.2. Trong iu ch kim loi

    Phc cht c dng trong vic iu ch cc kim loi tinh

    khit, tch ring cc nguyn t him, cc kim loi qu, c bit

    l h platin, cc nguyn t sau uranium.

    V d: tch Au ra khi qung ngi ta thng cho Au to

    phc vi CN- trong mi trng kim khi c mt oxy:

    4Au + O2 + 8NaCN + 2H2O 4Na[Au(CN)4] + 2NaOH

    Phn ng c s dng tch Au ra khi qung c hm

    lng vng thp v khng th tch bng phng php trng

    lc.

  • 31

    3.4. Trong i sng sinh vt

    Phc cht c ngha rt to ln trong hot ng sng ca sinh

    vt. C 24 nguyn t cn thit cho i sng sinh vt, trong

    c 7 nguyn t quan trng nht (Fe, Zn, Co, Cu, Mn, Cr, V)

    hot ng da trn c s to chelat.

    V d:

    Fe: Hemoglobin;

    Mg: chlorophyll;

    Co: Vitamin B

  • 32

    - Nhiu chelat t nhin c to thnh trn c s phn t

    porphyrin:

    Khi hai nguyn t H lin kt vi N b tch i, porphyrin l phi

    t 4 rng.

    Phn t porphyrin

  • 33

    Phc cht to thnh t cc dn xut ca porphyrin vi cc kim

    loi c gi l cc porphyrin.

    Hai porphyrin quan trng l heme (Fe2+, c l hem) v

    chlorophyll (Mg2+).

    - Heme

    L chelat m nguyn t trung tm l st v cc phi t l cc

    vng porphyrin.

  • 34Heme

  • 35

    Nh cc vng porphyrin lm cho heme c mu .

    Trong heme, st c s phi tr 6:

    + bn v tr trong s nm trong mt phng ca vng

    porphyrin

    + hai v tr cn li thng gc vi mt phng . Trong hai v tr

    ny th mt v tr s lin kt vi mt baz thuc cu trc protein

    (thng l globin khi to hemoglobin), cn v tr th hai lin

    kt vi oxi phn t khi vn chuyn oxi t phi n t bo trong

    c th.

  • 36

    - Hemoglobin

    Hemoglobin (c trong thnh phn ca mu ngi v ng vt)

    gm c cht albumin gi l "globin" v mt hp cht mu gi

    l "heme".

    Hemoglobin gm 4 n v protein, mi n v cha mt heme,

    lm nhim v vn chuyn oxi t phi n cc t bo:

    Hb + 4 O2 Hb-(O2)4 mu

    Khi t t bo v li phi, v tr ca O2 c thay bng H2O:

    Hb-(H2O)4 mu xanh da tri.

    CO lin kt rt bn vi Fe2+ trong heme nn khng cn v tr

    trng heme lin kt vi oxi (hemoglobin b ng c), v vy

    cc t bo cht do khng c oxi nui dng.

  • 37Hemoglobin

  • 38

    - Chlorophyll

    Chlorophyll l cht mu xanh lc ca thc vt (dip lc t),

    nhn dip lc l phn quan trng nht trong phn t dip lc,

    gm 1 nguyn t Mg trung tm lin kt vi 4 nguyn t N

    ca vng porphyrin.

  • 39Chlorophyll

  • 40

    iu quan trng nht ca phn t ny l n c h thng ni i

    lin hp lm cho dip lc t c hot tnh quang ho mnh. Kh

    nng hp th nh sng ph thuc vo s lng lin kt i

    trong phn t. Dip lc ng vai tr quan trng trong qu

    trnh quang hp ca cy xanh:

    - Hp th nng lng nh sng mt tri

    - Vn chuyn nng lng vo trung tm phn ng

    - Tham gia bin i nng lng nh sng thnh nng lng ho

    hc.

    Tng hp quang ha l phn ng thu nhit, chuyn CO2 v

    H2O thnh gluco v O2 nh thc vt khi c nh sng:

    6 CO2 + 6 H2O C6H12O6 + 6 O2

  • 41

    5.6. Trong dc phm

    - Vitamin B12:

    l nhng hp cht hu c c nguyn t cobalt trung tm, vi

    tn gi l nhng cobalamin v c hot tnh sinh hc trn c th

    ngi. Vitamin B12 tham gia phn ng tng hp thymidyla