UMass Amherst Created by Karsten Theis

Chem 341

Coordination Chemistry – ReactionsChapter 12: 464-469

HW:1 2 3 4 5 9 14 15 19

Goals: Rationalize LigExch products using mechanisms (SN1 and SN2)Predict products for LigExch using the trans effect (Pt2+)Don’t worry about kinetic expressions!

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FINAL exam

Friday 12/16 1:30 – 3:30 pm ISB 221

Snow policy: If inclement weather... If Univ is closed until 10AM or 1PM:

• Final is at normal time

If Univ is closed all day:• Final is on Saturday Dec 17 at 8:00 AM

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3

Review sessions

Wed Dec 16: 6:00 – 7:30 PM (room to be announced)

Thursday: what time would work? A) 10AM B) 12PM C) 2PM D) 4PM E) 6PM

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4

Trans-M(LL)2BX : bidentate ligands favors TBP intermediate

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5

Square Planar: SN2

PtL2Cl2 + Y PtL2ClY + Cl-Retain configuration (trans)

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6

HSAB to explain reactivity trend for entering:Y = PR3 > CN- > I- > py > NH3 ~ Cl- > CH3OH

108 1 HSAB to explain reactivity trend for leaving

group• X = PR3 < CN- < I- < py < NH3 ~ Cl- < CH3OH

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7

The trans effect in Square Planar Pr(II) complexes

Strong Pt-T bonds favors the proper TBP transition state

Best trans directors: CO ~ CN- > PR3 > SCN- ~ I- > Br- > Cl- > py,

NH3 ~ OH- ~ H2O

Pt(NH3)42+ + excess Cl- trans Pt(NH3)2Cl2

PtCl42- + excess NH3 cis Pt(NH3)2Cl2

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8

Pt(NH3)42+ + excess Cl- trans Pt(NH3)2Cl2

PtCl42- + excess NH3 cis Pt(NH3)2Cl2

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