Chapter 9 Coordination Chemistry I: Structures and Isomers 123 CHAPTER 9: COORDINATION CHEMISTRY I: STRUCTURES AND ISOMERS 9.1 Hexagonal: C2v C2v D2h Hexagonal pyramidal: Cs Cs C2v Trigonal prismatic: Cs C2v C2 Trigonal antiprismatic: Cs C2 C2h The structures with C2 symmetry would be optically active. 9.2 a. dicyanotetrakis(methylisocyano)iron(II) or dicyanotetrakis(methylisocyano)iron(0) b. rubidium tetrafluoroargentate(III) or rubidium tetrafluoroargentate(1–) c. cis- and trans-carbonylchlorobis(triphenylphosphine)iridium(I) or cis- and trans- carbon ylchlorobis(triphenylphospine)iridium(0) d. pentaammineazidocobalt(III) sulfate or pentaammineazidocobalt(2+) sulfate e. diamminesilver(I) tetrafluoroborate(III) or diamminesilver(1+) tetrafluoroborate(1–) – (The BF4 ion is commonly called “tetrafluoroborate.”) 9.3 a. tris(oxalato)vanadate(III) or tris(oxalato)vanadate(3–) b. sodium tetrachloroaluminate(III) or sodium tetrachloroaluminate(1–) c. carbonatobis(ethylenediamine)cobalt(III) chloride or carbonatobis(ethy lenediamine)cobalt(1+) chloride d. tris(2,2-bipyridine)nickel(II) nitrate or tris(2,2-bipyridine)nickel(2+) nitrate (The IUPAC name of the bidentate ligand, 2,2-bipyridyl may also be used; this ligand is most familiarly called “bipy.”) e. hexacarbonylmolybdenum(0) (also commonly called “molybdenum hexacarbonyl”). The (0) is often omitted. 9.4 a. tetraamminecopper(II) or tetraamminecopper(2+) b. tetrachloroplatinate(II) or tetrachloroplatinate(2–) c. tris(dimethyldithiocarbamato)iron(III) or tris(dimethyldithiocarbamato)iron(0) d. hexacyanomanganate(II) or hexacyanomanganate(4–) e. nonahydridorhenate(VII) or nonahydridorhenate(2–) (This ion is commonly called “enneahydridorhenate.”) Copyright © 2014 Pearson Education, Inc. 124 Chapter 9 Coordination Chemistry I: Structures and Isomers 9.5 a. triamminetrichloroplatinum(IV) or triamminetrichloroplatinum(1+) b. diamminediaquadichlorocobalt(III) or diamminediaquadichlorocobalt(1+) c. diamminediaquabromochlorocobalt(III) or diamminediaquabromochlorocobalt(1+) d. triaquabromochloroiodochromium(III) or triaquabromochloroiodochromium(0) e. dichlorobis(ethylenediamine)platinum(IV) or dichlorobis(ethylenediamine)platinum(2+) or dichlorobis(1,2-ethanediamine)platinum(IV) or dichlorobis(1,2- ethanediamine)platinum(2+) f. diamminedichloro(o-phenanthroline)chromium(III) or diamminedichloro(o- phenanthroline)chro mium(1+) or diamminedichloro(1,10-phenanthroline)chromium(III) or diamminedichloro(1,10-phenanthroline)chromium(1+) g. bis(2,2-bipyridine)bromochloroplatinum(IV) or bis(2,2- bypyridine)bromochloroplatinum(2+) or bis(2,2-bipyridyl)bromochloroplatinum(IV) or bis(2,2- bipyridyl)bromochloroplatinum(2+) h. dibromo[o-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(II) or dibrom o[o-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(0) or dibrom o[1,2-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(II) or dibrom o[1,2-phenylene(dimethylarsine)(dimethylphosphine)]rhenium(0) i. dibromochlorodiethylenetriaminerhenium(III) or dibrom ochlorodiethylenetriaminerhenium(0) or dibromochloro(2,2- diam inodiethylamine)rhenium(III) or dibromochloro(2,2- diam inodiethylamine)rhenium(0) 9.6 a. dicarbonylbis(dimethyldithiocarbamato)ruthenium(III) or dicarbonylbis(dimethyldithiocarbamato)ruthenium(1+) b. trisoxalatocobaltate(III) or trisoxalatocobaltate(3–) c. tris(ethylenediamine)ruthenium(II) or tris(ethylenediamine)ruthenium(2+) d. bis(2,2-bipyridine)dichloronickel(II) or bis(2,2-bipyridine)dichloronickel(2+) 9.7 a. Bis(en)Co(III)-µ-amido-µ-hydroxobis(en)Co(III) 4+ N N H2 N N N Co Co N O N H N N Copyright © 2014 Pearson Education, Inc. Chapter 9 Coordination Chemistry I: Structures and Isomers 125 b. Diaquadiiododinitritopalladium(IV) I H2O ONO OH2 ONO I Pd Pd H2O ONO H2O ONO I I I I ONO OH2 ONO OH2 Pd Pd ONO OH2 H2O I I ONO I I H2O I I OH2 Pd Pd ONO ONO ONO ONO H2O OH2 enantiomers c. Fe(dtc)3 S S – S CH3 S S S S S Fe Fe = C N S S S S S S H S S At low temperature, restricted rotation about the C—N bond can lead to additional isomers as a consequence of the different substituents on the nitrogen. These isomers can be observed by NMR. Copyright © 2014 Pearson Education, Inc. 126 Chapter 9 Coordination Chemistry I: Structures and Isomers 9.8 a. triammineaquadichlorocobalt(III) chloride Isomers are of the cation: + + + H2O Cl NH3 H3N Cl H3N OH2 H2O NH3 Co Co Co H3N NH3 H3N NH3 Cl NH3 Cl Cl Cl cis trans mer fac b. -oxo-bis(pentammine-chromium(III)) ion 4+ H N NH 3 H3N H3N 3 O Cr Cr H3N NH3 NH NH H3N 3 3 NH3 c. potassium diaquabis(oxalato)manganate(III) Isomers are of the anion: – – – O O H2O O O O O O O Mn Mn Mn H2O O O OH2 O O H2O OH2 H2O cis enantiomers trans Cl NH3 9.9 a. cis-diamminebromochloroplatinum(II) Pt Br NH3 I b. diaquadiiododinitritopalladium(IV) H2O ONO Pt ONO OH 2 I O O O C O C C C O c. tri--carbonylbis(tricarbonyliron(0)) C Fe Fe OC C C CO O O Copyright © 2014 Pearson Education, Inc. Chapter 9 Coordination Chemistry I: Structures and Isomers 127 9.10 O CH2 C H N O – = N O 2 O O N N N N N N O N N O M M M M O O O O N O O N N N O O fac mer 9.11 M(AB)3 B B A A A A A A B A A B M M M M B B B B A B B A A A B B fac mer 9.12 a. [Pt(NH ) Cl ]+ 3 3 3 + + NH3 Cl Cl NH3 H3N NH3 Pt Pt Cl NH3 Cl NH3 Cl Cl fac mer + b. [Co(NH3)2(H2O)2Cl2] + + + + NH3 Cl NH3 NH3 H2O NH3 H2O NH3 Cl OH2 Cl OH2 Co Co Co Co Cl OH2 H2O NH3 Cl OH2 H2O Cl Cl Cl NH3 NH3 + + OH2 H2O H2O NH3 H3N OH2 Co Co Cl NH3 H3N Cl Cl Cl enantiomers Copyright © 2014 Pearson Education, Inc. 128 Chapter 9 Coordination Chemistry I: Structures and Isomers + c. [Co(NH3)2(H2O)2BrCl] + + + + OH2 Cl NH3 NH3 H3N Br H2O NH3 Br OH2 Cl OH2 Co Co Co Co H3N Cl H2O NH3 Cl OH2 H2O Br OH Br NH NH 2 3 3 + + + + OH2 H2O OH2 H2O H2O NH3 H3N OH2 H2O NH3 H3N OH2 Co Co Co Co Br Br Cl Cl NH3 H3N NH3 H3N Cl Cl Br Br enantiomers enantiomers d. Cr(H2O)3BrClI OH2 H2O H2O OH2 H2O OH2 Cr Cr Cl I I Cl Br Br enantiomers OH2 OH2 OH2 Cl OH2 I OH2 Cl OH2 Cr Cr Cr H2O Br H2O Br H2O I I Cl Br 2+ e. [Pt(en)2Cl2] 2+ 2+ N N Cl 2+ N N N N N N Pt Pt Pt Cl N N Cl N N Cl Cl Cl cis enantiomers trans Copyright © 2014 Pearson Education, Inc. Chapter 9 Coordination Chemistry I: Structures and Isomers 129 + f. [Cr(o-phen)(NH3)2Cl2] + + + + N N N N N Cl N NH N N 3 NH3 H3N Cr Cr Cr Cr Cl NH3 H3N Cl Cl NH3 H3N Cl NH Cl Cl Cl 3 enantiomers trans Cl ligands trans NH3 ligands g. [Pt(bipy) BrCl]2+ 2 2+ 2+ 2+ Br N N N N N Br Br N Pt Pt Pt Cl Cl N N N N Cl N N enantiomers h. Re(arphos)2Br2 Abbreviating the bidentate ligands As P: Br Br P P P P P As Br As As Br Re Re Re Re As As As P Br As As Br Br Br P P As As As As Br P P Br Br P P Br Re Re Re Re Br P P Br Br As As Br As As P P Copyright © 2014 Pearson Education, Inc. 130 Chapter 9 Coordination Chemistry I: Structures and Isomers i. Re(dien)Br2Cl Cl Cl Br N Br Br N N Cl Re Re Re N Br Br N N Br N N N Br Cl N Cl N Br Re Re N N N N Br Br 9.13 a. M(ABA)(CDC) C A B B A D C B C A A C M M M M B A D A D A A D C C C C b. M(ABA)(CDE) C A A A D C B B C M M M B A D A A D E E E B B C A A C M M D A A D E E A A C A A C M M D B B D E E Copyright © 2014 Pearson Education, Inc. Chapter 9 Coordination Chemistry I: Structures and Isomers 131 9.14 A A A C B A B B A M M M B C B C C B A C C A A C C A B B A A A A A M M M M B C C B B B B B C C C C B B B B A C C A A A A A M M M M B A B B B C C B C C C C 9.15 a. The “softer” phosphorus atom bonds preferentially to the soft metal Pd (see Section 6.6.1). b, c. Abbreviating the bidentate ligands NP: Cl Cl P P P P P N Cl N N Cl Ni Ni Ni Ni N N N P Cl N N Cl Cl Cl P P N N N N Cl P P Cl Cl P P Cl Ni Ni Ni Ni Cl P P Cl Cl N N Cl N N P P Copyright © 2014 Pearson Education, Inc. 132 Chapter 9 Coordination Chemistry I: Structures and Isomers 9.16 a, b. Abbreviating the bidentate ligands N P and O S: Cl Cl S P S N M M O N O P Cl Cl N N P P Cl P P Cl Cl N N Cl M M M M Cl O O Cl Cl O O Cl S S S S N N P P Cl P P Cl Cl N N Cl M M M M Cl S S Cl Cl S S Cl O O O O N – 9.17 The single C–N stretching frequency indicates a trans structure for the cyanides (the symmetric stretch of the C C—N bonds is not IR active), while the two C–O bonds O O C C indicate a cis structure for the carbonyls (both the Co symmetric and antisymmetric C–O stretches are IR Br Br active).