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Solutions to the Problems Solutions to the Problems I.1 2 0 ReH9 − 18e, OS 7, d TaMe 10e, OS+ 5, d0 5 + [(Ph3P)3Ru (μ-Cl)3 Ru(PPh3)3]+ The bridge counts for 9e from which the posi- tive charge is deduced. Hence, each Ru gains 4e from the bridge. Overall: 18e, OS 2, d6. + I.2 0 MeReO3 14e, OS 7, d + 6 CpMn(CO)3 18e, OS 1, d 2 + [Re2Cl8] − The ReCl4− unit has 12e. A 16 e configuration with a Re–Re quadru- ple bond is likely. I.3 In M–Cl, chlorine has still three available lone pairs. Re(CO)3Cl has 14e and needs to use two additional lone pairs. Hence, chlorine must act as a μ3 ligand and the compound is a tetramer: M Cl Cl M M=Re(CO)3 Cl M M Cl F. Mathey, Transition Metal Organometallic Chemistry, 85 SpringerBriefs in Molecular Science, DOI: 10.1007/978-981-4451-09-3, © The Author(s) 2013 86 Solutions to the Problems I.4 Ph2P has three available electrons for complexation. The possible complexes are: Ph Ph P Ph PM P Ph M M Ph Ph M 1e terminal ligand 3e terminals igand, 3e, bridging ligand, pyramidal, one lone pair planar, P=M double bond tetrahedral, no lone pair no lone pair PhP has four available electrons for complexation. The possible complexes are: P M PM Ph M Ph 2e bridging ligand, 2e terminal ligand, bent, pyramidal, one lone pair P=M double bond one lone pair M M Ph PM Ph P P M Ph M M 4e terminal ligand, linear 4e bridging ligand, planar, 4e bridging ligand, P M triple bond no lone pair tetrahedral, no lone pair no lone pair M M Ph P 4e bridging ligand, M TBP, no lone pair M I.5 (OC)3Co(NO) has an 18e configuration with NO acting as a 3e ligand. The Co–NO unit is linear. The formal oxidation state of cobalt is 1 because NO is considered as NO+. − I.6 5 5 Nickelocene is a 20e complex. It fluctuates between (η Cp)2Ni and (η Cp) Ni (η1 Cp) (16e). The 16e complex can add L to give (η5 −Cp) Ni (η1 Cp)L.− The σ bond− Ni- (η1 Cp) reacts with IMe to give Me–Cp CpNi(I)L.− − − + Solutions to the Problems 87 I.7 Ph2 P (OC)4W W(CO)4 H The bridges count for 4e. Without the metal–metal bond, the tungsten atom has 16e. The OS is 1. A W–W double bond is possible. The reaction path is probably: + W(CO)6 W(CO)6 +Ph2PH W(CO)5(PHPh2) substitution PH oxidative addition Ph2 Ph2 P loss of CO P (OC)5W W(CO)5 (OC)4W W(CO)4 H H I.8 2 If NO is a 1e ligand, [Fe(CN)5NO] − is a 16e complex and Fe has the 4 oxida- tion. This is not likely. If NO is a 3e ligand, Fe has 18e and the OS is +2. This is the correct formulation. Fe–NO is linear and the salt diamagnetic. + I.9 The two elementary steps are insertion and β-H elimination: H H H -L H2 L4IrCl + L3Ir C C H O ClL3Ir O Cl O The oxidation state of Ir is 1 before and 3 after the reaction. + + I.10 fluctuation 3e -1eNO L Co(3e-NO)(CO) 3 Co(1e-NO)(CO) 3 Co(1e-NO)(L)(CO) 3 18e 16e (associative) 18e -CO Co(3e-NO)(L)(CO) 2 88 Solutions to the Problems I.11 Ph Ph Ph Ph oxidative coupling (OC) Fe (OC)3Fe 3 Ph Ph Ph Ph Ph Ph Ph CO insertion Ph Ph reductive elimination O O Fe Ph Ph Ph (CO)3 Ph Ph Ph Ph η4-complexation aromatization O Ph Ph M Ph Ph M I.12 R R R β-H elimination reductive elim. R' H Ru H H R' H Ru R' idem from: R' R Ru H II.1 Cp2MoCl(Me) AgPF6 ethylene. No free rotation+ means+ a lot of backbonding. Ethylene is parallel to Mo–Me to * maximize the overlap of π with dyz (the z axis bisects the Cl–Mo–Cl angle). 1 13 The two CH2 are not equivalent in H and C NMR. II.2 CR(OR) M(CO)5 CR(OR) CHMe CHMe Solutions to the Problems 89 II.3 1 R R1 OMe + A (OC) Cr Li B (OC)5Cr 5 R R R1 R2 C (two stereochemistries) R II.4 Cp Cp Mn Mn B OC C OC PR2H PR OC OC 2 R R C → D similar to the conversion of Fischer carbenes into η2-ketene complexes II.5 Cl Cl O Cp*Ir IrCp* 18e Cp*Ir CMe Cl O Cl AcO Me Me Cp* OAc Cp* OAc Ir Ir N N N A B Me N Me Me II.6 H R R C C Ru C C Ru (migration of HfromRutoC) H The attack of the first complex by the carboxylate gives: O R1 O R The attack of the carbene complex by the carboxylate gives: O R R1 O 90 Solutions to the Problems II.7 N Cl N N H N N H N Ir Ir Ir N Cl N N H N N N R H2 R R H R R R PMe3 C(16e) D E N H N H fluxional in D Ir N N H N R R F II.8 O O Ru O MeO C + Ru - H H C MeO H Ru Ru H A C H B C C Ru Ru final product II.9 t tBu tBu Bu BuLi metathesis Ph Ph O Ph O - Fe CO -BuCO2 Fe(CO)3 (CO) (OC)3Fe 3 O- CO Bu tBu Ph C Fe O (CO)3 Solutions to the Problems 91 II.10 The active species is benzyne-zirconocene. Ph RP( Ph)2 R migration Cp2Zr P Zr Cp2 Ph Ph Ph R R HCl P P product Ph ZrCp 2 Ph Zr Cp2 III.1 (1) H O Ir Ir O H Ir:16e,OS+2 (2) PPh3 Ir O H (3) O O Ir reductive O elimination O Ir O O Ir H H H2O product+Ir-OH(catalyst) Ir Ir(cod); the diene replaces PPh ≡ 3 92 Solutions to the Problems III.2 PdAr HN Ar-Pd-Br N PdAr Ar PdAr H H H N N N PdAr HN Ar-Pd-Br N PdAr PdAr ArPd Ar H H H H N N N N III.3 t The catalyst is probably [Pd(P Bu3)2] stabilized by the bulky phosphine. The α-CH’s of pyridine N-oxide are easily metallated. -HBr N + H N N Pd N N N Pd-Br O O O CO2Et the ester group facilitates the N N N double metallation O Solutions to the Problems 93 III.4 The double bond coordinates Pd. The most reactive oxygen is the epoxide oxygen. O HO O Cl2Pd O O O HO O Cl2Pd III.5 β-H elimination - L RuH LnRuCl2 +2RCH2O → LnRu(OCH2R)2 n 2 H Ru H -H2 Ru H Ru H R O R O R O H H H (A) R O H R O -H2 H Ru H Ru H R O H R O (B) O β-H elimination RuH2 R O R III.6 X X OH 3 R PtCl2 OH R3 1 R R1 Pt 2 R 2 R (A) X OH R3 H X 1 O -HX R1 O 1 R 3 R Pt R3 R R2 (A) 2 R2 Pt- R Pt (C) (nucleophilicattack on coordinatedligand) 1 O 1 R -Pt R O R1 O R3 R3 R3 2 2 2 R PtH R (D) R (D)gives themorestablearomaticfuran by [1,5]Hmigration 94 Solutions to the Problems III.7 Coordination of nitrogen to Pd(II) and ortho-metallation: RCH2OH N N PdCl Pd OCH2R -H elimination β N +RCH=O Pd-H oxidation N N +RCOOH O Pd-OH Pd OC R N +[Pd=O] R O III.8 Taking into account the polarization of the exocyclic double bond, this heptaful- vene is somewhat aromatic. The actual catalyst is a bis (η3-allyl) palladium. The reaction is a conjugate 1,8-addition. CN CN NC NC Pd -Pd Pd Solutions to the Problems 95 III.9 H O OH O O CO Pd(II) Pd Pd base R R (A) R (B) O O O O Pd Pd (C) R O R OH base R O O -Pd(0) R O R Oxygen is necessary to reoxidize Pd(0) to Pd(II) which is the actual catalyst. Index A Alkynes Acetaldehyde hydrosilylation, 63 Wacker process, 72 hydrozirconation, 35 Acidities of hydrides, 29 insertion into Zr–C, 36 Acylation metathesis, 46, 71 of butadiene-iron-tricarbonyl, 48 Allyl complexes of ferrocene, 49 Palladium, 76 Acyl complexes Arene complexes Cobalt, 65 Chromium, 50 by insertion of CO in M–R, 33 Aryl halides Acyl halides Heck reaction, 73 reaction with tantalum-carbene Stille reaction, 74 complexes, 45 Asymmetric catalysis, 60 reaction with stannanes, 75 Atactic polypropylene, 69 Adiponitrile, 64 Atomic orbitals (s, p, d), 6 Agostic C–H bond, 33 Atropisomerism, 61 Aldehydes by the oxo process, 65 by the Stille reaction, 75 B by the Wacker process, 72 Backbonding, 7 Alkenes Benzene arylation-vinylation η6-complexes, 50 (Heck), 73 Benzyne cyclopropanation, 42 η2-complex, 35 hydrocyanation, 64 Berry pseudorotation, 13 hydroformylation, 65 BINAP, 61 hydrogenation, 58 BINAPHOS, 66 hydrosilylation, 62 Bonds hydrozirconation, 34 force constants M–CO, 31 metathesis, 70 π-bonds, 8 polymerization, 67 Boron trihalides, 46 Alkyl complexes Bredt’s rule, 32 bond strength, 32 Butadiene Cobalt, 65 complex with Fe(CO)3, 47 Zirconium, 35 hydrocyanation, 64 F.
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