201233-83-2

Upstream product

• 15279-67-1 dimanganese octacarbonyl di-(triphenyl phosphine) 
• 544-77-4 1-iodohexadecane 
• 51371-63-2 Mn(CO)4(P(C₆H₅)3)Re(CO)4(P(C₆H₅)3) 
• 14879-42-6 iodo(pentacarbonyl)manganese(I) 

Relevant academic research and scientific papers

Photochemistry of organometallic halide complexes. Mechanisms for the formation of ionic products

The photochemical reactions of the Mn(CO)5X (X = Cl, Br, I), CpMo(CO)3X (X = Cl, I), and CpFe(CO)2I complexes with various ligands were investigated with an emphasis on determining how ionic products form in these reactions. Two pathways account for the formation of ionic products: (1) M-X heterolysis and (2) metal-metal-bonded dimer formation followed by subsequent disproportionation. The metal-metal-bonded dimer may form via a secondary photolysis of a M-CO-loss photoproduct, via M-X heterolysis, or via a minor M-X homolysis pathway, followed by coupling of two metal radicals. CpMo(CO)3X reacts photochemically with a variety of ligands to give substitution products, but ionic products form only with pyridine and DMSO. With pyridine, the following sequence of reactions was found to yield ionic products: (1) CpMo(CO)3Cl →hν CpMo(CO)3 + Cl; (2) 2CpMo(CO)3 → Cp2Mo2(CO)6; (3) Cp2Mo2(CO)6 →hν CpMo(CO)3- + CpMo(CO)3py+. (Reaction 3 is the photochemical disproportionation of Cp2Mo2(CO)6 described previously by us.) The CpMo(CO)3X complexes are the only halides studied for which some M-X homolysis occurs; however, homolysis of the Mo-X bond is very inefficient: Φ = 9 × 10-4. For CpMo(CO)3X in DMSO, the only ionic product is CpMo(CO)2(DMSO)2+, formed by the following route: CpMo(CO)3Cl + DMSO →hν CpMo(CO)2(DMSO)Cl →hν CpMo(CO)2DMSO+ + Cl- → CpMo(CO)2(DMSO)2+. Ionic products form in the photochemical reactions of Mn(CO)5X complexes via the following route involving initial Mn-CO bond dissociation: Mn(CO)5X →hν Mn2(CO)8X2 →hν MnX2 + 3CO + 1/2 Mn2(CO)10. Photochemical disproportionation of the Mn2(CO)10 complex then occurs. Ionic products also form in the photochemical reactions of the CpFe(CO)2I complex via the intermediate formation of the metal-metal-bonded dimer, followed by disproportionation of this species. In this case, however, the dimer is formed by initial heterolysis of the Fe-I bond (CpFe(CO)2I →hν CpFe(CO)2+ + I-) followed by the sequence of reactions in Scheme II.

Spontaneous and Induced Homolysis of Bis(triphenylphosphine)octacarbonyldimanganese (Mn-Mn)

Kinetic studies show that the complex Mn2(CO)8(PPh3)2 reacts thermally by two paths with C2H2Cl4, C16H33I, O2, NO, P(OEt)3, and P-n-Bu3 in decalin or cylcohexane.Reactions with CO or P(OPh)3 proceed only by one of these paths.The two paths are approximately equal importance and both show a very close fit to the same, rather complex, form of rate equation.The equation is quite inconsistent with any form of rate-determining dissociation, but it is consistent with two forms of reversible homolysis, one spontaneous and one induced.The latter involves initial, reversible formation of a reactive isomer of Mn2(CO)8(PPh3)2 which undergoes homolysis when attacked by a sufficiently reactive reagent.Both paths are therefore operative in reactions with the more reactive reagents, but reactions with CO and P(OPh)3 proceed only via spontaneous homolysis because these reagents are evidently unable to induce homolysis of the reactive isomer of the complex.A possible structure for the reactive isomer is one formed by metal migration, i.e., it can be formulated as (Ph3P)(OC)4Mn(μ-CO)Mn(CO)3(PPh3) which contains a bridging CO ligand, no Mn-Mn bond, and a vacant coordination site on one Mn atom.Attack at this site by suitably active reagents is postulated to lead to fragmentation.These results show that behavior previously thought to be uniquely indicative of spontaneous homolysis could also be explained by reversible homolysis induced by the reactant after isomerization of the complex.Rate constants are derived for halogen transfer from C2H2Cl4 or C16H33I to .Mn(CO)4(PPh3) and for nucleophilic displacement of PPh3 from .Mn(CO)4(PPh3) by P(OPh)3, P(OEt)3, and CO.

Homolytic Fission and Scrambling Reactions of Mn2(CO)8(PCy3)2 (Cy = cyclohexyl) and Mn2(CO)8(PPh3)2

The complexes Mn2(CO)8L2 (L=PCy3 and PPh3) (Cy=cyclohexyl) both react with 1,1,2,2-tetrachloroethane to form ClMn(CO)4L at rates which conform with initial homolytic fission of the Mn-Mn bond and this mechanistic assignment is confirmed by the occurence o

Electrophilic attack at metal carbonyls. Kinetics of reactions of halogens with some substituted dimetal carbonyls

The kinetics have been studied of reactions (in cyclohexane or decalin) of iodine with a number of dimetal carbonyls M3(CO)10-xLx (for x = 1, M = Re, L = PPh3; for x = 2, M2 = Mn2, MnRe, and Re2, L = PPh3; for x = 2, M = Mn L = P(OPh)3, P(OMe)3, PPh3, P(p-MeOC6H4)3, PPh2Et, PPhEt2, PEt3, P(n-Bu)3, and P(C6H11)3). The reactions are first order in the concentration of the reacting complex. The predominant term in most of the rate equations is k3[I2]2 but a term as high as k5[I2]4 is observed in one case, and for Mn2(CO)8{P(OPh)3}2 the rate equation is kobsd = {k3[I2]2 + k4[I2]3}/{1 + β1[I2] + β2[I2]2 + β3[I2]3}. Some reactions were also followed in CCl4, CH2Cl2, MeOH, EtOAc, and n-Bu2O. The reactions are concluded to involve rapid preformation of a series of adducts, complex·nI2, where n can be as high as 4. This is followed by electron transfer and fission of the metal-metal bond with formation of mononuclear iodo complexes. The effects of the nature of L on the rate constants for reactions with I2 or Br2 can best be interpreted in terms of initial electrophilic attack at the O atoms of the CO ligands, the surface of the complex providing an extended area of suitably high electron density which can bind several halogen molecules. The electronic effect appears to operate mainly through the σ-donor ability of the substituents and not their π-acid character. Some comparisons are drawn with reactions of halogens with other metal-carbonyl complexes and with some aryl-Sn compounds.