Π-Allyl COMPLEXES OF THE TRANSITION METALS

Lobach, M. I.; Babitskii, B. D.; Kormer, V. A.

doi:10.1070/rc1967v036n07abeh001658

Cited by 26 publications

(6 citation statements)

References 2 publications

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“…spectra were obtained in acetone-d, solution for comparison with other thiourea complexes. The n-ally1 and n-crotyl resonances are very similar to those reported for analogous complexes (13,14). Data on the thiourea resonances is given in Table 7.…”

Section: Nitrate Complexessupporting

confidence: 65%

The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

Eaton¹,

Zaw²

1975

Can. J. Chem.

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Can. J. Chem. 53,633 (1975).. A number of Ni(I1) complexes of thiourea, N-methylthiourea, N,N1-dimethylthiourea, N-naphthylthiourea, N,N1-diethylthiourea, and ethylene thiourea have been studied in acetone solution by proton magnetic resonance, magnetic susceptibility measurements, and conductivity measurements. In solution these complexes have tetrahedral, square planar, and octahedral geometries. In many cases equilibria between compounds with different geometries exist. Such equilibria have been studied as a function of temperature. The factors determining the relative stability of Ni(I1) compounds with different geometries are discussed. In the present series of compounds it is concluded that the charge on the metal ion has the predominant influence in determining geometry. Some qualitative results on ligand exchange rates and mechanisms are also reported. D. R. EATON e t K. ZAW. Can. J. Chem. 53, 633 (1975). On a CtudiC, en solution dans ['acetone, par resonance magnktique nuclkaire du proton, par d e s mesures de susceptibilit6 maanetique et par des mesures de conductivitC. une seriede complexes du Ni(1I) avec la ihiourke, la&-methylthiour&e, la N, ~' -d i m~t h~l t h i o u r & , la N-naphtylthibur6e, la N, N'-dibthylthiouree et I'ethyltne thiourke. En solution, ces complexes ont des gComCtries tetraedrique, plan carre et octabdrique. Dans plusieurs cas, des dquilibres existent entre des composes ayant des gCometries diffkrentes. On a BtudiC de tels Cquilibres en fonction de la temperature. On discute des facteurs determinant la stabilitC relative de composes du Ni(I1) avec diffkrentes geomCtries. Dans la s i n e de composts prksentks dans cette communication, o n conclut que la charge sur I'ion m8tallique a une influence prkponddrante dans la d6termination d e la gkombtrie. On rapporte aussi quelques resultats qualitatifs sur les vitesses d'bchanges d e s ligands et sur les mkcanismesde ces dchanges.[Traduit par le journal]Thiourea and substituted thioureas form complexes with most of the transition metal ions in the first period (1). These complexes are generally labile in solution and often partly solvolyzed. They therefore constitute a suitable series for systematic study of the kinetics and mechanisms of rapid ligand exchange reactions. We have previously reported some solution studies of the Co(I1) compounds (2). These latter complexes are uniformly tetrahedral in nonaqueous solution. The situation for the analogous Ni(I1) compounds is more complicated. Octahedral, square planar, and tetrahedral geometries are all plausible and in the case of thiourea complexes all occur. In a preliminary communication (3) we suggested that the relative stabilities of Ni(I1) thiourea complexes with different geometries were determined by electronic rather than steric factors. In the present paper we report the n.m.r. and magnetic susceptibility results that support this conclusion and will also discuss some aspects of the ligand exchange processes.A substantial number of papers have been published on the synthesis a...

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Section: Nitrate Complexessupporting

confidence: 65%

The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

Eaton¹,

Zaw²

1975

Can. J. Chem.

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“…According to the value of the H-H coupling constant, there is no doubt that the meso -CH and −C H Ph protons are mutually trans disposed. The syn disposition of both phenyl rings appears to be sterically more favored, being the usual form adopted for this type of ligands in other compounds. 4b, In addition, it should be mentioned that the chemical shift of the anti -C H Ph protons is displaced toward lower field with regard to that expected for anti -CH allyl protons . In this context, it should be noted that according to the structure proposed in eq 2, the anti -CH allyl protons of 4 are in the region of a negative shielding contribution produced by the ring current effect of the phenyl ring.…”

Section: Resultsmentioning

confidence: 99%

The Os(CO)(PⁱPr₃)₂ Unit as a Support for the Transformation of Two Alkyne Molecules into New Organometallic Ligands

et al. 1997

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In 2-propanol, the C−C triple bond of one of the two alkynyl ligands of the complex Os(C2Ph)2(CO)(PiPr3)2 (1) can be broken by water to give Os(CH2Ph)(C2Ph)(CO)2(PiPr3)2 (2). The reaction involves a metal-promoted, hydration−disproportionation of the transformed alkynyl ligand catalyzed by the solvent. Thus, the treatment of 1 with H2 18O yields Os(CH2Ph)(C2Ph)(C18O)(CO)(PiPr3)2 (2- 18 O ), and the reaction of 1 with water in the presence of deuterated 2-propanol (iPrOD-d 8) affords Os(CD2Ph)(C2Ph)(CO)2(PiPr3)2 (2- d 2 ). In methanol and in the presence of trifluoroacetic acid, complex 2 isomerizes into the osmaindene The structure of 3 has been determined by X-ray diffraction. The geometry around the osmium atom can be described as a distorted octahedron with the two triisopropylphosphine ligands occupying two relative trans positions. The remaining perpendicular plane is formed by the carbonyl ligands mutually cis disposed and the metallacycle, which forms a planar five-membered ring with the osmium atom. In methanol-d 4, complex 2 reacts with CF3COOD to (3- d 1 ) and 3 in a 2.5:1 molar ratio. Complex 2 also reacts with HBF4. The reaction leads to a mixture of 3 and the π-allyl complex [Os{η3-CH(Ph)CHCHPh}(CO)2(PiPr3)2]BF4 (4), which is a result from the addition of the proton from the acid and the carbon−carbon coupling of the benzyl and alkynyl ligands of 2. Similar to 2, complex 2- d 2 reacts with HBF4 to give a mixture and [Os{η3-CD(Ph)CDCHPh}(CO)2(PiPr3)2] BF4 (4- d 2 ). On the basis of the isotope labeling experiments, the mechanisms of the above-mentioned transformations are discussed.

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“…Investigations of the reactivity of metal allyl complexes have been central to the development of organometallic chemistry . Despite the number of studies focused on compounds possessing group 9 metal−allyl fragments, little is known of the reactivity of the homoleptic tris(allyl) complexes of these metals .…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Reactivity of M(allyl)₃ (M = Rh, Ir) with Donor Ligands

et al. 2000

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Reactions of M(allyl) 3 [M ) Rh, Ir] with a variety of donor ligands have been investigated. While both complexes are unreactive toward "hard" N-and O-donor ligands, "soft" ligands such as tolylisothiocyanate, tertiary phosphines, CO, and aryl isocyanides are readily added. Whereas ligand additions to Rh(allyl) 3 are often accompanied by reduction of the Rh(III) center, analogous reactions with Ir(allyl) 3 afford stable trivalent products containing σ-allyl ligands. The molecular structures of several derivatives are presented, including Ir(σ-allyl)-(π-allyl) 2 (PPh 3 ), Ir(σ-allyl) 2 (π-allyl)(PMe 3 ) 2 , and Ir(σ-allyl) 3 (CtN-2,6-Me 2 C 6 H 3 ) 3 .

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Π-Allyl COMPLEXES OF THE TRANSITION METALS

Cited by 26 publications

References 2 publications

The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

The Os(CO)(PⁱPr₃)₂ Unit as a Support for the Transformation of Two Alkyne Molecules into New Organometallic Ligands

Comparison of the Reactivity of M(allyl)₃ (M = Rh, Ir) with Donor Ligands

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Π-Allyl COMPLEXES OF THE TRANSITION METALS

Cited by 26 publications

References 2 publications

The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

The Os(CO)(PiPr3)2 Unit as a Support for the Transformation of Two Alkyne Molecules into New Organometallic Ligands

Comparison of the Reactivity of M(allyl)3 (M = Rh, Ir) with Donor Ligands

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The Os(CO)(PⁱPr₃)₂ Unit as a Support for the Transformation of Two Alkyne Molecules into New Organometallic Ligands

Comparison of the Reactivity of M(allyl)₃ (M = Rh, Ir) with Donor Ligands