Crystal and molecular structures of two polymethylferrocenes: sym-octamethylferrocene and decamethylferrocene

Struchkov, Yu. T.; Andrianov, V. G.; Sal'nikova, T.N.; Lyatifov, I.R.; Materikova, R.B.

doi:10.1016/s0022-328x(00)91127-6

Cited by 59 publications

(25 citation statements)

References 10 publications

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“…The same sense of displacement has been measured by electron diffraction in several unsubstituted metallocenes (Haaland, 1975). By contrast, in X-ray studies of the octa-and decamethyl derivatives (M%CP)2Mn, (Me4CP)2Fe, and (M%CP)2Fe, the methyl C atoms are found to be displaced approximately 0.06 A away from the metal atoms (Freyberg, Robbins, Raymond & Smart, 1979;Struchkov, Andrianov, Sal'nikova, Lyatifov & Materikova, 1978). This result is confirmed by a recent electron diffraction study of (M%CP)2Fe (Almenningen, Haaland, Samdal, Brunvoll, Robbins & Smart, 1979).…”

Section: Discussionmentioning

confidence: 55%

The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

Takusagawa¹,

Koetzle²

1979

Acta Crystallogr Sect B

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Section: Discussionmentioning

confidence: 55%

The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

Takusagawa¹,

Koetzle²

1979

Acta Crystallogr Sect B

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“…In this study, the initiation stage of methyl meth acrylate polymerization was studied in the presence of benzoyl peroxide and the following additives: Cp 2 Fe and ferrocenes modified with substituents incorpo rated into the cyclopentadienyl ring, such as (C 5 [4][5][6]) were used without further purifi cation.…”

Section: Introductionmentioning

confidence: 99%

Initiation of complex-radical polymerization of methyl methacrylate in the presence of metallocenes

et al. 2012

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The initiation of radical polymerization of methyl methacrylate in the presence of benzoyl perox ide-metallocene (Cp 2 Fe, Cp 2 ZrCl 2 , and Cp 2 TiCl 2 ; (C 5 Me 5 ) 2 Fe, (C 5 Me 5 ) 2 ZrCl 2 , and (AcC 5 H 4 )(C 5 H 5 )Fe) systems is studied. It is shown that a metallocene affects the rate of initiation and the initial rate of polymer ization. On the basis of quantum chemical calculations, a new mechanism of the initiation reaction may be advanced: Namely, the decomposition of benzoyl peroxide proceeds via the stage of complexation with a metallocene, while the nature of a metallocene determines the probability of complexation and decomposi tion.

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“…Whereas unsubstituted fer rocene is eclipsed (D 5h, r = 0°) [1 , 2 ], the permethylated analogue, Fe(C5Me5)2, is staggered (D5d, r = 36°) both in the crystal [3,4] and in the gas phase [5]. This can be ascribed to steric rea sons because the decamethylferrocenium cation, [Fe(C5Me5)2]+ , again prefers [6 -8 ] the ecliptic (D5h, r = 0) or almost ecliptic (e. g. r = 4° [8]) arrangement, as it is also found in ferrocenium salts such as [Fe^H s^JB iC U (r ~ 1° [9]) or [Fe(C5H5)2]FeCl4 (nearly eclipsed [10] A considerable amount of structural data has been reported for l,l'-disubstituted ferrocene derivatives (Table 1), and conformational angles r between 0 and 180° have been noted.…”

Section: Resultsmentioning

confidence: 99%

1,1′-Di(tert-butyl)metallocenium Cations. The X-Ray Crystal Structures of [M(C₅H₄ ^tBu)₂]PF₆ (M = Fe, Co) and [Co (C₅H₄ ^t Bu)₂]₂CoCl₄

Herberhold

Cheng

Jin

et al. 2000

Zeitschrift Für Naturforschung B

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The hexafluorophosphate salts [Fe(C5H4'Bu)2]PF6 (1 ) and [C o^H /B u^lP F ö (2) crystal lize in isotypic structures with centrosymmetric cations which have a staggered (transoid) conformation of the exactly parallel ring ligands (conformational angle r = 180°). The tetrachlorocobaltate salt, [Q^CsIL'Bu^hCoCU (3), contains one almost eclipsed (r = 140.4°) and one almost staggered (r = 101.4°) cobaltocenium cation; in both cases, the cyclopentadienyl ring planes are slightly inclined (by a = 5.4° and 4.1°, respectively) to give more room to the tert-butyl substituents which are bent away from the metal in all three complexes 1 -3. Intro d u ctio nIn the course of studies on ry5-(rerr-butyl-cyclopentadienyl) metal complexes, we have iso lated crystals of the salt [C o^IV B u^b C o C U (3) which contains two cobaltocenium sandwiches with different conformational arrangement of the ring ligands. For the purpose of comparison we then have determined the structures of the 1 ,1 '-di(/m-butyl)metallocenium hexafluorophosphates, [M(C5H4'Bu)2]PF6 (M = Fe (1), Co 2)). The struc tures of 1 and 2 are isotypic and contain strictly centrosymmetric (transoid) cations. Results and DiscussionGeneral remarks on the structure o f 1,1'-disubstitu ted metallocenesThe conformational angle (r) in 1,1 '-disubstituted metallocenes is defined as the torsional angle C 1 -Z-Z'-C1, i. e. the dihedral angle between the planes which include the two cyclopentadienyl ring cen ters (Z, Z') and the ring carbon atom bearing the substituent R (C1 or C 1, respectively).A l,l'-disubstituted metallocene with two equal substituents (R) may then assume angles of r = 72 and 144° in the ideal eclipsed forms, and angles of eclipsed (t = 72°) staggered (t = 180°, "transoid") t = 36, 108 and 180° in the ideal staggered confor mations.It is not easy to predict the conformation of 1,1'-disubstituted ferrocenes. Whereas unsubstituted fer rocene is eclipsed (D 5h, r = 0°) [1 , 2 ], the permethylated analogue, Fe(C5Me5)2, is staggered (D5d, r = 36°) both in the crystal [3,4] and in the gas phase [5]. This can be ascribed to steric rea sons because the decamethylferrocenium cation, [Fe(C5Me5)2]+ , again prefers [6 -8 ] the ecliptic (D5h, r = 0) or almost ecliptic (e. g. r = 4° [8]) arrangement, as it is also found in ferrocenium salts such as [Fe^H s^JB iC U (r ~ 1° [9]) or [Fe(C5H5)2]FeCl4 (nearly eclipsed [10]). A similar situation is observed in the salts of the cobaltocenium cation which is isoelectronic with the 18e molecule ferrocene; The unsubsti tuted cobaltocenium cation is eclipsed in salts such as [CoCp2][SbPh2Cl2] [11], [CoCp2][Sb(R)Cl3]

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Crystal and molecular structures of two polymethylferrocenes: sym-octamethylferrocene and decamethylferrocene

Cited by 59 publications

References 10 publications

The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

Initiation of complex-radical polymerization of methyl methacrylate in the presence of metallocenes

1,1′-Di(tert-butyl)metallocenium Cations. The X-Ray Crystal Structures of [M(C₅H₄ ^tBu)₂]PF₆ (M = Fe, Co) and [Co (C₅H₄ ^t Bu)₂]₂CoCl₄

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Crystal and molecular structures of two polymethylferrocenes: sym-octamethylferrocene and decamethylferrocene

Cited by 59 publications

References 10 publications

The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

The crystal and molecular structure of 1,1'-ferrocenedicarboxylic acid (triclinic modification): neutron and X-ray diffraction studies at 78 K and 298 K

Initiation of complex-radical polymerization of methyl methacrylate in the presence of metallocenes

1,1′-Di(tert-butyl)metallocenium Cations. The X-Ray Crystal Structures of [M(C5H4 tBu)2]PF6 (M = Fe, Co) and [Co (C5H4 t Bu)2]2CoCl4

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1,1′-Di(tert-butyl)metallocenium Cations. The X-Ray Crystal Structures of [M(C₅H₄ ^tBu)₂]PF₆ (M = Fe, Co) and [Co (C₅H₄ ^t Bu)₂]₂CoCl₄