Dichlorobis(4-methylpyridine)cobalt(II)

Laing, Michael; Carr, G. E.

doi:10.1107/s0567740875008461

Cited by 26 publications

(11 citation statements)

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“…29 The intermolecular kinetic isotope effect for alkane C-H oxidation was determined by the competitive oxidation of cyclohexane and cyclohexane-dlz (k& = 2.?!). 30 This small intermolecular KIE is consistent with some,3i-33 but not all,34 studies for the oxidation of alkanes by MMO and is indicative of only a minor contribution from C-H bond breaking in the rate-determining step of substrate oxidation.…”

Section: N-melmsupporting

confidence: 70%

“…2) shows Co2+ to be tetrahedrally coordinated; the bond lengths and angles in the molecule are normal within the observed standard deviations of the few tetrahedral CoA2X, compounds that have been characterized and are different from the polymeric six-coordinate violet form of CoPy2C1, [24,29]. The somewhat shorter Co-Nl (2.004 A) and Co-N3 (2.007 A) bond lengths of 1 versus those reported for the 4-methylpyridine complex (2.03 and 2.06 A) reflect the greater basicity of the N-MeIm ligand (pK, = 7.06) versus 4-MePy (pK, = 5.25) [30]. However, the largest variations in the CoA2Cl, structures are observed to occur in the N-Co-N angles that appear to depend intimately on the stereochemical requirements of the nitrogen heterocycles.…”

Section: Solution and Solid-state Structure Of Co(n-meim)(ci)2 (1)mentioning

confidence: 96%

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Binuclear Non-heme Iron Catalysts

Caradonna¹

2004

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This project involved the investigation of the ability of non-heme iron metalloenzyme reactivity model complexes to catalyze the oxidation of alkane and arene molecules. The objectives were to synthesize a series of non-heme mononuclear and dinuclear iron complexes, characterize their electronic structure and reactivity properties, characterize intermediates formed during oxygen atom transfer chemistry, and elucidate the mechanisms and specificity of the reactions. These data also were to be compared to analogous heme-based chemistry.A series of diferrous, ferrous/ferric, and diferric complexes were synthesized from simple polyamide and polycarboxylate ligands and characterized by visible absorption, EPR and IR spectroscopy and by cyclic voltametry. The diferrous compounds, which are all powerful reductants, heterolytically decompose peracids and are capable of acting as oxygen atom transfer catalysts when reacted with oxygen atom donor compounds and simple olefins, yielding both allylic oxidation and epoxidation products. Lowtemperature optical spectroscopic studies provide evidence in support of an Fe(IV)=O intermediate, rather than an 0-donor adduct, as the reactive species. An isostructural dicobalt(I1) complex gives rise only to epoxidation products. These reactivity studies provide important new information of the chemistry of dinuclear nonheme iron systems.Publications resulting from this project:1. 2.3. 4."Fe2+-catalyzed heterolytic RO-OH bond cleavage and substrate oxidation: A fhctional synthetic non-heme iron monooxygenase system", Foster TL, Caradonna ' in anhydrous 1% methanol-acetonitrile under anaerobic conditions afforded @?e22+(Hzbamb)2(N-MeIm)2] (1)25a (60% yield). Isothermal distillation techniquesls indicate that 1 has a molecular weight of 4 100, consistent with its dimeric formulation. EPR spectra of 1 show a g H % 16 signal, suggesting a ferromagnetically coupled S = 4 core as previously reported for an analogous binuclear system.I9 Cyclic voltammetry experiments show two coupled le-oxidationheduction processes; a scanrate-dependent quasi-reversible process at -310 mV ("E) and an electrochemically reversible couple at -690 mV ("E), giving K , , = 2.7 x loa. Repetitive scans showed no significant decrease in either cathodic or anodic current; ligand centered redox behavior was observed outside this region of interest. The scan-rate dependence of AEp, attributed to kinetic effects, allowed the measurement of an intrinsic rate constant, k = 2 x assuming pseudo-first-order kinetics. This rate constant, thought to reflect a structural change, is independent of [I] interfaced to a "33% series U integrator. Mass spectral analyses were performed on a HP 5971 mass-selective detector attached to a HPS890 Series 2 GC. Authentic samples were used to verify all retention times. Expected reaction products were stable to GC conditions.(21) Studies using Fa12 and FeCla were performed and analyzed by GC and GUMS techniques using identical conditions as reported for 1-3 (Table 1) with catalyst:OIF'h:sub...

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Section: N-melmsupporting

confidence: 70%

Section: Solution and Solid-state Structure Of Co(n-meim)(ci)2 (1)mentioning

confidence: 96%

Binuclear Non-heme Iron Catalysts

Caradonna¹

2004

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“…It is worth mentioning that except Co(3-pic) 2 Cl 2 exists as a six coordinated Co compound: dibromo-tetrakis(3-picoline)cobalt(II) [32]. The Co-N and Co-Cl bond lengths are compatible with those found in analogous compounds of 4-picoline [20], quinoline [21] and (8) 6,6¢-dimethyl-2,2¢-bipyridyl [22] and they are slightly shorter than those found in a polymeric form of a-Co(py) 2 Cl 2 (Co-N 2.14 Å ; Co-Cl 2.49 Å ) with cobalt(II) in the octahedral environment [3].…”

Section: Structural Descriptionmentioning

confidence: 61%

“…Structural studies of these compounds have shown them to be capable of polymerization whereby the cobalt atom assumes either an octahedral environment as highlighted by the violet-coloured Co(py) 2 Cl 2 compound [1][2][3], or a tetrahedral one displayed by the blue Co(py) 2 Cl 2 [1][2][3] and Co(4-pic) 2 Cl 2 [20] compounds. These results have shown that the structure of the compound is dependent on the nature of the pyridine ring substituent.…”

Section: Introductionmentioning

confidence: 98%

“…Hence, one of the objectives of this contribution was to elucidate the structure of CoL 2 Cl 2 with 2-and 3-substituted pyridines as ligands. Consequently, a crystalline Co(3-pic) 2 Cl 2 was prepared and its structure was determined and compared with that of the previously studied Co(4-pic) 2 Cl 2 [20]. This enabled evaluation of the influence of substituent position on the structure of complexes.…”

Section: Introductionmentioning

confidence: 99%

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Crystal structure of Co(3-pic)2Cl2 and thermal behaviour of a new complex, Co(py)(3-pic)Cl2

Wyrzykowski

Styczeń

Warnke

et al. 2006

Transition Met Chem

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A crystalline Co(3-pic) 2 Cl 2 compound was obtained and its structure determined by X-ray diffraction. The structure is characterized by the presence of two conformationally different molecules. A new cobalt(II) complex of molecular formula Co(py)(3-pic)Cl 2 was also synthesized. It was characterized by spectroscopic methods (IR, FIR, Raman spectra), elemental analysis and thermogravimetry (TG, DTA, DTG) carried out in both the oxidative and inert atmosphere. Each of the thermal decomposition steps was interpreted and the influence of substituent position in the pyridine ring on the thermal stability of the complex was discussed.

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Crystal Structures and Characterizations of Bis(1‐benzoyl‐methyl‐benzotriazole‐N³)dichoro Metal(ll) Complex: [MCl₂‐_‐(C_sH₄N₃CH₂COPh)₂] [M=Zn(ll), Co(ll)]

et al. 2004

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The structures of [MClK&&CH~COPh)d [M=Zn(II) (I). Co(II) (211 have been determined by X-ray crys-tallography. They were characterized by elemental analysis, IR spectrum, electronic spectrum and thermogravimetric-differential thermal analysis. They all crystallize in the triclinic system, space p u p Pi, with lattice parameters a=0.9449(2) nm, b=1.1291(2) nm, c=1.3637(3) nm, a= 111.70(3)', /3=94.33(3)', y=90.97(3), 2 = 2 for compound 1; a=0.9437(2) nm, b= 1.1277(2) nm, c=1.3650(3) nm, ~=111.76(3)~, )=94.50(3)', y=90.80(3)', 2 = 2 for compound 2. The metal ions are all coordinated by two C1anions and two nitrogen atoms of 1-benzoylmethyl-bentriazole ligands. forming the distorted tetrahedral geometry. The Zn-Cl and Zn-N bond lengths are 0.2209(2), 0.2210(2) nm and 0.2059(4), 0.2067(4) nm. respectively. The C 0 4 3 and Co-N bond lengths are 0.2215(2). 0.2222(2) nm and 0.2028(5), 0.2045(5) nm. respectively. The thermogravimetric (TG) data indicate that they are nearly similar in TG curve, and there are not sauctural transitions in the two compounds. They all have a high t h d stabidity. But, there is little difference in DTG (differential thermogravimetric) curves of those two compounds. Filementat analysis, electronic and IR spectra are in agreement with the structural data. Ruject suppod by the Educational Administration Key Roject of Shandong I'ruvince (No. JOlC05) and the Natural Science Foundation of Shandong Province (No. Y2002B06).

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Dichlorobis(4-methylpyridine)cobalt(II)

Abstract: Abstract. CoCI2(NCsH4.CH3)2, monoclinic, P2x/n, a= 5.70 (1), b=10.16 (1), c=24.36 (2) A,, fl=92.4 (1) °, Z=4, De= 1.49 g cm -3. C1-Co-CI= 121, N-Co-N= 107°; Co is tetrahedrally coordinated. The molecular packing differs from that of the ZnCI2 and ZnBr2 analogues.

Cited by 26 publications

References 2 publications

Binuclear Non-heme Iron Catalysts

Binuclear Non-heme Iron Catalysts

Crystal structure of Co(3-pic)2Cl2 and thermal behaviour of a new complex, Co(py)(3-pic)Cl2

Crystal Structures and Characterizations of Bis(1‐benzoyl‐methyl‐benzotriazole‐N³)dichoro Metal(ll) Complex: [MCl₂‐_‐(C_sH₄N₃CH₂COPh)₂] [M=Zn(ll), Co(ll)]

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Dichlorobis(4-methylpyridine)cobalt(II)

Abstract: Abstract. CoCI2(NCsH4.CH3)2, monoclinic, P2x/n, a= 5.70 (1), b=10.16 (1), c=24.36 (2) A,, fl=92.4 (1) °, Z=4, De= 1.49 g cm -3. C1-Co-CI= 121, N-Co-N= 107°; Co is tetrahedrally coordinated. The molecular packing differs from that of the ZnCI2 and ZnBr2 analogues.

Cited by 26 publications

References 2 publications

Binuclear Non-heme Iron Catalysts

Binuclear Non-heme Iron Catalysts

Crystal structure of Co(3-pic)2Cl2 and thermal behaviour of a new complex, Co(py)(3-pic)Cl2

Crystal Structures and Characterizations of Bis(1‐benzoyl‐methyl‐benzotriazole‐N3)dichoro Metal(ll) Complex: [MCl2‐‐(CsH4N3CH2COPh)2] [M=Zn(ll), Co(ll)]

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Crystal Structures and Characterizations of Bis(1‐benzoyl‐methyl‐benzotriazole‐N³)dichoro Metal(ll) Complex: [MCl₂‐_‐(C_sH₄N₃CH₂COPh)₂] [M=Zn(ll), Co(ll)]