A procedure has been developed for the synthesis of fullerene monoepoxide C 60 O via liquid-phase oxidation of fullerene C 60 in the presence of accessible catalysts [(Mn(acac) 3 , Ni(acac) 2 , and Co(acac) 2 ].Fullerene oxide C 60 O is considered to be a promising reagent for subsequent functionalization of fullerene via reactions involving opening of the strained oxirane ring [1-3]. For example, C 60 O was used to obtain dimeric structures in which two fullerene spheres are linked by oxygen (C 120 O) [4,5] or methylene bridge (C 120 CH 2 ) [5]. Furthermore, electrochemical reduction of C 60 O gives rise to solid redox-active films on the surface of platinum, gold, vitreous carbon, and appropriate oxide electrodes [6]. Fullerene epoxide C 60 O was synthesized for the first time in 27% yield by UV irradiation of a solution of C 60 in benzene saturated with oxygen [7]. Subsequent studies on liquid-phase oxidation of C 60 with a number of oxidants resulted in the following maximal yields of C 60 O, % (conversion of C 60 is given in parentheses): dimethyldioxirane, 4 (67) [8], m-chloroperoxybenzoic acid, 30 (40) [9], methyl(trifluoromethyl)dioxirane, 67 (55) [10], H 2 O 2 -urea complex, 35.4 (42.72) [11]. Fullerene monoepoxide was also synthesized by oxidation with ozone (conversion of C 60 30%) [12] and by joint action of ultrasound and the following oxidants: m-chloroperoxybenzoic acid, 4-methylmorpholine N-oxide, CrO 3 , KHSO 5 (Oxone R ) [13]. However, no yield of C 60 O was indicated in [12, 13], and it was only noted [13] that the oxidation under ultrasonic irradiation is more effective. The oxidation of C 60 to C 60 O was accompanied by formation of higher epoxides, C 60 O 2 and C 60 O 3 [7-14]; therefore, in some cases C 60 O was isolated by HPLC from the reaction mixture containing initial C 60 and C 60 O 2-3 . Only two examples of the synthesis of C 60 O by catalytic oxidation of C 60 have been reported. These are oxidation by cytochrome 450 chemical models [oxidant PhIO, catalyst tetraphenylporphyrinatoiron(III) chloride, yield 22%, the conversion of C 60 was not given] [14] and with hydrogen peroxideurea complex (catalyst MeReO 3 ) [11].Analysis of the results reported in [7][8][9][10][11][12][13][14] showed that the best yield of C 60 O and conversion of C 60 are attained with the use of expensive oxidants [methyl-(trifluoromethyl)dioxirane] and catalysts (P450, MeReO 3 ). Therefore, development of new procedures for the preparation of C 60 O with the use of accessible and inexpensive oxidants is an important problem. In the present work we examined liquid-phase oxidation of fullerene C 60 with molecular oxygen in the presence of transition metal complexes [Mn(acac) 3 , Ni(acac) 2 , Co(acac) 2, Fe(acac) 3 , Cu(acac) 2 ].No oxidation of fullerene occurred when its solution in 1,2-dichlorobenzene saturated with oxygen was heated for 1.5 h at 150°C in the absence of metal complex; HPLC analysis of the reaction mixture showed now other peaks on the chromatogram than that belonging to C 60 (Table 1). Under...
Сhemiluminescence (CL) upon the reaction of crystalline LnI 2 (Ln = Dy, Nd) with water was found. The CL emitters are the Ln 3+ * electron excited ions (Dy 3+ *, λ max = 470, 570 nm; Nd 3+ *, λ = 700-1200 nm) generated by the electron transfer from the Ln II ions to the H 2 O molecules. The identified reaction products are H 2 , dissolved LnI 3 , and insoluble LnI(OH) 2 (49-51% and 48-50% yield for DyI 2 and NdI 2 , respectively). The treatment of NdI 2 with an H 2 O solution in THF gives the NdI 2 OH(thf) 2 •3H 2 O complex and hydrogen.Chemiluminescence (CL) involving Ln II compounds, unlike Ln III compounds, was studied to less extent. The CL is known for the EuCl 2 complexes with organic ligands 1-3 and Cp 2 Yb, 4 Cp 2 Sm, and Cp 2 Eu lanthanido cenes (see Refs 5 and 6) upon oxidation with hydrogen peroxide and molecular oxygen. In all cases, the CL emit ters are the excited Ln 3+ * ions: Eu 3+ *, Yb 3+ *, and Sm 3+ *. The Eu II , Yb II , and Sm II compounds are rather stable, (E°(Ln 3+ /Ln 2+ ) = -(0.34-1.50 V) 7,8 ), whereas the compounds of other Ln II (Ln = Nd, Dy, and Tm) with very low oxidation potentials (E°(Ln 3+ /Ln 2+ ) = -(2.22-2.62 V) 7,8 ) are extremely unstable; they have been synthesized rather recently. 9-11 The properties of these compounds were studied to less extent, and their CL has not recently been examined. Therefore, investigation of the physicochemical properties of the labile Nd II and Dy II compounds is urgent.In this work, we studied for the first time the ability of DyI 2 (1) and NdI 2 (2) to enter chemical reactions and generate radiative excited states Ln 3+ *. The interaction of compounds 1 and 2 with water was chosen as this reac tion. The reaction has not been studied earlier: CL was not detected and no stable products were identified. ExperimentalCrystalline samples 1 and 2 (content of the main substance 95 and 93%, respectively) were synthesized according to earlier described procedures. 9,10 Bidistilled water was used; THF was purified by reflux over NaOH and metallic sodium and prior to use it was kept for 15 min over compound 1 or 2 for the addi tional purification from water traces.For recording IR spectra, the samples were prepared as a suspension in Nujol and placed between NaCl plates. Photolu minescence (PL) spectra were recorded on a home made spectrofluorimeter designed on the basis of an MDR 23 double monochromator. Absorption spectra were measured on Specord M 40 (UV visible region) and Specord M 40 (IR region) spec trophotometers.Chemiluminescence measurements. To measure the CL ki netics, a powder of compound 1 (18.20 mg, 0.04 mmol) or 2 (15.92 mg, 0.04 mmol) was placed under argon on the bottom of a glass cell mounted in a light tight chamber of the chemilumi nescence setup. 12 Water (2 mL) was added for 3 s from a doser to the cell, and CL was detected. The spectra of CL arisen upon the hydrolysis of compounds 1 (91.40 mg, 0.22 mmol) and 2 (87.60 mg, 0.22 mmol) were measured using a set of cut off color filters according to a known procedure 13 with FEU 39 (f...
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