phdpa铜配合物的晶体数据

Cu(ClO4)2induced ortho-benzylation of N-benzyl di(pyridylmethyl)amineand the formation of μ2-Br-bridged copper(II) complexes)Di(picolyl)amine (dpa) and its derivatives are used as neutral, deprotonated chelating ligands to complex copper(II) atoms to mimic non-heme dioxygenase [1,2]. The reaction of dpa with Cu(ClO4)2 or CuCl2 leads to hexa-coordinated [Cu(dpa)2](ClO4)2[3] or the mononuclear complex [Cu(dpa)Cl2] [4], respectively, in which the geometry of reported Copper(II)-dpa complexes is a distorted square pyramidal or trigonal bipyramidal. The utility of these ligands is enhanced by the ease with which substituents may be introduced on the imino nitrogen atom, thus resulting the different antitumor activities and catalyzing activities of manganese(II) complexes of dpa and its derivatives [5]. So the synthesis of N-substituted dpa derivatives is meaningful to design functional complexes [6]. Although the intramolecular hydroxylation reaction and the antitumor activities for complexes of N-substituted di(picolyl)amine were extensively studied, there is no report on its intramolecular benzylation [7-9].Friedel-Crafts reaction of aromatic compounds is one of the important reactions for forming carbon-carbon bonds, as the products serve as useful starting materials for synthesis of pharmaceuticals and materials [10]. They are formed due to replacement of a hydrogen atom of an aromatic compound by a benzyl group derived from benzylating agent in the presence of Lewis acid (e.g. AlCl3, BF3, FeCl3, ZnCl2, etc.) or protonic acids. The copper(I) complexes of (2-pyridyl)alkylamine were reported to activate C-X bond giving C-C bond formation [11]. Copper-containing mesoporous silicas (Cu-HMS-n) and CuCl2were also widely used as mild, heterogeneous Friedel–Crafts benzylation catalysts [12, 13]. Treatment of [Cu(NCMe)4][PF6] with chelating ligands gave [CuL(NCMe)][PF6] ( L = 9,9-dimethyl-4,5-bis(diphenylphosphino)- xanthene ), which could catalyze the alkylation of diphenylphosphine (PPh2) with PhCH2Br in the presence of the base NaOSiMe3 to yield intramolecular benzylation products (PPh2CH2Ph) [14]. Here we report a intramolecular ortho-benzylation of N-benzyl di(pyridylmethyl)amine with benzyl bromide and the form ation of μ2-Br-bridged copper(II) complexes.1 Experimental Section1.1 Chemical reagents, analysis and physical measurementsAll reagents are of commercial grade and used as received. Bis(2-pyridylmethyl)-benzylamine (phdpa) was synthesized as reported [15]. IR spectra were recorded on a Nicolet 210 spectrometer in KBr pellets. Elemental analyses were performed by the Perkin-Elemer 240. 1H NMR and 13C NMR spectra were measured on a Bruker 400 MHz spectrometer. The electronic absorption spectra were recorded in the 900-190 nm region using the UV-2450 spectrophotometer.1.2 Synthesis of [(phdpa)2Cu2(Br2)(μ2-Br](ClO4)(H2O)0.5 (1) and [phCH2phdpa+2H+](ClO4)2(2)A solution of Cu(ClO4)2•6H2O (471 mg, 1 mmol) in methanol (2 ml) was added dropwise to themethanol solution (10 ml) of Bis-(2-pyridylmethyl)-benzylamine (phdpa) (290 mg, 1 mmol). After stirred for 30 min at room temperature, benzyl bromide (12.7 mg,1 mmol) in methanol (20ml) was added and stirred at 80 ºC for 2 h, then cooled to room temperature. The purple crystals of (1) were obtained after evaporation of the methanol solution for 24h. Yield 0.31g (40%). Anal. Calcd for C38H38Br3ClCu2N6O4.5 C 43.26, H, 3.70, N, 7.96, Cu, 11.97; Found: C 43.13, H, 3.73, N, 7.84, Cu, 11.84. IR (KBr) (cm-1): ν(O-H) 3373 s, ν(=CH)3081m, ν(-CH2-) 2828 m, υ(C=N) 1612, ν(C=C), 1574 m, 1473 m, δ(CH, pyridine) 773 s, ν(ClO4)1100s, 623m. UV-vis (CH3OH / nm) (ε × 10 -4 / M-1 cm-1): 205 (2.73), 259 (1.59), 296 (0.40), 682 (0.01).The white powders [phCH2phdpa+2H+](ClO4)2(2) were obtained by further evaporation of above filtrate. Yield 0.14 g (20%). Anal. Calcd for C26H27Cl2N3O8C 50.83, H, 4.69 N, 7.24; Found: C 50.92, H, 4.60, N, 7.27. 1H NMR (400 MHz, DMSO-d6): δ=3.7 (s, 2H, CH2Ar); 4.0 (s, 2H, CH2Ar); 4.1 (s, 2H, CH2Py); 5.89 (s, 2H, CH2Py); 7.0-7.5 (m, 9H, Ar-); 7,7-8.8 (m, 8H, Py);9.1(s, 2H, H+). 13C NMR (400 MHz, DMSO-d6): δ=54.6-60.0 (CH2); 120-160 (Py or Ar) . IR (KBr) υ/cm-1: ν(N-H)3265m, ν(=CH) 3060 m, ν(-CH2-) 2925 m, υ(C=N) 1663, ν(C=C) 1589 s, 1569 m, 1473 m, 1433 m, δ(CH, pyridine) 760 s, 699 s. UV-vis (CHCl3 / nm) (ε × 10-4 / M-1 cm-1): 203 (4.12), 260 (1.75).1.3 Ortho-benzylation reactionThe intramolecular ortho-benzylation of phdpa by benzyl bromide was used as a model reaction for Cu(II) catalytic properties. A solution of CuX2 (1 mmol) (X= Cl-, NO3-, ClO4-) was added to the methanol solution (10 ml) of Bis-(2-pyridylmethyl)-benzylamine (phdpa) (290 mg, 1 mmol). After stirred for 30 min at room temperature, benzyl bromide (12.7 mg,1 mmol) in methanol (20ml) was added and the reaction was carried out with stirring at room temperature for 2 h. The conversion of phdpa was evaluated by analyzing samples of the reaction mixture collected by HPLC. The selectivity is expressed by the molar ratio of formed ortho-benzylaton products to converted phdpa.1.4 X-ray crystal structure determinations.Crystallographic data for [(phdpa)2Cu2(Br2)(μ2-Br](ClO4)(H2O)0.5 (1) are listed in Table 1. The blue prism crystals of the complex were selected for lattice parameter determination and collection of intensity data at 293 K on a Rigaku Mercury2 CCD Area Detector with monochromatized Mo Ka radiation (λ= 0.071073 nm). The data were corrected for Lorenz and polarization effects during data reduction. A semi-empirical absorption correction from equivalents based on multi- scans was applied. The structure was solved by direct methods and refined on F2 by full-matrix least-squares methods using SHELXTL program [16]. All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were introduced in their calculated positions. All computations were carried out using the SHELXTL-PC program package. CCDC number 759823Table 1 Crystal data and structure refinement details for the complex (1)Empirical formula C38H38Br3ClCu2N6O4.5Formular weight 2108.02Crystal system TriclinicSpace group P-1a (nm) 1.28064(12)b (nm) 1.38713(13)c (nm) 1.46715(14)α (°)102.2640(10)β (°)110.1990(10)γ (°)112.1170(10)V (nm3) /Z 2.0829(3) / 1Density (calc) (Mg/m3) 1.681Absorption coefficient (mm-1) 4.010F(000) 1050Index ranges -15≤h≤15; -15≤k≤17; -18≤l≤18Θ range (°) 2.61 - 26.37Reflection collected 20601Independent reflections [R int] 6580Data/restraints/parameters 8242/8/496Goodness-of-fit on F2 1.060F inal R indices [I>2ζ(I)]R1=0.0468; wR2=0.114R indices (all data) R1=0.0614; wR2=0.12492 Results and discussion2.1 The reaction of phdpa and Cu(ClO4)2 with benzyl bromideThe spectroscopic titration for the solution of phdpa and Cu(ClO4)2and its interaction with benzyl bromide in methanol solution is shown in Fig.1. The solution of phdpa and Cu(ClO4)2 show a d-d transition band at 641 nm indicating the formation of complex phdpa-Cu(ClO4)2 (Fig.1 line a). A strong increase of the absorbance of d-d transition with red shift about 40 nm was observed when the benzyl bromide was added in 30 min. The results indicate the possible coordination of bromide anion to the complex phdpa-Cu(ClO4)2 in methanol solution, which was confirmed by X-ray structure (Fig.2 and Scheme 1, (0)). However, there is no change for the absorption of d-d transition when the benzyl bromide was added to the solution of Cu(ClO4)4-phdpa system in MeCN, which are possible due to that the coordinated MeCN cannot be replaced by bromine atoms. This is similar to the reported complex [Cu(phdpa)(CH3CN)2](ClO4)2 [ 2].4005006007008000.00.10.20.30.40.5cbaA b s/ nmFig.1 The spectroscopic titration for the reaction of phdpa - Cu(ClO 4)2 (0.002 mol L -1) with benzyl bromide (phBr) (0.002 mol L -1) in methanol at 40 ºC. A, phdpa- Cu(ClO 4)2; b, phdpa - Cu(ClO 4)2,+ phBr 0.5h,; C, phdpa - Cu(ClO 4)2 + phBr, 1h.2.2 Formation of N-[(2-benzyl)benzyl]-di(picolyl)amine perchlorate (2)The formation of ortho-benzylation product N-[(2-benzyl)benzyl]-di(picolyl)amine perchlorate(2) was confirmed by 1HNMR data. 1H NMR spectra of N-[(2-benzyl)benzyl]-di(picolyl)amine showed the signals of the respective protons of the synthesized compounds (2), which were verified on the basis of their chemicals shifts, multiplicities. These spectra showed characteristic signals about CH 2 protons at 3.7 -4.1 ppm and 5.89 ppm, which are assigned to CH 2 (benzylmethyl group, phCH 2; pyridylmethyl group, pyCH 2) protons. The relative high chemical shifs indicate the existence of protonated N-[(2-benzyl)benzyl]-di(picolyl)amine perchlorate (2). The ortho-benzylation may be due to the coordination of bromine in benzyl bromine to the copper atom (Scheme 1, intermediate (0)).N N N N N NCu 2+NNNCu(ClO 4)2phdpa phCH 2Br N N N Cu Br --Br Br-ClO 4-+(1)H 2O H +(ClO 4)2(0)+H [phCH 2phdpa+2H +](ClO 4)2 (2)333Scheme 1 Possible mechanism for the formation of complex (1), [phCH 2phdpa+2H +](ClO 4)2 (2) and intermediate (0)2.3 The spectroscopic characteristics of the complex (1).The IR spectrum of the complex [(phdpa)2Cu2(Br2)(μ2-Br](ClO4)(H2O)0.5(1)shows a broad band at 3373 cm-1assigned to υ(OH) of the uncoordinated water which are con firmed by elemental analysis and X-ray structure. The bands between 2828 and 3081 cm-1 for complex (1) can be assigned to the stretching vibration of saturated hydrocarbon and arene C-H in the IR spectra. The pyridyl ring vibration bands and δ(CH) vibration of pyridyl ring in complexes are all shifted. The pyridyl ring vibrations bands were approximately 1612 cm-1and 1574 cm-1 for complex (1). The δ(CH) vibration bands of pyridyl ring for the complex (1) were found at approximately 773 cm-1. These shifts can be explained by the fact that the nitrogen atoms of pyridyl ring of the ligands donate a pair of electrons each to the central metal forming coordinate covalent bond. The absorption bands occurring in the IR spectra of the complex (1) at 1100 cm-1 and 623 cm-1 corresponds to the asymmetric Cl-O stretching mode and the asymmetric Cl-O bending mode respectively. The electronic spectrum of the complex (1) exhibits four bands at 205 nm, 359 nm, 296 nm and 682 nm and these are assigned due to π→π*, C-T, n→π*and d-d transitions, respectively, the visible spectra exhibits a band 682 nm corresponding to five-coordinated square pyramidal Cu(II) complex.2.4 Crystal structure of [(phdpa)2Cu2(Br2)(μ2-Br](ClO4)(H2O)0.5The molecular structure of [(phdpa)2Cu2(Br2)(μ2-Br](ClO4)(H2O)0.5with the atomic labeling scheme is shown in Fig.2 and selected bond lengths and angles are listed in Table 2. The ligand (phdpa) acts as a tridentate ligand toward the Cu(II) atom. The Cu(II) atoms are coordinated by three N atoms (N1, N2, N3 for Cu1, N4 , N5, N6 for Cu2), one coordinated bromine atoms (Br1 for Cu1 or Br2 for Cu2) and a bridged bromine atom Br3 resulting in dinuclear Cu(II) complex [(phdpa)2Cu2(Br2)(μ2-Br](ClO4)(H2O)0.5. The Cu1 and Cu2 thus show distorted trigonal bipyramidal geometry. Atoms N1, N2, N3 and Cu1 form the equatorial trigonal plane (mean deviation 0.0041) while Br3 and Br1 occupy the apical positions. The Cu1 atom locates in the center of this plane with N1-Cu1-N3 of 163.63 (15)° and N2-Cu1-Br1 of 164.731(10) °. Atoms N4, N5, N6 and Cu2 also form a equatorial trigonal plane (mean deviation 0.0454). Cu2 was shifted about 0.0793 Å to this plane and the bond angles of N4-Cu2-N6 and N5-Cu2-Br2 was 164.24° and 151.37 °, respectively. The angle of two trigonal plane is 130.7 °. The Cu-N bond distances are in the range of 0.1995(4)-0.2055(3) nm and the Cu1-Br3 and Cu2-Br3 bond distances are 0.28096(7) nm and 0.27470(7) nm, which are longer than those of Cu1-Br1 and Cu2-Br2 bond distances (0.23791(7) nm and 0.23939(7) nm). Cu1-Br3-Cu2 angle is 134.88(2)°.Table 2 Selected bond lengths (nm) and bond angles (°) for the complex (1)Bond distancesCu1-N1 0.2008(3) Cu2-N4 0.1995(4)Cu1-N2 0.2055(3) Cu2-N5 0.2059(3)Cu1-N3 0.2007(3) Cu2-N6 0.1987(3)Cu1-Br1 0.23791(7) Cu2-Br2 0.23939 (7)Cu1-Br3 0.28096(7) Cu2-Br3 0.27470(7)Bond anglesN3-Cu1-N1 163.63(15) N6- Cu2–N4 164.24(15)N3-Cu1-N2 81.39(14) N6-Cu2-N5 83.29(14)N1-Cu1-N2 82.25(14) N4-Cu2-N5 82.48(15)N3-Cu1-Br197.92(11) N6-Cu2-Br2 97.96(10) N2-Cu1-Br1164.71(10) N5-Cu2-Br2 151.37(10) N1-Cu1-Br197.70(10) N4-Cu2-Br2 97.77(11) N3-Cu1-Br388.27(10) N6-Cu2-Br3 88.53(10) N2-Cu1-Br393.97(10) N5-Cu2-Br3 96.54(9) N1-Cu1-Br393.46(10) N4-Cu2-Br3 86.39 (10) Br1-Cu1-Br3 101.28(2) Br2-Cu2-Br3 112.07(2)Fig.2 Crystal structure of [(phdpa)2Cu 2(Br)2(μ2-Br)]+. Thermal ellipsoids are drawn at 50%probability. Hydrogen atoms are omitted for clarity.Table 3 Cu(II) catalyzed ortho-benzylation of phdpaCu(II) saltmR a Selectivity of ortho-benzylation b （%） Conversion of phdpa c （%） Cu(ClO 4)21:1 90 51 Cu(ClO 4)21:1.5 84 62 CuCl 21:1 46 48 CuCl 21:1.5 40 59 Cu(NO 3)21 38 46 Cu(NO 3)21:1.5 34 61 Blank d0:1 34 32 Blank e0:1.5 30 39 a mR: molar ratio of Cu(II) salt and benzyl bromide; b Selectivity: ratio of the ortho-benzylationproduct to benzylation products of phdpa; c Conversion: the ratio of benzylation products based onphdpa; d blank: benzyl bromide and phdpa was mixed in the molar ration of 1:1 (Blank d ) or 1.5:1(blank e ) without Cu(II) salt.2.5 Cu(II) catalyzed ortho-benzylation of phdpaThe intramolecular ortho-benzylation of phdpa catalyzed by copper(II) salt were summarized in Table 3. All reactions proceeded smoothly, and 32-62% conversion of phdpa was reached in 2 h. In practice, when the benzylation was over, a purple deposit derived from reaction medium appeared gradually after magnetic stirring was discontinued. The selectivity of N-alkylation catalyzed by Cu(II) salt depended on anions. Among these copper salt catalysts, only Cu(ClO4)2 shows high ortho-benzylation activity. CuCl2 and Cu(NO3)2 has no obvious effect on the selectivity of ortho-benzylation of phdpa, but they increased total conversion of phdpa. The enhanced conversion in Cu(II) complex reaction system may be due to the activation of C-Br bond by Cu(II) complexes. The high selectivity (90%) for the intramolecular ortho-benzylation of phdpa-Cu(ClO4)2 system was possibly due to the coordination of bromine atom in benzyl bromide to the copper(II) atom in complex phdpa-Cu(ClO4)2 ( Scheme 1, intermediate (0)). The only 51% conversion of phdpa (in 1:1 molar ratio of Cu(II) salt and benzyl bromide) was due to the formation of Br bridged complexes, which is not a good catalyst to the ortho-benzylation. Experimental results indicate that Cu(ClO4)2was a good catalyst for the intramolecular ortho-benzylation of phdpa.3 ConclusionThe reaction of N-benzyl di(pyridylmethyl)amine (phdpa) and Cu(ClO4)2 with benzyl bromide in methanol leads to the ortho-benzylation of phdpa with the formation of μ2-Br-bridged copper(II) complexes due to the coordination of bromine atoms to the center copper atom in phdpa-Cu(ClO4)2.Experimental results indicate that Cu(ClO4)2was a good catalyst for the intamolecular ortho-benzylation of phdpa. This experimental result is meaningful to find selective benzylation catalysts.References:[1] Wurtele C, Sander O, Lutz V, Waitz T, et al. J. Am. Chem. Soc.2009, 131:7544-7545.[2] Ciana C L, Phipps R J, Brandt J R., et al. Angew. Chem. Int. Ed. Engl. 2011, 50:478-482.[3] M. 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