Wang Yenan,Liu Bo,Niu Xiaoqing

Coconut Research Institute of Chinese Academy of Tropical Agricultural Sciences,Hainan Innovation Center of Academician Team,Wenchang 571339,China

Abstract [Objective]The paper was to synthesize a new structure of metal organic framework,and to provide new materials for plant pathogens testing.[Method]A mixture of 2,6-di(2’,4’-di-carboxylphenyl)pyridine,1,4-bis(1-imidazolyl)benzene,Co(NO3)2·6H2O were added to the solution of DMF:H2O=3:3 and heated at 433K for 4 d.[Result]Red crystals of the title compound were obtained (yield 76.3%,based on Co).[Conclusion]The crystal data were obtained as follows:C39H24Co2N7O8,monoclinic,P21/c,a=16.222(7)Å,b=12.653(5)Å,c=17.456(7)Å,β=102.386(6)°,V=3 500(2)Å3,Z=4,Rgt(F)=0.055 0,wRref(F2)=0.150 9,T=293(2)K.

Keywords Poly[(2,6-di(2’,4’-dicarboxylphenyl)pyridine;Cobalt(II)

In the last two decades,a large number of cobalt(II)-based metal-organic frameworks(MOFs)and coordination polymers have been reported[1-7].The physical and chemical properties of the MOFs have a lot to do with the selection of organic complexes.Taking advantage of the channel structure of Co-MOFs with the aforementioned ideas in mind,2,6-di(2’,4’-dicarboxylphenyl)pyridine acid(H4L)and 1,4-bis(1-imidazolyl)benzene(bib)are selected to construct porous Co-MOFs based on the following reasons:(i)An unsaturated(open)pyridyl group is an excellent functional site to expanding its chemical properties;(ii)As a rigid ligand,H4L has the advantage of forming robust porous frameworks[8];(iii)1,4-bis(1-imidazolyl)benzene (bib),as a nitrogen donor ligand,serves as a bridging ligand,which can act as bidentate ligand to coordinate to two metal ions auxiliary ligand[9].

1 Material and Methods

All reagents were purchased from commercial sources and used without further purification.A mixture of 2,6-di(2’,4’-di-carboxylphenyl)pyridine(H4L,0.025 mmol),1,4-bis(1-imidazolyl)benzene(bib,0.05 mmol),Co(NO3)2·6H2O (0.1 mmol),were added to the solution of DMF ∶H2O=3∶3 in a 25 mL Teflon-lined autoclave.The mixture was heated at 433K for 4 d and then slowly cooled down to room temperature.Red crystals of the title compound were obtained(yield 76.3%,based on Co).H atoms were inserted in idealized positions and refined using a riding model,with Uiso(H)values equal to 1.2 or 1.5 times the Ueq value of the atom to which it was bonded.Data collection:4;program(s)used to solve structure:She lXT[10];program(s)used to refine structure:SHELXL[11];molecular graphics:Olex2;software used to prepare material for publication:Olex2[12].

2 Results and Analysis

All esds(except the esd in the dihedral angle between two l.s.planes)were estimated using the full covariance matrix.The cell esds were taken into account individually in the estimation of esds in distances,angles and torsion angles;correlations between esds in cell parameters were only used when they were defined by crystal symmetry. An approximate(isotropic)treatment of cell esds was used for estimating esds involving l.s.planes(Tables 1-4).

Table 1 Crystal data

Table 2 Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters(Å2)for(z)

Table 3 Atomic displacement parameters(Å2)for(z)

Table 4 Geometric parameters(Å,o)for(z)

(Continued)

Single-crystal X-ray analysis revealed crystallizes in the monoclinic space groupP21/c and featured a 3D 2-fold interpenetrating framework.There were two types of crystallographically inequivalent Co(II)sites,one five-coordinated distorted tetragonal pyramidal geometry (Co1)and a five-coordinated distorted hexahedron environment Co2cluster)[13].The asymmetric unit of the title structure consisted of two Co(II)ion,one and a half 1,4-bis(1-imidazolyl)benzene(bib)and one 2,6-di(2′,4′-dicarboxylphenyl)pyridine(H4L).A pair of Co1 atoms were bridged by four carboxylate groups in syn-syn coordination mode to form a paddlewheel dinuclear [Co2(RCOO)4]unit with the Co1-Co1#1 (#1:1-x,1-y,1-z)separation of 2.846 6 (14)A.Co2+4ion was also five-coordinated by two N atoms from two bib ligands and three O atoms from two H4L ligands,leading to a slightly distorted hexahedron environment.The Co-N bond lengths were 2.054 5(27)Å,2.030 7(25)Å and 2.025 7(36)Å,and the Co-O ones were in the range of 1.965 3(31)Å and 2.092 4 (24)Å,all of which were in the normal range of those observed in the reported Co(II)complexes.Each fully deprotonated L4-ligand coordinated to four Co atoms,with four carboxylate groups adopting μ1-η1:η1, μ1-η1:η1, μ1-η1:η1 and μ1-η1:η1 modes,resulting in the formation of a 1D sheet.Furthermore,the L4-and bib ligands linked the Co(II)atoms to form a complex 3D self-penetrating network(Fig.1).

Fig.1 Coordination environment

3 Conclusion

Red crystals of the title compound were obtained(yield 76.3%,based on Co).The crystal data were:C39H24Co2N7O8,monoclinic,P21/c,a=16.222 (7)Å,b=12.653(5)Å,c=17.456(7)Å,β =102.386(6)°,V=3 500 (2) Å3,Z=4,Rgt(F)=0.055 0,wRref(F2)=0.150 9,T=293(2)K.Nucleic acids of some viruses and bacteria that cause plant diseases have been used in detection research and some progress has been made.