由六亞甲基四胺和柔性芳香羧酸構筑的兩個一維配位聚合物的合成及晶體結構

袁厚群　肖　　偉　李艷霞　胡春燕　鮑光明（江西農業大學理學院，南昌　330045）（江西農業大學動物科學與技術學院，南昌　330045）

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由六亞甲基四胺和柔性芳香羧酸構筑的兩個一維配位聚合物的合成及晶體結構

袁厚群1肖偉1李艷霞1胡春燕1鮑光明＊，2
（1江西農業大學理學院，南昌330045）
（2江西農業大學動物科學與技術學院，南昌330045）

摘要：利用六亞甲基四胺分別與苯氧乙酸、Cu（NO3）2·3H2O及2，4-二氯苯氧乙酸、Zn（NO3）2·6H2O反應，得到了2個新的一維配位聚合物，｛［Cu2（pa）4］（μ2-hmt）｝n（1）和｛｛｛［Zn3（dcpa）4（OH）］2（μ2-dcpa）2｝（μ2-hmt）｝·5H2O｝n（2）（Hpa=苯氧乙酸，Hdcpa=2，4-二氯苯氧乙酸hmt=六亞甲基四胺）。2個配合物均用元素分析、紅外光譜、X射線單晶衍射及差熱分析進行了表征。晶體結構分析表明，在配合物1中，4個苯氧乙酸根橋聯2個Cu2+形成［Cu2（COO）4］雙核結構，相鄰的［Cu2（COO）4］雙核單元由六亞甲基四胺橋聯成一維的“zigzag”鏈；在配合物2中，6個2，4-二氯苯氧乙酸根和2個OH-橋聯6個Zn2+形成六核｛［Zn3（dcpa）4（μ3-OH）］2（μ2-dcpa）2｝結構單元然后相鄰的六核單元由2個六亞甲基四胺橋聯成一維雙鏈結構。

關鍵詞：六亞甲基四胺；苯氧乙酸；2，4-二氯苯氧乙酸；Cu2+；Zn2+；晶體結構

國家自然科學基金（No.21461011，31560712）、江西省自然科學（青年）基金（No.20132BAB213002，20142BAB214017，20151BAB204014）和人事部留學人員科技活動項目擇優資助（啟動類）。

＊通信聯系人。E-mail：bycb2005@163.com；會員登記號：C02M130521385，C05M140513144。

0　Introduction

The rational design and construction of coordination polymers with multidimensional structures are of much interest due to their intriguing topological structures as well as their potential applications such as catalysis，separation，gas storage，luminescence，and magnetism［1-10］.The common approach for construction of coordination polymers is self-assembly of organic molecules and metal ions.Anionic aromatic acids and neutral N-containing heterocyclic molecules are usually used as organic ligands for extending the structures.For aromatic acids，comparing to the rigid aromatic acids，flexible aromatic ligands have not been studied much.Phenoxyacetic acid（Hpa）and its derivatives have been reported not only as fungicides，plant growth regulators and agricultural herbicides，but also as ligands to build complexes［11］.For the N-heterocyclic ligands，4，4′-bipyridine and 2，2′-bipyridine derivatives have been widely used，while heterocyclic hexamethylenetetramine（hmt），which is commercial available，inexpensive，and high soluble，has been explored to a less extent［12］.However，hmt is a unique ligand，because it has various coordination modes that span from terminal monodentate to μ2-，μ3-，or μ4-bridging mode；moreover，it can act as hydrogen bondingacceptortogeneratesupramolecular networks［13-14］.There are some transition metal complexes containing phenoxy or 2，4-dichlorophenoxy acetic acid with bipyridine ligands have been reported，such as，［Co（pa）2（H2O）2］n［15］，［Fe3O（pa）6（H2O）3］NO3·2H2O［16］，［Cd2（2，4-dcpa）4（2，2′-bipy）2］［11］，［Zn3（2，4-dcpa）6（2，2′-bipy）2］［17］， ［VO（Tp）（Hpz）（2，4-dcpa）］ （Tp=hydrotris （pyrazolyl）borate，Hpz=pyrazole）［18］，［Cu3（PhPyCNO）3（μ3-OH）（2，4-dcpa）2］（PhPyCNO=phenyl 2-pyridyl ketoxime）［19］，［Cd2（2，4-dcpa）4（phen）2］［20］，however，only one compound comprising phenoxyl and hexamethylenetetramine，［Ag2（2，4-dcpa）4（hmt）2］［21］，was found in the current version of the Cambridge Structural Database （CSD）［22］.In this paper，we report the syntheses and crystal structures of two new complexes containing hmtandphenoxyl/2，4-dichlorophenoxylligands，｛［Cu2（pa）4］（μ2-hmt）｝n（1）and｛｛｛［Zn3（dcpa）4（OH）］2（μ2-dcpa）2｝（μ2-hmt）｝·5H2O｝n（2）.

1　Experimental

1.1Materials and measurements

All reagents and solvents were used as purchased without further purification.IR spectra were recorded on a Perkin-Elmer spectrum one spectrometer with KBr pellet in the region of 4 000～450 cm-1.Elemental analyses of C，H and N were performed on Vario EL Ⅲ apparatus.Thermogravimetric analysis（TG）data were collected on a Perkin-Elmer Diamond TG/DTA instrument under nitrogen atmosphere with a heating rate of 10℃·min-1.

1.2Syntheses of the complexes

Synthesis of complex 1.A H2O/EtOH solution（8 mL，1∶1，VEtOH/VH2O）of phenoxy acetic acid（60 mg，0.4 mmol）and NaHCO3（32 mg，0.4 mmol）was added into an ethanolic solution（4 mL）of Cu（NO3）2·6H2O （96 mg，0.4 mmol）.To the resulting solution was added an aqueous solution（4 mL）of hexamethylenetetramine（30 mg，0.2 mmol）.The resulting mixture was stirred for 2 h at room temperature，and then filtered.GreenplatecrystalssuitableforX-ray diffraction were obtained from the filtration（Yield 60 mg，68%）.Anal.Calcd.for C38H40N4O12Cu2（%）:C，52.35；H，4.62；N，6.43.Found（%）:C，52.48；H，4.50；N，6.40.IR（KBr，cm-1）:3 064（w），2 958（m），2 927 （m），1 645（br），1 600（s），1 496（vs），1 460（s），1 444（s），1 421（s），1 336（s），1 292（w），1 261（s），1 225（br），1 174 （s），1 084（s），1 064（sh），1 026（s），994（s），930（m），885 （m），835（w），822（w），808（w），789（s），756（s），719（s），690（s），663（s），623（w），609（w），511（w）.

Synthesis of complex 2.A H2O/MeOH solution（8 mL，1∶1，VMeOH/VH2O）of 2，4-dichlorophenoxy acetic acid （90 mg，0.4 mmol）and NaHCO3（32 mg，0.4 mmol）was added into a methanolic solution（4 mL）of Zn（NO3）2· 6H2O（120 mg，0.40 mmol）.To the resulting solution was added an aqueous solution（4 mL）of hexamethylenetetramine（30 mg，0.2 mmol）.The resulting mixture was stirred for 2 h at room temperature，and then filtered.Colorless plate crystals suitable for X-ray diffraction were obtained from the filtration（Yield 60 mg，49%）.Anal.Calcd.for C92H90Cl20N8O39Zn6（%）:C，36.43；H，2.99；N，3.69.Found（%）:C，36.65；H，2.84；N，3.72.IR（KBr，cm-1）:3 579（w），3 433（w），3 099 （w），2 966（w），2 933（w），1 660（s），1 645（sh），1 481（s），1 429（s），1 342（m），1 288（s），1 265（sh），1 250（s），1 236 （sh），1 105（m），1 077（m），1 028（m），991（m），925（w），870（w），837（w），800（m），765（m），717（m），696（w），683 （w），656（w），648（w），611（w），557（w），507（w）.

1.3Crystal structure determination

Crystallographic data of the two complexes were collected at room temperature on a Bruker Smart ApexⅡCCD diffractometer equipped with a graphite -monochromated Mo Κα radiation（λ=0.071 073 nm）by using an φ-ω scan mode at 296（2）K.The crystal structures was solved by direct method，using the program SHELXS-97［23］，and refined on F2by fullmatrix least-squares techniques using the SHELXTL-97［24］crystallographicsoftware package.All nonhydrogen atoms except the crystallization water molecules were refined anisotropically.All the hydrogen atomswereplacedincalculatedpositionsand constrained to ride on their parent atoms except tha the hydrogen atoms of hydroxyl group and wate molecules in complex 2.The hydrogen atoms o hydroxyl group and water molecules in complex 2 ar located from difference maps and refined isotropically Crystallographic data for both complexes are listed in Table 1，and selected bond lengths and angles are listed in Table 2.

CCDC:1469683，1；1469684，2.

Table 1　Crystallographic data for the complexes 1 and 2

2　Results and discussion

2.1IR spectra

The IR spectra show features attributable to each component of the complexes.The weak bands in the range of 3 064～2 879 cm-1in complex 1，and 3 099～2 933 cm-1in complex 2，are attributed to the C-H stretching of hmt molecules，respectively.The band a 994 cm-1in complex 1，and 991 cm-1in complex 2due to the C-N stretching of hmt，further confirms the existence of the hmt ligand in two complexes.The strong vibrations at 1 645，1 496 cm-1in complex 1，and 1 660，1 481 cm-1in complex 2，are attributed to the asymmetric and symmetric stretching vibrations of the carboxylate group，suggesting that the pa or dcpa exist in complex 1 or 2.In addition，the bands at 3 579，and 3 433 cm-1are also observed in complex 2，which could be assigned to the O-H stretching vibrations of the bridging hydroxyl group and water molecules involved in hydrogen bonding.

Table 2　Selected bond lengths（nm）and bond angles（°）for the complexes 1 and 2

2.2Crystal structures

2.2.1Crystal structure of complex 1

X-ray crystal structural analysis revealed that the asymmetric unit of complex 1 is comprised of two crystallographically independent Cu2+ions，Cu1 and Cu2，four pa ligands，and one hmt ligand.As shown in Fig.1，each Cu2+ion is five coordination in a square -pyramidal geometry with four oxygen atoms from four pa ligands that are occupying the equatorial positions and one nitrogen atom from hmt ligand that is at the axial position.The Cu2+ions are deviated by 0.151 7（1）nm for Cu1 and 0.209 7（2）nm for Cu2 from the equatorial plane toward the axial N atoms，respectively.

Fig.1　View of the coordination environment of the Cu(Ⅱ)centers in complex 1

The four pa ligands using four carboxylate groups link two Cu2+ions with distances of 0.268 6（1）for Cu1 …Cu1aand 0.264 7（1）nm for Cu2…Cu2b，respectively，to form［Cu2（COO）4］paddlewheel molecular building blocks.The oxyacetate groups are almost twisted out of the phenyl ring planes，with the torsion angles of C1-C2-O3-C3，C9-C10-O6-C11，C23-C24-O9-C25，and C31-C32-O12-C33 being 66.2（3）°，74.6（3）°，67.6（3）°，and 67.7（3）°，respectively.The four phenyl groups around Cu2…Cu2bare arranged in the same direction，thus，the shape of［Cu2（COO）4］paddlewheel in Cu2… Cu2bunits looks like“卐”character viewed through Cu2-Cu2bvector，which is different from the［Cu2（COO）4paddlewheel in Cu1-Cu1aunits.Hexamethylenetetra mine ligands link the vertices of［Cu2（COO）4］paddle wheel units using μ2-bridging mode.Therefore，a 1D zigzag chain structure forms in complex 1（Fig.2）.

Fig.2　（a）Shapes of［Cu2（COO）4］paddlewheels viewed through Cu-Cu vectors；（b）1D zigzag chain structure of complex 1

Fig.3　View of the coordination environment of the Zn(Ⅱ)centers in complex 2

2.2.2Crystal structure of complex 2

The asymmetric unit of complex 2 consists o three Zn2+ions，five dcpa-ligand，one OH-ion，on hmt ligand，and two and a half water molecules.As shown in Fig.3，Zn1 is six coordination in a distorted octahedral geometry with four oxygen atoms from four different dcpa ligands at the equatorial position（O1 O4，O10，and O13），one oxygen atom of OH-ion （O16）and one nitrogen atom from an hmt ligand（N1 whichoccupytheaxialposition.Zn2isfive coordinated with four oxygen atoms（O5，O7，O11，and O16）and one nitrogen atom（N2）in a square pyramidal geometry，in which O5，N2c，O11，and O16 are at the equatorial plane and the O7 is at the axia position.Zn3 is four coordination in a tetrahedra geometry with carboxylate oxygen atoms of O8dand O14，one oxygen atom of OH-ion O16，and one wate molecule O17.As described above，it is interested to find that there are four-，five-，and six-coordination Zn2+ions in the same units，and OH-ion bridges th three Zn2+ions.

The torsion angles of C1-C2-O3-C3，C9-C10-O6C11，C25-C26-O12-C27，and C33-C34-O15-C35 are 163.4（3）°，175.4（3）°，-173.4（3）°，and 179.9（3）°，respectively，indicating that the oxyacetate groups are almost in the same planes with the phenyl rings in dcpa1，dcpa2，dcpa3，and dcpa4 ligands.On the other hand，the oxyacetate group is almost out of the phenyl ring plane in dcpa5 ligand，with the torsion angle of C17-C18-O9-C19 being 83.8（4）°.There are two coordination modes of the carboxylate groups in complex 2.Only the carboxylate group in dcpa1 ligand coordinates to Zn1 using monodentated coordination mode. The carboxylate groups in dcpa2，dcpa3，and dcpa4 usingmonodentate-bridgedcoordinationmodesto connect the three Zn2+ions.Thus，atrinuclear ［Zn3（dcpa）4（μ3-OH）］+unit is formed，and the［Zn3（dcpa）4（μ3-OH）］+units are bridged by the carboxylate groups oftwodcpa5ligandsusingmonodentate-bridged coordination mode to form a hexanuclear｛［Zn3（dcpa）4（μ3-OH）］2（μ2-dcpa）2｝units（Fig.4）.Furthermore，the｛［Zn3（dcpa）4（μ3-OH）］2（μ2-dcpa）2｝units are connected by two hexamethylenetetramine ligands that use μ2-bridging mode.Therefore，a 1D double chain structure forms in complex 2（Fig.5）.

Fig.4　A perspective view of hexanuclear｛［Zn3（dcpa）4（μ3-OH）］2（μ2-dcpa）2｝unit

Fig.5　1D double chain structure of complex 2

The thermogravimetric analyses were carried out to examine the thermal stability of the two complexes （Fig.6）.Complex 1 started to decompose at 205℃. The weight loss of 69.38%from 205 to 320℃ is attributed to the loss of four pa ligands（Calcd. 69.34%）.Complex 2 is found to exhibit a two-step weight loss process.The first step is in the range of 80～135℃，with the weight loss of 3.23%，which is attributedtothelossoffivecrystallizedwater molecules（Calcd.2.97%）.The weight loss of 62.03% intherangeof190～420℃wasobserved，corresponding to the loss of two OH-，two coordination water molecules，two hmt and seven dcpa ligands （Calcd.62.33%）.

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“安劉1”與“安劉2”典源與典義均不同：“安劉1”的典義已不再是其字面的 “安定劉氏江山”之義，而是變異成“維護王朝”（維護的對象可以是任何一個朝代，不再僅限于劉氏江山）之義了。典源是一個語典，即漢劉邦（高祖）病危時對呂后說：“周勃重厚少文，然安劉氏者必勃也。”“安劉2”的典義為字面義，即“安定劉氏江山”之義。典源是一個事典：指漢初商山四皓輔助太子，安定劉氏江山之事。后世用典者根據詩文創作語境與表情達意的需要從上述兩個不同的典源中創造出了相同的典面“安劉”，這種相同只是偶然的相同，沒有必然聯系，所以“安劉1”與“安劉2”是同形典故詞語。

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中圖分類號：O614.121；O614.24+1

文獻標識碼：A

文章編號：1001-4861（2016）05-0899-07

DOI：10.11862/CJIC.2016.109

收稿日期：2015-12-17。收修改稿日期：2016-03-23。

Syntheses，Crystal Structures of Two 1D Coordination Polymers Based on Hexamethylenetetramine and Flexible Aromatic Acids

YUAN Hou-Qun1XIAO Wei1LI Yan-Xia1HU Chun-Yan1BAO Guang-Ming＊，2
（1School of Science，Jiangxi Agricultural University，Nanchang 330045，China）
（2School of Animal Science and Technology，Jiangxi Agricultural University，Nanchang 330045，China）

Abstract：Two 1D coordination polymers of｛［Cu2（pa）4］（μ2-hmt）｝n（1）and｛｛｛［Zn3（dcpa）4（OH）］2（μ2-dcpa）2｝（μ2-hmt）｝· 5H2O｝n（2）（Hpa=phenoxyacetic acid，Hdcpa=2，4-dichlorophenoxy acetic acid，hmt=hexamethylenetetramine）were obtained by the reactions of hexamethylenetetramine with phenoxy acetic acid and Cu（NO3）2·3H2O，or 2，4 dichlorophenoxy acetic acid and Zn（NO3）2·6H2O，respectively.The complexes were characterized by elementa analysis，IR，single X-ray diffraction and thermogravimetric analyses.The crystal structural analysis revealed that，in complex 1，two Cu2+ions are bridged by four pa ligands to form a［Cu2（COO）4］unit，and the neighborin ［Cu2（COO）4］units are further connected by hmt ligands to form a 1D zigzag chain；while in complex 2，six Zn2ions are bridged by six dcpa and two OH-ligands to form hexanuclear｛［Zn3（dcpa）4（μ3-OH）］2（μ2-dcpa）2｝subunit which are further connected by hmt ligands to form a 1D double chain.CCDC:1469683，1；1469684，2.

Keywords：hexamethylenetetramine；phenoxy acetic acid；2，4-dichlorophenoxy acetic acid；Cu2+；Zn2+；crystal structure