新型杂化材料[(2,2′-bipy)2Cu][((2,2′-bipy)2Cu)2PW12O40]·4H2O的水热合成及结构表征
2014-07-27马云飞孙乙庭王瑞库冯引弟刘双英马琢琪栾国有
张 科,马云飞,孙乙庭,王瑞库,冯引弟,刘双英,马琢琪,栾国有
(1.吉林省水利水电勘测设计研究院,吉林 长春 130012;2.现代天丰农业集团有限公司,吉林 长春 130000;3.吉林农业大学资源与环境学院,吉林 长春 130118)
新型杂化材料[(2,2′-bipy)2Cu][((2,2′-bipy)2Cu)2PW12O40]·4H2O的水热合成及结构表征
张 科1,马云飞1,孙乙庭1,王瑞库1,冯引弟2,刘双英1,马琢琪1,栾国有3
(1.吉林省水利水电勘测设计研究院,吉林 长春 130012;2.现代天丰农业集团有限公司,吉林 长春 130000;3.吉林农业大学资源与环境学院,吉林 长春 130118)
用水热方法合成了一种新型的无机-有机杂化材料[(2,2′-bipy)2Cu][((2,2′-bipy)2Cu)2PW12O40]·4H2O,并采用元素分析、形貌分析、红外光谱、紫外光谱、热重分析和X射线单晶结构分析对其进行了表征.结果表明:该化合物属于单斜晶系,P2(1)/n空间群;晶胞参数a=1.890 4 nm,b=2.047 8 nm,c=2.172 8 nm,α=90°,β=96.404°,γ=90°,V=8.358 9 nm3,Z=4,R1=0.050 2,wR2=0.117 1.
多金属氧酸盐;无机-有机杂化材料;晶体结构;水热合成
0 引言
1 实验部分
1.1 试剂与仪器
试剂:所用化学试剂均为分析纯;所用水为蒸馏水,使用时未进一步纯化.
仪器:元素分析采用美国Leeman labs Inc产PLASMASPE电感耦合等离子体发射光谱仪;样貌分析采用日本岛津公司产的SSX-550型扫描电子显微镜测定晶体的外观;红外光谱采用KBr压片,用美国Nicolet公司AV360型傅里叶红外光谱仪测定,测量范围400~4 000 cm-1;紫外光谱采用北京普析通用仪器有限责任公司TU-1901紫外可见分光光度计测量,测量范围190~900 nm;热重分析采用日本岛津公司产TA-60型差热分析仪,升温速度为10℃;晶体结构采用德国Bruker Smart CCD X单晶衍射仪测定.
1.2 化合物的合成
将H3PW12O40(0.22 g,0.076 mmol),Cu(CH3CO2)2·H2O (0.15 g,0.75 mmol),2,2′-bipy(0.10 g,0.64 mmol)溶解于10 mL H2O中,充分搅拌均匀,用1 mol/L的盐酸调节pH值至6.5,然后将溶液转移到25 mL的聚四氟乙烯反应釜中,填充度为60%,在160℃条件下晶化5 d,自然冷却至室温.过滤得到黑色块状晶体C60H56Cu3N12O44PW12.元素分析(单位为质量分数/%,括号内为计算值):C 17.66 (17.54),N 4.12 (4.21),H 1.37 (1.29).
1.3 晶体结构的测定
选取大小为0.29 mm×0.26 mm×0.22 mm的晶体用于单晶结构分析.晶体的X射线衍射数据在德国Bruker Smart CCD X单晶衍射仪上收取,在1.47<θ<26.05°范围内,采用直接法以SHELXTL-97程序解出,全矩阵最小二乘法修正[26].结果表明:晶体属于单斜晶系,P2(1)/n空间群;晶胞参数a=1.890 4 nm,b=2.047 8 nm,c=2.172 8 nm,α=90°,β=96.404°,γ=90°,V=8.358 9 nm3,Z=4,R1=0.050 2,wR2=0.117 1.
2 结果与讨论
2.1 晶体结构
标题化合物是由一个双支撑Keggin型[((2,2′-bipy)2Cu)2PW12O40]-阴离子、一个分离的[Cu(2,2′-bipy)2]+阳离子和4个溶剂水组合而成,[((2,2′-bipy)2Cu)2PW12O40]-通过过渡金属Cu将阴离子簇[PW12O40]3-与2个2,2′-bipy组装到一起,如图1所示.杂多阴离子[((2,2′-bipy)2Cu)2PW12O40]-是由典型的Keggin型[PW12O40]3-阴离子和2个复杂的[(2,2′-bipy)2Cu]+基团组合而成.在Keggin型[PW12O40]3-阴离子模型中包含一个稍微扭曲的PO4四面体,围绕着四面体周围的是12个WO6八面体.P—O键长范围为0.153 0(9)~0.153 5(9) nm,∠O—P—O范围为109.0(5)°~109.5(5)°.W—O键长范围为0.169 7(9)~0.249 2(8) nm,∠O—W—O范围为71.3(3)°~173.0(5)°.键价计算(BVS)表明[27],阴离子[PW12O40]3-中的P和W的价态分别是+5和+6价,阳离子[Cu(2,2′-bipy)2]+中Cu的价态是+1价,并且3个Cu的价态都一样.考虑元素分析、电荷平衡和配位体系,该有机-无机杂化多金属氧酸盐晶体化合物的化学分子式确定为[(2,2′-bipy)2Cu][((2,2′-bipy)2Cu)2PW12O40]·4H2O.磷钨多氧阴离子作为二齿配体,通过桥氧原子与[Cu(2,2′-bipy)2]+阳离子进行配位,Cu—O键长分别为0.210 5(9)和0.224 3(9) nm,Cu(1)与Cu(2)分别与来自2个2,2′-bipy的4个N原子和1个[PW12O40]3-阴离子的氧原子形成5配位环境,Cu—N键长范围为0.197(3)~0.212(3) nm.在被分离的阳离子[Cu(2,2′-bipy)2]+中,Cu(3)的化合价被确定为+1价,Cu(3)与来自2个2,2′-bipy的4个N原子相连构成四配位体系,Cu—N键长范围为0.201(3)~0.206(3) nm,Cu(3)与4个N原子构成扭曲的四面体结构.化合物的主要键长和键角见表1.
图1 标题化合物的晶体结构
化学键键长/nm化学键键角/(°)W(1)—O(36)0.172(2)O(36)—W(1)—O(10)102.2(9)W(1)—O(19)0.1914(19)O(36)—W(1)—O(19)101.5(10)W(1)—O(18)0.194(2)O(10)—W(1)—O(19)86.6(9)W(2)—O(7)0.1722(19)O(36)—W(1)—O(3)102.0(9)W(2)—O(29)0.1896(17)O(10)—W(1)—O(3)155.8(8)W(2)—O(30)0.1887(19)O(19)—W(1)—O(3)88.3(8)W(3)—O(33)0.1697(19)O(3)—W(1)—O(18)87.7(8)W(3)—O(4)0.1899(18)O(7)—W(2)—O(29)101.0(9)W(3)—O(12)0.1905(19)O(30)—W(2)—O(20)89.0(8)
在晶体结构中,存在着分子内氢键和分子间氢键(见表2).沿着bc面看,分子内氢键有2种形式构成:一是晶格水分子提供H原子与相邻杂多阴离子的桥氧(O(23))和(O(34))之间形成的O(3w)—H(3A)…O(23)和O(1w)—H(1B)…O(34)氢键;二是2个结晶水中的2个氧(OW)形成的O(3w)—H(3B)…O(4w)氢键.分子间的氢键是水分子与杂氧阴离子的氧形成的O(1w)—H(1B)…O(34)和O(1w)—H(1A)…O(40)氢键.2个相邻的杂多阴离子[((2,2′-bipy)2Cu)2PW12O40]-上的2,2′-bipy基团之间存在π-π堆积作用,苯环之间的质心距离为0.339 nm,化合物通过氢键作用和π-π堆积作用最终形成超分子网络结构.
表2 标题化合物的氢键参数
对称操作:#1为-x+1,-y+1,-z;#2为-x+1/2,y-1/2,-z+1/2;#3为-x+1,-y+1,-z+1.
2.2 形貌分析
将化合物粉晶放在双面导电胶上,进行喷金处理后,用扫描电子显微镜对其不同表面形貌进行分析,形貌见图2.从图2b看出,晶体中有大量孔隙,这种孔隙应该具有吸附作用,作为催化剂时可以增大表面积,提高催化效率.
2.3 红外光谱分析
图3 标题化合物的红外光谱
图4 标题化合物的紫外光谱
2.4 紫外-可见光谱分析
2.5 热重分析
标题化合物的热重分析是在室温条件下,空气中测定的.化合物在25℃~600℃之间存在2步失重,总失重为24.92%,与理论失重24.72%一致.第1步失重约为1.83%,对应着化合物中水的失去 (1.77%);第2步在375℃~600℃失重为23.09%,归属于配体2,2′-bipy的失去[24-25,31].
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Abstract:A novel inorganic-organic hybrid material [(2,2′-bipy)2Cu][((2,2′-bipy)2Cu)2PW12O40]·4H2O has been hydrothermally synthesized and structurally characterized by elemental analysis,scanning electron microscope,IR spectrum,UV-Vis,TGA-DSC and single-crystal X-ray diffraction. Crystal data:monoclinic,space groupP2(1)/n,a=1.890 4 nm,b=2.047 8 nm,c=2.172 8 nm,α=90°,β=96.404°,γ=90°,V=8.358 9 nm3,Z=4,R1=0.050 2,wR2=0.117 1.
Keywords:polyoxometalate;inorganic-organic hybrid material;crystal structure;hydrothermal synthesis
(责任编辑:石绍庆)
Hydrothermal synthesis and structure characterization of a novel hybrid material [(2,2′-bipy)2Cu][((2,2′-bipy)2Cu)2PW12O40]·4H2O
ZHANG Ke1,MA Yun-fei1,SUN Yi-ting1,WANG Rui-ku1,FENG Yin-di2,
LIU Shuang-ying1,MA Zhuo-qi1,LUAN Guo-you3
(1.Jilin Province Water Resource and Hydropower Consultaive Company,Changchun 130012,China;2.Modern Tianfeng Agriculture Grouplimtied Company,Changchun 130000,China;3.College of Resource and Environment Science,Jilin Agriculture University,Changchun 130118,China)
1000-1832(2014)03-0099-06
10.11672/dbsdzk2014-03-019
2013-09-13
全球环境基金资助项目(4632);吉林农业大学科研启动基金资助项目(201218).
张科(1982—),男,硕士研究生;通讯作者:栾国有(1968—),男,教授,主要从事多酸化学研究.
O 611.4 [学科代码] 150·10
A