三維超分子化合物[Cu2(phen)2(H2O)4]·(SO4)2的水熱合成、晶體結(jié)構(gòu)及熒光性質(zhì)研究

,,,奎蓉,

(1.延邊大學(xué) 理學(xué)院 化學(xué)系,吉林 延吉 133002;2.淮陰師范學(xué)院 化學(xué)化工學(xué)院,江蘇 淮安 223300)

0 引言

近年來(lái),配位聚合物由于其迷人的結(jié)構(gòu)及在催化、吸附、電子傳輸、磁性、光學(xué)性等領(lǐng)域的潛在應(yīng)用,引起國(guó)內(nèi)外研究人員的廣泛關(guān)注[1-6].水熱合成對(duì)于配位聚合物的制備是一種有效且簡(jiǎn)單的合成方法,其起始反應(yīng)物通常為簡(jiǎn)單的無(wú)機(jī)物和有機(jī)物,一些具有新奇結(jié)構(gòu)的配位聚合物大多數(shù)是由水熱法合成得到[7-11].鄰菲羅啉具有剛性、平面性和芳香性,在配位化學(xué)領(lǐng)域是一個(gè)很好的結(jié)構(gòu)構(gòu)筑模塊,其作為一種配位能力很強(qiáng)的二齒配體已被廣泛應(yīng)用于金屬-有機(jī)配位聚合物的合成,如Cu(II)離子與有機(jī)配體phen合成的配位聚合物[12-16],但在已報(bào)道的Cu(II)-phen化合物中具有一維交叉結(jié)構(gòu)的相對(duì)較少.本文中,我們報(bào)道了水熱條件下基于靜電引力、氫鍵和π—π堆積等弱的分子間作用力由一維交叉結(jié)構(gòu)構(gòu)筑而成的三維超分子[Cu2(phen)2(H2O)4]·(SO4)2(化合物1),同時(shí)研究了室溫下化合物1的固體熒光性質(zhì).

1 實(shí)驗(yàn)部分

1.1 試劑與儀器

2400II型元素分析儀(美國(guó)PE公司);SMART APEXII CCD單晶X-射線衍射儀(德國(guó)Bruker公司),鉬靶,λ=0.071073nm;ARL X`TRA型粉末X-射線衍射儀(瑞士Thermo公司),銅靶,λ=0.15418nm;AVATAR360型紅外光譜儀(美國(guó)Nicolet公司),KBr壓片,波數(shù)范圍4000～400cm-1;固態(tài)樣品熒光光譜是在Perkin-Elmer LS55型熒光光譜儀(美國(guó)PE公司)上于室溫下測(cè)定.所用試劑中哌嗪膦酸根據(jù)文獻(xiàn)合成[17].其他均為市售分析純,水為蒸餾水.

1.2 化合物1的合成

稱(chēng)取0.6mmol (0.150g)CuSO4·5H2O、0.8mmol (0.160g)鄰菲羅啉和0.6mmol (0.165g)哌嗪膦酸于25mL燒杯中,加入5mL去離子水,在室溫下攪拌0.5h.把混合物移到23mL內(nèi)襯為聚四氟乙烯的不銹鋼水熱反應(yīng)釜中,放入140℃烘箱內(nèi),在自生壓力條件下反應(yīng)4天后取出.冷卻至室溫,經(jīng)過(guò)濾、去離子水洗滌于室溫下晾干,得黃綠色晶體,產(chǎn)率30%(基于Cu計(jì)算).元素分析實(shí)驗(yàn)值(%): C 38.19,H 3.091,N 7.342;理論值(%): C 38.31,H: 3.193,N 7.450.IR分析(KBr壓片,cm-1): 3129 (m),1620 (w),1400 (m),1088 (m),614 (w),474 (m).

1.3 晶體結(jié)構(gòu)的測(cè)定

選取0.030mm×0.020mm×0.015mm的單晶,利用SMART PEX II CCD單晶衍射儀進(jìn)行衍射數(shù)據(jù)收集.在296(2)K下用Mo-Kα射線(λ=0.071073nm),以multi-scan掃描方式在1.69°≤θ≤25.00°范圍內(nèi)共收集13946個(gè)衍射點(diǎn),其中3614個(gè)獨(dú)立衍射點(diǎn)和3594個(gè)可觀測(cè)衍射點(diǎn)[I>2σ(I)]用于結(jié)構(gòu)分析和結(jié)構(gòu)修正.晶體結(jié)構(gòu)采用SHELXS-97程序由直接法解出,結(jié)構(gòu)精修采用SHELXS-97程序,對(duì)氫原子和非氫原子分別采用各向同性和各向異性溫度因子進(jìn)行全矩陣最小二乘法修正.相應(yīng)的晶體學(xué)數(shù)據(jù)及結(jié)構(gòu)修正數(shù)據(jù)見(jiàn)表1.

表1 化合物1的晶體學(xué)數(shù)據(jù)

2 結(jié)果與討論

2.1 晶體結(jié)構(gòu)描述

如圖1所示,化合物1的不對(duì)稱(chēng)結(jié)構(gòu)單元中包含2個(gè)晶體學(xué)獨(dú)立的二價(jià)銅離子、2個(gè)phen有機(jī)

圖1 化合物1的分子結(jié)構(gòu)

表2 化合物1的部分鍵長(zhǎng)(nm)和鍵角

表3 化合物1的氫鍵鍵長(zhǎng)(nm)和鍵角

對(duì)稱(chēng)操作: #1:-x,y,-z+1/2;#2:-x,y,-z-1/2;#3:-x,-y+1,-z;#4: x,-y,z+1/2;#5:-x,y,1/2-z;#6:x,1-y,1/2+z;#7: 1/2-x,1/2-y,-z

如圖2所示,以Cu(1)為中心的配位單元[Cu(1)N2O2]2+為A,以Cu(2)為中心的配位單元[Cu(2)N2O2]2+為B.各配位單元在眾多氫鍵的連接作用下,O(7)—H(72)…O(9)(0.264(2)nm,147.8°),O(7)—H(71)…O(8)(0.319(2)nm,120.3°),O(2)—H(21)…O(5)(0.267(2)nm,133.1°),O(1)—H(11)…O(4)(0.263(2)nm,115.3°),C(14)—H(14)…O(5)(0.334nm,152.0),C(9)—H(9)…O(9)(0.333nm,146.0°),C(5)—H(5)…O(6)(0.324nm,136.0°),C(2)—H(2)…O(4)(0.338nm,144.0°),以BAA的模式進(jìn)行交替排列,沿[100]面擴(kuò)展形成一維梯層狀鏈,如圖3.該一維鏈繼續(xù)在氫鍵O(7)—H(72)…O(8)(0.275(3)nm,124.9°),O(7)—H(71)…O(9)(0.269(2)nm,111.9°),O(2)—H(21)…O(1)(0.2.89(2)nm,122.9°),O(1)—H(11)…O(5)(0.347(2)nm,173.9°),O(1)—H(11)…O(2)(0.289(2)nm,113.0°)的連接作用下,以及芳環(huán)間的錯(cuò)位π—π堆積和面對(duì)面π—π堆積的作用下被構(gòu)筑成了三維超分子結(jié)構(gòu),如圖4所示.相應(yīng)的π—π堆積作用分別發(fā)生在六元環(huán)(N(1)—C(1)—C(2)—C(3)—C(4)—C(12))與(C(4)—C(5)—C(6)—C(7)—C(11)—C(12))之間(面心距為0.3941nm,二面角為1.08°)、六元環(huán)(N(2)—C(10)—C(9)—C(8)—C(7)—C(11))與(C(4)—C(5)—C(6)—C(7)—C(11)—C(12))之間(面心距為0.3935nm,二面角為0.59°)、六元環(huán)(C(4)—C(5)—C(6)—C(7)—C(11)—C(12))與(C(4)—C(5)—C(6)—C(7)—C(11)—C(12))之間(面心距為0.3534nm,二面角為0.33°)、六元環(huán)(N(3)—C(13)—C(14)—C(15)—C(16)—C(17))與(C(16)—C(17)—C(17A)—C(16A)—C(18A)—C(18))之間(面心距為0.3946nm,二面角為2.00°)以及六元環(huán)(C(16)—C(17)—C(17A)—C(16A)—C(18A)—C(18))與(C(16)—C(17)—C(17A)—C(16A)—C(18A)—C(18))之間(面心距為0.3531nm,二面角為0.00°).化合物1的氫鍵鍵長(zhǎng)和鍵角見(jiàn)表3.

(圖中為清晰起見(jiàn)刪除了游離的離子)

圖3 沿[100]面配位單元[CuN2O2]2+以BAA方式排列與離子通過(guò)氫鍵作用形成的一維梯層狀鏈

圖4 化合物1的三維超分子結(jié)構(gòu)圖

2.2 粉末XRD表征

對(duì)化合物1進(jìn)行了粉末X射線衍射分析(Cu Kα輻射,λ=0.15418nm),并根據(jù)單晶X射線衍射所得數(shù)據(jù),利用Powdercell For Windows v2.4(簡(jiǎn)稱(chēng)PCW)軟件模擬了該化合物的粉末X射線譜圖.實(shí)驗(yàn)所得譜圖中的衍射峰與模擬譜圖中的衍射峰的位置基本吻合(圖 5),表明化合物是純相.而衍射強(qiáng)度的不同主要是由粉末樣品在收集衍射數(shù)據(jù)時(shí)首選的取向不同所造成.

2.3 熒光性質(zhì)研究

室溫下,對(duì)化合物1的固態(tài)熒光性質(zhì)進(jìn)行了探討.固體熒光測(cè)試結(jié)果表明化合物1在270nm的激發(fā)波長(zhǎng)下于450nm波長(zhǎng)處有一個(gè)熒光發(fā)射峰,如圖 6 所示.據(jù)文獻(xiàn)報(bào)道[21],自由配體phen在310nm激發(fā)波長(zhǎng)下,在365nm和388nm兩個(gè)波長(zhǎng)處出現(xiàn)可歸為分子內(nèi)π*—π電荷轉(zhuǎn)移的熒光發(fā)射峰.所以化合物1在450nm處的熒光發(fā)射峰可能是由配體到金屬間的電荷轉(zhuǎn)移(LMCT)或者金屬到配體間的電荷轉(zhuǎn)移(MLCT)所致.

圖5 化合物1實(shí)驗(yàn)(a)與模擬(b)粉末XRD圖

圖6 化合物1的室溫固體熒光譜圖

3 結(jié)論

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