田小燕,胡愛(ài)云,袁愛(ài)華
(江蘇科技大學(xué)環(huán)境與化學(xué)工程學(xué)院,江蘇鎮(zhèn)江212003)
一維鏈狀氰基橋聯(lián)配合物Mn(bpac)2(H2O)2M(CN)4(bpac=bis(4-pyridyl) acetylene;M=Pt,Pd)的合成、結(jié)構(gòu)與熱穩(wěn)定性
田小燕,胡愛(ài)云,袁愛(ài)華*
(江蘇科技大學(xué)環(huán)境與化學(xué)工程學(xué)院,江蘇鎮(zhèn)江212003)
將過(guò)渡金屬離子Mn2+與柱狀配體bis(4-pyridyl)acetylene(bpac)和[M(CN)4]2-(M=Pt,Pd)通過(guò)緩慢擴(kuò)散法進(jìn)行組裝反應(yīng),得到了兩個(gè)一維鏈狀氰基橋聯(lián)配合物Mn(bpac)2(H2O)2M(CN)4(M=Pt(1),Pd(2)).單晶X射線(xiàn)衍射分析表明:配合物1和2為同構(gòu)體,均屬三斜晶系,空間群P1.其非對(duì)稱(chēng)單元由1個(gè)[Mn(bpac)2(H2O)2]2+陽(yáng)離子和1個(gè)[M (CN)4]2-陰離子組成,Mn和M中心分別處于六配位的八面體和四配位的平面四方構(gòu)型之中,兩者通過(guò)氰基交替連接形成無(wú)限延伸的一維直線(xiàn)鏈.同時(shí),文中研究了配合物1的熱穩(wěn)定性.
氰基橋聯(lián);配合物;合成;結(jié)構(gòu);熱穩(wěn)定性
近年來(lái),設(shè)計(jì)與合成具有特定拓?fù)浣Y(jié)構(gòu)和性質(zhì)的配合物引起了科學(xué)家們的廣泛關(guān)注[1-3].氰基合金屬陰離子(如[M(CN)4]2-(M=Ni,Pt,Pd)、[M (CN)6]3-(M=Cr,Mn,F(xiàn)e)和[M(CN)8]3/4-(M=Mo,W))常被用作構(gòu)筑單元,與過(guò)渡金屬(或稀土金屬)離子和有機(jī)配體通過(guò)組裝反應(yīng),制備結(jié)構(gòu)多樣的氰基橋聯(lián)配合物[4-6],這些配合物在磁性[7]、吸附[8]和負(fù)熱膨脹[9]等領(lǐng)域具有潛在的應(yīng)用[10-12].四氰合金屬基配合物作為一個(gè)重要分支,具有拓?fù)浣Y(jié)構(gòu)多樣、磁性和吸附性能優(yōu)異等優(yōu)點(diǎn),備受人們關(guān)注[13-19].為了豐富四氰合金屬基配合物的研究?jī)?nèi)容,本文采用[M(CN)4]2-(M=Pt,Pd)為構(gòu)筑基元與過(guò)渡金屬離子Mn2+和柱狀剛性有機(jī)配體bis(4-pyridyl)acetylene(bpac)進(jìn)行組裝反應(yīng),得到了兩個(gè)新型一維直線(xiàn)鏈狀配合物Mn(bpac)2(H2O)2M (CN)4(M=Pt(1),Pd(2)).文中重點(diǎn)介紹了配合物1和2的合成、結(jié)構(gòu)和熱穩(wěn)定性.
1.1 試劑與儀器
合成所用藥品及試劑均為市售分析純,使用時(shí)均未進(jìn)一步提純,所用水為去離子水.
粉末X射線(xiàn)衍射測(cè)試采用日本島津XRD-6000型衍射儀,管壓40 kV,管流30 mA,Cu-Kα輻射,測(cè)定范圍5°~50°,速率5°/min;紅外光譜測(cè)定采用Nicolet FT-1703X紅外光譜儀(KBr壓片),測(cè)試范圍為400~4 000 cm-1;熱重分析采用PE公司的Pyris Diamond熱分析儀,氮?dú)獗Wo(hù),室溫~800oC,升溫速率為15oC/min.
1.2 單晶結(jié)構(gòu)測(cè)定
配合物的單晶衍射數(shù)據(jù)在Bruker Smart APEX II X射線(xiàn)單晶衍射儀上收集,采用石墨單色器單色化的Mo-Kα射線(xiàn)(λ=0.710 73?)作為入射線(xiàn),用Bruker XSCANS程序測(cè)定.所有衍射數(shù)據(jù)均用SMART、SAINT和 XPREP程序[20]進(jìn)行分析和還原,并用SADABS方法[21]來(lái)校正洛倫茲因子、極化因子和吸收因子.初結(jié)構(gòu)由SHELXS-97程序的直接法解出,并用SHELXL-97程序精修[22].所有非氫原子的坐標(biāo)用全矩陣最小二乘法各向異性溫度因子修正,氫原子坐標(biāo)按理想幾何位置插入.這些氫原子的坐標(biāo)和各向同性溫度因子參加結(jié)構(gòu)計(jì)算,但不參加修正,全矩陣最小二乘法精修基于F2.
1.3 單晶培養(yǎng)
分別稱(chēng)取MnSO4·H2O(0.05 mmol)和配體dpac(0.05 mmol)于2 mL小瓶中,稱(chēng)取 K2[Pt (CN)4]·3H2O(0.05 mmol)于20 mL大瓶中,將小瓶放入大瓶?jī)?nèi).大小瓶中加入水直到?jīng)]過(guò)小瓶口1~2 cm,擰緊瓶蓋,在室溫下靜置三周,得到無(wú)色棒狀晶體1.配合物2的合成方法與1類(lèi)似,只需將K2[Pt(CN)4]·3H2O替換成K2[Pd(CN)4]·3H2O.
2.1 晶體結(jié)構(gòu)
單晶X射線(xiàn)衍射分析表明,配合物1和2為同構(gòu)體,均屬三斜晶系,空間群P1.配合物1和2的晶體學(xué)數(shù)據(jù)列于表1,部分鍵長(zhǎng)和鍵角列于表2.
表1 配合物1和2的晶體學(xué)數(shù)據(jù)Table 1 Crystal data collection and refinement parameters for complexes 1 and 2
文中以配合物1為例進(jìn)行了詳細(xì)的晶體結(jié)構(gòu)描述.圖1為配合物1的ORTEP圖,其非對(duì)稱(chēng)單元由1個(gè)[Mn(bpac)2(H2O)2]2+陽(yáng)離子和1個(gè)[Pt (CN)4]2-陰離子組成.[Pt(CN)4]2-中的Pt原子處于四配位的平面四方構(gòu)型之中,其中兩個(gè)氰基(C2N2,C4N4)為端基,其他(C1N1,C3N3)為橋聯(lián)氰基.在[Mn(bpac)2(H2O)2]2+結(jié)構(gòu)中,Mn原子為六配位的畸變八面體構(gòu)型,赤道位置被兩個(gè)氰基氮原子和兩個(gè)dpac配體中的兩個(gè)氮原子占據(jù),Mn1—N1和Mn1—N5鍵長(zhǎng)分別為2.28 ?和2.34 ?.而軸向位置則被兩個(gè)配位水占據(jù),Mn1—O1和Mn1—O2鍵長(zhǎng)分別為 2.26 ?和2.17 ?,O1—Mn1—O2的鍵角為 177.5°.如圖 2所示,[Mn (bpac)2(H2O)2]2+和[Pt(CN)4]2-之間通過(guò)氰基交替連接形成無(wú)限伸展的一維鏈狀結(jié)構(gòu),其中C1—N1—Mn1和N1—C1—Pt1的鍵角分別為170°和174.3°,彎曲角度較小,可近似為直線(xiàn)鏈.
表2 配合物1和2的部分鍵長(zhǎng)和鍵角Table 2 Selected bond distances and bond angles for complexes 1 and 2
圖1 配合物1的ORTEP圖(省略了H原子,橢球度30%)Fig.1 ORTEP diagram of complex 1(Hydrogen atoms are omitted for clarity and thermal ellipsoids are presented at the 30%probability level)
圖2 配合物1的一維直線(xiàn)鏈結(jié)構(gòu)Fig.2 1D linear chain structure of complex 1
2.2 紅外光譜分析
圖3為配合物1的紅外光譜譜圖.2 164 cm-1和2 142 cm-1處為氰基的特征吸收峰,其中2 164 cm-1處為橋聯(lián)氰基吸收峰,2 142 cm-1則為端基氰基吸收峰.與K2[Pt(CN)4]·H2O中的氰基振動(dòng)吸收峰(2 121 cm-1)相比,氰基吸收峰向高頻方向移動(dòng),表明氰基與第二金屬中心橋聯(lián).3 417 cm-1為游離水分子中O—H的伸縮振動(dòng)吸收峰,可能由于樣品吸附了部分水導(dǎo)致,3 228 cm-1為結(jié)構(gòu)中配位水的O-H伸縮振動(dòng)吸收峰,1 606 cm-1為吡啶環(huán)上的C=C伸縮振動(dòng)峰,1 415 cm-1處為吡啶環(huán)上C-N的伸縮振動(dòng)吸收峰.
圖3 配合物1的紅外光譜圖Fig.3 FT-IR spectrum of complex 1
2.3 熱重分析
圖4 配合物1的TG曲線(xiàn)Fig.4 TG curve of complex 1
圖4為配合物1的熱重曲線(xiàn).從圖中可看出,室溫到70℃區(qū)間配合物結(jié)構(gòu)穩(wěn)定.溫度升高至90℃時(shí),開(kāi)始失去兩個(gè)配位水分子,其失重率為5.1%,接近理論值4.8%.90~140℃之間出現(xiàn)短的平臺(tái),表明脫水配合物在該溫度區(qū)域內(nèi)保持穩(wěn)定.隨著溫度繼續(xù)升高,熱重曲線(xiàn)出現(xiàn)多個(gè)轉(zhuǎn)折點(diǎn),說(shuō)明配合物主體骨架的分解過(guò)程是逐步進(jìn)行的.550℃左右時(shí)分解基本完全,殘余率約為26.99%.
以[M(CN)4]2-(M=Pt,Pd)為構(gòu)筑模塊與過(guò)渡金屬離子Mn2+和剛性有機(jī)配體bpac通過(guò)擴(kuò)散反應(yīng),得到了兩個(gè)一維鏈狀氰基橋聯(lián)配合物.晶體結(jié)構(gòu)分析表明:這兩個(gè)配合物為同構(gòu)體,Mn和M金屬中心之間通過(guò)氰基連接形成一維直線(xiàn)鏈結(jié)構(gòu),加入的bpac柱狀配體并未起到橋聯(lián)作用.對(duì)于失去配位水后的配合物,其主體骨架隨著溫度的升高而開(kāi)始分解.
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(責(zé)任編輯:繆文樺)
Synthesis,structures and thermal stabilities of two cyano-bridged one-dimensional complexes Mn(bpac)2(H2O)2M(CN)4(bpac=bis(4-pyridyl)acetylene;M=Pt,Pd)
Tian Xiaoyan,Hu Aiyun,Yuan Aihua*
(School of Environment and Chemical Engineering,Jiangsu University of Science and Technology,Zhenjiang Jiangsu 212003,China)
Two new one-dimensional(1D)complexes Mn(bpac)2(H2O)2M(CN)4bpac=(bis(4-pyridyl)acetylene;M=Pt(1),Pd(2))were synthesized by the self-assembly reactions of Mn2+ion,pillar ligand bpac and[M(CN)4]2-(M=Pt,Pd).Single-crystal X-ray diffraction analysis revealed that complexes 1 and 2 are isostructural and they belong to triclinic space group P1.The asymmetric unit of both complexes consist of one[Mn (bpac)2(H2O)2]2+cation and one[M(CN)4]2-anion.The Mn and M centers adopt six-coordinated octahedral and four-coordinated planar square geometries,respectively.[Mn(bpac)2(H2O)2]2+and[M(CN)4]2-units are linked alternatively to generate a 1D linear chain.In addition,the thermal stability of complex 1 was also investigated.
cyano-bridged;complex;synthesis;structure; thermal stability
O614.4
A
1673-4807(2015)06-0602-05
10.3969/j.issn.1673-4807.2015.06.017
2015-05-11
國(guó)家自然科學(xué)基金資助項(xiàng)目(51272095)
田小燕(1988—),女,碩士.*
袁愛(ài)華(1965—),女,博士,教授,研究方向?yàn)楣δ芘浜衔锖图{米材料.E-mail:aihuaayuan@163.com
田小燕,胡愛(ài)云,袁愛(ài)華.一維鏈狀氰基橋聯(lián)配合物Mn(bpac)2(H2O)2M(CN)4(bpac=bis(4-pyridyl)acetylene;M=pt,pd)的合成、結(jié)構(gòu)與熱穩(wěn)定性.江蘇科技大學(xué)學(xué)報(bào)(自然科學(xué)版),2015,29(6):602-606.