袁 巍, 李樂慶, 李文戈
(蚌埠醫(yī)學(xué)院 化學(xué)教研室,安徽 蚌埠 233000)
具有特定拓?fù)浣Y(jié)構(gòu)的配位聚合物具有許多特殊的性能,在選擇性催化、分子識別、超高純度分離、光、電、磁性及半導(dǎo)體性質(zhì)等方面顯示出廣闊的應(yīng)用前景[1~5]?;瘜W(xué)工作者積極探索這些聚合物的自組裝、定向組裝方法,選擇了多種多樣的有機(jī)橋聯(lián)配體,構(gòu)筑出大量具有新穎拓?fù)浣Y(jié)構(gòu)的配位聚合物。目前常選用含N, O, S和P等有較強(qiáng)的給電子能力的原子的有機(jī)配體和各種金屬離子去構(gòu)建具有新型拓?fù)浣Y(jié)構(gòu)的一維、二維、三維配位聚合物[6~11]。具有較強(qiáng)配位能力的吡啶羧酸類有機(jī)配體在設(shè)計(jì)合成配位聚合物時(shí)經(jīng)常被用到,因?yàn)轸然卸喾N配位方式,可以與一個(gè)金屬離子配位,也可以與兩個(gè)或兩個(gè)以上金屬離子配位,另外,氮原子也可參與配位,從而構(gòu)建出大量新奇結(jié)構(gòu)的配聚物。
迄今為止,已報(bào)導(dǎo)的利用3-(4-吡啶基)丙烯酸(4-HPYA)配體合成的配聚物與稀土金屬離子形成配聚物報(bào)導(dǎo)較少[12~14]。本文用4-HPYA和Nd(NO3)3通過水熱法合成了一種新的一維鏈狀配位聚合物[Nd(4-PYA)3(H2O)2]n(1),其結(jié)構(gòu)經(jīng)IR,元素分析和X-射線單晶衍射表征。
Bruker VECTOR-22型紅外光譜儀(KBr壓片); Perkin-Elmer 240C型元素分析;Bruker Smart Apex CCD型X-射線單晶衍射儀。
所用試劑均為市售化學(xué)純或分析純。
在以聚四氟乙烯為內(nèi)襯的不銹鋼高壓反應(yīng)釜中依次加入4-HPYA 37.5 mg(0.25 mmol), Nd(NO3)3·6H2O 100 mg(0.25 mmol ), NaOH 10 mg(0.25 mmol)和去離子水10 mL,攪拌均勻后置入烘箱,于120 ℃反應(yīng)72 h。自然冷卻至室溫得淡紫色柱狀晶體1,產(chǎn)率70%; FT-IRν: 3 387, 3 213, 1 649, 1 541, 1 412, 1 408, 1 256, 992, 824, 744, 592 cm-1; Anal.calcd for C24H26N3O10Nd: C 43.63, H 3.94, N 6.36; found C 43.59, H 3.90, N 6.31。
1的晶體學(xué)數(shù)據(jù)及結(jié)構(gòu)修正數(shù)據(jù)見表1,主要鍵長和鍵角見表2;分子結(jié)構(gòu)、一維鏈狀結(jié)構(gòu)和晶胞堆積圖分別見圖1,圖2和圖3。
表 1 1的晶體學(xué)和結(jié)構(gòu)修正數(shù)據(jù)Table 1 Crystal data collection and structure refinement detail of 1
由圖1可見,1由[Nd(4-PYA)3(H2O)2]單元構(gòu)成。[Nd(4-PYA)3(H2O)2]單元的Nd(Ⅲ)與9個(gè)O原子配位,形成一個(gè)扭曲的多面體結(jié)構(gòu)。在1的分子中存在著3個(gè)獨(dú)立的3-(4-吡啶基)丙酸根(4-PYA)和兩個(gè)H2O分子;Nd(Ⅲ)原子與9個(gè)O原子配位,形成一個(gè)扭曲的多面體結(jié)構(gòu),其中配位O原子7個(gè)來自4-PYA的羧基,另外兩個(gè)來自配位水分子。鍵角在49.29(16)°(O6-Nd1-O5)~161.35(14)°(O1-Nd1-O5);鍵長在0.243 1(5) nm(Nd1-O1)~0.272 3(5) nm(Nd1-O5)。
表21的主要鍵長和鍵角
Table2Selected bond lengths and bond angles of1
BondLength/?BondAngle/(°)BondAngle/(°)Nd1-O12.431(5)O1-Nd1-O776.77(16)O5-Nd1-O2142.86(15)Nd1-O42.508(5)O1-Nd1-O6154.49(17)O8-Nd1-O276.92(15)Nd1-O22.557(4)O7-Nd1-O684.02(15)O1-Nd1-O375.84(16)Nd1-O72.484(5)O7-Nd1-O4136.70(17)O7-Nd1-O3141.41(16)Nd1-O52.518(5)O2-Nd1-O1104.96(15) O6-Nd1-O3128.66(15)Nd1-O12.669(5)O6-Nd1-O480.59(15)O4-Nd1-O569.23(15)Nd1-O62.490(5)O1-Nd1-O579.61(16)O5-Nd1-O562.01(18)Nd1-O82.541(5)O7-Nd1-O574.21(16)O1-Nd1-O5161.35(14)Nd1-O52.723(5)O6-Nd1-O5111.28(16)O4-Nd1-O350.89(15)O4-Nd1-O574.26(15)O5-Nd1-O374.53(16)O1-Nd1-O883.52(17)O8-Nd1-O3135.01(16)O7-Nd1-O866.91(16)O2-Nd1-O375.84(15)O7-Nd1-O570.06(16)O7-Nd1-O1121.89(17)O6-Nd1-O549.29(16)O6-Nd1-O1114.56(15)O3-Nd1-O5113.11(16)O4-Nd1-O1101.30(16)O6-Nd1-O873.49(16)O5-Nd1-O1132.48(15)O4-Nd1-O8142.75(15)O8-Nd1-O167.36(16)O5-Nd1-O8140.20(16)O2-Nd1-O149.89(14)O1-Nd1-O2113.97(15)O3-Nd1-O167.69(16)O7-Nd1-O2141.02(16)O1-Nd1-O5134.37(15)O6-Nd1-O271.88(15)O8-Nd1-O5109.94(16)O4-Nd1-O269.78(15)O2-Nd1-O5111.55(14)
圖 1 1的分子結(jié)構(gòu)圖
由圖2可見,Nd原子的鏈接由作為三配位的4-PYA的O原子作為橋聯(lián)原子,其鏈接方式是由兩個(gè)O原子作為橋聯(lián)原子一個(gè)Nd(Ⅲ)原子連接為四員環(huán),其中一個(gè)O原子與另一個(gè)Nd(Ⅲ)原子再配位,通過這種橋聯(lián)方式進(jìn)而形成無限的一維鏈狀結(jié)構(gòu)。從圖3可見,1中存在多種類型的氫鍵{O7-H7A┈N2[2.874(8) ?], O7-H7B┈O4[2.701(7) ?], O8-H8A┈N3[2.903(8) ?]和O8-H8B┈O3[2.752(7) ?]},最終通過這種分子間氫鍵的相互作用將一維鏈緊密堆積成三維網(wǎng)狀結(jié)構(gòu)。
圖 3 1的晶胞堆積圖
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