王思宏, 尹秀梅, 闞玉和, 張敬東
(1.延邊大學(xué)分析測試中心,吉林 延吉133002;2.延邊大學(xué)藥學(xué)院,吉林 延吉133002;3.淮陰師范學(xué)院 化學(xué)系,江蘇 淮安223300)
3-硝基苯并蒽酮的碳和氫的化學(xué)位移歸屬
王思宏1, 尹秀梅2, 闞玉和3, 張敬東1
(1.延邊大學(xué)分析測試中心,吉林 延吉133002;2.延邊大學(xué)藥學(xué)院,吉林 延吉133002;3.淮陰師范學(xué)院 化學(xué)系,江蘇 淮安223300)
為探討多環(huán)芳香體系的季碳化學(xué)位移難歸屬問題,采用1H、13C、ATP等1D NMR技術(shù)以及1H-1H COSY、HMQC、HMBC等2D NMR技術(shù),在6-311+G(3df)水平上,結(jié)合密度泛函理論B3LYP方法,對(duì)3-硝基苯并蒽酮(3-NBA)的碳和氫的化學(xué)位移進(jìn)行歸屬.計(jì)算結(jié)果顯示,計(jì)算值與實(shí)驗(yàn)值相吻合,該研究結(jié)果可為3-NBA基準(zhǔn)物質(zhì)標(biāo)定提供依據(jù).
3-硝基苯并蒽酮;核磁共振解析;量子化學(xué)計(jì)算
3-硝基苯并蒽酮(3-NBA)為多環(huán)芳烴酮類化合物,廣泛地存在于大氣、土壤、沉積物、機(jī)動(dòng)車尾氣等環(huán)境 介 質(zhì) 中[1-2].3-NBA 具 有 很 強(qiáng) 的 致 突 變性,不但會(huì)使人體組織出血,還可以使腸壁的茸毛脫落并讓腸壁變脆[3-6].由于3-NBA 是多環(huán)芳烴酮體系,因此,其季碳的化學(xué)位移難以采用一維核磁共振技術(shù)或者經(jīng)驗(yàn)規(guī)則進(jìn)行準(zhǔn)確的歸屬.本文采用 APT、HMQC、HMBC、1H-1H COSY 等核磁共振波譜技術(shù),并結(jié)合量子化學(xué)中的密度泛函理論,對(duì)3-NBA的碳和氫的化學(xué)位移進(jìn)行歸屬[7],為3-NBA基準(zhǔn)物質(zhì)標(biāo)定提供依據(jù).
依據(jù)文獻(xiàn)[8-11]合成3-NBA,樣品為黃色粉末,熔點(diǎn)為256~257℃.樣品的NMR實(shí)驗(yàn)均在Bruker AV 300核磁共振波儀上完成,樣品均用5 mm BBI探頭在室溫條件下測試,溶劑為氘代氯仿(Cambridge Isotope Laboratories,Inc.).
1H NMR,13C NMR觀察頻率分別為300 MHz和75 MHz,脈沖序列采用Bruker Xwinnmr 3.5標(biāo)準(zhǔn) 參 數(shù) 組,APT 及 二 維 NMR(HMBC,HMQC,1H-1H COSY)實(shí)驗(yàn)均按標(biāo)準(zhǔn)脈沖序列進(jìn)行.
計(jì)算運(yùn)用密度泛函理論B3LYP方法,并采用6-311G(d,p)基組對(duì)模型體系進(jìn)行幾何優(yōu)化.用規(guī)范不變?cè)榆壍溃℅IAO)量化計(jì)算方法得到核磁共振屏蔽張量.參照在同一理論水平計(jì)算出的TMS的對(duì)應(yīng)值得到氫和碳的各向同性的化學(xué)位移.溶劑化對(duì)理論核磁共振的參數(shù)影響,擬合在積分方程體系的IEF-PCM 中[12-13]正常所有的量化計(jì)算均用Gaussian03程序包完成.
3-NBA的結(jié)構(gòu)式和編號(hào)如圖1所示.3-NBA的核磁共振氫譜見圖2.由圖1和圖2可知,3-NBA的核磁共振氫譜中有8組峰:δH8.95(d,J=8.6 Hz),8.84(d,J=8.6 Hz),8.51(d,J=7.2 Hz),8.40(d,J=8.3 Hz),8.35(d,J=8.1 Hz),7.99(t,J=8.6 Hz),7.83(t,J=7.7 Hz),7.58(t,J=7.5 Hz).依據(jù)偶合常數(shù),δH8.95、8.84、7.99,δH8.51、7.58,δH8.40、8.35、7.83是在空間上分別有鄰近關(guān)系的3組氫.
圖1 B3LYP/6-311+G**優(yōu)化計(jì)算前和后的3-NBA的編號(hào)
圖2 3-NBA的氫譜圖
3-NBA的碳譜和APT譜見圖3和圖4.由圖1、圖3和圖4可知,3-NBA的碳譜和APT譜中有17種碳,說明測試結(jié)果與3-NBA的碳骨架相符.將3-NBA的碳譜與 APT譜相比較可知δC184.8、148.7、135.8、134.4、132.6、130.2 130.1、126.4是季碳的吸收峰化學(xué)位移,而δC135.9、132.5、131.8、131.7、131.1、130.0、126.9 125.7、123.8是仲碳的吸收峰化學(xué)位移.另外,由3-NBA的結(jié)構(gòu)可知,δC184.8是3-NBA 中酮羰基的碳的吸收峰化學(xué)位移.
圖3 3-NBA的碳譜圖
圖4 3-NBA的APT譜圖
3-NBA的1H-1H COSY譜見圖5.由圖1和圖5可知,3-NBA的1H-1H COSY譜中δH8.95、8.84、7.99,δH8.51、7.58,δH8.40、8.35、7.83是3組相關(guān)峰,表明3-NBA中苯環(huán)上氫之間的空間臨近的位置關(guān)系.
圖5 3-NBA的1 H-1 H COSY譜圖
3-NBA的HMQC譜見圖6.由圖1和圖6可知,3-NBA的 HMQC譜中δC131.74(C-13)與δH8.95(H-20)相對(duì)應(yīng),即δC131.7與δH8.95是3-NBA的13位的碳和20位的氫,δC132.5與δH8.84,δC130.0、125.7與δH8.51,δC125.7與δH8.40,δC126.9與δH8.35,δC131.8與δH7.99,δC132.5與δH7.83,δC135.8與δH7.58分別相對(duì)應(yīng),這些對(duì)應(yīng)是3-NBA中含氫的碳之間的一鍵相連,而δC184.8、148.7、135.8、134.4、132.6、130.2、130.1、126.4在 HMQC譜中沒有對(duì)應(yīng)的氫相關(guān),說明它們是3-NBA中季碳的吸收峰,這與ATP譜得出的結(jié)論是一致的.
3-NBA的HMBC譜見圖7.由圖1和圖7可知,3-NBA 的 HMBC譜中δC184.8(C-7)與δH8.84(H-12)相關(guān),驗(yàn)證了δC184.8是酮羰基碳,是7位的碳.δC148.7與δH8.51相關(guān),因?yàn)镃-23與強(qiáng)吸電子的硝基相連,其碳吸收峰化學(xué)位移低場移動(dòng),δC148.7(C-23)與δH8.51(H-27)兩鍵相關(guān),因此C-23化學(xué)位移為δC148.7.與 H-16、H-17都相關(guān)的是C-3,化學(xué)位移是δC135.8.與 H-18、H-19都相關(guān)的是 C-4,化學(xué)位移是δC132.6.與H-12、H-20都相關(guān)的是 C-10,化學(xué)位移是δC130.1.與 H-26、H-20都相關(guān)的是 C-15,化學(xué)位移是δC126.4.位于稠環(huán)中心9位的季碳,沒有與之相關(guān)的氫,其化學(xué)位移為δC130.2.
圖6 3-NBA的HMQC譜圖
圖7 3-NBA的HMBC譜圖
文獻(xiàn)[14-15]利用密度泛函理論和時(shí)間相關(guān)密度泛函理論研究了單硝化苯并蒽酮的吸收譜電子親和性、電離勢、熒光譜.本文運(yùn)用密度泛函理論方法B3LYP/6-311++G**對(duì)模型體系進(jìn)行幾何優(yōu)化,量化計(jì)算結(jié)果見表1和表2.同時(shí)還對(duì)3-NBA氫和碳化學(xué)位移的計(jì)算值與實(shí)驗(yàn)值進(jìn)行了線性回歸,其相關(guān)系數(shù)(R2)氫為0.994 0,碳為0.997 9[16],結(jié)果顯示,計(jì)算值與實(shí)驗(yàn)值相吻合.
采用 APT、HMQC、HMBC、1H-1H COSY等核磁共振技術(shù),對(duì)3-NBA的碳和氫的化學(xué)位移進(jìn)行了全歸屬,解決了用經(jīng)驗(yàn)規(guī)則難以進(jìn)行準(zhǔn)確歸屬的季碳的碳化學(xué)位移歸屬問題,如3-NBA中的季碳δC148.7、135.8、134.4、132.6、130.2、130.1、126.4的歸屬結(jié)果與量化計(jì)算一致.
表1 3-NBA的氫化學(xué)位移理論值與計(jì)算值
表2 3-NBA的碳化學(xué)位移理論值與計(jì)算值
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Assignment of carbon and proton chemical shifts of 3-nitrobenzanthrone
WANG Si-h(huán)ong1, YIN Xiu-mei2, KAN Yu-h(huán)e3, ZHANG Jing-dong1
(1.Center of Analysis and Test,Yanbian University,Yanji 133002,China;2.College of Pharmacy,Yanbian University,Yanji 133002,China;3.Department of Chemistry,Huaiyin Normal University,Huai’an 223300,China )
The carbon and proton chemical shifts of 3-nitrobenzanthrone is elucidated by 1D NMR using1H,13C,APT and the homo/hetero-nuclear 2D NMR techniques,combining density functional theory (DFT)calculations for the NMR spectra using the B3LYP functional and the 6-311+G**basis set.Assignment puzzle to quarterly carbon of polycyclic aromatic compound is solved.The results can supply the foundation to calibration of standard substance of 3-nitrobenzanthrone.
3-nitrobenzanthrone;NMR assignments;quantum chemistry calculation
O641
A
1004-4353(2012)02-0138-04
2012-03-28
延邊大學(xué)科研項(xiàng)目(601010003)
王思宏(1969—),男,博士,副教授,研究方向?yàn)椴ㄗV分析.