[第四章核磁共振波谱法.ppt

NMR固体样品管 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 1．芳环的各向异性效应 苯环的各向异性效应 ?H= 7.26 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 2．乙炔分子的各向异性效应 叁键的各向异性效应 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 3．双键的各向异性效应 双键的各向异性效应 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. （三）氢键 具有氢键的质子其化学位移比无氢键的质子大. 氢键的形成 降低了核外电子云密度。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 随样品浓度的增加，羟基氢信号移向低场。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 分子内氢键, 其化学位移变化与溶液浓度无关, 取决于分子 本身结构。 高温使OH、NH、SH等氢键程度降低, 信号的共振位置移 向较高场。 ? 识别活泼氢可采用重水交换。 ? 活泼氢的?值与样品的浓度温度及所用溶剂的化学性质有关。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. （四）质子交换 1．构象交换 环己烷的核磁共振图谱 2．位置交换 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. （五）溶剂效应 由于溶剂影响而使化学位移发生变化的现象，称为溶剂效应。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 有机分子中质子的化学位移近似表 三、不同类别质子的化学位移 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 第三节 偶合和分裂 乙醇的核磁共振谱 －OH －CH2－ －CH3 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 相邻近氢核自旋之间的相互干扰作用称为自旋偶合。 由自旋偶合引起的谱线增多现象叫做自旋裂分。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 一、简单原理 Evaluation only. Created with Aspose.S