Symbols and Abbreviations,continued REAGENTS AND SOLVENTS.continued Nuc or:Nuc or Nuc-is a generic nucleophile,a Lewis base:Eor E+is a generic electrophile,a Lewis acid PCC pyridinium ehlorochromate.CrOHCIN CH3H HH CH3 SiazBH disiamylborane H -H CH:CH CH CH3 0、 THF tetrahydrofuran SPECTROSCOPY IR infrared spectroscopy NMR nuclear magnetic resonance spectroscopy MS mass spectrometry ultraviolet spectroscopy parts per million,a unit used in NMR MHz megahertz,millions of cycles per second TMS tetramethylsilane,(CH3)Si,the reference compound in NMR s.d.tm singlet,doublet,triplet,quartet,multiplet:the number of peaks an NMR absorption gives nm nanometers,10meters(usually used as a unit of wavelength) m/z mass-to-charge ratio,in mass spectrometry in NMR,chemical shift value,measured in ppm(Greek lower case delta) wavelength(Greek lambda) v frequency(Greek nu) coupling constant in NMR OTHER .or unshared electron pair a.ax axial (in chair forms of cyclohexane) e,eq equatorial (in chair forms of cyclohexane) HOMO highest occupied molecular orbital LUMO lowest unoccupied molecular orbital NR no reaction 0,m,p ortho,meta,para (positions on an aromatic ring) △ when written over an arrow:"heat";when written before a letter:"change in" 8,8 partial positive charge,partial negative charge energy from electromagnetic radiation (light) [a]p specific rotation at the D line of sodium(589 nm) ix Copyright2013 Pearson Education,I