I Homonuclear shift correlation

Correlations through the chemical bond I Homonuclear shift correlation 

COSY-90 Correlating coupled homonuclear spins. Typically used for correlating protons coupled over two or three bonds but may be used 

DQF-COS Y Correlating coupled homonuclear spins. Typically used for conelating protons coupled over two or three bonds. Higher-resolution display than basic COSY. Additional information on magnitudes of coupling constants may be extracted from 2D peak fine 

Delayed COSY Correlating coupled homonuclear spins through small couplings. Often used to identify proton correlations over many bonds ( 3), hence also known as long-range COSY 

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