title: "Perfect echo" HMQC: sensitivity and resolution enhancement by broadband homonuclear decoupling.
abstract: Homonuclear (1)H-(1)H J-modulation leads to J-multiplets in F1 dimension of 2D (1)H-(13)C HMQC spectra. This hampers unambiguous signal assignment for overcrowded (13)C spectra. Broadband homonuclear decoupling has been achieved in the indirect t1 evolution period by incorporating blocks of perfect echo. This method of perfect echo HMQC demonstrates better resolution and sensitivity than conventional HMQC spectra. The results on Cyclosporine demonstrate that the method is very efficient for refocusing geminal couplings in weakly coupled -(13)CH2 groups. Partial refocusing of vicinal couplings is also observed for -(13)CH and -(13)CH3 groups. Interpretation of the result based on product operator formalism is also given. Comparison of pe-HMQC, HMQC and HSQC reveals that the F1 linewidth of pe-HMQC is much narrower than HMQC and very close to that of HSQC for CH2 groups.
authors.affiliation: Center of Biomedical Magnetic Resonance, SGPGIMS Campus, Raebareli Road, Lucknow 226 014, India. bikashbaishya@gmail.com
authors.forename: Bikash
authors.initials: B
authors.lastname: Baishya
authors.forename: C L
authors.initials: CL
authors.lastname: Khetrapal
authors.forename: Krishna Kishor
authors.initials: KK
authors.lastname: Dey
keywords: Broadband homonuclear decoupling; HMQC; J-Multiplets; J-Refocusing; Perfect echo