Constant time inverse-detection gradient accordion rescaled heteronuclear multiple bond correlation spectroscopy: CIGAR-HMBC

Measurement ofJ(H,H) and long-rangeJ(X,H) coupling constants in small molecules. Broadband XLOC and J-HMBC

“…n J(C,H), we propose to extend by a lowpass J filter (LPJF) 1 the J-HMBC pulse sequences that were successfully applied for measuring long-range n J(P,H) coupling constants in nucleic acids. 2 These pulse sequences extend earlier work by Willker and Leibfritz 3 and they are similar to more recent work of Furihata and Seto, 4 Hadden et al 5 and Seki et al 6 The original work of Willker and Leibfritz 3 suggested measuring the heteronuclear longrange coupling constants in a separate third dimension in either the time or the frequency domain. In contrast, the newer experiments are accordion-like, 7 i.e.…”

Synthesis and characterization of the first diorganotin(IV) complexes containing mixed arylazobenzoic acids and having skew trapezoidal bipyramidal geometry

“…The signals were assigned by the use of correlated spectroscopy (COSY), heteronuclear single-quantum correlation (HSQC) and Constant time Inverse-detection Gradient Accordion Rescaled (CIGAR) heteronuclear multiple-bond connectivities (HMBC) [21] experiments using gradient coherence selection. The conclusions drawn from the ligand assignments have subsequently been extrapolated to the complexes owing to the similarity in the data.…”

Characterization of n -butyl acrylate centered triads in poly( n -butyl acrylate- co -carbon monoxide- co -ethylene) by isotopic labeling and two dimensional NMR

“…Some of the crosspeaks are barely detectable (but are more prominent in a second HMBC spectrum obtained with delays optimized for different couplings) as the experimental delays cannot be optimized for all couplings simultaneously. Accordian-optimized HMBC type experiments [24,25,26] that permit simultaneous observation of correlations from a broad range of J-couplings have limited value for studying these polymers as fast T 2 relaxation causes loss of signal. Since the mechanism that explains their formation predicts that ethyl branches will occur in pairs, the structure in Fig.…”