bluuebunny/crossref_metadata_2025_split huggingface dataset:
1H NMR of acetylated β‐ether/β‐ether lignin model trimers
Authors: Ralph John 
Published: May 2005

AbstractDetailed examination of the 1H NMR spectra of acetylated β‐ether/β‐ether lignin model trimers, particularly those synthesized with partially defined stereochemistry, revealed that all of the eight chemically distinct isomers (sixteen optical isomers from four optical centers) are detectable. These compounds provide excellent models for both internal (etherified) and terminal (free‐phenolic) units in lignin and clearly delineate the chemical shifts for each isomer. High‐field two‐dimensional TOCSY or relayed coherence transfer NMR experiments allow correlation of all the side‐chain protons in each isomer, while J‐resolved experiments clearly show the presence of all expected isomers. The degree of complexity already encountered with these simple compounds points to the overwhelming improbability of finding even small crystalline regions in lignin.
1H NMR lanthanide‐induced shift (LIS) investigations of highly flexible molecules—a new approach. Part II
Authors: Lehmann J. , Kleinpeter E. 
Published: May 2005

AbstractA new method and computer program for LIS calculations of highly flexible molecules was developed using molecular geometries obtained by randomly varied dihedral angles (up to ten angles rotating freely and independently from each other are possible) as start conformations for a STEEpest Descent (STEED) search algorithm to find minima characterized by the R factor at the ‘LIS R factor hyper surface.’ This STEED–LIS method allows easy, accurate and rapid access to the probable global minimum of the R factor depending on up to ten variable dihedral angles. This means that LIS investigations of highly flexible molecules with more than one freely rotating dihedral angle are no longer complicated and time consuming, but can be carried out automatically using the developed programs [JLLISSD (with interactive parameter dialogue) and LISSDEMU (using parameter input files prepared by LISSDINP)]. The results obtained are in very good agreement with known or reported preferred conformations of the investigated test compounds, propan‐1‐ol, butan‐1‐ol and ethyl p‐methoxycinnamate.
13C NMR spectroscopy of keratan sulphates: Assignments for the reduced form of a repeat unit tetrasaccharide derived from keratan sulphate by keratanase digestion and partial assignments for two fucosylated pentasaccharides
Authors: Huckerby Thomas N. , Dickenson John M. , Tai Gui‐Hua , Lauder Robert M. , Brown Gavin M. , Nieduszynski Ian A. 
Published: May 2005

AbstractA full assignment of the 60°C 13C NMR spectrum for the reduced form of a repeat unit β‐linked tetrasaccharide derived by keratanase digestion from keratan sulphate, GlcNAc(6SO4)β1–3Gal(6SO4)β1–4GlcNAc(6SO4)β1–3‐Gal‐ol, was achieved via two‐dimensional C/H correlation and 1H COSY experiments, and a complete first‐order analysis of the 600 MHz proton spectrum. Partial 13C assignments for two fucosylated keratan sulphate pentasc‐charides derived using hydrazinolysis and nitrous acid treatment are discussed.
Use of cyclodextrins in chiral discrimination by NMR spectroscopy: An example of atropisomerism
Authors: Casy Alan F. 
Published: May 2005

AbstractThe influence of α‐, β‐ and γ‐cyclodextrin (CD) on the 1H NMR spectrum of the muscarinic antagonist telenzepine dihydrochloride in D2O is reported. Duplication of thienyl‐H and thienyl‐Me signals was observed in the presence of β‐ and γ‐CD, with regard to the minor amido conformer in the former case and both major and minor amido conformers in the latter case. Use of CDs in chiral discrimination by NMR is now well known; the present results provide the first example of their application to an atropisomeric example.
Interpretation of the 13C NMR spectra of 3‐benzylideneflavanones, 3‐benzylflavone and 3‐benzyl‐1‐thioflavone derivatives
Authors: Szabó Zoltán , Lévai Albert 
Published: May 2005

Abstract13C NMR spectra of 3‐benzylflavones, 3‐benzylideneflavanones, 3‐benzyl‐4‐thioflavones, 3‐benzyl‐1‐thioflavones, 3‐benzyl‐1,4‐dithioflavones and 3‐benzyl‐1‐thioflavone‐1,1‐dioxides were analysed and correlated to evaluate the consequences of the replacement of oxygen with sulphur.
1H and 13C NMR relaxation investigation of methotrexate in [2H6]dimethyl sulphoxide solution
Authors: Gaggelli Elena , Valensin Gianni , Vivi Antonio , Macotta Antonella 
Published: May 2005

Abstract1H and 13C NMR parameters of methotrexate in [2H6]dimethyl sulphoxide were obtained and analysed in terms of a ‘preferred’ conformation. The effective correlation time of the anisotropic motion of the pteridinylbenzoyl moiety was evaluated as ca. 10 ns at 300 K. The 1H1H and 13C1H distances obtained were used to construct the molecular structure in solution.
Determining C‐7 stereochemistry in C‐7‐substituted 6α,14α‐endo‐ethano‐ and 6α, 14α‐endo‐ethenotetrahydrothebaines by 13C NMR; a re‐analysis
Authors: Mazza Samuel M. 
Published: May 2005

AbstractA re‐analysis of previously published 13C NMR data on C‐7‐substituted 6α,14α‐endo‐ethanotetrahydrothebaines shows that the 13C chemical shift of C‐18 in these medicinally important compounds can be used as an indicator of C‐7 stereochemistry, this being due to a steric gamma effect between C‐18 and C‐7 substituents in an α orientation. In seven examples of α‐isomers the C‐18 chemical shift ranges from δ17.02 to δ18.42 (average δ17.72), whereas in four examples of β‐isomers the C‐18 chemical shift ranges from δ22.09 to δ24.00 (average δ22.73‐23.40). Since suitable etheno compounds can be chemically reduced to ethano compounds, C‐7 stereochemistry in such 6α,14α‐endo‐etheno compounds can be determined indirectly.
High‐field NMR techniques and molecular modelling in the study of the inclusion complex of the cognition activator suronacrine (HP‐128) with cyclodextrins
Authors: Amato Maria E. , Pappalardo Giuseppe C. , Perly Bruno 
Published: May 2005

AbstractThe structural features of the inclusion complexes of cyclodextrins (CDs) with the chiral cognition activator drug (±)9‐[(phenylmethyl)amino]‐1,2,3,4‐tetrahydroacridin‐1‐ol maleate (suronacrine maleate, HP‐128) were studied using both high‐resolution 1H NMR spectroscopy and molecular modelling methods. The partial inclusion of the guest from the secondary hydroxyl side of α‐CD was demonstrated in aqueous solution, in addition to a higher degree of penetration into the cavity of β‐CD from the same side. NMR‐ROESY experiments allowed the unambiguous location of the benzylic ring of the guest inside the β‐CD cavity. The formation of diastereoisomeric pairs was demonstrated by the duplication of the benzylic proton signals. Molecular mechanics calculations were used to complement the NMR analysis. Molecular modelling procedures (MacroModel interactive computer program) allowed the prediction of the most stable structures of the complexes, and showed that specific site interactions, provided by hydrogen bond formation, are capable of differentiating the diastereoisomeric intramolecular inclusion complexes according to available experimental NMR data.
Conformations of triglycyl‐lysylvasopressin: 1H NMR spectroscopic and molecular dynamics study
Authors: Nutz K. I. , Fabian W. M. F. , Sterk H. 
Published: May 2005

AbstractThe conformation of N‐(Gly‐Gly‐Gly)‐Lys‐vasopressin (TGVP) in aqueous solution was determined by 1H NMR spectroscopy. The structural data were compared with those obtained in DMSO. Refinement of the structure derived from NMR data and a description of the conformational dynamics were accomplished by molecular dynamics simulations in aqueous solution.
Compounds with bridgehead nitrogen. Part 72—NMR spectra and stereochemistry of 8,9,10,11,11a,11b,12,13‐octahydro‐7aH‐quino [1,2‐c][1,3]benzoxazines and perhydropyrido [1,2‐c][1,3]benzoxazines. NMR chemical shifts of methylene group protons adjacent to a nitrogen atom
Authors: Crabb Trevor A. , Ingate Simon T. , Nevell Thomas G. , Sumner Steven 
Published: May 2005

AbstractThe positions of conformational equilibria in the four diastereoisomers of 8,9,11,11a,11b,12,13‐octahydro‐7aH‐quino [1,2‐c] [1,3] benzoxazines were investigated using 13C and 1H NMR spectroscopy. Comparison of the NMR chemical shifts of these isomers with those in the corresponding isomers of perhydropyrido [1,2‐c] [1,3]benzoxazine shows the effect on NMR shifts of fusion of the aromatic ring on to the fully saturated system. The Δδ values are discussed in terms of degree of overlap of the nitrogen lone pair orbitals with the aromatic π‐system.
Selective 2H, 2H 1D‐TOCSY NMR spectroscopy for signal assignment in perdeuteriated compounds
Authors: Mons Hans‐Egbert , Bergander Klaus , Günther Harald 
Published: May 2005

AbstractThe 1D‐TOCSY experiment for 2H NMR is introduced and applications for signal assignments are illustrated with the spectra of pyridine‐d5 and iodo‐ and chlorocyclohexane‐d11. The potential of the method for the analysis of overlapping 2H spectra is demonstrated.
1H, 13C, 17O and 19F NMR spectroscopic study of isomeric ring‐substituted monofluoro‐(E)‐3‐phenylpropenals
Authors: Laihia K. , Kolehmainen E. , Mänttäri P. , Kauppinen R. 
Published: May 2005

AbstractIsomeric ring substituted monofluoro‐(E)‐3‐phenylpropenals (cinnamaldehydes) were synthesized in order to provide, with the NMR‐active 19F nucleus, an insight into the influence of substituents and the transmission of electronic effects between the aromatic ring and the side‐chain. Their 1H, 13C and 17O NMR chemical shifts and their nJ(H,H), nJ(H,F), nJ(C,H) and nJ(C,F) values were determined. Generally, the nJ(C,F) coupling constants correlate with the length of the coupling route and thus simplify the assignments of the 13C NMR spectra. Only the side‐chain carbons C‐2 and C‐3 in the ortho‐substituted compounds showed an exception to this rule. Many long‐range nJ(H,F) (n = 4–7) values were easily observed. The 17O NMR chemical shift of the carbonyl oxygen in the o‐ and m‐fluoro derivatives show clear substituent effects, whereas p‐fluorocinnamaldehyde shows a value comparable to that of that parent compound.
NMR chemical shift assignments for 7′‐substituted aromatic‐7′‐apo‐β‐caro‐tenes
Authors: Hand E. S. , Belmore K. A. , Kispert L. D. 
Published: May 2005

AbstractChemical shifts of all protons at 8.46 T and 13C atoms are presented for substituted 7′‐aryl‐7′‐apo‐β‐carotenes, where aryl = C6H5, 4‐C6H4NO2, 4‐C6H4OCH3, 4‐C6H4CO2CH3, C6F5 and 2,4,6‐C6H2(CH3)3. Assignments were established by NOE, COSY, HMBC and HETCOR studies.
Thermodynamic characterization of tautomeric equilibria by multinuclear magnetic resonance. Application to 3‐hydroxypyridine
Authors: Llor Juan , Lopez‐Mayorga Obdulio , Muñoz Luis 
Published: May 2005

AbstractA marked temperature dependence of the 13C and 15N chemical shifts of 3‐hydroxypyridine in D2O (pD = 7.0) was observed. This dependence is explained in terms of thermally induced equilibrium shifts between the neutral form and the zwitterionic form of 3‐hydroxypyridine. A method was developed to characterize the thermodynamics of the equilibria that are rapid on the NMR time scale, using the observed average 13C and 15N chemical shifts at different temperatures. This method was applied to the thermodynamics of the tautomerization equilibria of 3‐hydroxypyridine. The equilibrium constants and the standard enthalpy change of the tautomerization equilibrium obtained by 13C and 15N methods agree very well with the results obtained by other spectroscopic methods.
Substituent‐induced chemical shifts along CC double bonds
Authors: Knorr Rudolf , von Roman Therese , Freudenreich Johannes , Hoang Thi Phung , Mehlstäubl Johann , Böhrer Petra , Stephenson David S. , Huber Helmut , Schubert Bernhard 
Published: May 2005

Abstract1H and 13C NMR signals were assigned and CH coupling constants (1J, 2J, 3J) determined for a series of α‐mono‐and α,α‐disubstituted (1,1,3,3‐tetramethyl‐2‐indanylidene)methanes with the following α‐substituents: (mesityl)2B, n‐propyl, phenyl, tert‐butyl‐C(NH), cyano, (tert‐butyl)2C(OH), pivaloyl, H2N‐CO, PhNH‐CO, carboxy, ritro, acetoxy, Me3SiO, Me3Si, PhS, PhSMe+, PhSO, PhSO2, bromo and trimethylstannyl. The 1J couplings with the olefinic proton span the range 124.3–193.7 Hz. Substituent‐induced chemical shifts (SCS) of most of the nuclei with respect to the α‐unsubstituted olefin obey simple additivity in the α,α‐disubstituted compounds and are very similar to the SCS values along the CN double bond in the isoelectronic (1,1,3,3‐tetramethyl‐2‐indanylidene)amines within the error limits. The exceptions concern nuclei in the immediate vicinity of the perturbing substituent. A dominant mechanistic contribution of electric field effects appears likely for the more distant aromatic part of the indanylidene moiety. The chemical shifts of two (2,2,5,5‐tetramethylcyclopentylidene)methanes are shown to be compatible with the SCS parameters from the indanylidene series.
NMR 1H relaxation and NOESY studies of spiperone conformational features in solution
Authors: Keller Charles E. , Carper W. Robert 
Published: May 2005

AbstractThe high‐field 1H, 19F and 13C NMR spectra of spiperone in CDCl3 solution were analyzed with the aid of homonuclear (H‐H‐COSY) and heteronuclear (H,C‐COSY) chemical shift correlation experiments. Multiple through‐space intersections were identified using phase‐sensitive nuclear Overhauser and exchange spectroscopy (NOESY). Proton relaxation rates and activation energies were determined over the temperature range −60 to 50°C. The chemical shift, NOESY and proton relaxation rate results support the formation of cyclic dimers and multiple spiperone conformations in solution.
Conformational analysis of substituted 5,6‐dihydro‐4H‐1,3‐oxazines
Authors: Katritzky Alan R. , Shcherbakova Irina V. , Mancheño Balbino , Tack Robert D. 
Published: May 2005

AbstractThe assignment of the proton and carbon signals and conformations of substituted 5,6‐dihydro‐4H‐1,3‐oxazines were determined by the combination of 1H, 13C, COSY and HETCOR spectral data.
Broadband excitation composite pulses for pure NQR spectroscopy in powders
Authors: Li Geng‐Ying , Xu Liang , Wu Xue‐Wen 
Published: May 2005

AbstractComposite pulses that compensate for resonance offset and electric field gradient inhomogeneity are proposed for broadband excitation of pure nuclear quadrupole resonance systems in powders. The excitation band width of the composite pulse sequences was obtained with a numerical calculation procedure and confirmed by 35Cl experimental spectra of powdered NaClO3.
1H and 13C NMR spectra of multibridged [2n]cyclophanes
Authors: Ernst Ludger , Boekelheide Virgil , Hopf Henning 
Published: May 2005

AbstractThe 1H and 13C NMR spectra of all [2n] cyclophanes with the same substitution pattern in both benzene rings and of the skew [2.2.2](1,2,4)(1,2,5)cyclophane were assigned by one‐dimensional NOE difference and two‐dimensional correlation spectroscopy. The 1H NMR spectra of the bridge protons including the 13C satellites of the symmetrical compounds [2.2]paracyclophane, [2.2.2](1,3,5)cyclophane and superphane were analysed by iterative methods. Chemical shifts and H,H coupling constants are discussed with regard to molecular geometries.
Schiff's base formation rater than molecular association between acetone and 3‐amino‐6‐methoxypyridine
Authors: Maguire John , Morris David G. , Rycroft David S. , Ortiz F. S. 
Published: May 2005

AbstractA previous report of a complex between 3‐amino‐6‐methoxypyridine and acetone has been shown to be incorrect. The 1H and 13C NMR signals that were attributed to the complex have been shown to be due to the formation of a Schiff's base.
Experimental (13C and 15N NMR spectroscopy) and theoretical (6–31G) study of the protonation of N‐methylazoles and N‐methylbenzazoles
Authors: Claramunt Rosa Maria , Sanz Dionisia , Boyer Gérard , Catalän Javier , de Paz José Luis G. , Elguero José 
Published: May 2005

AbstractThe 13C and 15N NMR spectra of 11 N‐methyl derivatives of azoles and benzazoles (imidazole, pyrazole, 1,2,4‐triazole, indole, benzimidazole, 2H‐indazole, 1H‐indazole, 2H‐benzotriazole, 1H‐benzotriazole and carbazole) in trifluoroacetic and sulphuric acid are reported. Quaternary salts were used as model compounds. In the case of azoles (from pyrrole to pentazole) ab initio calculations at the 6–31G level were carried out to determine the protonation site.
Deuterium isotope effects on nuclear shielding. Cross‐ring effects in rigid cyclic molecules
Authors: Mlinarić‐Majerski Kata , Vinković Vladimir , Chyall Leonard J. , Gassman Paul G. 
Published: May 2005

AbstractDeuterium isotope effects on 13C NMR chemical shifts, (2H/1H)nΔ(13C), of 2‐methylene‐d2‐adamantane, 4‐methylene‐d2‐2‐adamantanone and 6‐methylene‐d2‐2‐adamantanone are presented. Long‐range effects (4Δ, 5Δ and 6Δ) in a range from 5 to – 23 ppb were observed. The results for 5Δ and 6Δ are explained in terms of cross‐ring field effects resulting from the change of dipole due to deuterium substitution.
Solution conformation of the ketone and epoxide synthetic precursors of β‐chamigrene determined by 1H and 13C NMR spectroscopy and distance geometry
Authors: Leonard Scott F. , Jones Paul‐James , Spero Denice M. , Pitner T. Phil 
Published: May 2005

AbstractUtilizing 2D NMR spectroscopy (COSY, NOESY, TOCSY, inverse detected 1H/13C correlation spectroscopy), the 1H and 13C NMR spectra of the ketone and epoxide precursors of β‐chamigrene were assigned. The dihedral angles and distances determined from NMR measurements provide input parameters to calculate the molecules' solution conformation by distance geometry. The factors which are important in influencing the conformation of these molecules are discussed.
Evidence for a novel β‐bend structure with prolines at the corner: 1H and 13C NMR study of cyclo(Pro‐Pro‐Gly)2
Authors: Prachand Mamta S. , Singh Shanteri , Dhingra M. M. , Singh Usha , Ghosh Sunil K. , Mamdapur V. R. , Chadha M. S. 
Published: May 2005

AbstractThe solution conformation of cyclo‐(Pro‐Pro‐Gly)2 in CDCl3 and DMSO‐d6 was investigated by 1H and 13C NMR spectroscopy. In CDCl3 solution the peptide maintains a conformational homogeneity at 300 K and the single asymmetric conformation observed is characterized by a single Pro‐Pro cis‐peptide bond and an intramolecularly hydrogen‐bonded β‐bend structure involving CO of one glycine to the NH of the other glycine. The segment Gly‐Pro‐Pro‐Gly responsible for the β‐bend has a Pro‐Pro peptide bond in the trans configuration. However, in DMSO‐d6 solution, there is a conformational heterogeneity and the population of the two main conformers present is in the ratio of ca. 80:20. The major component is characterized as having two contiguous cis‐peptide bonds involving Gly‐Pro and Pro‐Pro peptide bonds, while the minor component has a conformation characterized by a single Pro‐Pro cis‐peptide bond which is included in the β‐bend structure. The equilibrium between the major and minor components is insensitive to temperature in the range 300‐‐360 K. However, the conformational homogeneity in CDCl3 solution appears to be disturbed by addition of DMSO‐d6 and becomes detectable beyond 20% (v/v) of DMSO‐d6 and at 50:50 (v/v) the populations of the major and minor components become almost equal.
Synthesis and NMR spectrum of [13C18]‐meso‐hexestrol, a fully carbon‐13 substituted ligand for NMR studies of the estrogen receptor
Authors: Kochanny Monica J. , Härd Torleif , Katzenellenbogen John A. 
Published: May 2005

AbstractThe estrogen receptor ligand meso‐hexestrol has been synthesized with 13C enrichment (98 at.%) at every position. 13C NMR spectra of the intermediates were obtained and 13C−13C coupling patterns analyzed. The complex 13C NMR spectrum of [13C18]‐meso‐hexestrol was simplified through the use of selective 13C decoupling. Several 13C−13C coupling constants were estimated from the decoupled spectra and refined via iterative simulation. Some additional coupling constants were measured in selective one‐dimensional 13C COSY spectra. Coupling constants are reported to an accuracy of ±0.4–1 Hz. This study demonstrates the feasibility of determining 13C−13C coupling constants in highly 13C−substituted compounds; such compounds are expected to be used with increased frequency in studying receptor‐ligand interactions by polarization transfer methods.
Proton magnetic resonance study of the conformations of 3′,5′‐O‐(di‐tert‐butylsilanediyl) nucleosides
Authors: Katsura Tatsuo , Ueno Katsuhiko , Furusawa Kiyotaka 
Published: May 2005

AbstractThe solution conformations of nine 3′,5′‐O‐(di‐tert‐butylsilanediyl) nucleosides, new sila analogues of cyclic nucleotides, were studied by proton NMR spectroscopy. The furanose rings of all the compounds studied are forced to take on the C‐3′‐endo conformation by the 3′,5′‐cyclization. The conformations at the glycosidic bond of the adenosine and deoxyadenosine derivatives were determined as mixtures of syn and anti conformations by the DESERT method; the fractions of anti conformation for these derivatives were 0.58 and 0.41, respectively.
NMR spectroscopic characterization of ZE isomers of cyclododeca‐1,5,9‐triene
Authors: Radeglia Reiner , Poleschner Helmut , Haufe GÜNter 
Published: May 2005

AbstractThe four ZE isomers of cyclododeca‐1,5,9‐triene were examined by 13C NMR spectroscopy. The vicinal 1H1H coupling constants of the olefinic protons were used to determine the stereochemistry at the double bonds. For the symmetrically substituted CHCH fragments (chemically equivalent H atoms) this parameter was obtained from the 13C NMR multiplets which are observed in 1H continuous‐wave off‐resonance 13C NMR experiments. The precise assignment of the 1H and 13C chemical shifts, in particular for the Z,Z,E and Z,E,E isomers, was possible on the basis of off‐resonance measurements in combination with 13C/1H heteronuclear correlated and 1H/1H‐COSY‐45 2D experiments.
High‐field nuclear magnetic resonance of thallium in zeolites
Authors: Groombridge Christopher J. , Coker Eric N. , Rees Lovat V. C. 
Published: May 2005

AbstractThallium‐205 NMR is reported for several zeolite samples (A, X and Y; hydrated and dehydrated) with thallium(I) exchanged for sodium. Detection at high field (7.05 T) clarifies the spectrum appearance, and it is seen that chemical shift anisotropy (CSA) dominates some of the band shapes. The large CSAs dictate that the spectrum is recorded piecewise by a frequency‐stepped spin‐echo integral (FUSSI) method. Magic‐angle sample spinning has been observed to give only a very minor line‐narrowing effect. Threefold‐coordinated zeolite A Tl+ sites adjacent to six‐membered rings [Tl(1) and Tl(3)] are both assigned to a resonance which has large CSA (δiso 1183, δδ—1842), while the remaining zeolite A site [Tl(2)] gives an isotropic line shape (δiso 300). Dehydrated zeolite X gives an isotropic peak (δiso 854) which is assigned to the double six‐ring Tl(I), and a broader anisotropic resonance which is tentatively attributed to supercage Tl(III). Data for dehydrated zeolite Y indicate that this has a disordered cation distribution.
Carbon‐13 NMR spectroscopy of some 4‐substituted 3‐halo‐2,6‐dimethylpyridine N‐Oxides
Authors: Ban‐Oganowska Hanna 
Published: May 2005

Abstract13C NMR spectra of 4‐substituted 3‐chloro‐ and 3‐bromo‐2,6‐dimethylpyridine N‐oxides in CDCI3 and their chemical shifts are reported. The influence of the electronic properties of the substituent in the 4‐position and the ortho effect on the direction of chemical shifts and the values of coupling constants 1J(C‐5,1H) is discussed.
Paramagnetic 1H NMR saturation transfer study of ligand exchange in iron(III) myoglobins
Authors: Yamamoto Yasuhiko , Inoue Yoshio , Suzuki Tomohiko 
Published: May 2005

Abstract1H NMR saturation transfer experiments were successfully used in connecting iron(III) high‐ and low‐spin forms of equine, the mollusc Dolabella auricularia and the shark Mustelus japonicus myoglobins. With the known signal assignments in the high‐spin form, a haem peripheral proton resonances in met‐azido and met‐imidazole complexes of the myoglobins have been straightforwardly assigned via the saturation transfer connectivities. Analysis of the extent of the saturation transfer provided the kinetics of the ligand exchange.