71771-09-0

Upstream product

• 26120-22-9 (¹⁵N)pyrrole 
• 100-52-7 benzaldehyde 

Downstream Products

• 118102-31-1 5,10,15,20-Tetraphenyl<¹⁵N₄>bakteriochlorin 
• 118102-32-2 5,10,15,20-Tetraphenyl<¹⁵N₄>isobakteriochlorin 
• 133164-94-0 5,10,15,20-Tetraphenyl<¹⁵N₄>chlorin 

Relevant academic research and scientific papers

Consistent Porphyrin Force Field. 1. Normal-Mode Analysis for Nickel Porphine and Nickel Tetraphenylporphine from Resonance Raman and Infrared Spectra and Isotope Shifts

Resonance Raman spectra with variable-wavelength excitation are reported for Ni(II) porphine (NiP) and for the pyrrole-d8, meso-d4, and (pyrrole + meso)-d12 isotopomers, as well as for Ni(II) meso-tetraphenylporphine (NiTPP) and its pyrrole 15N4, pyrrole-d8, 13C4-meso, and phenyl-d20 isotopomers.All the Raman-active in-plane modes have been identified and are assigned to local coordinates which take into account the phasing of adjacent bond stretches within the pyrrole rings and at the methine bridges.The IR spectra of NiP and its isotopomers are also assigned.For most of the local coordinates good frequency agreement is seen for the different symmetry blocks, showing that longer range phasings have minor effects.These in-plane mode assignments are supported by normal-coordinate calculations with a physically reasonable valence force field, which is nearly the same for NiP and NiTPP.The principal force constants are in good accord with bond length relationships selected on the basis of scaled ab initio calculations.The phenyl substituents of NiTPP lower the frequencies of the asymmetric methine bridge stretching modes ν10(B1g) and ν19(A2g) by ca. 60 cm-1; this shift is attributable partly to the loss of coupling with the CmH bending modes in NiP and partly to an electronic effect of the phenyl group.There are also near-resonant interactions in NiTPP between porphyrin and phenyl modes near 740 and 200 cm-1 resulting in strongly displaced modes.Otherwise the phenyl groups have little influence on the porphyrin skeletal mode frequencies.Several phenyl modes are subject to moderate RR enhancement, probably via intensity borrowing from nearby porphyrin modes.Large intensities associated with CH bending modes in NiP imply significant excited-state changes in the pyrrole CβH and methine CmH bond angles.RR spectra for Ni(II) meso-tetramethylporphyrin (TMP) and its methyl-d12 isotopomer reveal methyl group modes and somewhat altered skeletal frequencies.Altered polarizations of ν10 and ν19 in NiTMP and NiTEP (meso-tetraethylporphine) reveal a lowering of the effective molecular symmetry, which is attributed to substituent orientation effects.All of these Ni porphyrins show strong overtone and combination band enhancement in resonance with the Q1 absorption band.

NMR and NIR Studies of the Tautomerism of 5,10,15,20-Tetraphenylporphyrin including Kinetic HH/HD/DD Isotope and Solid State Effects

Chemical Kinetics / Isotope Effects / Proton Transfer / Solid State Effects / Spectroscopy, Nuclear Magnetic Resonance.The liquid and solid state tautomerism of 5,10,15,20-tetraphenylporphyrin-15N4 (meso-tetraphenylporphyrin, TPP) has been studied by dynamic NMR spectroscopy and by NIR spectroscopy.The kinetic HH/HD/DD isotope effects on the liquid state tautomerism were reinvestigated in the temperature region between 200 K and 300 K.It was confirmed that the kinetic HH/HD isotope effects are large and the HD/DD isotope effects small.At 298 K the values 9.7 and 1.8 were obtained.The Arrhenius curve of the HH reaction is non-linear indicating that the proton transfer takes place by thermally activated tunneling at low temperatures.The kinetic isotope effects are consistent with a stepwise proton transfer pathway involving intermediate tautomeric states in which protons are bound to adjacent nitrogen atoms.Solid state NMR experiments were performed on triclinic TPP, where the reaction barrier is higher compared to TPP in the liquid state.In addition, the degeneracy of the tautomerism in the solid state is lost due to intermolecular interactions.The latter conclusion is supported by the finding that for tetragonal mixed crystals of the degeneracy of the tautomerism and its barrier is equal to the values found for the liguid solution.The NIR measurements show the presence of NH-stretching overtones in the region of about 6450 cm-1.The anharmonicity of this vibration is of the usual order, which indicates that the reaction coordinate of proton transfer is not identical with the normal modes of the NH-stretching vibrations, but rather a combination of various vibrational modes including the stretching, bending and skeletal modes.As a consequence, there will be a large number of vibrational states from which tunneling might occur.