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A Structure Comparison of Ni(II) Complexes Supported by PNCNP and POCOP Pincer Ligands
Author(s) -
Fang Fei,
Chang Jiarui,
Kang Jiaxin,
Zhang Jie,
Li Shujun,
Chen Xuenian
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202001413
Subject(s) - pincer movement , chemistry , ligand (biochemistry) , nickel , phosphinite , crystallography , pincer ligand , center (category theory) , population , stereochemistry , biochemistry , catalysis , receptor , demography , organic chemistry , sociology
In order to compare the structure and property of the same metal center supported by different types of pincer ligands, a series of Ni(II) pincer complexes, [2,6‐( i Pr 2 PNH) 2 C 6 H 3 ]NiX (X=SH, 1 a ; SPh, 1 b ; SBn, 1 c ; BH 4 , 1 d ), were synthesized based on m ‐( i Pr 2 PNH) 2 C 6 H 4 (PNCNP) and fully characterized by multinuclear NMR, FTIR, X‐ray crystallography and elemental analysis. The structures of complexes 1 a – d were compared with those of the corresponding Ni(II) complexes supported by a bis(phosphinite) (POCOP) pincer ligand, [2,6‐( i Pr 2 PO) 2 C 6 H 3 ]NiX (X=SH, 2 a ; SPh, 2 b ; SBn, 2 c ; BH 4 , 2 d ). It was found that the Ni‐C ipso and Ni−S bond lengths and the Ni⋅⋅⋅B distance in complexes 1 a – d are comparable to those in complexes 2 a – d ; however, the Ni−P bond lengths in complexes 1 a – d are longer than those in complexes 2 a – d . As a result, the nickel center is less tightly chelated by the PNCNP backbone compared with the POCOP framework. Natural population analysis (NPA) of complexes 1 a , 2 a , 1 b and 2 b indicated that the nickel center supported by a PNCNP pincer ligand is less electron‐rich. Cyclic voltammetry study of 1 a and 2 a showed that 2 a is easier to be oxidized.