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Experimental and quantum‐chemical studies of 1 H, 13 C and 15 N NMR coordination shifts in Pd(II) and Pt(II) chloride complexes with methyl and phenyl derivatives of 2,2′‐bipyridine and 1,10‐phenanthroline
Author(s) -
Pazderski Leszek,
Toušek Jaromír,
Sitkowski Jerzy,
Kozerski Lech,
Szłyk Edward
Publication year - 2007
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2104
Subject(s) - chemistry , chemical shift , chloride , nuclear magnetic resonance spectroscopy , stereochemistry , organic chemistry
1 H, 13 C and 15 N NMR studies of platinide(II) (M = Pd, Pt) chloride complexes with methyl and phenyl derivatives of 2,2′‐bipyridine and 1,10‐phenanthroline [LL = 4,4′‐dimethyl‐2,2′‐bipyridine (dmbpy); 4,4′‐diphenyl‐2,2′‐bipyridine (dpbpy); 4,7‐dimethyl‐1,10‐phenanthroline (dmphen); 4,7‐diphenyl‐1,10‐phenanthroline (dpphen)] having a general [M(LL)Cl 2 ] formula were performed and the respective chemical shifts (δ 1H , δ 13C , δ 15N ) reported. 1 H high‐frequency coordination shifts (Δ 1H coord = δ 1H complex − δ 1H ligand ) were discussed in relation to the changes of diamagnetic contribution in the relevant 1 H shielding constants. The comparison to literature data for similar [M(LL)(XX)], [M(LL)X 2 ] and [M(LL)XY] coordination or organometallic compounds containing various auxiliary ligands revealed a large dependence of δ 1H parameters on inductive and anisotropic effects. 15 N low‐frequency coordination shifts (Δ 15N coord = δ 15N complex − δ 15N ligand ) of ca 88–96 ppm for M = Pd and ca 103–111 ppm for M = Pt were attributed to both the decrease of the absolute value of paramagnetic contribution and the increase of the diamagnetic term in the expression for 15 N shielding constants. The absolute magnitude of Δ 15N coord parameter increased by ca 15 ppm upon Pd(II) → Pt(II) transition and by ca 6–7 ppm following dmbpy → dmphen or dpbpy → dpphen ligand replacement; variations between analogous complexes containing methyl and phenyl ligands (dmbpy vs dpbpy; dmphen vs dpphen) did not exceed ± 1.5 ppm. Experimental 1 H, 13 C, 15 N NMR chemical shifts were compared to those quantum‐chemically calculated by B3LYP/LanL2DZ + 6–31G**//B3LYP/LanL2DZ + 6–31G*, both in vacuo and in DMSO or DMF solution. Copyright © 2007 John Wiley & Sons, Ltd.