Measuring Self‐Association of Pt Complexes by ¹⁹⁵Pt NMR

Abstract

A highly soluble neutral cyclometallated Pt complex of C N N type was prepared and its self‐aggregation in CDCl3 solution was studied by NMR dilution method. It was shown that 195Pt NMR can be used to quantify aggregation and therefore be potentially applied to many other Pt complexes. Two‐dimensional HMBC 1H‐195Pt technique increases sensitivity of experiment and allowed recording 195Pt chemical shift values at concentration as low as 1 mM and it was observed that opposite to shielding of aromatic protons, Pt nucleus is deshielded upon increase of concentration.

Synthesis, mesomorphism, photophysics and device performance of liquid-crystalline pincer complexes of gold(iii)

“…[42][43][44] Similar effects have been observed by Suleymanova et al for a cyclometallated platinum(II) complex studied by both 1 H and 195 Pt NMR spectroscopy. 54 In order to quantify this effect to determine if the aggregation might influence the photophysical properties of these complexes, rigorous, concentration-dependent studies of 13a…”

Multinuclear PtII Complexes: Why Three is Better Than Two to Enhance Photophysical Properties

“…Square planarP t II complexes containingc onjugated coordinated ligandsa re particularly interesting building blocks for the creationo fs upramolecular nanostructures sincet heir flat geometry makes them prone to stack through noncovalent interaction, such as p-p stacking. [1][2][3][4][5][6][7][8][9][10] Furthermore, when Pt II complexes are close enough (distance below 3.5 ) [11][12][13][14] metallophilic interactions between Pt centers may be established and stable aggregates [15][16][17] can be observed that possess spectroscopic properties which can be dramatically different from those of the monomeric metal complex. [1][2][3][4][18][19][20][21][22][23] In fact, the establishmento fg round state intermolecular interactions between protruding d z 2 orbitals resultsi nt he formation of lower-lying molecular orbitals, thus an ew optical transition appears ascribed to metal-metal-to-ligand charget ransfer (MMLCT).…”

Tuning the Aggregation of N^N^C Pt(II) Complexes by Varying the Aliphatic Side Chain and Auxiliary Halide Ligand: 1H and 195Pt NMR Investigation

“…The synthesis of Pt‐Cl was described previously and involved the reaction of a corresponding proligand with potassium tetrachloroplatinate in boiling acetic acid. Complexes n ‐C 8 H 17 ‐Pt‐Cl, n ‐C 12 H 25 ‐Pt‐Cl and n ‐C 16 H 33 ‐Pt‐Cl were synthesized according to the same procedure using corresponding linear alkoxy proligands.…”

“…Signal of solvent was used as reference. Ligands were prepared as described previously by alkylation of 2‐(pyridin‐2‐yl)‐6‐(4‐oxyphenyl)pyridine using appropriate bromoalkane . Pt‐Cl was synthesized as described previously …”

“…The method is simple and involves measurement of samples at variable concentrations monitoring the change in chemical shifts of protons of the ligands. More recently, 195 Pt NMR has also successfully been used in dilution experiments, which is an important milestone because 195 Pt NMR methodology can potentially be applied to any Pt complex regardless of the presence or absence of other NMR active nuclei. Indeed, while not every Pt complex contains protons, every Pt complex contains 195 Pt atom.…”