Organometallic Complexes of Iridium, Palladium, Chromium and Iron from 2-Phenyl-5(4H)-oxazolones − Organometallic Labelled Dipeptides

Abstract

Reactions of 2‐phenyl‐4‐R‐5(4H)‐oxazolones (R = Me, CH2Ph, CHMeEt) with [(η5‐C5Me5)IrCl2]2 afforded the cyclometallated complexes (η5‐C5Me5)(Cl)Ir(L) (1−3) [L = 2‐phenyl‐4‐R‐5(4H)‐oxazolone(C‐o,N)]. 2‐Phenyl‐5(4H)‐oxazolone reacts with [(η5‐C5Me5)IrCl2]2 and palladium(II) acetate to give complexes with a C‐o,N‐bridging oxazolone [(η5‐C5Me5)(Cl)Ir]2(μ‐Cl)(μ‐L‐H+) (4) and Pd3(μ‐ac)5(μ‐L‐H+) (5). 2‐Phenyloxazolone anions were added to the π ligands of [(η5‐C6H7)Fe(CO)3]+ and [(η7‐C7H7)Cr(CO)3]+ to give the adducts 6−11. Dipeptide derivatives 12−18 were obtained by reaction of 1, 2 and by reaction of the adduct 6 from [(η5‐C6H7)Fe(CO)3]+; and the anion of 2‐phenyloxazolone with α‐amino acid esters. These reactions may be used for the labelling of peptides. Saponification of 15−18 yields the organometallic substituted peptide acids 19−22. Their dianions (deprotonation of COOH and peptide amide) were used as ligands towards (Ph3P)2PtCl2 to yield the bimetallic complexes 23−25. The structures of 4, 5, 9 and 10 were determined by X‐ray diffraction.

Selective Manipulation of Well‐Defined Trinuclear Pd(II)‐Complexes

“…1 H NMR (CDCl 3 , 500 MHz, 305 K, ppm): δ 8.68 (d, J = 5.0 Hz, 1H), 8.05 (d, J = 5.5 Hz, 1H), 7.70 (d, J = 2.5 Hz, 1H), 7.63 (t, J = 7.0 Hz, 1H), 7.22 (t, J = 6.5 Hz, 1H), 7.12 (t, J = 8.0 Hz, 1H), 6.78-6.74 (m, 3H), 6.67 (t, J = 6.0 Hz, 1H), 6.34 (d, J = 2.0 Hz, 1H), 5.74 (d, J = 2.0 Hz, 1H), 2.49 (s, 3H), 2.31 (s, 3H), 2.49 (s, 3H), 1.96 (s, 3H), 1.48 (s, 3H), 1.38 (s, 3H), 1.31 (s, 9H), 1.28 (s, 9H), 1.16 (s, 9H), 1.06 (s, 3H), 0.84 (s, 9H). 13 [Pd 3 (PNO)(OAc) 4 ] (4). Inside a glovebox, a solution of [Pd 3 (OAc) 6 ] (140 mg; 0.21 mmol) in 2 mL of dry THF was prepared.…”

“…1 H NMR (CDCl 3 , 500 MHz, 305 K, ppm): δ 8.54 (s, 4H), 7.86 (dd, J = 8.0, 4.0 Hz, 2H), 7.79-7.75 (m, 4H), 7.73-7.68 (m, 4H), 7.49-7.40 (m, 8H), 7.31-7.23 (m, 6H), 7.16-7.09 (m, 4H), 6.63 (d, J = 2.5 Hz, 2H), 5.59 (d, J = 2.5 Hz, 2H), 1.66 (s, 6H), 0.82 (s, 18H), 0.71 (s, 18H). 13 C { 1 H} NMR (CDCl 3 , 126 MHz, 305 K ppm) δ 187.5 (CO(CH 3 )), 186.9 (CO(CH 3 )), 186.8 (CO(CH 3 )), 183.9 (CO(CH 3 )), 165.9 (C Ar ), 165.0 (d, J = 21.4 Hz, C Ar ), 145.2 (C Ar ), 137.5 (d, J = 10.1 Hz, C Ar ), 134.3 (C Ar H), 133.0 (q, J = 6. (100 mg; 0.21 mmol) in 2 mL of THF and 50 μL of distilled water were added at room temperature.…”

“…[11] The substoichiometric substitution of acetate ligands in this trinuclear assembly has attracted only minor attention to date, despite its obvious appeal to access mixed-ligand multinuclear architectures. Selective acetate exchange has been achieved with only a small number of exogenous ligands -nitrite, [3,12] oxazolone, [13] water and alcohols [14] -although not always through direct proton-transfer reactivity (Figure 2). However, in all cases known to date, only single acetate displacement is realized.…”

“…+ (C 24 H 34 N 2 O 3 Pd 1 ): 504.1608, found 504.1640. 3H), 1.25 (s, 9H), 1.20 (s, 3H), 1.12 (s, 9H) 13. C{ 1 H} NMR (CDCl 3 , 126 MHz, 305 K, ppm): δ 187.0 (CO(CH 3 )), 186.1 (CO(CH 3 )), 185.8 (CO(CH 3 )), 185.4 (CO(CH 3 )), 173.4 (C Ar ), 166.3 (C Ar ), 146.4 (C Ar H), 141.1 (C Ar ), 139.2 (C Ar H), 137.3 (C Ar ), 135.4 (C Ar ), 126.3 (C Ar H), 122.7 (C Ar H), 121.7 (C Ar H), 121.1 (C Ar H), 79.…”

Synthesis, Structures, and Reactivity of Single and Double Cyclometalated Complexes Formed by Reactions of [Cp*MCl2]2 (M = Ir and Rh) with Dinaphthyl Phosphines

“…To date, cyclometalation reactions are the most actively investigated reactions in the field of organometallic chemistry, which have been carried out with the most transition metal compounds, especially platinum group metal complexes . In the last 2 decades, especially after Davies et al developed an efficient acetate-assisted cyclometalation of some N-donor ligands with [Cp*MCl 2 ] 2 (M = Rh and Ir) and [( p -cymene)­RuCl 2 ] 2 , a significant number of N-containing functional arene or heteroarene derivatives were cyclometalated by [Cp*RhCl 2 ] 2 , especially by [Cp*IrCl 2 ] 2 , such as benzylamine, − imine, ,− 2-phenylpyridine, ,− 2-benzylpyridine, 2-benzoylpyridine, , 2-phenylpyrroline, 2-phenylpyrrolidine, phenylpyrazole, ,,, benzo­[ h ]­quinoline, ,, oxazoline, ,,, oxazolone, oxime, imidazole, and trizole . Later on, Jones et al investigated the reactivity and regioselectivity of cyclometalation reactions of substituted phenyl imines and 2-phenylpyridines with [Cp*MCl 2 ] 2 , including electronic and steric effects of substituted groups and solvent and temperature effects .…”