Synthesis of Chiral, Half‐Sandwich Ruthenium Complexes from Weakly Coordinated Solvent Species

Abstract

The bis(acetonitrile) species 7 has been synthesized in a multistep protocol. This chiral phosphaferrocene‐containing, half‐sandwich ruthenium complex easily provides two coordination sites due to the high lability of the coordinated solvent molecules. Although complex 7 could not be isolated in pure form, it serves as a valuable starting material for the preparation of other half‐sandwich complexes with, for example, pyridine (8), tmeda (9), N‐(2‐dimethylaminoethyl)‐morpholine (10), or tricyclohexylphosphine (11) as ligands. Whereas the morpholine complex 10 was obtained as almost a 1:1 mixture of diastereomers, the mixed MeCN/PCy3 complex 11 was formed with a high level of diastereoselectivity (90% de). The molecular structures of complexes 8, 10, and the cyclopentadiene derivative 3a were determined by X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

New cyclopentadienylethylphosphane chelate complexes with unsymmetrical phosphane substitution

“…13,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Complexes with two different substituents at phosphorus are comparatively rare. The few, in some cases rather special examples of such complexes, have been reported by Nakazawa and Miyoshi et al (Zr, Hf), [31][32][33] Hey-Hawkins et al (Ti, Zr), 34 Ganter et al (Mn, Ru), [35][36][37] and Saunders et al (Rh). [38][39][40][41] Different substituents at phosphorus render the complexes less symmetric and are expected to affect the chemical and spectroscopic properties of the complexes as well as the energy of activation of an ethene rotation, which has earlier been reported for 2.…”

“…IR: v˜= 3092 (w), 3055 (w), 2959 (w, C-H), 2361 (w), 1474 (m, C-H), 1435 (m, P-Ph), 1366 (m, t-Bu), 1172 (m), 1100 (m), 1053 (w), 892 (w), 819 (m), 810 (s, Cp), 747 (s, Cp), 699 (s) cm À1 . MS: m/z (%) = 379 (30) [M + ], 288 (54), 286 (100), 202 (44), 124 (26), 109 (37), 91 (36), 57 (76)…”

Noble metals

“…67 The synthesis of an unusual chiral tethered Cp complex [Ru(Z 1 -P:Z 5 -Cp-22)(PPh 3 )Cl] has also been reported. 68 [(C 6 Me 6 )Ru(Z 3 -C 3 H 5 )(OTf)] on addition to ethyne gives an unprecedented coordination mode to an Z 1 ,Z 4 -cycloheptadienyl complex on cycloaddition to ethyne; this slowly rearranges thermally to the more stable Z 5 -coordination mode, obtained directly on addition of tert-butylacetylene. 69 The phosphaallyl complex [MeCpRu (Z 1 -L)(Z 3 -L)]PF 6 has also be isolated [L = Cy 2 PCHQCH 2 ] and readily displaces the coordinated vinyl moiety, while the compound [MeCpRu(CO)(CH 3 CN) (L)]PF 6 has been shown to react with 3,4-dimethyl-1-phenylphosphole to undergo a Diels-Alder cycloaddition.…”

Synthesis of Manganese and Rhenium Half-Sandwich Complexes with Cp-Phosphaferrocene Ligands

“…If the Cp substituent is a chiral entity, the formation of complexes with defined configuration of the stereogenic metal center via intramolecular chelation becomes possible . In previous papers we have demonstrated the use of the planar chiral phosphaferrocene bearing Cp ligands 1a , b employed as either the sodium or thallium salts, respectivelyfor the synthesis of chiral ruthenium half-sandwich complexes, where the phosphaferrocene donor is coordinated in an intramolecularly chelating fashion, which allows a high degree of stereocontrol at the Ru atom . In this contribution we describe the formation of Cp manganese and rhenium half-sandwich complexes employing the chiral ligand 1a as its thallium salt.…”