Synthesis and reaction of ruthenium(II) complexes containing heteroatom donor (O, N, and P) tethered to η6-arene ring

Synthesis of ruthenium(II) complexes chelated by the eta(6)-arene ring and a pendent donor atom (O, N, and P) is described. The alcohol-containing eta(6)-arene ruthenium complexes [Ru{eta(6)-C6H5(CH2)(3)OH}(PR3)Cl-2] (1a R = Ph; 1b R = Et) and [Ru{eta(6)- H-6(5)(CH2)OH}L2Cl]BF4 (2a L-2 = 2,2'-bipyridine; 2b L-2 = 1,10-phenanthroline; 2c L-2 = 2,2-bis[4(R)-phenyl-1,3-oxazolon-2-yl]propane, (R)-bpop) were prepared by treatment of [Ru{eta(6)-C6H5(CH2)(3)OH}Cl-2](2) with tertiary phosphines or N,N'-chelate ligands/NaBF4, respectively. Addition of 1 equiv. of AgBF4 to a solution of complexes 1 or 2 gave alcohol chelate complexes [Ru{eta(6):eta(1)-C6H5(CH2)(3)OH}(PR3)Cl]BF4 (3a-b) or [Ru{eta(6):eta(1)-C6H5(CH2)(3)OH}L-2](BF4)(2) (4a-c), respectively. Although stable in MeOH, the alcohol-Ru chelate bond of 3 and 4 was cleaved by Cl- ion. Treatment of 4 with bases (OH-, R3N) led to abstraction of the hydroxy proton to give alkoxy chelate complexes [Ru{eta(6):eta(1)-C6H5(CH2)(3)O}L-2]BF4 (5a-c), In CH2Cl2 acidity of the hydroxy proton in 4c was revealed to be comparable to that of N-methylbenzylammonium cation (pK(a) in H2O, ca. 11). Amino chelate complexes [Ru(eta(6):eta(1)-C6H5(CH2)(n)NH2} (PPh3)Cl]BF4 (7a n = 3; 7b n = 2) were prepared by treatment of ammonium complexes [Ru{eta(6)-C6H5(CH2)(n)NH3Cl}(PPh3)Cl-2] (6a n = 3; 6b n = 2) with 1 equiv. of NaOH and NaBF4. 7 were stable to the attack of Cl- ion. In contrast, the similar treatment of dimethylammonium derivative [Ru{eta(6)-C6H5(CH2)(3)NMe2- HCl}(PPh3)Cl-2] (8) with KOH gave a non-chelate complex [Ru{eta(6)-C6H5(CH2)(3)NMe2}(PPh3)Cl-2] (9). Phosphorous chelate complexes [Ru{eta(6):eta(1)-C6H5(CH2)(3)OPPR2}Cl-2] (10a R = Ph; 10b R = Pr-i) were prepared by reaction of [Ru{eta(6-)C(6)H(5)(CH2)(3)OH)Cl-2](2), PPR2Cl, and (EtNPr2)-Pr-i. Treatment of 10b with AgBF4 and CO (1 atm) gave the cationic carbonyl complex [Ru{eta(6):eta(1)-C6H5(CH2)(3)(OPPr2)-Pr-i}(CO)Cl]BF4 (11). (C) 2000 Elsevier Science S.A. All rights reserved.