Metallorganische Lewis‐Säuren, XLVIII. Neue Vorläufer metallorganischer, kationischer Lewis‐Säuren mit zwei freien Koordinationsstellen: (OC) 4 Re(OEt 2 )FBF 3 und (OC) 2 (PPh 3 ) 2 Ru(FBF 3 ) 2

Organometallic Lewis Acids, XLVIII [1] . – New Precursors to Organometallic Cationic Lewis Acids with two Accessible Coordination Sites: (OC) 4 Re(OEt 2 )FBF 3 and (OC) 2 (PPh 3 ) 2 Ru(FBF 3 ) 2 The allyl transfer reaction between Re(CO) 5 − and [(η 3 1‐allyl)PdCl] 2 complexes leads to (allyl)rhenium complexes (η 3 1‐H 2 CCR 1 CR 2 R 3 ) Re(CO) 4 ( 1 : R 1 , R 2 , R 3 H; 2 ; R 2 , R 3 H, R 1 Me; 3 : R 1 , R 2 H, R 3 Me; 4 : R 1 H, R 2 , R 3 Me). The 2‐methylallyl complex 2 has been characterized by low‐temperature X‐ray diffraction. Protonation of 1 with HBF 4 · OEt 2 in CH 2 Cl 2 gives the complex (OC) 4 Re(OEt 2 )FBF 3 ( 5 ), which is a precursor for the 14 e − System “(OC) 4 Re + ”. THF and H 2 O replace the diethyl ether in 5 to give [(OC) 4 Re(solvent) 2 ]BF 4 ( 6, 7 ). The reaction of (OC) 2 (PPh 3 ) 2 RuCl 2 with AgBF 4 yields the complex (OC) 2 (PPh 3 ) 2 Ru(FBF 3 ) 2 ( 8 ), which can be considered as a precursor for the 14 e − cation “(OC) 2 (PPh 3 ) 2 Ru 2+ ” and reacts with H 2 O to give [(OC) 2 (PPh 3 ) 2 Ru(F)(H 2 O)]BF 4 ( 9 ). Complexes 5–9 are characterized by IR, 1 H‐, 13 C‐, 31 P‐and 19 F‐NMR spectroscopy.