Heteroatom-Substituted Bicyclo[1.1.1]pentanes with Two Boron Atoms as Electron-Deficient Centers

✍ Scribed by Dr. Matthias Menzel; Dr. Christine Wieczorek; Dr. Sigrid Mehle; Dr. Jürgen Allwohn; Dipl.-Chem. Heinz-Jürgen Winkler; Markus Unverzagt; Dipl.-Chem. Matthias Hofmann; Prof. Dr. Paul von Ragué Schleyer; Prof. Dr. Stefan Berger; Prof. Dr. Werner Massa; Prof. Dr. Armin Berndt

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 446 KB
• Volume: 34
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.199506571

✦ Synopsis

precursor [Cp*Ir(PPh,)(S,fc)] (6 b) .[l91 In the very stable 18electron complexes 6 a and 6 c [S,fc] functions as a two-electron ligand. The dimeric structure of 5 has been confirmed by an X-ray crystal structure analysis for the selenium analogue, In summary, the 1,l'-ferrocenedithiolato unit [S,fc] is a versatile ligand system which may function as a two-electron (in 6 a and 6 b), four-electron (in 5 ) , or six-electron donor (in 1-4) and [CpTIr,(Se,fc),l. which may act as either chelating or bridging ligand.

Experimental Procedure

I : A green solution of [(Cp*CoCI,),] [9] (0.42 g, 0.80 mmol) in T H F (20 mL) and an orange solution of [fc(SLi),] (0.45 g, 1.1 mmol) in T H F (100 mL) were combined at -78 ' C. The color of the homogeneous mixture changed to violet. The solution was stirred for 3 h at room temperature. After removal of the solvent, the residue was separated hy column chromatography on silica gel (Merck, Kieselgel60). Elution with pentaneiCH,CI, (1 : 2) gave 1. Recrystalliztion from CHCl,/toluene/hexane mixtures at -25 "C gave violet microcrystals of 1 (0.15 g, 30.1 %, m.p. 248 "C). EI-MS(70eV): prominentpeaksatm/z(%): 943( )[M+],808(10)[Mt -Cp*], 636 (48) [Cp:Co,(S,fc)+], 501 (22) [Cp*Co,(S,fc)+]. 442 (42) [Cp*Co(S,fc) 'I; strong peaks due to the ferrocene oligomers (m/z 370 [Fc:], 554 [Fc(fc)Fc+], 738 [Fc(fc),Fc+]) were also observed. The effective magnetic moment was found to be 5.6 gLH at room temperature; it decreases with decreasing temperature to reach 3.4 pB at 6 K 1201 2. The reaction of [(Cp*RhCI,),] [15] (0.24 g, 0.38 mmol) with [fc(SLi),] (0.31 g, 0.76 mmol) in T H F (130 mL) was started at -78 'C and then continued for 4 h a t room temperature. Chromatography over silica (with CH,Cl,/hexane mixtures for elution) gave several bands; isolation of the first (violet) zone which follows [FcH] and recrystallization from hexane or pentane gave violet crystals of(2) (0.12 g, 41 %, m.p. 168 'C). 'H N M R (CDCI,): 6 = 1.99 (s, C,Me,, 30H), 3.74, 4.39 (vt, fc, 4 + 4H). EI-MS (70eV): m/z 723 (100%) [M' -HI.