Silabenzene and Disilabenzene Complexes of Ruthenium

Abstract

The syntheses of sila-and disilabenzene complexes of "Cp*Ru" (Cp* ) C 5 Me 5 ) are described. Li[C 5 H 5 SiH( t Bu)] reacted with [Cp*RuCl] 4 to give the neutral silacyclohexadienyl complex Cp*Ru[η 5 -C 5 H 5 SiH( t Bu)] (2), characterized by NMR spectroscopy. Reaction of 2 with the Lewis acid B(C 6 F 5 ) 3 gave the product of Si-H abstraction, [Cp*Ru(η 6 -C 5 H 5 Si t Bu)][BH(C 6 F 5 ) 3 ] (3). Complex 3 represents the first example of an isolated silabenzene complex. The characterization of 3 follows from 1 H, 13 C, 29 Si, 19 F, and 11 B NMR and IR spectroscopies. Finally, trans-1,4-dihydrohexamethyl-1,4-disilacyclohexa-2,5-diene reacted with Cp′(PMe 3 ) 2 -RuCH 2 SiMe 3 (Cp′ ) C 5 Me 4 Et) to give Cp′(PMe 3 )RuH(η 2 -hexamethyl-1,4-disilabenzene) (4), whose structure (by X-ray crystallography) may be described as a metallodisilanorbornadiene.

Coordination Chemistry of a Kinetically Stabilized Germabenzene: Syntheses and Properties of Stable η6‐Germabenzene Complexes Coordinated to Transition Metals

“…Synthesis of h 6 -germabenzene complexes: There are two main known approaches for the synthesis of arene tricarbonylmetal complexes [M(CO) 3 A C H T U N G T R E N N U N G (h 6 -arene)] (M = Cr, Mo, and W).…”

“…On the other hand, milder complexation conditions and shorter reaction times can be achieved by the use of suitable precursors such as [M(CO) 3 L 3 ] (L = CH 3 CN, pyridine, NH 3 , etc. ), which offer better compatibility with arenes bearing functional groups, and so we selected [M(CO) 3 A C H T U N G T R E N N U N G (CH 3 CN) 3 ] (M = Cr, Mo, and W) as starting materials for the synthesis of h 6 -germabenzene-Group 6 metal tricarbonyl complexes (Scheme 1).…”

“…As one example, the first cationic ruthenocene complex containing an h 6 -silabenzene ligand-[RuCp*{h 6 -C 5 H 5 SiA C H T U N G T R E N N U N G (tBu)}][BHA C H T U N G T R E N N U N G (C 6 F 5 ) 3 ]-was synthesized and characterized by NMR and IR spectroscopy. [3] Meanwhile, we have already reported the synthesis and isolation of kinetically stabilized 1-Tbt-silabenzene, [4] 1-Tbt-1-sila-and 2-Tbt-2-silanaphthalenes, [5,6] and 9-Tbt-silaanthracene, [7] with the aid of some efficient steric protection groups: 2,4,6-trisA C H T U N G T R E N N U N G [bis(trimethylsilyl)methyl]phenyl (denoted as Tbt) and 2,6-bisA C H T U N G T R E N N U N G [bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl (denoted as Bbt). [8] Furthermore, the germanium analogues, 1-Tbt-germabenzene, [9] 2-Tbt-2-germanaphthalene, [10] 9-Tbt-9-germaanthracene, and 9-Tbt-9-germaphenanthrene, [11] have been synthesized as stable compounds.…”

“…The first stable h 6 -germabenzene complexes, that is, [M(CO) 3 (h 6 -C 5 H 5 GeTbt)] {M = Cr (2), Mo (3), and W (4); Tbt = 2,4,6-tris- 3 ] (M = Cr, Mo, and W) and the kinetically stabilized germabenzene 1 and characterized by 1 H and 13 C NMR, IR, and UV/Vis spectroscopy. In the 1 H and 13 C NMR spectra of 2-4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1.…”

“…In the 1 H and 13 C NMR spectra of 2-4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1. X-ray crystallographic analysis of 2 and 4 revealed that the germabenzene ligand was nearly planar and was coordinated to the M(CO) 3 3 A C H T U N G T R E N N U N G (CH 3 CN)] (M = Cr, Mo), resulting in the formation of the first stable h 6 -germabenzene-Group 6 metal complexes, [M(CO) 3 (h 6 -C 5 H 5 GeTbt)]. [13] In this paper we describe the details of the synthesis and characterization of the first stable h 6 -germabenzene-Group 6 metal complexes, [M(CO) 3 …”