Competing formation of bridging diphenylphosphido and bridging (diphenylphosphino)cyclopentadienyl ligands during the reaction of [M(CO)5PPh2]- (M = Cr, Mo, W) with CpRu(CO)2Cl. X-ray structure of (CO)5W(.mu.-C5H4PPh2)Ru(CO)2(.mu.-CO)2Ru(CO)CP.cntdot.CH2Cl2

1989 ◽  
Vol 28 (10) ◽  
pp. 1884-1887 ◽  
Author(s):  
Martine Cazanoue ◽  
Noel Lugan ◽  
Jean Jacques Bonnet ◽  
Rene Mathieu
Keyword(s):  
X Ray ◽  
Cyclopentadienyl Ligands

The synthesis and polymerization behaviour of silicon-bridged [1]- and [2]ferrocenophanes with sterically demanding trimethylsilyl substituents attached to the cyclopentadienyl rings

1995 ◽  
Vol 73 (11) ◽  
pp. 2069-2078 ◽  
Author(s):  
Timothy J. Peckham ◽  
Daniel A. Foucher ◽  
Alan J. Lough ◽  
Ian Manners
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Monoclinic Space Group ◽  
Organometallic Polymers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Sterically Demanding ◽  
High Molecular Weight Poly

The silicon-bridged [1]ferrocenophane Fe(η-C5H3SiMe3)2(SiMe2) (5) was synthesized via the reaction of Li2[Fe(η-C5H3SiMe3)2]•tmeda (tmeda = tetramethylethylenediamine) with Me2SiCl2 in hexanes. The disilane-bridged [2]ferrocenophane Fe(η-C5H3SiMe3)2(Si2Me4) (7) was prepared using a similar route from the disilane ClMe2SiSiMe2Cl. Despite the presence of sterically demanding SiMe3 substituents on the cyclopentadienyl rings, compound 5 was found to undergo thermal ring-opening polymerization at 170 °C to produce very soluble, high molecular weight poly(ferrocenylsilane) 6 with Mw = 1.4 × 105, Mn = 8.4 × 104. However, the [2]ferrocenophane 7 was found to be resistant to thermal ring-opening polymerization even at 350 °C and decomposed above 380 °C. A single-crystal X-ray diffraction study of 7 revealed that the steric interactions between the bulky SiMe3 groups are relieved by a significant twisting of the disilane bridge with respect to the plane defined by the centroids of the cyclopentadienyl ligands and the metal atom. The angle between the planes of the cyclopentadienyl rings in 7 was found to be 5.4(6)°, slightly greater than that in the non-silylated analogue Fe(η-C5H4)2(Si2Me4) (4a) (4.19(2)°), and dramatically less than the corresponding tilt angle of the strained, polymerizable, silicon-bridged [1]ferrocenophane Fe(η-C5H4)2(SiMe2) (1) (20.8(5)°). The length of the Si—Si bond in 7 (2.342(3) Å) was found to be close to the sum of the covalent radii (2.34 Å). Crystals of 7 are monoclinic, space group C2/c, with a = 23.689(3) Å, b = 11.174(1) Å, c = 31.027(3) Å, β = 109.16(1)°, V = 7758(2) Å3, and Z = 12. Keywords: ring-opening polymerization, ferrocenophane, organometallic polymers.

Synthesis of Rhodium Complexes with Novel Perfluoroalkyl Substituted Cyclopentadienyl Ligands

2001 ◽  
Vol 66 (2) ◽  
pp. 382-396 ◽  
Author(s):  
Jan Čermák ◽  
Kateřina Auerová ◽  
Huong Thi Thu Nguyen ◽  
Vratislav Blechta ◽  
Pavel Vojtíšek ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Chemical Shifts ◽  
Rhodium Complexes ◽  
Carbonyl Complexes ◽  
X Ray Diffraction ◽  
Metal Catalysis ◽  
Chloro Complexes ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
C Nmr

Mixtures of isomers of (perfluoroalkyl)tetramethylcyclopenta-1,3-dienes (CH3)4C5H(CF2)nCF3 (n = 3, 5, 7, 9) were synthesized as precursors of new cyclopentadienyl ligands for organotransition metal catalysis in fluorous biphase media and characterized by combination of GC-MS and 13C NMR spectroscopy. Rhodium(III) chloro complexes [Rh{(CH3)4C5(CF2)nCF3}Cl2]2 and rhodium(I) carbonyl complexes [Rh{(CH3)4C5(CF2)nCF3}(CO)2] were prepared from the cyclopentadienes and molecular structure of [Rh{(CH3)4C5(CF2)5CF3}Cl2]2 was determined by X-ray diffraction. The ligands are electronically close to the unsubstituted cyclopentadienyl as shown by values of carbonyl stretching frequencies in the carbonyl complexes. Neither carbonyl frequencies nor NMR chemical shifts of the complexes are substantially affected by the length of the perfluoroalkyl chain.

Preparation and Crystal Structures of Low-Valent Zirconocene Complexes Containing Tetramethyl(phenyl)cyclopentadienyl Ligands

2007 ◽  
Vol 72 (5-6) ◽  
pp. 679-696 ◽  
Author(s):  
Michal Horáček ◽  
Jiří Pinkas ◽  
Jiří Kubišta ◽  
Ivana Císařová ◽  
Róbert Gyepes ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Spectroscopic Methods ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Low Valent

Zirconocene complex [ZrCl2(η5-C5Me4Ph)2] (1) prepared by metathesis of the appropriate lithium cyclopentadienide and ZrCl4 was reduced with magnesium in tetrahydrofuran in the presence of excess bis(trimethylsilyl)acetylene, yielding the low-valent complex [Zr(η5-C5Me4Ph)2- (η2-Me3SiC≡CSiMe3)] (2). However, in addition to 2, the reduction afforded an unexpected Zr(II) complex [Zr(η5-C5Me4Ph)2(s-trans-η4-buta-1,3-diene)] (3). Compounds 1-3 were characterized by spectroscopic methods and by X-ray single-crystal diffraction.

Optically Active Cyclopentadienyl Ligands from the Chiral Pool, Part 1. The Synthetic Utility of a Camphor-Derived Pentafulvene

2002 ◽  
Vol 57 (3) ◽  
pp. 338-342 ◽  
Author(s):  
Valeri Quindt ◽  
Mark Wallasch ◽  
Gotthelf Wolmershäuser ◽  
Helmut Sitzmann
Keyword(s):  
Optically Active ◽  
Tertiary Alcohol ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Water Elimination ◽  
Synthetic Utility ◽  
Orthorhombic Crystals

AbstractStarting from (1R)-(+)-camphor, the reaction with cyclopentadienylmagnesium chloride gave the corresponding tertiary alcohol 1, which was transformed into the optically active pentafulvene 5-(1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene)cyclopentadiene (2) by acidcatalyzed water elimination. Deprotonation with tert-butyllithium yielded the corresponding lithium 5-{(1R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl}cyclopentadienide (3), which was converted into the non-racemic 1,1β-bis{(1R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2- yl}ferrocene (4). 4 forms orthorhombic crystals of the space group P212121 with a = 7.7163(4), b = 10.7381(6), and c = 28.804(2) A˚ , which have been subjected to X-ray diffraction.

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