Photochemically Activated Phosphorus-Carbon Bond Cleavage in the Binuclear Ruthenium Complex [cyclic] Ru2(CO)6(bpcd). Redox Reactivity, Molecular Orbital Properties, and X-ray Diffraction Structures of [cyclic] Ru2(CO)6(bpcd) and [cyclic] Ru2(CO)6[.mu.-C:C(PPh2)C(O)CH2C(O)](.mu.2-PPh2)

1995 ◽  
Vol 14 (10) ◽  
pp. 4625-4634 ◽  
Author(s):  
Huafeng Shen ◽  
Simon G. Bott ◽  
Michael G. Richmond
Keyword(s):  
Molecular Orbital ◽  
Ruthenium Complex ◽  
Bond Cleavage ◽  
X Ray Diffraction ◽  
Carbon Bond ◽  
X Ray ◽  
Redox Reactivity

Trifluoromethylaryl-Substituted Quinoxalines: Unusual Ruthenium- Amidininate Complexes and their Suitability for Anellation Reactions

2005 ◽  
Vol 60 (8) ◽  
pp. 843-852 ◽  
Author(s):  
Frank Schramm ◽  
Dirk Walther ◽  
Helmar Görls ◽  
Christian Käpplinger ◽  
Rainer Beckert
Keyword(s):  
Boron Trifluoride ◽  
Chelate Ring ◽  
Ruthenium Complex ◽  
Structural Motif ◽  
X Ray Diffraction ◽  
Quinoxaline Derivative ◽  
Imidazolium Salt ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Complex Fragment

The reaction of the 2,3-dianilino-quinoxaline 1 with an equivalent of triethyl orthoformiate results in a cyclic aminalester 2. An excess of triethyl orthoformate results in the carbene dimer 4. With the help of boron trifluoride, 2 can be transformed into the imidazolium salt 3. Reaction of 1 with KOtC4H9 leads to a quinoxaline derivative 5 under anellation of a benzene ring whereas the related pyrazino-quinoxaline 6 (formed from tetraaminobenzene tetrahydrochloride and bis-(3- trifluoromethylphenyl) oxalimidoyl chloride) does not react under similar conditions. However, 6 can be activated towards anellation by employing the complex fragment [(tbbpy)2Ru]2+, tbbpy: bis(4,4’-di-tert-butyl-2,2’-bipyridine). This generates an unusual ruthenium complex 9 which could be characterised by X-ray diffraction. Complex 9 contains a pentacene derivative and coordinates the ruthenium fragment at the amidinate moiety thus forming a four-membered chelate ring. Isolation of a second ruthenium complex 8 which contains an intact pyrazino-quinoxaline 6 in which the metal is also coordinated to an amidinato group supports the assumption that the anellation reaction occurs only after metal complexation at the amidinate group. In contrast to this, the smaller [(tmeda)2Pd]2+ fragment reacts with the pyrazino-quinoxaline 6 to form the mononuclear Pd complex 10. Its structural motif (X-ray diffraction) shows that the palladium centre coordinates at the 1,4-diamino group of the intact pyrazino-quinoxaline to form a five-membered chelate ring. This suggests that the bulkiness of the complex fragment determines whether or not an anellation reaction can take place.

N–O Bond Cleavage During the Deprotonation of N,O-Bis(trimethylsilyl)hydroxylamine

2008 ◽  
Vol 63 (3) ◽  
pp. 339-341 ◽  
Author(s):  
Ajay Venugopal ◽  
Alexander Willner ◽  
Norbert W. Mitzel
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Bond Cleavage ◽  
State Structure ◽  
X Ray Diffraction ◽  
Solid State Structure ◽  
X Ray ◽  
Potassium Hydride ◽  
Oxygen Atoms

The reaction of N,O-bis(trimethylsilyl)hydroxylamine with potassium hydride in pentane affords a product of the formula {K6[OSiMe3]4[ON(SiMe3)2]2}, resulting from deprotonation followed by N-O bond cleavage and 1,2-silylshift. The compound was characterised by elemental analysis and by single crystal X-ray diffraction. The aggregate consists of a K3O3 bis-cubane core, with N(SiMe3)2 groups at the oxygen atoms shared by the two cubes, andMe3Si groups attached to the four O vertices. Two weak K···N interactions are also detected in the solid state structure.

scholarly journals Synthesis and Characterization of New Diiron and Diruthenium μ-Aminocarbyne Complexes Containing Terminal S-, P- and C-Ligands

2007 ◽  
Vol 62 (3) ◽  
pp. 427-438 ◽  
Author(s):  
Vincenzo G. Albano ◽  
Luigi Busetto ◽  
Fabio Marchetti ◽  
Magda Monari ◽  
Stefano Zacchini ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Diffraction Study ◽  
Coordination Mode ◽  
Bond Cleavage ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dithiocarbamate Ligand ◽  
High Yields

The diiron aminocarbyne complexes [Fe2{μ-CN(Me)(R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (R = Xy1, 1a; R = Me, 1b; R = CH2Ph, 1c; Xy1 = 2,6-Me2C6H3) undergo replacement of the coordinated nitrile by halides, diethyldithiocarbamate, and dicyanomethanide to give [Fe2{μ-CN(Me) (R)}(μ-CO)(CO)(X)(Cp)2] complexes (R = Me, X = Br, 4a; R = Me, X = I, 4b; R = CH2Ph, X = Cl, 4c; R = CH2Ph, X = Br, 4d; R = CH2Ph, X = I, 4e; R = Xy1, X = SC(S)NEt2, 5a; R = Me, X = SC(S)NEt2, 5b; R = Xy1, X = CH(CN)2, 7), in good yields. The molecular structure of 5a shows an unusual η1 coordination mode of the dithiocarbamate ligand. Similarly, treatment of [M2{μ-CN(Me) (R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (M = Fe, R = Xy1, 1a; M = Fe, R = Me, 1b; M = Ru, R = Xy1, 2a; M = Ru, R = Me, 2b) with a series of phosphanes generates the cationic complexes [M2{μ- CN(Me)(R)}(μ-CO)(CO)(P)(Cp)2][SO3CF3] (M = Fe, R = Xy1, P = PPh2H, 6a; M = Fe, R = Xy1, P = PPh3, 6b; M = Fe, R = Xy1, P = PMe3, 6c; M = Fe, R = Me, P = PMe2Ph, 6d; M = Fe, R = Me, P = PPh3, 6e; M = Fe, R = Me, P = PMePh2, 6f; M = Ru, R = Xy1, P = PPh2H, 6g; M = Ru, R = Me, P = PPh2H, 6h), in high yields. The molecular structure of 6a has been elucidated by an X-ray diffraction study. The reactions of [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(NCR′)(Cp)2][SO3CF3] [R′ = Me, 1a; R′ = tBu, 3] with PhLi and PPh2Li yield [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(Ph)(Cp)2] (8) and [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(PPh2)(Cp)2] (9), respectively. The molecular structure of 8 has been ascertained by X-ray diffraction. Conversely, the reaction of 1a with MeLi generates the aminoalkylidene compound [Fe2{C(Me)N(Me)(Xy1)}(μ-CO)2(CO)(Cp)2] (10).Finally, the acetone complex [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(OCMe2)(Cp)2][SO3CF3] (12) reacts with lithium acetylides to give complexes [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(C≡CR)(Cp)2] (R = p-C6H4Me, 11a; R = Ph, 11b; R = SiMe3, 11c), in high yields. Filtration through alumina of a solution of 11a in CH2Cl2 results in hydration of the acetylide group and C-Si bond cleavage, affording [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO){C(O)Me}(Cp)2] (12).

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