Substituents drive ligand rearrangements, giving dinuclear rather than mononuclear complexes, and tune CoII/III redox potential

2018 ◽  
Vol 47 (34) ◽  
pp. 11749-11759 ◽  
Author(s):  
Fabrice N. H. Karabulut ◽  
Humphrey L. C. Feltham ◽  
Sally Brooker

Sterically encumbered 6-halo-substituents lead to BF4/MeOH/ligand rearrangement, forming doubly bridged {Co1–[O(Me)–B(F2)–O(R)]2–Co1A} dinuclear complexes (6-Cl, 6-Br) of the modified ligands.

2019 ◽  
Vol 48 (33) ◽  
pp. 12755-12756
Author(s):  
Fabrice N. H. Karabulut ◽  
Humphrey L. C. Feltham ◽  
Sally Brooker

Correction for ‘Substituents drive ligand rearrangements, giving dinuclear rather than mononuclear complexes, and tune CoII/III redox potential’ by Fabrice N. H. Karabulut et al., Dalton Trans., 2018, 47, 11749–11759, DOI: 10.1039/c8dt01502c.


1985 ◽  
Vol 40 (10) ◽  
pp. 1243-1249 ◽  
Author(s):  
Henri Brunner ◽  
Alfons Knott

The chelate phosphanes Diphos, Diop, and Norphos were reacted with C5H5Mn(CO)2THF and CH3C5H4Mn(CO)2THF to give mononuclear complexes, containing the phosphanes as unidentate or as bidentate ligands, and dinuclear complexes, containing bridging phosphane ligands. In C5H5Mn(CO)2Diop one of the two P(C6H5)2 groups of Diop is coordinated to the C5H5Mn(CO)2 fragment; the uncoordinated P(C6H5)2 group makes it a monodentate ligand. C5H5Mn(CO)2Diop together with [Rh(cod)Cl]2 was used as an in situ catalyst in the enantioselective hydrogenation of (Z)-a-[N -acetam ino]cinnamic acid (78.4% ee) and in the enantioselective hydrosilylation of acetophenone with diphenylsilane (6.7% ee).


1998 ◽  
Vol 53 (11) ◽  
pp. 1379-1385 ◽  
Author(s):  
Berthold Kersting

The syntheses of N-alkylated derivatives of the arenethiol 4-tert-butyl-2,6-(diaminomethyl)- thiophenol and their coordination properties are reported. Compounds 4-tert-butyl-2,6-di(N-isopropyl- aminomethyl)thiophenol (3) and 4-tert-butyl-2-(N-isopropyl-aminomethyl)-6-hydroxymethylthiophenol (6 ) react with Ni(II) salts to give compounds of composition [Ni(3)2]·2HCl (7) and [Ni(6)2] (8). The solid- and solution-state structures of both complexes consist of mononuclear complexes with four-coordinate nickel(II) ions in approximately planar trans- N2S2 coordination environments. In contrast to the parent arenethiol 4a, the sterically more encumbered ligands do not form dinuclear complexes.


1992 ◽  
Vol 47 (11) ◽  
pp. 1571-1579 ◽  
Author(s):  
Falk Olbrich ◽  
Bärbel Zimmer ◽  
Michael Kastner ◽  
Carl von Schlabrendorff ◽  
Gottlieb Vetter ◽  
...  

X-ray analysis shows silver(I) aminomethylnitrosolate to have dimers as structural units, in which the W-shaped nitrosolate ions act as μ2-bridging ligands via the nitrogen atoms of the NO groups. The nearly planar dinuclear complexes form stacks, which are connected by additional AgO contacts leading to a kind of layer structure. These layers are held together by hydrogen bonds.Mononuclear complexes of composition [Ag(nitrosolate)L2] can be obtained from silver(I) ethylnitrosolate and bipyridyl in methanol and from silver(I) benzylnitrosolate and triphenylphosphane in diethylether/liquid ammonia. In these complexes the nitrosolate ions are supposed to act as chelating ligands, again with N,N′-coordination.


1995 ◽  
Vol 50 (4) ◽  
pp. 448-459 ◽  
Author(s):  
Jörg J. Schneider ◽  
Richard Goddard ◽  
Carl Krüger

The homonuclear cobalt cluster [(η5-Cp*)Co]3H4 2 reacts with various organic and inorganic substrates with complete degradation of the cluster core to afford mainly mononuclear organometallic cobalt compounds. Thus, whereas reaction of the cluster with CO, NO or alkynes results in the retention of the Co3 ring, the cluster reacts with Br2, I2, I2/CO , I2/ P(C 2H5)3, CCl4, HCI3, (CH2)2Br2, Hacac, CH2Br2, (C6H5CO)OOC(CH3)3, HBF4, and BrCN to give mononuclear complexes or bridged dinuclear complexes without a metal-metal bond. In all cases formal oxidation of the metal center is observed. The crystal structures of six organocobalt complexes have been determined by X-ray crystallography.


1979 ◽  
Vol 34 (4) ◽  
pp. 599-605 ◽  
Author(s):  
Wolfgang Malisch ◽  
Reinhard Janta ◽  
Günter Künzel

Abstract The transition metal arsines C5H5(CO)2LM-As(CH3)2 (M = Mo, W; L = CO, P(CH3)3) react with elementary sulfur (selenium) in CS2 to give the transition metal substituted arsine chalcogenides C5H5(CO)2LM-As(CH3)2S(Se). Due to the pronounced basicity of the chalcogen centre they are easily converted into cationic mononuclear complexes [trans-C5H5(CO)2P(CH3)3Mo-As(CH3)2SR]⊕X⊖ by alkylhalides, and into bridged dinuclear complexes tans-C5H5(CO)2P(CH3)3Mo-As(CH3)2S-MLn on treatment with THF · Cr(CO)5 or AgI. The structures of the new compounds are established by spectroscopic investigations.


1995 ◽  
Vol 50 (3) ◽  
pp. 368-376 ◽  
Author(s):  
Uwe Rosenthal ◽  
Siegmar Pulst ◽  
Perdita Arndt ◽  
Wolfgang Baumann ◽  
Annegret Tillack ◽  
...  

It has been shown that disubstituted butadiynes react with L2Ni(C2H4) to yield mononuclear complexes L2Ni(η2(1:2 )-RC≡C -C ≡CR) (L = o-Tol-O)3P, R = SiMe3 (1), tBu (2), Ph (3)). For the first time, the crystal structure of a nickel(O) alkyne complex carrying phosphite ligands (2) has been determined. The reaction of (dipy)Ni(cod) (L2 = dipy) with butadiynes R'C ≡ C -C ≡ CR is strongly influenced by the substituents of the butadiyne. With R' = R = SiMe3 (4), tBu (5) and Ph (6) or R' = Ph, R = SiMe3 (7) and R ' = tBu, R = SiMe3 (8) mononuclear complexes (dipy)Ni(η2(1:2 )-R'C ≡ C-C ≡ CR ) have been observed. Depending on the stoichiometry with R = R' = Ph (9) and tBu (10) dinuclear complexes {(dipy)Ni}2(μ-η2(1:2),η2(3 :4 )-R'C ≡ C -C ≡ CR ) having two Ni atoms coordinated to two C ≡ C triple bonds were obtained. By contrast, with R' = R = SiMe3 (11), R' = tBu, R = SiMe3 (12) and R' = Ph, R = SiMe3 (13) the two Ni-centers were found to coordinate to the same C≡C triple bond to yield another type of a dinuclear complex {(dipy)Ni}2(μ-η2(1:2),η2(1:2 )-R'C ≡ C -C ≡C R). Compound 5 has been characterized by Xray crystal structure analysis. The structures of 2 and 5 are compared to that of the wellknown complex (Ph3P)2Ni(η2(1:2 )-tBuC ≡ C-C ≡CtBu) [1] to study the influence of different ligands L on the structural details. In comparison to the alkyne complexes L2Ni(η2-RC≡CR) in butadiyne complexes of the L2Ni(η2(1:2 )-R'C ≡ C-C ≡ CR ) type there is only a slight effect of the different ligands. The uncomplexed C ≡ C triple bond as a part of the second substituent in conjugation to the complexed C ≡ C triple bond appears to level out the influence of ligands and substituents.


1995 ◽  
Vol 50 (3) ◽  
pp. 377-384 ◽  
Author(s):  
Uwe Rosenthal ◽  
Siegmar Pulst ◽  
Perdita Arndt ◽  
Wolfgang Baumann ◽  
Annegret Tillack ◽  
...  

It has been shown that disubstituted butadiynes react with (Ph3P)2Ni(C2H4) [1] or (cod)2Ni [2] in the presence of Ph3P to yield mononuclear complexes (Ph3P)2Ni(η2(1 :2 ) - R'C ≡ C - C ≡CR) (R' = R = SiMe3 (1), tBu (2) Ph (3) and R' = tBu, R = SiMe3 (4) or R' = Ph, R = SiMe3 (5)) or dinuclear complexes {(Ph3P)2Ni}2(μ-η2(1 :2),η2(3 :4) - R'C ≡C - C ≡CR ) (R' = R = SiMe3 (6), Ph (7)) depending on the stoichiometry applied. For R' = R = tBu or R' = tBu, R = SiMe3 the dinuclear complexes could not be obtained. Some of the mononuclear complexes with symmetrical (R' = R = SiMe3, tBu, Ph) and unsymmetrical disubstituted (R' = tBu, R = SiMe3) butadiynes have been characterized by X-ray crystal structure analysis to study the influence of different substituents on the structural details of the bonding. As compared to the alkyne complexes (Ph3P)2Ni(η2-RC ≡CR ) the influence of the different substituents in mononuclear butadiyne-complexes (Ph3P)2Ni(η2(1:2) - R'C ≡C - C ≡CR ) is strongly diminished by the conjugated uncomplexed C ≡C triple bond.


1997 ◽  
Vol 52 (6) ◽  
pp. 679-686 ◽  
Author(s):  
Thomas Häusler ◽  
William S. Sheldrick

Abstract A metal-assisted ring expansion from the preferred solution species (EtAsO)n, n = 3,4, to the hexameric ligand (EtAsO)6 is observed for the reactions of [ReBr(CO)5], [RuCL2(Ph3P)3], RhCl3 ·3H2O and [Cu2CF3SO3)2(C6H6)] with ethylcycloarsoxane. Whereas two metal frag­ments are facially coordinated by the upper and lower three As atoms of a flattened As6O6 cuboctahedron in both [{ReBr(CO)2}2 {μ-[cyclo-(EtAsO)6]}] (1) and [Cu2{μ-[cyclo-(EtAsO)6]}(Me2PhP)2](CF3SO3)2 (4), potential ring strain restricts the reaction with the other compounds to the formation of mononuclear complexes [RuCl2{cyvclo-(EtAsO)6}(Ph3P)] (2)and [RhCl3{cyclo-(EtAsO)6}] (3) with k3As1,3,5 coordination. The structures of 1 - 4 were established by X-ray structure analysis. A shift in the ν(As-O) IR absorption bands to higher wavenumbers (830 - 788 cm-1 ) is characteristic for (EtAsO)6 complexes in comparison to those of the cyclic tetramer (781-747 cm-1 ).


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