Characterization and electronic structures of trigonal-bipyramidal nickel(II) complexes

Chastain, Ben B.; Rick, E. A.; Pruett, Roy L.; Gray, Harry B.

doi:10.1021/ja01017a015

Cited by 44 publications

(17 citation statements)

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“…Based on the reduced 2 test (26), the best fit among all considered models was obtained for a nickel ion coordinated by three sulfur atoms at ϳ2.20 or ϳ2.23 Å and one CN group with a Ni-C distance of 1.81 or 1.84 Å for CODH-CN a and CODH-CN b , respectively ( Table 1). The refined Ni-C and C-N bond lengths are consistent with Ni 2ϩ complexes with cyanide ligands (29). Assuming Ni-C distances of 1.81 or 1.84 Å, Ni-N distances of 3.00 Å, and C-N distance in cyanide of 1.15-1.18 Å (29, 30), cyanide binds to the nickel ion of cluster C by its carbon atom in a linear fashion.…”

Section: Xas Of Dithionite-reduced Codhii Ch Reversiblysupporting

confidence: 56%

Interaction of Potassium Cyanide with the [Ni-4Fe-5S] Active Site Cluster of CO Dehydrogenase from Carboxydothermus hydrogenoformans

Korbas

Klepsch

et al. 2007

Journal of Biological Chemistry

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It has been assumed that CODHII Ch catalyzes the oxidation of CO at the Ni-( 2 S)-Fe1 subsite of cluster C (3). The prime candidate for CO binding is the nickel ion because of its facile accessibility through the substrate channel and its empty apical coordination site (3). Fe1 is the presumed OH Ϫ donor ligand in CO 2 formation (3, 6). The CODH Oc from the aerobic bacterium Oligotropha carboxidovorans oxidizes CO at the Mo-( 2 S)-Cu subsite of the [Cu-S-MoO 2 ] active site, in which copper and molybdenum are bridged by a cyanolyzable sulfane 2 S (7, 8). The enzyme is inactivated when 2 S is removed and reactivated when 2 S is reinserted (9). The Mo-( 2 S)-Cu subsite resembles the Ni-( 2 S)-Fe1 bridge in cluster C of CODHII Ch . The mechanism of CO oxidation based on the x-ray structure of [Cu-S-MoO 2 ] CODH Oc with bound inhibitor n-butyl isocyanide involves a thiocarbonate-like intermediate state and proposes the binding of CO between the 2 S and copper (equivalent to nickel in CODHII Ch ) and the binding of an OH Ϫ group at molybdenum (equivalent to Fe1 in CODHII Ch ) (7).Structures of cluster C of Ni-Fe CODHs from Rhodospirillum rubrum (CODH Rr ) (10) and Moorella thermoacetica (CODH Mt ) (11, 12) also showed the positions of the five metal ions in cluster C of CODHII Ch but did not reveal the bridging 2 S. Since sodium sulfide was found to inhibit CODH Rr and CODH Mt , it has been concluded that cluster C with the bridging 2 S, as has been observed in CODHII Ch from C. hydrogenoformans (3, 4), might represent an inhibited form (13). On the other hand, it has been shown that the [Ni-4Fe-4S] cluster miss-

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Section: Xas Of Dithionite-reduced Codhii Ch Reversiblysupporting

confidence: 56%

Interaction of Potassium Cyanide with the [Ni-4Fe-5S] Active Site Cluster of CO Dehydrogenase from Carboxydothermus hydrogenoformans

Korbas

Klepsch

et al. 2007

Journal of Biological Chemistry

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“…It may be noted, however, that the square-pyramidal arrangement of donor atoms is preserved in these five-coordinate systems and that this arrangement leads to more effective bonding between the metal and the other ligands in the complex than does the other five-coordinate geometry, the trigonal bipyramid. 42 The structure of RuH (NO) (P (C8H5) 3) 3 illustrates that a stable alternative to the tetragonal pyramid-bent nitrosyl structure is indeed open to 22electron nitrosyl complexes whereby the placement of electrons into a strongly antibonding level is avoided through a change in the ligand field geometry about the metal ion. In the trigonal-bipyramidal geometry of essentially C3o symmetry, the significant metalnitrosyl tt interaction is preserved, but the effectiveness of the metal-ligand bonding in the rest of the structure is somewhat diminished.…”

Section: Discussionmentioning

confidence: 99%

Crystal and molecular structure of the catalytically active complex hydridonitrosyltris(triphenylphosphine)ruthenium, RuH(NO)(P(C6H5)3)3

Pierpont¹,

Eisenberg²

1972

Inorg. Chem.

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This was accomplished by preparing the isotopically labeled complex [RuCl(14NO) (16NO) (P(C6H6)3)2 ] + and monitoring the r(NO) values in the infrared spectrum. Our structure determination of the related complex [Ru(NO) (diphos) 2 ]+,15 which possesses a linear nitrosyl in the equatorial position of a trigonal bipyramid, suggests a very simple and plausible pathway by which the interconversion of the two nitrosyl groups in the present structure is effected. This suggested jnechanism is illustrated below. The scrambling of the labeled Cortlandt G. Pierpont and Richard Eisenberg nitrosyl ligand occurs through a trigonal-bipyramidal intermediate with equivalent linear (or slightly bent) nitrosyl groups in the equatorial plane.Acknowledgments.-We wish to thank the National Science Foundation (Grant GP-23139) and the Advanced Research Projects Agency for support of this work. We also wish to thank Mr. Donald G. Van Derveer and Mr. William Durland for their help in bringing this problem to fruition.

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“…Studies have revealed that both steric54 and electronic55 factors play a role in determining whether a d 8 complex will be four‐ or five‐coordinate. Larger ligands will favor the four‐coordinate form so as to minimize steric interactions.…”

Section: Halide Ligands and Stoichiometric Processesmentioning

confidence: 99%

Halide Effects in Transition Metal Catalysis

Fagnou

Lautens

2002

Angew. Chem. Int. Ed.

492

286

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Among the most common ligands found on transition metal catalysts are halide ions. Of the commercially available catalysts or pre‐catalysts, most are halo–metal complexes. In recent years, manipulation of this metal‐halide functionality has revealed that this can be used as a highly valuable method of tuning the reactivity of the complex. Variation of the halide ligand will usually not alter the nature of the system to the extent that it becomes unreactive but will impart sufficiently large changes that differences in reactivity or selectivity occur. These differences are a product of the steric and electronic properties of the halide ligand which has the ability to donate electron density to the metal occurs in a predictable manner. Despite the common perception in asymmetric catalysis that halide ligands are of secondary importance compared to chiral ligands, halide ligands have been found to exert dramatic effects on the enantioselectivity of asymmetric transformations. While the mechanism of action is known for relatively few of the cases, many intriguing and potentially synthetically useful trends are apparent. This review discusses the physical properties of the halides and their effects on stoichiometric and catalytic transition metal processes. The metal‐halide moiety thus emerges as a tunable functionality on the transition metal catalyst that can be used in the development of new catalytic systems.

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Characterization and electronic structures of trigonal-bipyramidal nickel(II) complexes

Cited by 44 publications

References 1 publication

Interaction of Potassium Cyanide with the [Ni-4Fe-5S] Active Site Cluster of CO Dehydrogenase from Carboxydothermus hydrogenoformans

Interaction of Potassium Cyanide with the [Ni-4Fe-5S] Active Site Cluster of CO Dehydrogenase from Carboxydothermus hydrogenoformans

Crystal and molecular structure of the catalytically active complex hydridonitrosyltris(triphenylphosphine)ruthenium, RuH(NO)(P(C6H5)3)3

Halide Effects in Transition Metal Catalysis

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