The Chemistry of the Dithioacid and 1, 1‐Dithiolate Complexes, 1968–1977

Coucouvanis, D.

doi:10.1002/9780470166277.ch5

Cited by 337 publications

(9 citation statements)

References 443 publications

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“…One motivation for using oxygen donor ligands to build a chiral bis(L- -X) 2 M d 4 moiety comparable to (dtc) 2 W(CO) 3 was to use a more robust fragment as an auxiliary. The rich chemistry of (dtc) 2 WL 3 includes sulfur redox chemistry, evident in unwanted dtc C−S cleavage reactions. − We chose to investigate acac to better control both electronic and steric factors around the metal center and to avoid the undesirable reactivity of the sulfur donor chelates. Acetylacetonate was an attractive choice because of its ease of preparation and storied history.…”

Section: Introductionmentioning

confidence: 99%

Bis(acetylacetonato)tricarbonyl Tungsten(II): A Convenient Precursor to Chiral Bis(acac) Tungsten(II) Complexes

2006

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Two equivalents of acetylacetonate (acac) have been successfully introduced into a monomeric tungsten(II) coordination sphere. With the tetracarbonyltriiodotungsten(II) anion as a precursor, the formation of a tungsten(II) bis(acac) tricarbonyl complex, W(CO)3(acac)2, 1, has been accomplished. The addition of PMe3 or PMe2Ph to tricarbonyl complex 1 formed tungsten(II)bis(acac)dicarbonylphosphine complexes 2a and 2b, respectively. Single-crystal X-ray diffraction studies of the parent tricarbonyl complex, 1, and dicarbonyl trimethylphosphine complex 2a confirmed seven-coordinate geometries for both complexes. Variable-temperature 1H and 13C{1H} NMR spectroscopy revealed fluxional behavior for these seven-coordinate molecules: rapid exchange of the three carbon monoxide ligands in 1 was observed, and movement of the phosphine ligand through a mirror plane in a C(S) intermediate species was observed for both 2a and 2b. Tricarbonyl complex 1 reacted readily with alkyne reagents to form bis(acac)monocarbonylmonoalkynetungsten(II) complexes 3a (PhC(triple bond)CH) and 3b (MeC(triple bond)CMe). Variable-temperature 1H NMR spectroscopy was used to probe rotation of the alkyne ligand in 3a and 3b. The introduction of two alkyne ligands was accomplished thermally using excess PhC(triple bond)CPh to form bis(alkyne) complex 4 which was characterized crystallographically, as well as by 1H and 13C NMR spectroscopy. The availability of W(CO)3(acac)2 as a source of the W(acac)2 d4 moiety lies at the heart of the chemistry reported here.

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Section: Introductionmentioning

confidence: 99%

Bis(acetylacetonato)tricarbonyl Tungsten(II): A Convenient Precursor to Chiral Bis(acac) Tungsten(II) Complexes

2006

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“…Transition metal complexes containing unsaturated dithiolato ligands attract considerable attention because of their electronic, magnetic, and redox properties . Although 1,1-ethylenedithiolato complexes have been studied less than their 1,2 isomers, they show interesting photophysical properties, , including solvatochromic behavior and luminescence, and are thus potential photocatalysts in light-to-chemical energy conversion . Additionally, 1,1-ethylenedithiolato ligands display a great variety of coordination modes, being able to form homo- 7 or heteropolynuclear complexes 8 and clusters 9 and to stabilize high oxidation states .…”

mentioning

confidence: 99%

Dancing of Palladacycles around a “Juggler” 2,2-Diacetyl-1,1-Ethylenedithiolato Ligand in a Trinuclear Pd(II) Complex

et al. 2006

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A trinuclear Pd complex containing a mu3-1,1-ethylenedithiolato ligand has been synthesized and its structure confirmed by X-ray crystallography. It is the first example of a 1,1-ethylenedithiolato complex containing an anionic carbon sigma donor. This compound shows an unprecedented fluxional behavior in solution, by which the three palladacycles exchange around the dithiolene. The activation parameters for this process have been derived by NMR line shape analysis, and a mechanism is proposed.

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“…This has been driven partly by the ease of formation of dithiocarbamates from (usually secondary) amines in the presence of base and carbon disulfide . The fact that dithiocarbamate compounds are known for their ability to coordinate to all of the transition metals in all common oxidation states (both high and low) indicates the vast potential that dithiocarbamates with additional functionality could promise. , …”

Section: Introductionmentioning

confidence: 99%

Metallostar Assemblies Based on Dithiocarbamates for Use as MRI Contrast Agents

et al. 2020

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Two different octadentate gadolinium chelates based on DO3A and DOTAGA chelates (hydration number q = 1) have been used to prepare a series of bi-, tri-and tetrametallic d-f mixed-metal complexes. The piperazine-based dithiocarbamate linker ensures that rotation of the gadolinium chelates is restricted, leading to enhanced relaxivity (r1) values, which increase with overall mass and the number of gadolinium units. The r1 value (at 10 MHz, 25 °C) per Gd unit rises from 5.0 mM −1 s −1 for the Gd-DO3A-NH2 monogadolinium chelate to 9.2 mM −1 s −1 in a trigadolinium complex with a ruthenium(III) core. Using a 1.5 T clinical scanner operating at 63.87 MHz (25 °C), an 86% increase in relaxivity per gadolinium unit is observed for this multimetallic compound compared to clinically-approved Dotarem. The gadolinium complexes based on the DOTAGA chelate also performed well at 63.87 MHz, with a relaxivity value of 9.5 mM −1 s −1 per gadolinium unit being observed for the trigadolinium d-f mixed-metal complex with a ruthenium(III) core. The versatility of dithiocarbamate coordination chemistry thus provides access to a wide range of d-f hybrids with potential for use as high-performance MRI contrast agents.

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The Chemistry of the Dithioacid and 1, 1‐Dithiolate Complexes, 1968–1977

Cited by 337 publications

References 443 publications

Bis(acetylacetonato)tricarbonyl Tungsten(II): A Convenient Precursor to Chiral Bis(acac) Tungsten(II) Complexes

Bis(acetylacetonato)tricarbonyl Tungsten(II): A Convenient Precursor to Chiral Bis(acac) Tungsten(II) Complexes

Dancing of Palladacycles around a “Juggler” 2,2-Diacetyl-1,1-Ethylenedithiolato Ligand in a Trinuclear Pd(II) Complex

Metallostar Assemblies Based on Dithiocarbamates for Use as MRI Contrast Agents

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