Acetylenic Dicobalt Hexacarbonyls. Organometallic Compounds Derived from Alkynes and Dicobalt Octacarbonyl<sup>1,2</sup>

Greenfield, Harold; Sternberg, Heinz W.; Friedel, R. A.; Wotiz, John H.; Markby, Raymond; Wender, I.

doi:10.1021/ja01582a036

Cited by 245 publications

(123 citation statements)

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“…The butterfly structures with a direct metal-metal bond are predicted to be nearly isoenergetic to open structures without a Co-Co bond. Unsuccessful attempts to optimize a previously proposed Co 2 (CO) 6 (μ-η 2 :η 2 -S 2 R 2 ) structure with a central Co 2 S 2 tetrahedrane unit with one Co-Co bond, one S-S bond, and four Co-S bonds are consistent with the previous reformulation of the originally claimed Co 2 S 2 tetrahedranes Co 2 (CO) 6 [μ-η 2 :η 2 -S 2 (C 6 X 5 ) 2 ] (X = F, Cl) as the trinuclear derivatives Co 3 (μ 3 -S)-(C 6 F 5 )(CO) 8 .…”

Section: Introductionsupporting

confidence: 91%

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Metal–Metal Bonding in Bis(alkylthio)hexacarbonyldicobalt Complexes: Open Structures vs. Butterfly and Tetrahedrane Structures

2011

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Density functional calculations on the Co 2 (CO) 6 (SR) 2 compounds (R = CH 3 , CF 3 ) predict both open and butterfly structure types of similar energies. The open Co 2 (CO) 6 (μ-SR) 2 structures have non-planar central Co 2 S 2 units with two bridging RS groups and ca. 3.4 Å Co···Co distances indicating a lack of direct metal-metal bonding. The butterfly Co 2 (CO) 5 (μ-SR)(μ-CO)(SR) structures have direct Co-Co bonds of lengths ca. 2.5 Å forming the "body" of the butterfly, one terminal RS group, one bridging RS group, and one bridging CO group. The lowest energy Co 2 (CO) 6 (SCH 3 ) 2 structure is an open isomer. However, this open isomer lies only 0.4 kcal/mol below the corresponding butterfly isomer. For the corresponding fluorinated derivative Co 2 (CO) 6 -(SCF 3 ) 2 a butterfly structure with a direct Co-Co bond and a bridging CO group lies at a slightly lower energy than the lowest energy open structures. The relative energy differ-

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Section: Introductionsupporting

confidence: 91%

“…At that time Hieber and Spacu also reported an analogous reaction of Co 2 (CO) 8 with benzenethiol to give a product formulated as Co 2 (CO) 6 -(SC 6 H 5 ) 2 .…”

Section: Introductionmentioning

confidence: 97%

Metal–Metal Bonding in Bis(alkylthio)hexacarbonyldicobalt Complexes: Open Structures vs. Butterfly and Tetrahedrane Structures

2011

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“…Cobalt alkyne complexes had been described for the first time by Greenfield et al [25] and have found application in synthetic organic chemistry in form of the Pauson-Khand and Nicholas reaction since that [26 -29].…”

Section: Cobalt Compoundsmentioning

confidence: 99%

Non Platinum Metal Complexes as Anti‐cancer Drugs

Ott¹,

Gust

2007

Archiv der Pharmazie

544

403

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The development of metal complexes with platinum central atoms such as cisplatin or carboplatin had an enormous impact on current cancer chemotherapy. However, the spectrum of cancers that can be treated with platinum agents is narrow and treatment efficacy suffers from side effects and resistance phenomena. These unresolved problems in platinum-based anti-cancer therapy have stimulated increased research efforts in the search for novel non platinum-containing metal species as cytostatic agents. Preclinical and clinical investigations showed that the development of new metal agents with modes of action different from cisplatin is possible. Thus, complexes with iron, cobalt, or gold central atoms have shown promising results in preclinical studies and compounds with titanium, ruthenium, or gallium central atoms have already been evaluated in phase I and phase II trials. This review covers some relevant examples of preclinical and clinical research on novel non platinum metal complexes.

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“…The Mn 2 C 2 tetrahedron in 20-7 is analogous to the Co 2 C 2 tetrahedron found in the well-known [(alkyne)-Co 2 (CO) 6 ] complexes, first synthesized in 1956. [53][54][55] In the [Cp 2 Mn 2 (CS) 2 ] triplet 20-2T with no Mn-Mn bond, the Mn 2 C 2 unit forms a butterfly structure (two triangles sharing an edge) and each manganese atom has a formal 15-electron configuration. There is also an alternative model for the bonding of the bridging acetylenedithiolate ligand to the two manganese atoms in 20-2T and 20-7, if there is additional involvement of one of the two lone pairs on each sulfur atom in the manganese-sulfur bonding ( Figure 9).…”

Section: Discussionmentioning

confidence: 99%

Binuclear Cyclopentadienylmanganese Carbonyl Thiocarbonyls: Four‐Electron Donor Bridging Thiocarbonyl Groups of Two Types and a Bridging Acetylenedithiolate Ligand

Zhang

Xie

et al. 2010

Eur J Inorg Chem

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As a starting point, the mononuclear cyclopentadienylmanganese carbonyl thiocarbonyls [CpMn(CS)(CO)n] (Cp = η5‐C5H5; n = 2, 1, 0) and binuclear derivatives [Cp2Mn2(CS)2(CO)n] (n = 3, 2, 1, 0) have been studied by density functional theory (DFT). For coordinately saturated binuclear [Cp2Mn2(CS)2(CO)3], the four electron donor end‐on CE(E = O, S) bridged structures are preferred energetically over the normal CE (E = O, S) bridged structures, analogous to [Cr2(CS)2(CO)9]. The lowest energy structure for [Cp2Mn2(CS)2(CO)2] has one four‐electron donor bridging η2‐μ‐CS group. However, this structure is thermodynamically unstable with respect to disproportionation into [Cp2Mn2(CS)2(CO)3] and [Cp2Mn2(CS)2(CO)]. Only two structures are found for [Cp2Mn2(CS)2(CO)] as is the case for the carbonyl analogue [Cp2Mn2(CO)3]. The global minimum of [Cp2Mn2(CS)2(CO)], a singlet triply bridged structure, is very favorable energetically with respect to loss of a CO group, disproportionation into [Cp2Mn2(CS)2(CO)2] + [(Cp)2Mn2(CS)2], and dissociation into mononuclear fragments. The lowest energy structure for [Cp2Mn2(CS)2] is a triplet structure with two bridging CS groups and the Mn≡Mn triple bond required to give each Mn atom a 17‐electron configuration for a binuclear triplet. A higher energy singlet [Cp2Mn2(CS)2] structure is found with a very short MnblablaMn distance of about 2.1 Å suggesting the formal quadruple bond required to give each Mn atom the favored 18‐electron configuration. In other higher energy singlet and triplet [Cp2Mn2(CS)2] structures the two CS ligands have coupled to form an acetylenedithiolate ligand bridging the two manganese atoms.

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Acetylenic Dicobalt Hexacarbonyls. Organometallic Compounds Derived from Alkynes and Dicobalt Octacarbonyl^1,2

Cited by 245 publications

References 2 publications

Metal–Metal Bonding in Bis(alkylthio)hexacarbonyldicobalt Complexes: Open Structures vs. Butterfly and Tetrahedrane Structures

Metal–Metal Bonding in Bis(alkylthio)hexacarbonyldicobalt Complexes: Open Structures vs. Butterfly and Tetrahedrane Structures

Non Platinum Metal Complexes as Anti‐cancer Drugs

Binuclear Cyclopentadienylmanganese Carbonyl Thiocarbonyls: Four‐Electron Donor Bridging Thiocarbonyl Groups of Two Types and a Bridging Acetylenedithiolate Ligand

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Acetylenic Dicobalt Hexacarbonyls. Organometallic Compounds Derived from Alkynes and Dicobalt Octacarbonyl1,2

Cited by 245 publications

References 2 publications

Metal–Metal Bonding in Bis(alkylthio)hexacarbonyldicobalt Complexes: Open Structures vs. Butterfly and Tetrahedrane Structures

Metal–Metal Bonding in Bis(alkylthio)hexacarbonyldicobalt Complexes: Open Structures vs. Butterfly and Tetrahedrane Structures

Non Platinum Metal Complexes as Anti‐cancer Drugs

Binuclear Cyclopentadienylmanganese Carbonyl Thiocarbonyls: Four‐Electron Donor Bridging Thiocarbonyl Groups of Two Types and a Bridging Acetylenedithiolate Ligand

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Acetylenic Dicobalt Hexacarbonyls. Organometallic Compounds Derived from Alkynes and Dicobalt Octacarbonyl^1,2