Reaktionen der Bis(μ-hydrid-cyclopentadienyl-dicarbonyl-wolfram)-Komplexe [C5R5W(CO)2(μ-H)]2 (R = H, Me) mit SOCl2, Br2, I2, HCl, CF3COOH, PMe3, NO, ClNO und CS2

Alt, Helmut G.; Frister, Thomas; Trapl, Elli E.; Engelhardt, Heidi E.

doi:10.1016/0022-328x(89)85286-6

Cited by 10 publications

(3 citation statements)

References 31 publications

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“…Treatment of the methyl(pyridine)tungsten complex Cp*W(CO) 2 (py)Me with borane–NHC adducts gave NHC-stabilized hydrido(hydroborylene)tungsten complexes Cp*(CO) 2 W(H)(BH·NHC) ( 1a , NHC = Me IMe; 1b , NHC = Me I i Pr) as dark brown crystals in high yields accompanied by liberation of pyridine and methane (Scheme ). Complex 1a was thermally unstable and slowly decomposed at 60 °C in C 6 D 6 ( t 1/2 = 1 week) to give a complicated mixture including [Cp*W(CO) 2 ] 2 (29% NMR yield). On the other hand, no decomposition of 1b in C 6 D 6 was observed at 60 °C within 1 week.…”

Section: Resultsmentioning

confidence: 72%

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η³-Boraallyl Complexes

2017

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Reaction of the methyl(pyridine)tungsten complex Cp*(CO)2W(py)Me with borane–NHC (NHC = N-heterocyclic carbene; MeIMe, MeI i Pr) (MeIMe = 1,3,4,5-tetramethylimidazol-2-ylidene, MeI i Pr = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) adducts gave the NHC-stabilized hydrido(hydroborylene)tungsten complexes Cp*(CO)2W(H)(BH·NHC) (1a: NHC = MeIMe, 1b: NHC = MeI i Pr) as dark brown crystals in high yields accompanied by liberation of pyridine and methane. X-ray crystal structure analysis revealed that the W–B bond of 1b is bridged by a hydrido ligand. Reactions of 1a,b with phenylacetylene at room temperature afforded NHC-stabilized η3-boraallyl complexes 2a,b, respectively, through a new type of hydroboration of the alkyne triple bond: i.e., addition of a hydrogen and a borylene. Reaction of 1a with 3-butyn-2-one also led to hydroboration of the triple bond, not the CO double bond, to give η3-boraallyl complex 3. In the reaction of 1a with (trimethylsilyl)acetylene, 1-oxo-4-borabutenyl complex 4 was formed as a primary product through carboboration of the alkyne triple bond. The subsequent slow reaction of 4 at ambient temperature resulted in the formation of η3-boraallyl complex 5 and carbyne complex 6 in the ratio of 5:4. In all of these reactions, regioselective boration of the terminal carbon of alkynes was observed.

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Section: Resultsmentioning

confidence: 72%

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η³-Boraallyl Complexes

2017

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“…47 In our process the advantage is that the reaction time is less, there is no need of any solvent addition for performing the reaction and the isolation method of the desired complex is simple. In this context it would be worth mentioning that although SOCl 2 is known to oxidize various other metal centers by oxidative chlorination, [48][49][50][51][52][53] our reaction is the first report of the use of SOCl 2 for oxidative chlorination of the platinum centre. The sole relevant report in this regard is of a Pt(II) complex, where in the presence of SOCl 2 the ligand's -OH group converted to the -Cl group.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Anticancer activity of a chelating nitrogen mustard bearing tetrachloridoplatinum(iv) complex: better stability yet equipotent to the Pt(ii) analogue

et al. 2016

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Two Pt(iv) complexes cis,cis,trans-[Pt(IV)(L1)Cl4] (1a) & cis,cis,trans-[Pt(IV)(L2)Cl4] (2a) containing the nitrogen mustard moieties -N(CH2CH2Cl)2 & -NHCH2CH2Cl, were prepared in a single step from the Pt(ii) complexes containing -N(CH2CH2OH)2 (1) & -NHCH2CH2OH (2) moieties respectively using only thionyl chloride. The characterization of both the Pt(iv) complexes was performed by NMR, IR, UV and elemental analysis. Complex 1a was also characterized by single crystal X-ray diffraction. 1a crystallized in the I2/a space group. 1a exhibited much higher solution stability than 2a in kinetic studies by (1)H NMR. 1a shows a prodrug like activity as it converts to its Pt(ii) congener, [Pt(II)(L1)Cl2] (3) after 2 days in buffered solution. The binding experiment of 1a with model nucleobase 9-ethylguanine (9-EtG), showed that 1a converts to 3 and forms mono-adducts with 9-EtG. In the presence of reduced glutathione (GSH), the formation of 3 from 1a is quicker and upon the formation of 3 it binds almost instantaneously to GSH to form cis-[PtCl(L1)SG] (3c). Complex 3c transformed within a day to give a free aziridinium ion of L1 (3b) by dissociation. The in vitro cytotoxicity of the complexes and the clinical anticancer drug cisplatin show that 1a is potent against MCF-7, A549, HepG2 and MIA PaCa-2. The potency is highest against MIA PaCa-2 exhibiting an IC50 value of 4.4 ± 0.5 μM. The in vitro cytotoxicity data also showed that between the two complexes only 1a is active against MCF-7, A549 and MIA PaCa-2 in normoxia and hypoxia, both in the presence and absence of added GSH. Even in the presence of excess GSH in hypoxia, 1a exhibits significant cytotoxicity against MIA PaCa-2 and MCF-7 with IC50 values of 4.5 ± 0.3 and 11.2 ± 1.8 μM respectively. Platinum accumulation studies by ICP-MS display greater internalization of 1a, than 2a, 3 and cisplatin inside MCF-7 cells. 1a arrests cell cycle at the G2/M phase in MCF-7, exhibits capability to inhibit metastasis, induces apoptotic cell death and displays blood compatibility with human blood.

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“…Among organometallic species, only a few complexes with metal–metal multiple bonds have been reacted with NO so far. The 32-electron dihydride complexes [W 2 L 2 (μ-H) 2 (CO) 4 ] (L = η 5 -C 5 H 5 or Cp, C 5 Me 5 or Cp*) and [Mn 2 (μ-H) 2 (CO) 6 (μ-L′ 2 )] (L′ 2 = Ph 2 PCH 2 PPh 2 , (OEt) 2 POP(OEt) 2 ) reacted rapidly with NO, but just to give nitrosyl derivatives after displacement of H 2 and CO. , In contrast, an unusual nitrosyl dimerization takes place in the reaction of NO with the isoelectronic hydrides [Ru 2 (μ-H)(μ-P t Bu 2 )(CO) 4 (μ-Ph 2 PXPPh 2 )] (X = CR 2 , NR) to give hyponitrite derivatives which eventually release N 2 O upon protonation and heating . In the absence of bridging ligands, a metal–metal triple bond is likely to be fully cleaved by NO (rather than the opposite), as shown by reactions of the latter with tetracarbonyls [M 2 Cp* 2 (CO) 4 ] (M = Cr, Mo) to give the corresponding mononuclear nitrosyls [MCp*(CO) 2 (NO)] .…”

Section: Introductionmentioning

confidence: 99%

Reactions of the Unsaturated Ditungsten Complexes [W₂Cp₂(μ-PPh₂)₂(CO)_x] (x = 1, 2) with Nitric Oxide: Stereoselective Carbonyl Displacement and Oxygen-Transfer Reactions of a Nitrite Ligand

et al. 2014

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The dicarbonyl complex trans-[W2Cp2(μ-PPh2)2(CO)2] (Cp = η(5)-C5H5) reacted rapidly with NO (5% in N2) at 273 K to give selectively cis-[W2Cp2(μ-PPh2)2(NO)2]. In contrast, the analogous reactions of monocarbonyl [W2Cp2(μ-PPh2)2(μ-CO)] yielded either trans-[W2Cp2(μ-PPh2)2(NO)2] or the nitrito complex [W2Cp2(μ-PPh2)2(ONO)(CO)(NO)] (W-W = 2.9797(4) Å), depending on experimental conditions, with the latter presumably arising from reaction with trace amounts of oxygen in the medium. The stereoselectivity of the above reactions can be rationalized by assuming the participation of 33-electron [W2Cp2(μ-PPh2)2(CO)(NO)] intermediates which rapidly add a second molecule of NO via η(2)-C5H5 intermediates to eventually yield the corresponding dinitrosyls with inversion of the stereochemistry at the dimetal center, as supported by density functional theory (DFT) calculations. The nitrito complex was thermally unstable and evolved through oxygen transfer either to the carbonyl ligand, to yield the above dinitrosyls with release of CO2, or to the phosphide ligand, to give the phosphinito derivative cis-[W2Cp2(μ-OPPh2)(μ-PPh2)(NO)2], depending on experimental conditions. According to DFT calculations, the first process would involve transient dissociation/recombination of the nitrite ligand followed by coupling to carbonyl to give an intermediate with a chelate W{C,N-C(O)ON(O)} ring. Indeed, the nitrite ligand could be easily removed upon reaction of the nitrito complex with Na(BAr'4), but immediate decomposition also took place to render the electron-precise dicarbonyl [W2Cp2(μ-PPh2)2(CO)2(NO)]BAr'4 (W-W = 2.9663(3) Å) as the unique product (Ar' = 3,5-C6H3(CF3)2). Attempts to decarbonylate the latter complex photochemically yielded instead the oxo derivatives cis- and trans-[W2Cp2(μ-PPh2)2(O)(NO)]BAr'4 as the only isolable products (W-W = 2.980(2) and 3.0077(3) Å, respectively).

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Reaktionen der Bis(μ-hydrid-cyclopentadienyl-dicarbonyl-wolfram)-Komplexe [C5R5W(CO)2(μ-H)]2 (R = H, Me) mit SOCl2, Br2, I2, HCl, CF3COOH, PMe3, NO, ClNO und CS2

Cited by 10 publications

References 31 publications

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η³-Boraallyl Complexes

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η³-Boraallyl Complexes

Anticancer activity of a chelating nitrogen mustard bearing tetrachloridoplatinum(iv) complex: better stability yet equipotent to the Pt(ii) analogue

Reactions of the Unsaturated Ditungsten Complexes [W₂Cp₂(μ-PPh₂)₂(CO)_x] (x = 1, 2) with Nitric Oxide: Stereoselective Carbonyl Displacement and Oxygen-Transfer Reactions of a Nitrite Ligand

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Reaktionen der Bis(μ-hydrid-cyclopentadienyl-dicarbonyl-wolfram)-Komplexe [C5R5W(CO)2(μ-H)]2 (R = H, Me) mit SOCl2, Br2, I2, HCl, CF3COOH, PMe3, NO, ClNO und CS2

Cited by 10 publications

References 31 publications

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η3-Boraallyl Complexes

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η3-Boraallyl Complexes

Anticancer activity of a chelating nitrogen mustard bearing tetrachloridoplatinum(iv) complex: better stability yet equipotent to the Pt(ii) analogue

Reactions of the Unsaturated Ditungsten Complexes [W2Cp2(μ-PPh2)2(CO)x] (x = 1, 2) with Nitric Oxide: Stereoselective Carbonyl Displacement and Oxygen-Transfer Reactions of a Nitrite Ligand

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Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η³-Boraallyl Complexes

Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η³-Boraallyl Complexes

Reactions of the Unsaturated Ditungsten Complexes [W₂Cp₂(μ-PPh₂)₂(CO)_x] (x = 1, 2) with Nitric Oxide: Stereoselective Carbonyl Displacement and Oxygen-Transfer Reactions of a Nitrite Ligand