Dinuclear Rhodium and Iridium Complexes with Mixed Amido/Methoxo and Amido/Hydroxo Bridges

Tejel, Cristina; Ciriano, Miguel A.; Bordonaba, Marta; López, José A.; Lahoz, Fernando J.; Oro, Luis A.

doi:10.1021/ic0109952

Cited by 24 publications

(17 citation statements)

References 61 publications

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“…This pattern extends the previously reported ones in (frequently) dinuclear m-amido and/or m-hydroxo complexes containing two [4,20] or even three [21] different bridges. With regard to Pt and/or Pd representatives, the bonds between the metal ions and the NH 2 and OH ligands, respectively, are normal.…”

Section: H T U N G T R E N N U N G (Nh 2 ) 2 (Oh)-a C H T U N G T Rsupporting

confidence: 90%

“…With regard to Pt and/or Pd representatives, the bonds between the metal ions and the NH 2 and OH ligands, respectively, are normal. [20] It is evident that the Ag2 and Ag2' atoms are instrumental in keeping together the two halves of the molecular cation in the solid state. Furthermore, the relatively short separation of the two m-OH sites (O1···O1', 3.062 (11) ) suggests that there are two weak hydrogen bonds between the protons of the OH groups and the neighboring oxygen atoms.…”

Section: H T U N G T R E N N U N G (Nh 2 ) 2 (Oh)-a C H T U N G T Rmentioning

confidence: 99%

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Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt₄,Pd₄,Ag₄ Platform for Four Cytosine Model Nucleobases

Kampf

Miguel

Cerdà

et al. 2008

Chemistry A European J

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The reaction of a potential mono(nucleobase) model adduct of cisplatin, cis-[Pt(NH(3))(2)(1-MeC-N3)(H(2)O)](2+) (6; 1-MeC: 1-methylcytosine), with the electrophile [Pd(en)(H(2)O)(2)](2+) (en: ethylenediamine) at pH approximately 6 yields a kinetic product X which is likely to be a dinuclear Pt,Pd complex containing 1-MeC(-)-N3,N4 and OH bridges, namely cis-[Pt(NH(3))(2)(1-MeC(-)-N3,N4)(OH)Pd(en)](2+). Upon addition of excess Ag(+) ions, conversion takes place to form a thermodynamic product, which, according to (1)H NMR spectroscopy and X-ray crystallography, is dominated by a mu-NH(2) bridge between the Pt(II) and Pd(II) centers. X-ray crystallography reveals that the compound crystallizes out of solution as a dodecanuclear complex containing four Pt(II), four Pd(II), and four Ag(+) entities: [{Pt(2)(1-MeC(-)-N3,N4)(2)(NH(3))(2)(NH(2))(2)(OH)Pd(2)(en)(2)Ag}(2){Ag(H(2)O)}(2)](NO(3))(10) 6 H(2)O (10) is composed of a roughly planar array of the 12 metal ions, in which the metal ions are interconnected by mu-NH(2) groups (between Pt and Pd centers), mu-OH groups (between pairs of Pt atoms), and metal-metal donor bonds (Pt-->Ag, Pd-->Ag). The four 1-methylcytosinato ligands, which are stacked pairwise, as well as the four NH(3) ligands and parts of the en rings, are approximately perpendicular to the metal plane. Two of the four Ag ions (Ag2, Ag2') of 10 are labile in solution and show the expected behavior of Ag(+) ions in water, that is, they are readily precipitated as AgCl by Cl(-) ions. The resulting pentanuclear complex [Pt(2)Pd(2)Ag(1-MeC(-))(2)(NH(2))(2)(OH)(NH(3))(2)(en)(2)](NO(3))(4)7 H(2)O (11) largely maintains the structural features of one half of 10. The other two Ag(+) ions (Ag1, Ag1') of 10 are remarkably unreactive toward excess NaCl. In fact, the pentanuclear complex [Pt(2)Pd(2)AgCl(1-MeC(-))(2)(NH(2))(2)(OH)(NH(3))(2)(en)(2)](NO(3))(3)4.5 H(2)O (12), obtained from 10 with excess NaCl, displays a Cl(-) anion bound to the Ag center (2.459(3) A) and is thus a rare case of a crystallized "AgCl molecule".

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Section: H T U N G T R E N N U N G (Nh 2 ) 2 (Oh)-a C H T U N G T Rsupporting

confidence: 90%

Section: H T U N G T R E N N U N G (Nh 2 ) 2 (Oh)-a C H T U N G T Rmentioning

confidence: 99%

Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt₄,Pd₄,Ag₄ Platform for Four Cytosine Model Nucleobases

Kampf

Miguel

Cerdà

et al. 2008

Chemistry A European J

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“…Electrically neutral and diamagnetic 1 – 6 (Scheme ) essentially differ with special reference to (i) varying binding modes of BDF (bidentate versus bridging) as a function of unsymmetrical cleavage of its furoxan ring(s) as well as (ii) corresponding isomeric identities. Isomeric 1 or 2 was formed by selective unsymmetrical cleavage of one of the furoxan rings of BDF moiety at 2,3 or 5,6 position, respectively (Schemes and ), leading to monoanionic NH,O (nitroanilido) coordinated bidentate six‐membered chelate. On the other hand, monoanionic N,N′ coordinated isomeric 3 a and 3 b with varying relative orientation of CO and Cl groups were developed via unsymmetric N−O bond scission (hydrogen bonded nitroanilido and nitrosoamine functions) of both the furoxan rings of BDF.…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, the same reaction of BDF and [Ru II (H)(Cl) (CO)(PPh 3 ) 3 ] in non-polar toluene or polar aprotic CH 3 CN at 298 K led to the exclusive formation of isomeric 1 and 2 without any impression of other complexes (3)(4)(5)(6), reflecting the effective role of polar protic EtOH solvent in the product formation process in Scheme 3 (see later).…”

Section: Syntheses and Characterizationmentioning

confidence: 98%

“…SQUEEZE was applied to a disordered unidentified solvent molecule in the crystal of 3 a by using the PLATON [22] program. Supplementary crystallographic data for the compounds mentioned in this paper may be obtained free of cost from The Cambridge Crystallographic Data Centre (www.ccdc.cam.ac.uk/data_request/cif) using the CCDC numbers 1996391(1), 1996392(2), 1996393(6), 1996394 (5), 1996395(3 b), 1996396(3 a) and 1996397(4), respectively.…”

Section: Crystal-structure Determinationmentioning

confidence: 99%

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Ruthenium‐Hydride Assisted Remarkable Diversity Towards Non‐Spectator Feature of Benzodifuroxan

Dey

Panda

Lahiri

2020

Chemistry An Asian Journal

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The present article demonstrates that rutheniumhydride [Ru II (H)(Cl)(CO)(PPh 3) 3 ] mediated diverse functionalization modes of benzodifuroxan (BDF) encompassing two furoxan rings. Hydride transfer from the metal precursor facilitated multiple cascade reactions involving unsymmetrical cleavage of the furoxan rings of BDF, leading to the onepot formation of a series of ruthenium (II) coordinated functionalized ligands exhibiting bidentate k 2-N,O, k 2-N,N' and bis-bidentate μ-bis(k 2-N,O) modes. Further, a moderately stable intermediate species was also encountered in the reaction sequence in which the transformed deoxygenated ligand coordinated to the metal ion via the rarely manifested furazan ring (k 2-N,N'' mode). The products were authenticated by their single-crystal X-ray structures and other spectroscopic/analytical techniques. Redox non-innocence of the functionalized ligands in the complexes was illustrated by spectroelectrochemistry (cyclic voltammmetry, UV-Vis. and EPR) in conjunction with DFT/TD-DFT calculations. Mechanistic outline for the facile ring opening processes of BDF including interconversions of complexes (e. g. reductive ring opening) were also addressed.

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Direct Access to Parent Amido Complexes of Rhodium and Iridium through NH Activation of Ammonia

Mena¹,

Garcı́a-Orduña²,

Polo³

et al. 2011

Angewandte Chemie

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Ammonia is a low-cost and potentially valuable building block for almost every nitrogen-containing compound required by industry. There is an obvious interest in utilizing this chemical as feedstock in catalytic organic transformations to produce higher-value products, an issue that has began to be explored with some degree of success. [1] However, most of late transition metal catalyzed reactions do not occur with ammonia. Several factors have been invoked to explain this lack of reactivity: [2] 1) The high strength of the NÀH bond of ammonia (107 kcal mol À1 ) makes its activation very difficult to achieve by metal centers; 2) the catalyst often deactivates through the formation of stable Werner ammine (M ! NH 3 ) adducts; and 3) the low acidity of ammonia prevents its participation in proton exchange reactions that could lead to NÀH activation.In order to achieve a metal-mediated functionalization of ammonia, an imperative requisite should be the formation of M À NH 2 bonds directly from ammonia (i.e. rather than leading to stable M ! NH 3 adducts). [3] So far, only few early examples involving interaction of NH 3 with iridium complexes followed an oxidative addition profile. [4] This concept was elegantly illustrated by Hartwig et al., who reported on the formal oxidative addition of ammonia to an electron-rich Ir I pincer system, leading to the first structurally characterized terminal amido hydrido Ir III complex. [5] In spite of the efficacy of this N À H activation, uptake and homolytic breakage of ammonia by late transition metal complexes still remains a difficult goal. [6] We assumed that a good approach to induce the formation of M À NH 2 bonds, circumventing the formation of Werner adducts, should rely on an appropriate design of organometallic precursors. Herein we report on a synthetic protocol that uses gaseous ammonia as "NH 2 " source to generate stable novel parent bridging and terminal amido Rh I and Ir I complexes under very mild conditions. We chose as metallic precursors dinuclear complexes bearing alkoxo-bridging ligands, well suited to induce NÀH activation. [7] In this way, treatment of the methoxo-bridged compounds [{M(m-OMe)(tfbb)} 2 ] (M = Rh, Ir; tfbb = tetrafluorobenzobarrelene) with gaseous ammonia in diethyl ether at atmospheric pressure rapidly afforded the parent amidobridged trinuclear complexes [{M(m 2 -NH 2 )(tfbb)} 3 ] (M = Rh (1), Ir (2)) which were isolated in good yields. On the other hand, reactions of the cod complexes [{M(m-OMe)(cod)} 2 ] (cod = 1,5-cycloctadiene) with gaseous ammonia yielded dinuclear amido-bridged complexes [{M(m-NH 2 )(cod)} 2 ] (M = Rh (3), Ir (4)) in excellent yields (Scheme 1). All the reactions leading to complexes 1-4 were found to be reversible. For example, monitoring by NMR spectroscopy the reaction of 3 with MeOH in a 1:1 ratio in [D 6 ]benzene showed upon 10 min, when the equilibrium was considered to be reached, the presence of unchanged 3, the original methoxo-bridged complex [{Rh(m-OMe)(cod)} 2 ] and the mixed amido-alkoxo species [{...

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Dinuclear Rhodium and Iridium Complexes with Mixed Amido/Methoxo and Amido/Hydroxo Bridges

Cited by 24 publications

References 61 publications

Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt₄,Pd₄,Ag₄ Platform for Four Cytosine Model Nucleobases

Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt₄,Pd₄,Ag₄ Platform for Four Cytosine Model Nucleobases

Ruthenium‐Hydride Assisted Remarkable Diversity Towards Non‐Spectator Feature of Benzodifuroxan

Direct Access to Parent Amido Complexes of Rhodium and Iridium through NH Activation of Ammonia

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Dinuclear Rhodium and Iridium Complexes with Mixed Amido/Methoxo and Amido/Hydroxo Bridges

Cited by 24 publications

References 61 publications

Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt4,Pd4,Ag4 Platform for Four Cytosine Model Nucleobases

Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt4,Pd4,Ag4 Platform for Four Cytosine Model Nucleobases

Ruthenium‐Hydride Assisted Remarkable Diversity Towards Non‐Spectator Feature of Benzodifuroxan

Direct Access to Parent Amido Complexes of Rhodium and Iridium through NH Activation of Ammonia

Contact Info

Product

Resources

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Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt₄,Pd₄,Ag₄ Platform for Four Cytosine Model Nucleobases

Reactivity of Ammonia Ligands of the Antitumor Agent Cisplatin: A Unique Dodecanuclear Pt₄,Pd₄,Ag₄ Platform for Four Cytosine Model Nucleobases