[(μ4-H)Rh4(PNNP)2(CO)4]+: A Novel Hydride Bridging Mode

Tanaka, Shukichi; Akita, Munetaka

doi:10.1002/1521-3773(20010803)40:15<2865::aid-anie2865>3.0.co;2-5

Cited by 19 publications

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References 16 publications

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“…This anion appears to be the only example of a first-row hydride containing a (metal) 4 (μ 4 -H) core. The only other examples of this type of tetranuclear arrangement to be structurally characterized throughout the periodic table are Y III complexes such as [{(L)YH 2 ] 4 [L = tris-dimethylpyrazolyl-borate (TpMe 2 ), Me 4 C 5 SiMe 3 ], the W III complex [( t BuCH 2 O) 12 W 4 (μ 4 -H)] − , and the Rh I complex [Rh 2 (PNNP)(CO) 2 } 2 (μ 4 -H)] [PNNP = 3,5-bis(diphenylphosphinomethyl)pyrazolate] …”

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The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH₂)₃Fe}₄(μ₄-H)]⁻

et al. 2010

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The metal-exchange reaction of the lithium complex [{PhP(CH 2 ) 3 } 2 (Li 3 thf) 4 ] (1) with FeI 2 gives the tetranuclear Fe II compound [Li(thf) 4 ] þ [{PhP(CH 2 ) 3 Fe} 4 (μ 4 -H)] -(2), a rare example of a first-row transition metal interstitial hydride.In the past decade or so there has been considerable interest in the coordination chemistry of main group element-based anionic ligands containing nitrogen donor functionality. 1-4 Most well studied are the series of isoelectronic tripodal anions [RE-(NR) 3 ] x-(E=main group element) (Figure 1a,b,c), which exhibit a rich coordination chemistry with a broad range of transition and main group metals. Our interest in these species has been renewed by the realization that isovalent phosphorus-based group 13 anions of this class, [MeE(PPh) 3 ] 4-(E=Al, Ga, In, Figure 1d), have the remarkable ability to form supramolecular ionic cages. 5 This feature is seen in the series of isostructural anions [{MeE(PPh) 3 Li 4 } 4 (μ 4 -Cl)] -, composed of a supramolecular, tetrahedral arrangement of four [MeE(PPh) 3 ] 4-anions that surround a Li 16 core. The inverse coordination of the Clanion by a Li 4 unit at the center of the [{MeE(PPh) 3 Li 4 } 4 (μ 4 -Cl)] -anion effectively templates this structure. 6 We showed recently that deprotonation of the commercially available phosphonium salt [PhP(CH 3 ) 3 ] þ I -with t BuLi results in a new carbon-based representative of this class of ligands, [PhP(CH 2 ) 3 ] 2-(Scheme 1). 7 This novel phospholide arrangement offers new opportunities in organometallic chemistry, being a strong σ-donor (via the lone pairs of the CH 2 groups) and a σ-acceptor (via the σ* orbital of the Ph-P bond). 8 We present here the first study of the coordination chemistry of this type of ligand with a transition metal; the tetranuclear anion [{PhP(CH 2 ) 3 Fe} 4 (μ 4 -H)] -(2) reported is a rare example of a first-row transition metal interstitial hydride.The 1:1 stoichiometric reaction of the lithium precursor 1 with FeI 2 in thf produces a dark brown solution, from which dark brown crystals of [Li(thf) 4 ] þ [{PhP(CH 2 ) 3 Fe} 4 (μ 4 -H)] -(2) were isolated in 44% yield. 9 The 1 H and 31 P{ 1 H} NMR spectra of the complex at room temperature show sharp resonances, strongly suggesting that it is diamagnetic in solution. In addition, 2 is also EPR silent at room temperature in thf solution and in the solid state. This provides key evidence that the Fe II centers in the anion of 2 are low-spin (t 2 g 6 eg 0 ). It also provides indirect evidence of the presence of the H -ion within the [{PhP(CH 2 ) 3 Fe} 4 (μ 4 -H)] -anion, which would otherwise have to possess a single, unpaired electron to balance the charge in 2, i.e., paramagnetic (Fe II ) 3 (Fe I ) rather than diamagnetic (Fe II ) 4 (μ 4 -H). In addition to the Ph and CH 2 resonances for the [PhP(CH 2 ) 3 ] 2-ligands, the room-temperature 1 H NMR spectrum shows a broad resonance at δ -11.2, which we assign to the μ 4 -H atom. 10 Although the reaction producing 2 can be reproduced easily, the origin of th...

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The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH₂)₃Fe}₄(μ₄-H)]⁻

et al. 2010

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“…The crystallographic data for 5c and 7a are summarized in Table . The crystallographic data and CIF files for the other compounds, which appeared in ref d and therefore are not included in the Supporting Information, are available from the CSD ( 7b , CCDC 243414; 8b , CCDC 243413; 12 , CCDC 243415).…”

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confidence: 99%

“…To shed light on the non-metal−metal-bonded organometallic systems, we have been studying polynuclear complexes based on the PNNP ligand 1 (3,5-bis((diphenylphosphino)methyl)pyrazolato), which separates the two metal centers beyond the metal−metal bonding interaction but is flexible enough to fit substrates of various sizes (Scheme ). In previous papers, we reported that the dirhodium tetracarbonyl complex [(PNNP)Rh 2 (CO) 4 ]BF 4 was labile enough to release the two inner CO ligands trans to the P atoms and generated a coordinately unsaturated species ( A ) with cis-divacant coordination sites, which could bind a substrate with up to four donating electrons 1 …”

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Synthesis of a Library of Iridium-Containing Dinuclear Complexes with Bridging PNNN and PNNP Ligands (BL), [LM(μ-BL)M‘L‘]BF₄. 1. Specific Synthesis of Isomeric Heterodinuclear Complexes with Switched Metal Arrangements

et al. 2006

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Specific synthesis of a series of Ir-containing homo- and heterodinuclear complexes with the PNNP (3,5-bis((diphenylphosphino)methyl)pyrazolato) and PNNN ligands (3-(diphenylphosphino)methyl-5-pyridylpyrazolato) is reported. Reaction of the PNNX-H precursors (X = P, N) with [Ir(cod)2]BF4 gives pale yellow precipitates, which are characterized as the cyclic dimers of the 1:1 adduct, [(μ-κ1(P): κ2(N,X)-PNNX-H)Ir(cod)]2(BF4)2 (X = P, N). In the case of the PNNN system, subsequent sequential treatment of the 1:1 adduct with NEt3 and a second metal reagent ([M(L)(cod)]BF4: M(L) = Rh(cod), Pd(allyl)) (reaction 1) gives [(cod)Ir(PNNN)M(L)]BF4, whereas the reversed addition of the reagents (reaction 2) furnishes [(L)M(PNNN)Ir(cod)]BF4, the regioisomer with the switched metal arrangement. Selective preparation of the heterodinuclear PNNP complexes [(cod)Ir(PNNP)M(L)]BF4 requires the addition according to reaction 1. In reaction 1 of the 1:1 dinuclear adduct of the PNNN system, deprotonation of the N−H part triggers interligand migration of the Ir(cod) fragment from the N,N site of one ligand to the P,N site of the other ligand to give [(cod)Ir(PNNN)]BF4, which reacts with the second metal fragment at the N,N site to furnish [(cod)Ir(PNNN)M(L)]BF4. On the other hand, reaction 2 involves dissociation of the dinuclear species into the mononuclear N,N-coordinated one, [(PNNN-H)Ir(cod)]BF4, and subsequent interaction at the free P moiety followed by deprotonation and coordination gives the other regioisomer. These intriguing transformations result from the unique coordination properties of Ir (cationic vs neutral, hard vs soft, 5- vs 4-coordination, N,N vs P,N chelation), which are controlled by the deprotonation−protonation procedure. As a result of the present study, a library for Ir-containing homo- and heterodinuclear Ir(I) complexes with the PNNP and PNNN ligands has been constructed.

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“…3 We are now carrying out a synthetic study on heterodinuclear complexes with the PNNN ligand 1 (3-diphenylphosphinomethyl-5-pyridylpyrazolate; Scheme 1), 4 which follows that on homometallic polynuclear complexes with a symmetric PNNP ligand. 5,6 The PNNN ligand 1 has one PN-and one NN-coordination site and herein we wish to report the selective synthesis of pairs of isomeric heterodinuclear complexes with a reversed metal arrangement from the same sources by simply changing the addition procedure of the reagents. These results suggest that the deprotonation-protonation processes bring about reversible migration of the Ir fragment between the NN-and PN-coordination sites, which can account for the selective formation of 3?BF 4 and 4?BF 4 .…”

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Selective synthesis of isomeric heterodinuclear complexes with switched metal arrangements via proton-induced reversible metal migration

2004

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[(μ4-H)Rh4(PNNP)2(CO)4]+: A Novel Hydride Bridging Mode

Cited by 19 publications

References 16 publications

The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH₂)₃Fe}₄(μ₄-H)]⁻

The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH₂)₃Fe}₄(μ₄-H)]⁻

Synthesis of a Library of Iridium-Containing Dinuclear Complexes with Bridging PNNN and PNNP Ligands (BL), [LM(μ-BL)M‘L‘]BF₄. 1. Specific Synthesis of Isomeric Heterodinuclear Complexes with Switched Metal Arrangements

Selective synthesis of isomeric heterodinuclear complexes with switched metal arrangements via proton-induced reversible metal migration

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[(μ4-H)Rh4(PNNP)2(CO)4]+: A Novel Hydride Bridging Mode

Cited by 19 publications

References 16 publications

The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH2)3Fe}4(μ4-H)]−

The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH2)3Fe}4(μ4-H)]−

Synthesis of a Library of Iridium-Containing Dinuclear Complexes with Bridging PNNN and PNNP Ligands (BL), [LM(μ-BL)M‘L‘]BF4. 1. Specific Synthesis of Isomeric Heterodinuclear Complexes with Switched Metal Arrangements

Selective synthesis of isomeric heterodinuclear complexes with switched metal arrangements via proton-induced reversible metal migration

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The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH₂)₃Fe}₄(μ₄-H)]⁻

The First-Row Transition Metal Interstitial Hydride Anion [{PhP(CH₂)₃Fe}₄(μ₄-H)]⁻

Synthesis of a Library of Iridium-Containing Dinuclear Complexes with Bridging PNNN and PNNP Ligands (BL), [LM(μ-BL)M‘L‘]BF₄. 1. Specific Synthesis of Isomeric Heterodinuclear Complexes with Switched Metal Arrangements