Synthesis, Crystal Structures, and Oxidation States of MM′X‐Type Platinum–Rhodium Dinuclear Complexes Having Amidate Bridging Ligands

Uemura, Kazuhiro; Yamasaki, Kana; Fukui, Kôichi; Matsumoto, Kazuko

doi:10.1002/ejic.200600902

Cited by 15 publications

(10 citation statements)

References 32 publications

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“…Table summarizes the Rh–Pt distances of 2 – 7 and the related compounds. ,− , In all compounds, bridged and unbridged Rh–Pt distances are shorter than the sum of the van der Waals radii (4.1 Å) of Rh and Pt atoms, indicating overlap of the d z 2 orbitals. The metal oxidation states in the previous compounds are Rh II –Pt II or Rh III –Pt II in both bridged and unbridged compounds. ,− , The unbridged Rh–Pt distances in 2 – 7 are longer than the bridged distances ,, and also longer than that of the prototype compound [{Rh 2 (O 2 CCH 3 ) 4 }{Pt 2 (piam) 2 (NH 3 ) 4 } 2 ] n (PF 6 ) 4 n ·6 n H 2 O…”

Section: Resultsmentioning

confidence: 99%

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Paramagnetic One-Dimensional Chains Comprised of Trinuclear Pt–Cu–Pt and Paddlewheel Dirhodium Complexes with Metal–Metal Bonds

Uemura

Ebihara

2013

Inorg. Chem.

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One-dimensional (1-D) chain complexes constructed by metal-metal bonds containing three types of metal species-platinum, rhodium, and copper-have been rationally synthesized and characterized by single-crystal X-ray analyses and physical measurements. The paddlewheel or lantern type complex, [Rh2(O2CCH3)4] (i.e., [Rh2]), has a vacant σ* orbital which accepts the electrons from the filled dz(2) orbital of cis-[Pt(piam)2(NH3)2]·2H2O (1, i.e. [Pt], where piam = pivalamidate) to afford a tetranuclear complex, [{Rh2(O2CCH3)4}{Pt(piam)2(NH3)2}2]·2H2O (2). Compound 2 forms a linear alignment as [Pt]-[Rh2]-[Pt] with unbridged Rh-Pt bonds, where the oxygen atoms of the piam ligands in the [Pt] are noncoordinated, showing the capability of binding another metal ion. Simply mixing [Rh2] and the heterometallic trinuclear complex [Pt2Cu(piam)4(NH3)4](PF6)2 (3, i.e. [Pt-Cu-Pt]) in a ratio of 1:1 in MeOH, EtOH, or Me2CO affords [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}]n(PF6)2n (4), [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}]n(PF6)2n (5), or [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}]n(PF6)2n·6nMe2CO (6), respectively. Compounds 4-6 form infinite chains with the repetition of -{[Rh2]-[Pt-Cu-Pt]}n-, which to our knowledge, are the first examples of heterometallic 1-D chains comprised of three types of metal species with direct metal-metal bonds. The CF3CO2(-), ClO4(-), and water molecules influence the crystal packing to form an octanuclear complex of [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}2](CF3CO2)2(ClO4)2·2H2O (7) with [Pt-Cu-Pt]-[Rh2]-[Pt-Cu-Pt] alignment. Considering the crystal structures and X-ray photoelectron spectra (XPS) measurements in 4-7, the oxidation states of the metal atoms are -{[Rh2(II,II)]-[Pt(II)-Cu(II)-Pt(II)]}n- or [Pt(II)-Cu(II)-Pt(II)]-[Rh2(II,II)]-[Pt(II)-Cu(II)-Pt(II)], which are unchanged from those in the starting compounds. Electron paramagnetic resonance spectra of 4-7 show axially symmetric spectra with g∥ > g⊥, indicating that the HOMO (SOMO) is a Cu d(x(2)-y(2)) orbital. In 7, the hyperfine coupling in the spectrum indicates that the unpaired spin on Cu is perturbed by the Pt atoms.

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Section: Resultsmentioning

confidence: 99%

“…Yield 55%. For elemental analysis, the dehydrated sample was obtained by vacuum drying at room temperature for 24 h. Elemental analysis calcd for C28 H 64 N 8 O 12 Pt 2 Rh 2 : C, 25.85; H, 4.96; N, 8.61%. Found: C, 25.53; H, 4.82; N, 8.30%.…”

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confidence: 99%

Paramagnetic One-Dimensional Chains Comprised of Trinuclear Pt–Cu–Pt and Paddlewheel Dirhodium Complexes with Metal–Metal Bonds

Uemura

Ebihara

2013

Inorg. Chem.

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“…A coordination number of six is rare for Pt(II) centers but has been observed in other cases with metal and nonmetal ligand atoms. Heteroleptic amidate compounds have Pt(II) with {Cl 4 Pt(III) 2 } coordination and {N 4 ClRh(III)} coordination. Several metallasilatrane complexes [XSi(μ-mt) 4 PtX] with mt = methimazolylsilane and X = halogen have been prepared that have octahedral coordination of Pt(II) by virtue of Pt(II) Lewis base donation to the Lewis acidic Si(IV) atom. − Divalent, six-coordinate Pt is also seen in a bis(phosphinoamide) species [Pt(η 3 -C 3 H 4 Me)TiCl 2 { t BuNP(Ph) 2 } 2 ], and [PtRh(tfepma) 2 (CN t Bu)X 3 ] with tfepma = bis(trifluoroethoxyl)phosphinomethylamine formed after halogen oxidation with Pt(0) and Rh(I) precursors .…”

Section: Resultsmentioning

confidence: 99%

Pt···Pt vs Pt···S Contacts Between Pt-Containing Heterobimetallic Lantern Complexes

et al. 2013

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A trio of Pt-based heterobimetallic lantern complexes of the form [(py)PtM(SAc)4(py)] (M = Co, 1; Ni, 2; Zn, 3) with unusual octahedral coordination of Pt(II) was prepared from a reaction of [PtM(SAc)4] with excess pyridine. These dipyridine lantern complexes could be converted to monopyridine derivatives with gentle heat to give the series [PtM(SAc)4(py)] (M = Co, 4; Ni, 5; Zn, 6). An additional family of the form [PtM(SAc)4(pyNH2)] (M = Co, 7; Ni, 8; Zn, 9) was synthesized from reaction of [PtM(SAc)4(OH2)] or [PtM(SAc)4] with 4-aminopyridine. Dimethylsulfoxide and N,N-dimethylformamide were also determined to react with [PtM(SAc)4] (M = Co, Ni), respectively, to give [PtCo(SAc)4(DMSO)](DMSO), 10, and [PtNi(SAc)4(DMF)](DMF), 11. Structural and magnetic data for these compounds and those for two other previously published families, [PtM(tba)4(OH2)] and [PtM(SAc)4(L)], L = OH2, pyNO2, are used to divide the structures among three distinct categories based on Pt···Pt and Pt···S distances. In general, the weaker donors H2O and pyNO2 seem to favor metallophilicity and antiferromagnetic coupling between 3d metal centers. When Pt···S interactions are favored over Pt···Pt ones, no coupling is observed and the pKa of the pyridine donor correlates with the interlantern S···S distance. UV-vis-NIR electronic and (1)H NMR spectra provide complementary characterization as well.

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“…In this context, the preparation of new heterobimetallic MM′X chains is certainly an interesting solution. Indeed, while mixed-metal MX-chains have been reported decades ago, related MM′X compounds are limited to a few examples. ,,− In particular, we have recently reported the first attempt to prepare heterobimetallic MM′X chains combining platinum with nickel or palladium containing dithiocarboxylato ligands . The use of dithiocarboxylates as bridging ligands of the dimetal entities has led to formation of compounds with noncontrolled stoichiometries due to the scarce selectivity in the metal transmetalation reactions.…”

Section: Introductionmentioning

confidence: 99%

On the Road to MM′X Polymers: Redox Properties of Heterometallic Ni···Pt Paddlewheel Complexes

et al. 2014

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On the quest of heterometallic mixed-valence MM'X chains, we have prepared two stable discrete bimetallic compounds: the reduced (PPN)[ClNi(μ-OSCPh)4Pt] (PPN = bis(triphenylphosphine)iminium; OSCPh = benzothiocarboxylato) and the oxidized [(H2O)Ni(μ-OSCPh)4PtCl] species. The role of the aqua and chlorido axial ligands is crucial to facilitate oxidation of the {Ni(μ-OSCPh)4Pt} core. Experimental and theoretical analyses indicate that a NiPt-Cl/Cl-NiPt isomerization process occurs in the oxidized species. The electronic structure of the reduced system shows two unpaired electrons, one located in a d(x(2)-y(2)) orbital of the Ni(II) ion and a second in the antibonding d(z(2)-dz(2)) combination from the Ni(II) and Pt(II) centers. Oxidation occurs by removing one electron from this second multicenter molecular orbital. Although the mixed-valence character of the oxidized species makes the isolation of MM'X chains very attractive, such polymeric structure is prevented by the low Pt-Cl···Ni interaction energy and the high tendency of Ni centers to coordinate water molecules. Thus, this work offers valuable insights and hints to engage the production of heterometallic mixed-valence MM'X chains, which still is a challenging task.

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Synthesis, Crystal Structures, and Oxidation States of MM′X‐Type Platinum–Rhodium Dinuclear Complexes Having Amidate Bridging Ligands

Cited by 15 publications

References 32 publications

Paramagnetic One-Dimensional Chains Comprised of Trinuclear Pt–Cu–Pt and Paddlewheel Dirhodium Complexes with Metal–Metal Bonds

Paramagnetic One-Dimensional Chains Comprised of Trinuclear Pt–Cu–Pt and Paddlewheel Dirhodium Complexes with Metal–Metal Bonds

Pt···Pt vs Pt···S Contacts Between Pt-Containing Heterobimetallic Lantern Complexes

On the Road to MM′X Polymers: Redox Properties of Heterometallic Ni···Pt Paddlewheel Complexes

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