-
Seiji Akatsu,
Yasunori Kanematsu,
Taka-aki Kurihara,
Shota Sueyoshi, Yasuhiro Arikawa,
Masayoshi Onishi,
Shoji Ishizaka,
Noboru Kitamura,
Yoshihide Nakao,
Shigeyoshi Sakaki,
Keisuke Umakoshi
[show abstract]
[hide abstract]
ABSTRACT: Heteropolynuclear Pt(II) complexes with 3,5-diphenylpyrazolate [Pt(2)Ag(4)(μ-Cl)(2)(μ-Ph(2)pz)(6)] (3), [Pt(2)Ag(2)Cl(2)(μ-Ph(2)pz)(4)(Ph(2)pzH)(2)] (4), [Pt(2)Cu(2)Cl(2)(μ-Ph(2)pz)(4)(Ph(2)pzH)(2)] (5), [Pt(2)Ag(4)(μ-Cl)(μ-Me(2)pz)(μ-Ph(2)pz)(6)] (7), and [Pt(2)Ag(4)(μ-Me(2)pz)(2)(μ-Ph(2)pz)(6)] (8) have been prepared and structurally characterized. These complexes are luminescent except for 5 in the solid state at an ambient temperature with emissions of red-orange (3), orange (4), yellow-orange (7), and green (8) light, respectively. Systematic red shift of the emission energies with the number of chloride ligands was observed for 3, 7, and 8. DFT calculations indicate that the highest occupied molecular orbital (HOMO) as well as HOMO-1 of the heterohexanuclear complexes, 3, 7, and 8, having Pt(2)Ag(4) core, mainly consist of dδ orbital of Pt(II) and π orbitals of Ph(2)pz ligands, while the lowest unoccupied molecular orbital (LUMO) of these complexes mainly consists of in-phase combination of 6p of two Pt(II) centers and 5p of four Ag(I) centers. It is likely that the emissions of 3, 7, and 8 are attributed to emissive states derived from the Pt(2)(d)/π → Pt(2)Ag(4) transitions, the emission energy of which depends on the ratio of chloride ligands to pyrazolate ligands.
Inorganic Chemistry 07/2012; 51(15):7977-92. · 4.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Doctor NO: Unprecedented β-carbon nitrosation of aliphatic tertiary amines on nitrosylruthenium complexes was revealed, where aerobic oxidative dehydrogenation of amines, CH bond activation, NC coupling, and enamine hydrolysis were involved.
Chemistry - An Asian Journal 01/2012; 7(4):664-6. · 4.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Diastereomeric geminate pairs of chiral bis(2-oxazoline) ruthenium complexes with bipyridyl-type N-heteroaromatics, Λ- and Δ-[Ru(L-L)(2)(iPr-biox)](2+) (iPr-biox=(4S,4'S)-4,4'-diisopropyl-2,2'-bis(2-oxazoline); L-L=2,2'-bipyridyl (bpy) for 1Λ and 1Δ, 4,4'-dimethyl-2,2'-bipyridyl (dmbpy) for 2Λ and 2Δ, and 1,10-phenanthroline (phen) for 3Λ and 3Δ), were separated as BF(4) and PF(6) salts and were subjected to the comparative studies of their stereochemical and photochemical characterization. DFT calculations of 1Λ and 1Δ electronic configurations for the lowest triplet excited state revealed that their MO-149 (HOMO) and MO-150 (lower SOMO) characters are interchanged between them and that the phosphorescence-emissive states are an admixture of a Ru-to-biox charge-transfer state and an intraligand excited state within the iPr-biox. Furthermore, photoluminescence properties of the two Λ,Δ-diastereomeric series are discussed with reference to [Ru(bpy)(3)](2+).
Chemistry - An Asian Journal 03/2011; 6(6):1405-15. · 4.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The hydroxido-bridged dinuclear ruthenium complex 4, which is supported by Tp ligands, has been prepared from protonation of the oxido-bridged dinuclear ruthenium complex 3. Additional protonation of 4, affording the aqua-bridged dinuclear ruthenium complex 5 in situ, and subsequent treatment with NO gave rise to the dicationic dinitrosyl complex 2. These indicate completion of the NO reduction cycle on the dinuclear ruthenium complex.
Dalton Transactions 10/2010; 40(10):2148-50. · 3.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Vinylidene ruthenium complexes were prepared from trichloronitrosylbis(phosphine)rutheniums and terminal alkynes, subsequent cycloaddition of methyl propiolate to the vinylidene complexes giving rise to unusual ruthenacyclobutene species; in these transformations, an interesting electrostructurally-flexible behaviour of the NO ligand was observed.
Chemical Communications 06/2009; · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Swap the coins! The Pt(2)Au(2), Pt(2)Au(2)Cu(2), and Pt(2)Au(2)Ag(2) complexes of 3,5-dimethylpyrazolate exhibit yellow-green, orange, and sky-blue luminescence, respectively (see figure). The emission energies of Pt(2)Au(2)M(2) complexes can be controlled by the change of the third coinage metal ions M. The Pt(2)Au(2)M(2) complexes take the cis configuration with respect to the Au(2)M(2) plane.
Chemistry 04/2009; 15(17):4238-42. · 5.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The N-C coupling of ligating NO with 2-vinylpyridines, affording nitrosovinyl complexes, was found. This is of significance since the reaction process involves a C-H activation of the vinyl moiety and subsequent C-N bond formation. Furthermore, we show that the resulting nitrosovinyl complexes are chemically versatile and potentially valuable species. Protonation of the resulting nitrosovinyl complexes in refluxing alcohol afforded the alcohol-incorporated complexes, as well as the ketoimine species. It is interesting to note that a proton-induced reaction with PPh3 trapped their intermediates, leading to the explication of these reaction mechanisms.
Journal of the American Chemical Society 08/2008; 130(32):10508-9. · 9.91 Impact Factor
-
Journal of the American Chemical Society 12/2007; 129(46):14160-1. · 9.91 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Symmetrically disubstituted bis(3-hydroxyalkynyl) complex [TpRu{C[triple chemical bond]CCPh(2)(OH)}(2)(NO)] (1) (Tp = BH(pyrazol-1-yl)(3)) and unsymmetrically mixed (arylalkynyl)(3-hydroxyalkynyl) congener [TpRu(C[triple chemical bond]CC(6)H(4)Me){C[triple chemical bond]CCPh(2)(OH)}(NO)] (2) were newly prepared. Treatment of 1 or 2 with p-toluenesulfonic acid monohydrate was carried out to give unusual four-membered metallacyclic complexes [TpRu{C(=C=CPh(2))C(O)C(=CPh(2))}(NO)] (3) and [TpRu{C(=C=CPh(2))C(O)CH(C(6)H(4)Me)}(NO)] (5), respectively, as major products. Formation mechanism of 3 and 5 would involve insertion of the generated allenylidene group (Ru=C=C=CPh(2)) into the other Ru--C(alkynyl) bond, followed by hydration of the resulting alpha-alkynyl--allenyl fragment. With regards to the chemical reactivity of their four-membered metallacycles, treatment with aq. HCl in MeOH afforded the ring-opened one-HCl adducts, [TpRuCl{C(=C=CPh(2))C(O)CH=CPh(2)}(NO)] (7) and [TpRuCl{C(=C=CPh(2))C(O)CH(2)(C(6)H(4)Me)}(NO)] (8). On the other hand, the use of CH(2)Cl(2) and THF as the reaction solvent gave another type of one-HCl adducts [TpRu{CH(C(Cl)=CPh(2))C(O)C(==CPh(2))}(NO)] (9 a/9 b) and [TpRu{CH(C(Cl)=CPh(2))C(O)CH(C(6)H(4)Me)}(NO)] (11 a/11 b) as diastereomeric pairs, still retaining the four-membered ring structure. Moreover, their kinetically controlled products 9 b and 11 b were treated with aq. HCl to afford the ring-opened two-HCl adducts [TpRuCl{C(C(Cl)=CPh(2))(H)C(O)CH=CPh(2)}(NO)] (10) and [TpRuCl{CH(C(6)H(4)Me)C(O)CH(2)(C(Cl)=CPh(2))}(NO)] (12), respectively. In 10 and 12, each one Ru--C bond is cleaved at mutually different positions in the ring. Protonation on the carbonyl group would trigger the formation of 7-12.
Chemistry 02/2007; 13(14):4024-36. · 5.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The heteropolynuclear complexes [Pd(2)M'(2)(mu-pz)(6)] (M'=Ag (1), Au (2); pzH=pyrazole), HT-[Pd(2)M'(2)(mu-3-tBupz)(6)] (M'=Ag (3 a), Au (4 a); 3-tBupzH=3-tert-butylpyrazole), and HH-[Pd(2)Au(2)(mu-3-tBupz)(6)] (4 b) have been prepared and some of them were structurally characterized. When 3-tert-butylpyrazolate was employed as a bridging ligand, two linkage isomers (head-to-tail (HT) and head-to-head (HH)) arise from the difference in orientation of the substituent groups on the pyrazolate bridges between the two Pd atoms. (1)H NMR spectroscopy has been used to identify and to follow the reversible stereochemical rearrangement of the HH isomer of [Pd(2)Ag(2)(mu-3-tBupz)(6)] (3 b) to form the HT isomer 3 a in CDCl(3) and the HT isomer of [Pd(2)Au(2)(mu-3-tBupz)(6)] (4 a) to form the HH isomer 4 b in C(6)D(6). Kinetic studies of the reaction have established the rate law to be -d(HH)/dt=d(HT)/dt=k(2)[HH]-k(1)[HT] for 3 b and -d(HT)/dt=d(HH)/dt=k(1)[HT]-k(2)[HH] for 4 a, where k(1) and k(2) denote the rate of isomerization from the HT to the HH isomer and that from the HH to the HT isomer, respectively. For typical runs at 50 degrees C in C(6)D(6), k(1)=13.8x10(-5) s(-1), k(2)=18.6x10(-5) s(-1), and K(eq)=k(2)/k(1)=1.24 for 3 b, and k(1)=1.26x10(-5) s(-1), k(2)=3.52x10(-5) s(-1), and K(eq)=k(1)/k(2)=0.36 for 4 a. Temperature-dependent rate measurements reveal DeltaH(not equal) and DeltaS(not equal) to be 100(1) kJ mol(-1) and 0(3) J mol(-1) K(-1) for 3 b and 112(5) kJ mol(-1) and 20(17) J mol(-1) K(-1) for 4 a, respectively. The rate of isomerization is essentially unaffected by the concentration of the complex or by the presence of neutral bridging ligands. These data and observations imply that the isomerization involves an intramolecular exchange process.
Chemistry 07/2006; 12(19):5094-104. · 5.93 Impact Factor
-
Angewandte Chemie International Edition 09/2005; 44(34):5509-13. · 13.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A nitrosylruthenium alkynyl complex of TpRuCl(C[triple bond]CPh)(NO)(1a) was reacted with PPh3 in the presence of HBF4.Et2O at room temperature to give a beta-phosphonio-alkenyl complex (E)-[TpRuCl{CH=C(PPh3)Ph}(NO)]BF4(2.BF4). On the other hand, for gamma-hydroxyalkynyl complexes TpRuCl{C[triple bond]CC(R)2OH}(NO)(R = Me (1b), Ph (1c), H (1d)), similar treatments with PPh3 were found to give gamma-phosphonio-alkynyl [TpRuCl{C[triple bond]CC(Me)2PPh3}(NO)]BF4(3.BF4),alpha-phosphonio-allenyl [TpRuCl{C(PPh3)=C=CPh2}(NO)]BF4(4.BF4), and a novel product of gamma-hydroxy-beta-phosphonio-alkenyl (E)-[TpRuCl{CH=C(PPh3)CH2OH}(NO)]BF4(5.BF4), respectively. Dominant factors for the selectivity in affording 3-5 were associated with the steric congestion and electronic properties at the gamma-carbons, along with those around the metal fragment. From the bis(alkynyl) complex TpRu(C[triple bond]CPh)2(NO)6, a bis(beta-phosphonio-alkenyl)(E,E)-[TpRu{CH=C(PPh3)Ph}2(NO)](BF4)2{7.(BF4)2} was produced at room temperature. However, similar reactions at 0 degrees C gave an alkynyl beta-phosphonio-alkenyl complex (E)-[TpRu(C[triple bondCPh){CH=C(PPh3)Ph}(NO)]BF4(8.BF4) as a sole product, of which additional hydration in the presence of HBF4.Et2O afforded a [small beta]-phosphonio-alkenyl ketonyl (E)-[TpRu{CH2C(O)Ph}{CH=C(PPh3)Ph}(NO)]BF(.9BF4). Five complexes, 2-5 and 7 were crystallographically characterized.
Dalton Transactions 04/2005; · 3.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hydration of nitrosylruthenium bis(alkynyl) complex TpRu(CCPh)2(NO) (1) (Tp = BH(pyrazol-1-yl)3) was carried out in the presence of HBF4.Et2O in distilled MeOH and afforded the metallacycle TpRu{CH=C(Ph)C(O)CH(Ph)}(NO) (2) (39%) and the bis(ketonyl) TpRu(CH2C(O)Ph)2(NO) (3) (37%). While double hydration of 1 gave 3, 2 was produced through a combination of insertion and hydration processes. On the other hand, a similar reaction performed in THF instead of MeOH afforded 2 (52%), the acyl-ketonyl complex TpRu(C(O)CH2Ph)(CH2C(O)Ph)(NO) (4) (8.9%), and trace amounts of 3 and TpRu(CCPh)(CH2C(O)Ph)(NO) (5). Moreover, the 1/HBF4.Et2O/H2O reaction system in distilled MeOH at 0 degrees C gave rise to 5 exclusively (79%). Treatment of THF solution of isolated 5 with water in the presence of protic acid furnished 3 and 4, revealing that 5 is the intermediate in their formation.
Journal of the American Chemical Society 04/2004; 126(12):3706-7. · 9.91 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Treatment of the monoacetylide complexes TpRuCl(CCR)(NO) (R = Ph (1a), p-CH3C6H4 (1b), tBu (1c), CH2CH2OH (1d), CH2OH (1e), C(Me)2OH (1f), C(Ph)2OH (1g); Tp = BH(pyrazol-1-yl)3) with HBF4·Et2O in methanol afforded the ketonyl complexes TpRuCl(CH2C(O)R)(NO) (R = Ph (2a), p-CH3C6H4 (2b), tBu (2c), CH2CH2OMe (2d), CH2OH (2e)) and the α,β-unsaturated acyl complexes TpRuCl(C(O)CHCR‘2)(NO) (R‘ = Me (3f), Ph (3g)), respectively. While the latter were produced by hydration via allenylidene species, the former were presumably generated from the reaction of η2-coordinated 1-alkyne species with adventitious water.
07/2003;
-
[show abstract]
[hide abstract]
ABSTRACT: In the presence of 2.5 mol % of [Pd(2)(dba)(3)] (dba=dibenzylideneacetone) and 5 mol % of PPh(3), nearly equimolar amounts of dimethyl nona-2,7-diyne-1,9-dioate derivatives (diyne diesters) and dialkyl acetylenedicarboxylates were allowed to react in toluene at 110 degrees C to afford [2+2+2] cycloadducts in moderate-to-good yields. Similarly, dimethyl trideca-2,7,12-triyne-1,13-dioate derivatives (triyne diesters) were catalytically transformed into phthalic acid ester analogues in excellent yields. To gain insight into the mechanism of these intramolecular alkyne cyclotrimerizations, stoichiometric reactions of [Pd(2)(dba)(3)] with a diyne diester and a triyne diester bearing ether tethers were conducted in acetone at room temperature to furnish an oligomeric bicyclopalladacyclopentadiene and a Pd(0) triyne complex, respectively. The structures of these novel complexes were unequivocally determined by Xray structure analysis. The isolated triyne complex was heated at 50 degrees C or treated with PPh(3) in acetone at room temperature to afford the arene product. Furthermore, the same complex catalyzed the triyne cyclization with or without PPh(3).
Chemistry 07/2003; 9(11):2469-83. · 5.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Five-coordinated trithiotungsten complexes (PPh(4))[(dmsp)W(S)(3)] (1a) and (PPh(4))[(dpsp)W(S)(3)] (1b) (R(2)PCH(2)CH(2)S(-); R = Me (dmsp-)), Ph (dpsp-))) were synthesized by addition of Hdmsp and Hdpsp to a THF solution of (PPh(4))[(EtS)W(S)(3)]. Treatment of 1a with CuBr in the presence of PPh(3) in CH(3)CN afforded a WCu(2) cluster (dmsp)WS(3)Cu(2)(PPh(3))(2)Br (2). The reaction of 1a with 1 equiv of FeCl(2) went smoothly to generate a 1:1 adduct (PPh(4))[(dmsp)WS(3)(FeCl(2))] (3), while 3 did not react further with excess FeCl(2). On the other hand, 3 was found to react with [Fe(CH(3)CN)(6)](ClO(4))(2), giving rise to an unusual tetranuclear cluster, [(dmsp)WS(3)](2)Fe(2)Cl (4), while the reaction of 1a with 2 equiv of [Fe(CH(3)CN)(6)](ClO(4))(2) led to a cyclic octanuclear cluster [(dmsp)WS(3)Fe](4) (5). Although the oxidation states of W(VI), Cu(I), and Fe(II) are retained in 2 and 3, reduction of the metal ions occurs in the formation of 4 and 5. All the complexes reported in this paper were structurally characterized by X-ray analysis. It is anticipated that the new type of trithiotungsten complexes, 1a and 1b, will serve as potential synthons for various heterometallic sulfide clusters.
Inorganic Chemistry 03/2002; 41(3):513-20. · 4.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Five-coordinated trithiotungsten complexes (PPh4)[(dmsp)W(S)3] (1a) and (PPh4)[(dpsp)W(S)3] (1b) (R2PCH2CH2S-; R = Me (dmsp-), Ph (dpsp-)) were synthesized by addition of Hdmsp and Hdpsp to a THF solution of (PPh4)[(EtS)W(S)3]. Treatment of 1a with CuBr in the presence of PPh3 in CH3CN afforded a WCu2 cluster (dmsp)WS3Cu2(PPh3)2Br (2). The reaction of 1a with 1 equiv of FeCl2 went smoothly to generate a 1:1 adduct (PPh4)[(dmsp)WS3(FeCl2)] (3), while 3 did not react further with excess FeCl2. On the other hand, 3 was found to react with [Fe(CH3CN)6](ClO4)2, giving rise to an unusual tetranuclear cluster, [(dmsp)WS3]2Fe2Cl (4), while the reaction of 1a with 2 equiv of [Fe(CH3CN)6](ClO4)2 led to a cyclic octanuclear cluster [(dmsp)WS3Fe]4 (5). Although the oxidation states of W(VI), Cu(I), and Fe(II) are retained in 2 and 3, reduction of the metal ions occurs in the formation of 4 and 5. All the complexes reported in this paper were structurally characterized by X-ray analysis. It is anticipated that the new type of trithiotungsten complexes, 1a and 1b, will serve as potential synthons for various heterometallic sulfide clusters.
12/2001;
-
[show abstract]
[hide abstract]
ABSTRACT: The reaction of Pd2(dba)3·CHCl3 with dimethyl 4,9-dioxatrideca-2,7,12-triyne-1,13-dioate gave the first palladium(0) triyne complex in good yield. The triyne complex was confirmed to be an efficient catalyst precursor for the cyclization of the triyne ligand.
05/2000;
-
[show abstract]
[hide abstract]
ABSTRACT: Reaction of Mo(S(t)Bu)(4) with 2 equiv of HSCH(2)CH(2)PMe(2) (Hdmsp) produced Mo(dmsp)(2)(S(t)Bu)(2) (1) in high yield. Treatment of 1 with FeCl(2) and CuBr led to the formation of heterometallic clusters, [Mo(O)(dmsp)(2)](2)FeCl(2) (2) and [MoBr(dmsp)(2)(&mgr;(3)-S)Cu(2)](2)(&mgr;(2)-S(t)Bu)(2) (3), respectively. The structures of 1-3 were determined by X-ray analyses. Complex 1 assumes a distorted octahedral geometry with a cis-disposition of two (t)BuS ligands. In the structure of 2, an FeCl(2) unit bridges two square-pyramidal Mo(O)(dmsp)(2) fragments through interactions between Fe and dmsp sulfur atoms, where the MoS(2)Fe quadrilateral is puckered. Formation of 3 involves C-S bond cleavage of one (t)BuS ligand of 1 and rearrangement of ligands between the Mo and Cu coordination sites, resulting in the structure consisting of two MoCu(2)BrS(dmsp)(2) cluster units and two (t)BuS bridges.
Inorganic Chemistry 11/1999; 38(20):4549-4553. · 4.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: ナノダイナミクス国際シンポジウム 平成22年1月21日(木) 於長崎大学 Nagasaki Symposium on Nano-Dynamics 2010 (NSND2010), January 21, 2010, Nagasaki University, Nagasaki, Japan, Invited Lecture
