Yasushi Mizobe

Synthesis and reactivities of diazoalkane complexes

Abstract Diazoalkane complexes have been attracting wide interest because of their rich coordination chemistry. Diazoalkane ligands, derived from either free diazoalkanes or other precursors such as coordinated dinitrogen, azines, and hydrazones, display numerous coordination modes acting as π− and/or σ-bound terminal, bridging, or chelating ligands to form mono- or multimetallic complexes. The reactivities of coordinated diazoalkanes are largely affected by their coordination modes. The variety of reactivities observed for these coordinated diazoalkanes is quite different from those of free diazoalkanes. In this review are described the synthesis, structures, and reactivities of diazoalkane complexes.

Stereoselective addition of carboxylic acids to electron deficient acetylenes catalyzed by the PdMo3S4 cubane-type cluster

Abstract The mixed-metal sulfide cubane-type cluster complex [PdMo 3 S 4 (tacn) 3 Cl][PF 6 ] 3 ( 1 ; tacn = 1,4,7-triazacyclononane) was found to be a highly efficient and selective catalyst for the addition of carboxylic acids to acetylenes with electron-withdrawing groups. The corresponding trans addition products were exclusively obtained in good yields under mild reaction conditions in the presence of a catalytic amount of triethylamine.

Preparation and reactivity of dinuclear RuII complexes with bridging thiolate ligands [Cp★Ru(μ-SR)2RuCp★] (Cp★ η5-C5Me5; R iPr, tBu, 2,6-Me2C6H3).Oxidative addition of alkyl halides at the diruthenium center

Abstract Reactions of [Cp★RuCl] 4 (Cp★  η 5 -C 5 Me 5 ) with NaSR (R  i Pr, t Bu, 2,6-Me 2 C 6 H 3 ) in THF afforded dinuclear Ru II complexes with two bridging thiolate ligands [Cp★Ru(μ-SR) 2 RuCp★] ( 3 ). An X-ray analysis of 3c (R = 2,6-Me 2 C 6 H 3 ) has disclosed the folded Ru 2 S 2 core structure with two equatorial C 6 H 3 Me 2 -2,6 groups in a solid state, while the results of variable-temperature 1 H NMR study are diagnostic of the fluxional nature of complexes 3 in solution resulting from the Ru 2 S 2 ring inversion. Complex 3a (R  i Pr) underwent oxidative addition of RX (R  PhCH 2 CH 2 or PhCH 2 , X  Br; R  Me or Et, X  I) and H 2 across the Ru 2 center to give [Cp★RuR(μ-S i Pr) 2 RuCp★X] ( 7 ) and [Cp★RuH(μ-S i Pr) 2 RuCp★H], respectively. The structure of 7a (R  PhCH 2 CH 2 , X  Br) has been determined by X-ray crystallography. Crystal data for 3c : space group P 4 2 / mnm , a = 15.307(4) A, c = 16.070(4) A, V = 3765(2) A 3 , Z = 4; 7a : space group P 2 1 / c , a = 10.348(2) A, b = 15.113(2) A, c = 22.340(5) A, β = 93.10(2)°, V = 3488(1) A 3 , Z = 4.

Syntheses, structures and properties of hydrosulfido-bridged diiridium and dirhodium complexes,

Abstract The reaction of [ Cp ∗ MCl (μ 2 - Cl ) 2 MCp ∗ Cl ] ( M  Ir , Rh ; Cp ∗ = η 5 - C 5 Me 5 ) with excess H2S gas for 5 min afforded the dobly bridged hydrosulfido complexes [ Cp ∗ MCl (μ 2 - SH ) 2 MCp ∗ Cl ] (3: M = Ir, 4: M = Rh) which were further transformed into the triply bridged cationic hydrosulfido complexes [ Cp ∗ M (μ 2 - SH ) 3 MCp ∗ ] Cl (5·Cl: M = Ir, 6·Cl: M = Rh) by continuous stirring under H2S. The molecular structures of 3, 4, 5 · [BPh4] and 6·Cl·C6H6 were determined by X-ray analyses. The SH ligands in complexes 3 and 4 take anti configuration in the solid state, whilst these complexes exist as mixtures of the syn and anti isomers in solution. Strong hydrogen bonds between the Cl anion and two of the SH ligands were found in 5·Cl and 6·Cl, and were maintained in CDCl4 solution. When complexes 3 and 4 were treated with NEt3 at room temperature, the cubane-type sulfido clusters [ Cp ∗ M ) 4 (μ 4 - S ) 4 ] (M = Ir, Rh) were produced in high yields. In the reaction of 3, an intermediary complex, most probably [ Cp ∗ Ir (μ 2 - S ) 2 IrCp ∗ ] , was detected by 1H NMR.

Towards novel organic synthesis on multimetallic centres: Syntheses and reactivities of dinuclear ruthenium thiolate complexes

From the reactions of [Cp★RuCl(μ2-Cl)2RuCp★Cl] (Cp★ = η5-C5Me5) with thiolate compounds, four types of thiolate-bridged diruthenium complexes have been obtained depending upon the thiolate source. These diruthenium complexes serve not only as a potential precursor for the synthesis of dinuclear disulfide-thiolate complexes and mixed-metal sulfide-thiolate clusters but also provide unique bimetallic reaction sites for the activation and transformations of various substrates such as alkynes, organic halides and H2.

Heterolytic cleavage of hydrogen molecule by rhodium thiolate complexes that catalyze chemoselective hydrogenation of imines under ambient conditions.

The bis(thiolate)Rh(III) complex having a tris(3,5-dimethylpyrazolyl)borate (Tp(Me2)) coligand [Tp(Me2)Rh(SPh)(2)(MeCN)] reacts reversibly with H(2) to form the hydridothiolato complex [Tp(Me2)RhH(SPh)(MeCN)] and PhSH. The benzenedithiolate analogue [Tp(Me2)Rh(o-S(2)C(6)H(4))(MeCN)], which can also heterolytically activate H(2), catalyzes hydrogenation of imines under ambient temperature and pressure with high chemoselectivity.

Two-dimensional metamagnet composed of cyano-bridged CuII-WV bimetallic assembly.

Two-dimensional cyanide-bridged copper(II) octacyanotungstates(V), [(Cu(3-CNpy)2(H2O))2(Cu(3-CNpy)2(H2O)2)(W(CN)8)2] (3-CNpy = 3-cyanopyridine) (1) and [(Cu(4-CNpy)2)2(Cu(4-CNpy)2(H2O)2)(W(CN)8)2] x 6H2O (4-CNpy = 4-cyanopyridine) (2), were prepared and these compounds exhibited metamagnetic behavior with Néel temperatures of 8.0 K (1) and 4.4 K (2).

Preparation and properties of molybdenum and tungsten dinitrogen complexes: XLI. Silylation and germylation of a coordinated dinitrogen in cis-[M(N2)2(PMe2Ph)4](M Mo, W) using R3ECl/NaI and R3ECl/Na mixtures (E Si, Ge). X-ray structure of trans-[WI(NNGePh3)(PMe2Ph)4]· C6H6☆

Treatment of cis-[W(N2)2(PMe2Ph)4] (1) with R3SiCl and excess NaI in benzene afforded a series of silyldiazenido complexes trans-[WI(NNSiR3)(PMe2Ph)4](R3  Me3, EtMe2,Et3, Me3-nPhn(n  1–3), (MeO)Me2,(MeO)2Me), while a dinuclear complex with bridging silyldiazenido ligand [(PhMe2P)4IW(NNSiMe2-p-C6H4 SiMe2NN)WI(PMe2Ph)4] was obtained from the reaction of 1 with p-ClMe2SiC6H4SiMe2Cl and NaI. Analogous treatment of 1 with a mixture of R3GeCl and excess NaI gave novel germylated dinitrogen complexes trans-[WI(NNGeR3)(PMe2Ph)4](R  Me, Ph (13)). The molecular structure of 13 · C6H6 was determined by an X-ray analysis. Crystal data for 13 · C6H6: triclinic, space group P1 with a = 13.533(3), b = 19.629(7), c = 11.941(6) A, α = 103.59(3), β = 116.11(3), γ = 81.12(2)°, V = 2763.7(16)A3 , Z = 2 and R = 0.042 for 7476 reflections. On the other hand, when a variety of chlorosilanes or Me3GeCl was reacted with one equiv of Na in THF under nitrogen in the presence of a catalytic amount of cis-[Mo(N2) 2(PMe2Ph)4], molecular nitrogen was converted into the N1 products, whose yields, detected as NH3 after hydrolysis, varied from 0.2 to 7.5 mol/Mo atom depending on the substituent in R3ECl (ESi, Ge).

Preparation and properties of molybdenum and tungsten dinitrogen complexes: XXXV. Synthesis of diazoalkane and hydrazido(2 − ) complexes of tungsten containing a π-acceptor ligand

Abstract Diazoalkane complexes [MCl 2 (NNCRR′)(PMe 2 Ph) 3 ] (M = W or Mo; R, R′ = Me or Ph), derived from dinitrogen complexes cis -[M(N 2 ) 2 (PMe 2 Ph) 4 ], reacted with various π-acceptor molecules at 50°C to give a series of new diazoalkane complexes [MCl 2 (L)(NNCRR′)(PMe 2 Ph) 2 ] (L = olefins, CO, t BuNC, or aldehydes). Analogous substitution of ethylene or CO for one phosphine ligand occurred in the hydrazido(2 −) complex [WCl 2 (NNH 2 (PMe 2 Ph) 3 ], which resulted in the formation of [WCl 2 (L)(NNH(in2) (PMe 2 Ph) 2 ]. Condensation of this new hydrazido(2 − ) complex (L = CO) with aldehyde or ketone gives the diazoalkane complexes of the type [WCl 2 (CO)(NNCRR′)(PMe 2 Ph) 2 ]. The structures of [WCl 2 (C 2 H 4 )(NNCMe 2 (PMe 2 Ph) 2 ] 4 and [WCl 2 (η 2 - p -CH 3 C 6 H 4 CHO)(NNCMePh) (PMe 2 Ph) 2 ] 13 were determined by single-crystal X-ray diffraction studies: 4 crystallizes in the monoclinic space group P 2 1 / n with a = 12.755(7), b = 18.528(6), c = 10.791(3) A, β = 93.25(4)°, Z = 4, and R = 0.036 for 4199 reflections, while 13 crystallizes in the monoclinic space group P 2 1 / n with a = 31.519(13), b = 11.360(5), c = 9.348(3) A, β = 92.28(3)°, Z = 4, and R = 0.053 for 3522 reflections. Both have an octahedral geometry with the diazoalkane and the π-acceptor ligands in mutual cis positions.

Preparation and properties of molybdenum and tungsten dinitrogen complexes: XXI. Trimethylsilylation of coordinated dinitrogen

Abstract The treatment of cis -[W(N 2 ) 2 (PMe 2 Ph) 3 with trimethylsilyl iodide in benzene gave two silylated compounds trans -[WI(NNSiMe 3 )(PMe 2 Ph) 4 ] and mer -[WI 2 (NNHSiMe 3 )(PMe 2 Ph) 3 ], X-ray analyses of which disclosed the trimethylsilyldiazenido and trimethylsilylhydrazido(2−) structures, respectively. Analogous products were also prepared from the reactions of trans -[W(N 2 ) 2 (dpe) 2 ], trans -[W(N 2 ) 2 (dpe)(PPh 2 Me) 2 ] and trans -[W( n PrCN)(N 2 )(dpe) 2 ] (dpe = Ph 2 PCH 2 CH 2 PPh 2 ) with trimethylsilyl iodide.