Sulfoxide carbon-sulfur bond activation

The alkynylsulfoxide, TMSCCSO(p-tolyl) (TMS = trimethylsilyl, tolyl = C6H4Me), undergoes reaction with (eta5-C5H5)Co(PPh3)2 at room temperature to give the cobaltosulfoxide complex, (C5H5)Co(PPh3)(eta1-CCTMS)[eta1-(S)-SO(p-tolyl)], which was characterized by X-ray crystallography. Exposure of this cobaltosulfoxide complex to oxygen gas leads to the formation of the corresponding metallosulfone complex, (C5H5)Co(PPh3)(eta1-CCTMS)[eta1-(S)-SO2(p-tolyl)], which was characterized by X-ray crystallography. Alternatively, in solution at room temperature, the metallosulfoxide is converted to a 1:4 mixture of the equatorial-equatorial and equatorial-axial bridging cobalt-thiolato dimers, {(C5H5)Co[mu-S(p-tolyl)]}2, respectively. The equatorial-equatorial isomer was characterized by X-ray crystallography.     

Cube-type nitrido complexes containing titanium and zinc/copper

Several azaheterometallocubane complexes containing [MTi3N4] cores have been prepared by the reaction of [{Ti(eta5-C5Me5)(mu-NH)}3(mu3-N)] (1) with zinc(II) and copper(I) derivatives. The treatment of 1 with zinc dichloride in toluene at room temperature produces the adduct [Cl2Zn{(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)}] (2). Attempts to crystallize 2 in dichloromethane gave yellow crystals of the ammonia adduct [(H3N)Cl2Zn{(mu3-NH)Ti3(eta5-C5Me5)3(mu-NH)2(mu3-N)}] (3). The analogous reaction of 1 with alkyl, (trimethylsilyl)cyclopentadienyl, or amido zinc complexes [ZnR2] leads to the cube-type derivatives [RZn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (R = CH2SiMe3 (5), CH2Ph (6), Me (7), C5H4SiMe3 (8), N(SiMe3)2 (9)) via RH elimination. The amido complex 9 decomposes in the presence of ambient light to generate the alkyl derivative [{Me3Si(H)N(Me)2SiCH2}Zn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (10). The chloride complex 2 reacts with lithium cyclopentadienyl or lithium indenyl reagents to give the cyclopentadienyl or indenyl zinc derivatives [RZn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (R = C5H5 (11), C9H7 (12)). Treatment of 1 with copper(I) halides in toluene at room temperature leads to the adducts [XCu{(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)}] (X = Cl (13), I (14)). Complex 13 reacts with lithium bis(trimethylsilyl)amido in toluene to give the precipitation of [{Cu(mu4-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}2] (15). Complex 15 is prepared in a higher yield through the reaction of 1 with [{CuN(SiMe3)2}4] in toluene at 150 degrees C. The addition of triphenylphosphane to 15 in toluene produces the single-cube compound [(Ph3P)Cu{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (16). The X-ray crystal structures of 3, 8, 9, and 15 have been determined.     

Amido-bridged double-cube nitrido complexes containing titanium and magnesium/calcium

Treatment of the single cube nitrido complexes [(thf)x((Me3Si)2N)M((mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N))](M = Mg, x= 0; Ca, x= 1) with one equivalent of anilines NH2Ar in toluene affords the arylamido complexes [(ArHN)M((mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N))]n[M = Mg (3), n= 1, Ar = 4-MeC6H4; Ca (4), n= 2, Ar = 2,4,6-Me3C6H2]. The magnesium complex 3 has a single-cube structure whereas the X-ray crystal structure of the analogous calcium derivative 4 shows two cube-type azaheterometallocubane moieties Ca((mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)) held together by two mu-2,4,6-trimethylanilido ligands. Complexes 3 and 4 react with chloroform-d1 at room temperature to give the metal halide adducts [Cl2M((mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N))](M = Mg, Ca). A solution of 3 in n-hexane gave complex [(Mg2(mu3-N)(mu3-NH)5[Ti3(eta5-C5Me5)3(mu3-N)]2)(mu-NHAr)3] which shows three mu-4-methylanilido ligands bridging two [MgTi3N4] cube type cores according to an X-ray crystal structure determination.     

Novel nucleophilic reactivity of disulfido ligands coordinated parallel to M-M (M = Rh, Ir) bonds

Reaction of trans-[(MCp)(2)(mu-CH(2))(2)Cl(2)] (M = Rh, Ir; Cp = eta(5)-C(5)Me(5)) with Li(2)S(2) afforded the disulfido complexes [(MCp)(2)(mu-CH(2))(2)(mu-S(2)-S:S')] which were easily oxidized by O(2) to give the oxygenated complexes [(MCp)(2)(mu-CH(2))(2)(mu-SSO(2)-S:S')]. Although [(RhCp)(2)(mu-CH(2))(2)(mu-S(2)-S:S')] gave a complicated mixture when reacted with CH(2)Cl(2) or CHCl(3), [(IrCp)(2)(mu-CH(2))(2)(mu-S(2)-S:S')] reacted with both CH(2)Cl(2) and CHCl(3) to give the dithioformato complex [(IrCp)(2)(mu-CH(2))(2)(mu-S(2)CH-S:S')]Cl and the cyclotetrasulfido complex [((IrCp)(2)(mu-CH(2))(2))(2)(mu-S(4)-S:S':S":S"')]Cl(2). The oxygenated complexes [(RhCp)(2)(mu-CH(2))(2)(mu-SSO(2)-S:S')] reacted with hydrocarbyl halides to afford bridging hydrocarbyl thiolato complexes accompanied by the generation of SO(2) gas. These complexes have been characterized by NMR spectroscopy, ESI-MS, and X-ray diffraction.     

Synthesis, characterization, and structure of cyclopenta[c]thiophenes and their manganese complexes

1,3-Diaryl-4H-cyclopenta[c]thiophenes are efficiently prepared from 1,2-diaroylcyclopentadienes by use of Lawesson's reagent. eta5-Cyclopenta[c]thienyl complexes, [Mn(eta5-SC7H3-1,3-R2)(CO)3] (R = Me, Ph), are prepared in high yield by ligand substitution reactions of [MnBr(CO)5] with [SnMe3(SC7H3-1,3-R2)]. Alternatively, thiation with P4S10/NaHCO3 converts [Mn{eta5-1,2-C5H3(COR)2)(CO)3] to [Mn(eta5-SC7H3-1,3-R2)(CO)3] (R = Ph, 4-tolyl, 4-MeOC6H4, benzo[2,3-b]thienyl). The molecular structures of complexes with R = Me, Ph show planar eta5-cyclopenta[c]thienyl ligands, with the manganese atom slightly displaced away from the ring-fusion bond.     

Arene-ruthenium complexes of an acyclic thiolate-thioether and tridentate thioether derivatives resulting from ring-closure reactions

The reaction of [(eta(6)-arene)RuCl(2)](2) (arene = C(6)Me(6), 1,4-MeC(6)H(4)CHMe(2)) with a large excess of the dianion of bis(2-mercaptoethyl) sulfide, (HSCH(2)CH(2))(2)S, obtained from deprotonation of the dithiol with freshly prepared NaOMe, gives the deep red, monomeric complexes [(eta(6)-arene)Ru(eta(3)-C(4)H(8)S(3))] (arene = C(6)Me(6) (5), 1,4-MeC(6)H(4)CHMe(2) (6)) in which the dianion is bound to the metal atom through one thioether and two thiolate sulfur atoms. Complex 5 reacts with [(eta(6)-C(6)Me(6))RuCl(2)](2) (4) in a 2:1 mole ratio to give a quantitative yield of the chloride salt of a binuclear cation [((eta(6)-C(6)Me(6))Ru)(2)Cl(mu(2)-eta(2):eta(3)-C(4)H(8)S(3))](+) (7) in which the thiolate sulfur atoms of the [(eta(6)-C(6)Me(6))Ru(eta(3)-C(4)H(8)S(3))] group bridge to a (eta(6)-C(6)Me(6))RuCl unit. This compound is also obtained directly from the reaction of 4 with the dithiolate, if the Ru dimer is used in large excess. The binuclear complex [((eta(6)-C(6)Me(6))Ru)(2)(MeCN)(mu(2)-eta(2):eta(3)-C(4)H(8)S(3))](PF(6))(2).MeCN, (9)(PF(6))(2).MeCN, is obtained by treatment of (7)Cl with NH(4)PF(6) in acetonitrile. Protonation of 5 with HCl gave the mono- and diprotonated derivatives viz. [(eta(6)-C(6)Me(6))Ru(eta(3)-C(4)H(9)S(3))]Cl, (8)Cl, and [(eta(6)-C(6)Me(6))Ru(eta(3)-C(4)H(10)S(3))]Cl(2), (10)Cl(2), respectively. The reaction of 5 with methyl iodide gives both the mono- and di-S-methylated derivatives. Treatment of 5 with dibromoalkanes, Br(CH(2))(n)Br (n = 1-5), effects ring closure to give the (eta(6)-C(6)Me(6))Ru dications containing the trithia mesocyclic zS3 (z = 8-12) ligands, isolated as their PF(6) salts. The X-ray crystal structures of 5, 6, the solvates of (7)Cl and (9)(PF(6))(2), and the trithia mesocyclic Ru complexes (eta(6)-C(6)Me(6))Ru(zS3)(PF(6))(2) (z = 8-11) are reported.     

Reactivity of molybdenum and rhenium hydroxo-carbonyl complexes toward organic electrophiles

The hydroxo compounds [Re(OH)(CO)(3)(N-N)] (N-N=bipy, 2 a; Me(2)-bipy, 2 b) were prepared in a biphasic H(2)O/CH(2)Cl(2) medium by reaction of [Re(OTf)(CO)(3)(N-N)] with KOH. In contrast, when anhydrous CH(2)Cl(2) was used, the binuclear hydroxo-bridged compound [[Re(CO)(3)(bipy)](2)(mu-OH)]OTf (3-OTf) was obtained. Compound [Re(OH)(CO)(3)(Me(2)-bipy)] (2 b) reacted with phenyl acetate or vinyl acetate to afford [Re(OAc)(CO)(3)(Me(2)-bipy)] (4) and phenol or acetaldehyde, respectively. The reactions of [Mo(OH)(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (1), 2 a, and 2 b toward several unsaturated organic electrophiles were studied. The reaction of 1 with (p-tolyl)isocyanate afforded an adduct of N,N'-di(p-tolyl)urea and the carbonato-bridged compound [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](2)(mu-eta(1)(O),eta(1)(O)-CO(3))] (5). In contrast, the reaction of 2 a with phenylisocyanate afforded [Re(OC(O)NHPh)(CO)(3)(bipy)] (6); this results from formal PhNCO insertion into the O-H bond. On the other hand, compounds [Mo[SC(O)NH(p-tolyl)](eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (7), [Re[SC(O)NH(p-tolyl)](CO)(3)(Me(2)-bipy)] (8 a), and [Re[SC(O)NHEt](CO)(3)(Me(2)-bipy)] (8 b) were obtained by reaction of 1 or 2 b with the corresponding alkyl or aryl isothiocyanates. In those cases, RNCS was inserted into the M-O bond. The reactions of 1, 2 a, and 2 b with dimethylacetylenedicarboxylate (DMAD) gave the complexes [Mo[C(OH)-C(CO(2)Me)C(CO(2)Me)-O](eta(3)-C(3)H(4)-Me-2)(CO)(phen)] (9) and [Re[C(OH)C(CO(2)Me)C(CO(2)Me)O](CO)(2)(N-N)] (N-N=bipy, 10 a; Me(2)-bipy, 10 b). The molecules of these compounds contain five-membered metallacycles that are the result of coupling between the hydroxo ligand, DMAD, and one of the CO ligands. The new compounds were characterized by a combination of IR and NMR spectroscopy, and for [[Re(CO)(3)(bipy)(2)(mu-OH)]BF(4) (3-BF(4)), 4, 5, 6, 7, 8 b, 9, and 10 b, also by means of single-crystal X-ray diffraction.     

Ammonolysis of mono(pentamethylcyclopentadienyl) titanium(IV) derivatives

Ammonolyses of mono(pentamethylcyclopentadienyl) titanium(IV) derivatives [Ti(eta5-C5Me5)X3] (X = NMe2, Me, Cl) have been carried out in solution to give polynuclear nitrido complexes. Reaction of the tris(dimethylamido) derivative [Ti(eta5-C5Me5)(NMe2)3] with excess of ammonia at 80-100 degrees C gives the cubane complex [[Ti(eta5-C5Me5)]4(mu3-N)4] (1). Treatment of the trimethyl derivative [Ti(eta5-C5Me5)Me3] with NH3 at room temperature leads to the trinuclear imido-nitrido complex [[Ti(eta/5-CsMes)(mu-NH)]3(mu3-N)] (2) via the intermediate [[Ti(eta5-C5Me5)Me]2(mu-NH)2] (3). The analogous reaction of [Ti(eta5-C5Me5)Me3] with 2,4,6-trimethylaniline (ArNH2) gives the dinuclear imido complex [[Ti(eta5-C5Me5)Me])2(mu-NAr)2] (4) which reacts with ammonia to afford [[Ti(eta5-C5Me5)(NH2)]2(mu-NAr)2] (5). Complex 2 has been used, by treatments with the tris(dimethylamido) derivatives [Ti(eta5-C5H5-nRn)(NMe2)3], as precursor of the cubane nitrido systems [[Ti4(eta5-C5Me5)3(eta5-C5H5-nRn)](mu3-N)4] [R = Me n = 5 (1), R = H n = 0 (6), R = SiMe3 n = 1 (7), R = Me n = 1 (8)] via dimethylamine elimination. Reaction of [Ti(eta5-C5Me5)Cl3] or [Ti(eta5-C5Me5)(NMe2)Cl2] with excess of ammonia at room temperature gives the dinuclear complex [[Ti2(eta5-C5Me5)2Cl3(NH3)](mu-N)] (9) where an intramolecular hydrogen bonding and a nonlineal nitrido ligand bridge the "Ti(eta5-C5Me5)Cl(NH3)" and "Ti(eta5-C5Me5)Cl2" moieties. The molecular structures of [[Ti(eta5-C5Me5)Me]2 (mu-NAr)2] (4) and [[Ti2(eta5-C5Me5)2Cl3(NH3)](mu-N)] (9) have been determined by X-ray crystallographic studies. Density functional theory calculations also have been conducted on complex 9 to confirm the existence of an intramolecular N-H...Cl hydrogen bond and to evaluate different aspects of its molecular disposition.     

Rhodium/iridium-titanium azaheterometallocubanes

Treatment of [[Ti(eta5-C5Me5)(mu-NH)]3(mu3-N)] (1) with the diolefin complexes [[MCl(cod)]2] (M = Rh, Ir; cod = 1,5-cyclooctadiene) in toluene afforded the ionic complexes [M-(cod)(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)]Cl [M = Rh (2), Ir (3)]. Reaction of complexes 2 and 3 with [Ag(BPh4)] in dichloromethane leads to anion metathesis and formation of the analogous ionic derivatives [M(cod)(mu3-NH)3Ti3-(eta5-C5Me5)3(mu3-N)][BPh4] [M = Rh (4), Ir (5)]. An X-ray crystal structure determination for 5 reveals a cube-type core [IrTi3N4] for the cationic fragment, in which 1 coordinates in a tripodal fashion to the iridium atom. Reaction of the diolefin complexes [[MCl(cod))2] (M = Rh, Ir) and [[RhCl(C2H4)2]2] with the lithium derivative [[Li(mu3-NH)2(mu3-N)-Ti3(eta5-C5Me5)3(mu3-N)]2] x C7H8 (6 C7H8) in toluene gave the neutral cube-type complexes [M(cod)(mu-NH)2(mu3-N)Ti3-(eta5-C5Me5)3(mu3-N)] [M = Rh (7), Ir (8)] and [Rh(C2H4)2(mu3-NH)2(mu3-N)Ti3(eta5-C5Me5)3(mu3-N)] (9), respectively. Density functional theory calculations have been carried out on the ionic and neutral azaheterometallocubane complexes to understand their electronic structures.     

Electron-structure calculations and bond order analysis using density functional theory of cationic dinuclear arene ruthenium complexes

The structure and nature of the metal-metal bonding interaction in the cationic complexes [(eta6-C6Me6)2Ru2(mu2-H)3]+ (1), [(eta6-C6Me6)2Ru2(mu2-H)2(mu2-1,4-SC6H4Br)]+ (2), [(eta6-C6Me6)2Ru2(mu2-H)(mu2-1,4-SC6H4Br)2]+ (3), and [(eta6-C6Me6)2Ru2(mu2-1,4-SC6H4Br)3]+ (4) have been studied at the density functional theory (DFT) level using molecular orbital (MO) theory, bond order (BO) analysis, bond decomposition energy (BDE), electron localization function (ELF), and Laplacian of the density methods. The results show that there is no direct bond between the two ruthenium atoms in 1-4, the MO interaction within the diruthenium backbone being stabilized by the bridging ligands. For complex 1, the ELF clearly shows that the bond within the diruthenium backbone is through the three bridging hydride ligands, which act as a sort of glue by forming three-center two-electron bonds characterized by (Ru, H, Ru) basins with 1.8 e mostly located in the H atomic basin.     

Novel Mo(V)-dithiolene compounds: characterization of nonsymmetric dithiolene complexes by electrospray ionization mass spectrometry

Three new Mo(V) dithiolene compounds have been synthesized by addition of alkynes ((Me(3)Si)(2)C(2) (TMSA), (Me(3)Si)(2)C(4), and (Ph)(2)C(4) to MoO(2)S(2)(2-) in a MeOH/NH(3) mixture: [Mo(2)(O)(2)(mu-S)(2)(eta(2)-S(2))(eta(2)-S(2)C(2)H(2))](2)(-) 1, [Mo(2)(O)(X)(mu-S)(2)(eta(2)-S(2))(eta(2)-S(2)C(2)Ph(C(2)Ph))](2-) 2 (X = O or S), and [Mo(2)(O)(2)(mu-S)(2)(eta(2)-S(2))(eta(2)-S(2)C(2)H(C(2)H))](2-) 3. The structure of 1 as determined by single-crystal X-ray diffraction study (space group Pbca, a = 13.3148(1) A, b = 15.7467(4) A, c = 28.4108(7) A, V = 5956.7(2) A(3)) is discussed. 2 and 3 have been identified by ESMS (electrospray mass spectrometry), (1)H NMR, (13)C NMR, and infrared spectroscopies. This investigation completes our previous study devoted to the addition of DPA (C(2)Ph(2)) to MoO(2)S(2)(2-) which led to [Mo(2)(O)(X)(mu-S)(2)(eta(2)-S(2))(eta(2)-S(2)C(2)Ph(2))](2-) 4 (X = O or S). A reaction scheme is proposed to explain the formation of the different species present in solution. The reactivity of the remaining nucleophilic site of these complexes (eta(2)-S(2)) toward dicarbomethoxyacetylene (DMA) is also discussed.     

Synthesis and Reaction of [MnRe(CO)_6(μ-SH)(μ-SC(H)PPr_3~i)(PPh_3)]

In recent years the chemistry of mono- or hetero-binuclear complexes containing metal-S(C) bonding modes is a very active field of research. Many useful applications of this kind of complexes have been exploited, such as industrial catalytic hydrodesulfurization (HDS)1,2 and transition metals mediated organic synthesis3-5. In this paper we report that the reduction and subsequent protonation of hetero-binuclear complex [MnRe(CO)6(-S2CPPri3)] occur with cleavage of metal-metal bond and o…     

Oxygen atom transfer reactions from dioxygen to phosphines via a bridging sulfur dioxide in a trinuclear cluster complex of rhenium, [(Ph(3)P)(2)N][Re(3)(mu(3)-S)(mu-S)(2)(mu-SO(2))Cl(6)(PMe(2)Ph)(3)

A trinuclear rhenium sulfide cluster complex, [(Ph(3)P)(2)N][Re(3)(mu(3)-S)(mu-S)(3)Cl(6)(PMe(2)Ph)(3)], synthesized from Re(3)S(7)Cl(7), dimethylphenylphosphine, and [(Ph(3)P)(2)N]Cl is readily converted to a bridging SO(2) complex, [(Ph(3)P)(2)N][Re(3)(mu(3)-S)(mu-S)(2)(mu-SO(2))Cl(6)(PMe(2)Ph)(3)], by reaction with O(2). The oxygen atoms on the SO(2) ligand react with phosphines or phosphites to form phosphine oxides or phosphates, and the original cluster complex is recovered. The reaction course has been monitored by (31)P NMR as well as by UV-vis spectroscopy. The catalytic oxygenation of PMePh(2) in the presence of the SO(2) complex shows that turnovers are 8 per hour at 23 degrees C in CDCl(3). The X-ray structures of the cluster complexes are described.     

Versatility of heterocyclic thioamides in the construction of a trinuclear cluster [Cu3I3(dppe)3 (SC5H4NH)] and Cu(I) linear polymers {Cu6(SC5H4NH)6I6}n x 2nCH3CN and {Cu(I)6 (SC3H6N2)6X6}n (X = Br, I)

Reaction of copper(I) iodide with pyridine-2-thione (2-SC5H4NH) and 1,2-bis(diphenylphosphino)ethane (dppe) in a CH3CN-CHCl3 mixture yielded a triangular cluster, [Cu3I3(mu2-P,P-dppe)3 (eta1-SC5H4NH)], 1. Similar reaction with 2-SC5H4NH and a series of diphosphanes, Ph2P-X-Ph2P {X = -CH2- (dppm), -(CH2)3- (dppp), -(CH2)4- (dppb), -CH=CH- (dppen)}, gave a novel iodo-bridged hexanuclear Cu(I) linear polymer,{Cu6(mu3-SC5H4NH)4 (mu2-SC5H4NH)2 (I4)(mu-I)2-}n x 2nCH3CN, 2. Reactions of copper(I) iodide/copper(I) bromide with 1,3-imidazolidine-2-thione (SC3H6N2) in a CH3CN-CHCl3 mixture yielded hexanuclear Cu(I) linear chain polymers, [{Cu6(mu3-SC3H6N2)2 (mu2-SC3H6N2)4X2 (mu-X)4}n] (X = Br, 4; I, 5). In compound 1, two iodide atoms and one dppe form the dinuclear Cu(mu2-I)2 (mu2-dppe)Cu core, and two dppe ligands bridge this core with the third Cu(I) center coordinated to 2-SC5H4NH via the S atom. The chain polymer 2 has a centrosymmetric hexanuclear central core, Cu6S6I4 (mu-I)2--, formed by dimerization of six-membered trinuclear motifs, Cu3(mu2-SC3H6N2)3I3 via (mu3-S) bonding modes of the thione ligand, and has four terminal and two bridging iodine atoms in trans-orientations. Linear chains are separated by the nonbonded acetonitrile molecules. In 4 and 5, three copper(I) bromide or copper(I) iodide moieties and three SC3H6N2 ligands combined via bridging S donor atoms to form the six-membered trinuclear Cu3(mu2-SC3H6N2)3I3 cores which polymerized via S and X atoms in a side-on fashion to form linear chain polymers, [{Cu6(mu3-SC3H6N2)2 (mu2-SC3H6N2)4X2(mu-X)4}n]. The (mu3-S) modes of bonding of neutral heterocyclic thioamides are first examples, as are trinuclear cluster and linear polymers rare examples in copper chemistry.     

Complexation of the triply-bonded dirhenium(II) complex Re(2)Cl(4)(mu-dppm)(2) (dppm = Ph(2)PCH(2)PPh(2)) by up to three acetylene molecules

The triply bonded dirhenium(II) synthons Re(2)X(4)(mu-dppm)(2) (X = Cl, Br; dppm = Ph(2)PCH(2)PPh(2)) react with acetylene at room temperature in CH(2)Cl(2) and acetone to afford the bis(acetylene) complexes Re(2)X(4)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(eta(2)-HCCH) (X = Cl (3), Br(4)). Compound 3 has been derivatized by reaction with RNC ligands in the presence of TlPF(6) to give unsymmetrical complexes of the type [Re(2)Cl(3)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(eta(2)-HCCH)(CNR)]PF(6) (R = Xyl (5), Mes (6), t-Bu (7)), in which the RCN ligand has displaced the chloride ligand cis to the eta(2)-HCCH ligand. The reaction of 3 with an additional 1 equiv of acetylene in the presence of TlPF(6) gives the symmetrical all-cis isomer of [Re(2)Cl(3)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(eta(2)-HCCH)(2)]PF(6) (8). The two terminal eta(2)-HCCH ligands in 8 are very labile and can be displaced by CO and XylNC to give the complexes [Re(2)Cl(3)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(L)(2)]Y (L = CO when Y = PF(6) (9); L = CO when Y = (PF(6))(0.5)/(H(2)PO(4))(0.5) (10); L = XylNC when Y = PF(6) (11)). These substitution reactions proceed with retention of the all-cis stereochemistry. Single-crystal X-ray structure determinations have been carried out on complexes 3, 5, 8, 10, and 11. In no instance have we found that the acetylene ligands undergo reductive coupling reactions.     

Preparation and characterization of diarylphosphazene and diarylphosphinohydrazide complexes of titanium, tungsten and ruthenium and phosphorylketimido complexes of rhenium

Reaction of the proligand Ph2PN(SiMe3)2 (L1) with WCl6 gives the oligomeric phosphazene complex [WCl4(NPPh2)]n, 1 and subsequent reaction with PMe2Ph or NBu4Cl gives [WCl4(NPPh2)(PMe2Ph)] (2) or [WCl5(NPPh2)][NBu4] (3), respectively. DF calculations on [WCl5(NPPh2)][NBu4] show a W=N double bond (1.756 A) and a P-N bond distance of 1.701 A, which combined with the geometry about the P atom suggests, there is no P-N multiple bonding. Reaction of L1 with [ReOX3(PPh3)2] in MeCN (X = Cl or Br) gives [ReX2(NC(CH3)P(O)Ph2)(MeCN)(PPh3)](X = Cl, 4, X = Br, 5) which contains the new phosphorylketimido ligand. It is bound to the rhenium centre with a virtually linear Re-N-C arrangement (Re-N-C angle = 176.6 degrees, when X = Cl) and there is multiple bonding between Re and N (Re-N = 1.809(7) A when X = Cl). The proligand Ph2PNHNMe2(L2H) reacts with [(C5H5)TiCl3] to give [(C5H5)TiCl2(Me2NNPPh2)] (6). An X-ray crystal structure of the complex shows the ligand (L2) is bound by both nitrogen atoms. Reaction of the proligands Ph2PNHNR2[R2 = Me2 (L2H), -(CH2CH2)2NCH3 (L3H), (CH2CH2)2CH2 (L4H)] with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave [RuCl2(eta6-p-MeC6H4iPr)L] {L = L2H (7), L3H (8), L4H (9)}. The X-ray crystal structures of 7-9 confirmed that the phosphinohydrazine ligand is neutral and bound via the phosphorus only. Reaction of complexes 7-9 with AgBF4 resulted in chloride ion abstraction and the formation of the cationic species [RuCl(6-p-MeC6H4iPr)(L)]+ BF4- {(L = L2H (10), L3H (11), L4H (12)}. Finally, reaction of complex 6 with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave the binuclear species [(eta6-p-MeC6H4iPr)Cl2Ru(mu2,eta3-Ph2PNNMe2)TiCl2(C5H5)], 13.     

Titanium alkali metal nitrido complexes

Treatment of [(Ti(eta5-C5Me5)(mu-NH))3(mu3-N)] with alkali metal bis(trimethylsilyl)amido reagents in toluene afforded the complexes [M(mu3-N)(mu3-NH)2[Ti3(mu5-C5Me5)3(mu3-N)]]2 (M = Li (2), Na, (3), K (4)). The molecular structures of 2 and 3 have been determined by X-ray crystallographic studies and show two azaheterometallocubane cores [MTi3N4] linked by metal-nitrogen bonds. Reaction of the lithium derivative 2 with chlorotrimethylsilane or trimethyltin chloride in toluene gave the incomplete cube nitrido complexes [Ti3(eta5-C5Me5)3(mu-NH)2(mu-NMMe3)(mu3-N)] (M = Si (5), Sn (6)). A similar reaction with indium(I) or thallium(I) chlorides yielded cube-type derivatives [M(mu3-N)(mu3-NH)2[Ti(eta5-C5Me5)3(mu3-N)] (M=In (7), Tl (8)).     

Synthesis and Reaction of [MnRe（CO）6（μ—SH）（μ—SC（H）PPr^i3）（PPh3）]

The synthesis,the crystal structure and the reaction of the hetero-binuclear complex[MnRe(CO)6(μ-SH）（μ-SC(H)PPr^i3)(PPh3)] are reported.The results of single crystal X-ray structure analysis showed that the fragments Mn(CO)3 and Re(CO)3 were bridged by SH and SC(H)PPr^i3.The title complexes can react with Bu^nLi and RX forming complexes MnRe(CO)6(μ-SR）（μ-SC(H)PPr^i3)(PPh3)](R=Me,CH2CH=CH2,SnBu3^n).     

Chelated hydrazido(3-)rhenium(V) complexes: on the way to the nitrido-M(V) core (M = Tc, Re)

Neutral and asymmetrical hydrazido(3-)rhenium(V) heterocomplexes of the type [Re(eta(2)-L(4))(L(n))(PPh(3))] (eta(2)-L(4) = NNC(SCH(3))S; H(2)L(1) = S-methyl beta-N-((2-hydroxyphenyl)ethylidene)dithiocarbazate, 1, H(2)L(2) = S-methyl beta-N-((2-hydroxyphenyl)methylidene)dithiocarbazate, 2) are prepared via ligand-exchange reactions in ethanolic solutions starting from [Re(V)(O)Cl(4)](-) in the presence of PPh(3) or from [Re(V)(O)Cl(3)(PPh(3))(2)]. The distorted octahedral coordination sphere of these compounds is saturated by a chelated hydrazido group, a facially ligated ONS Schiff base, and PPh(3). Reduction-substitution reactions starting from [NH(4)][Re(VII)O(4)] in acidic ethanolic mixtures containing PPh(3) and H(2)L(n) (or its dithiocarbazic acid precursor H(3)L(4)) produce another example of chelated hydrazido(3-) rhenium(V) derivative, namely [Re(eta(2)-L(4))Cl(2)(PPh(3))(2)], 3. On the contrary, the N-methyl-substituted dithiocarbazic acid H(2)L(3) reacts with perrhenate to give the known nitrido complex [Re(N)Cl(2)(PPh(3))(2)]. Rhenium(V) complexes incorporating the robust eta(2)-hydrazido moiety represent key intermediates helpful for the comprehension of the reaction pathway which generates nitridorhenium(V) species starting from oxo precursors. An essential requirement for the stabilization of such chelated hydrazido-Re(V) units is the triple deprotonation at the hydrazine nitrogens, thereby providing efficient pi-electron circulation in the resulting five-membered ring. The thermal stability of these units is affected by the nature of the anchoring donor, thione sulfur ensuring stronger chelation than nitrogen and oxygen. The eta(2)-hydrazido complexes are characterized by conventional physicochemical techniques, including the X-ray crystal structure determination of 1 and 3.     

Dithiolate complexes of manganese and rhenium: X-ray structure and properties of an unusual mixed valence cluster Mn3(CO)6(mu-eta2-SCH2CH2CH2S)3

Treatment of Mn(2)(CO)(10) with 3,4-toluenedithiol and 1,2-ethanedithiol in the presence of Me(3)NO.2H(2)O in CH(2)Cl(2) at room temperature afforded the dinuclear complexes Mn(2)(CO)(6)(mu-eta(4)-SC(6)H(3)(CH(3))S-SC(6)H(3)(CH(3))S) (1), and Mn(2)(CO)(6)(mu-eta(4)-SCH(2)CH(2)S-SCH(2)CH(2)S) (2), respectively. Similar reactions of Re(2)(CO)(10) with 3,4-toluenedithiol, 1,2-benzenedithiol, and 1,2-ethanedithiol yielded the dirhenium complexes Re(2)(CO)(6)(mu-eta(4)-SC(6)H(3)(CH(3))S-SC(6)H(3)(CH(3))S) (3), Re(2)(CO)(6)(mu-eta(4)-SC(6)H(4)S-SC(6)H(4)S) (4), and Re(2)(CO)(6)(SCH(2)CH(2)S-SCH(2)CH(2)S) (5), respectively. In contrast, treatment of Mn(2)(CO)(10) with 1,3-propanedithiol afforded the trimanganese compound Mn(3)(CO)(6)(mu-eta(2)-SCH(2)CH(2)CH(2)S)(3) (6), whereas Re(2)(CO)(10) gave only intractable materials. The molecular structures of 1, 3, and 6 have been determined by single-crystal X-ray diffraction studies. The dimanganese and dirhenium carbonyl compounds 1-5contain a binucleating disulfide ligand, formed by interligand disulfide bond formation between two dithiolate ligands identical in structure to that of the previously reported dimanganese complex Mn(2)(CO)(6)(mu-eta(4)-SC(6)H(4)S-SC(6)H(4)S). Complex 6, on the other hand, forms a unique example of a mixed-valence trimangenese carbonyl compound containing three bridging 1,3-propanedithiolate ligands. The solution properties of 6 have been investigated by UV-vis and EPR spectroscopies as well as electrochemical techniques.