Disulfides of manganese carbonyl. Synthesis of Mn(2)(CO)(7)(mu-S2) and its reactions with tertiary phosphines and arsines

The reaction of Mn(2)(CO)(9)(NCMe) with thiirane yielded the sulfidomanganese carbonyl compounds Mn(2)(CO)(7)(mu-S(2)), 2, Mn(4)(CO)(15)(mu(3)-S(2))(mu(4)-S(2)), 3, and Mn(4)(CO)(14)(NCMe)(mu(3)-S(2))(mu(4)-S(2)), 4, by transfer of sulfur from the thiirane to the manganese complex. Compound 3 was obtained in better yield from the reaction of 2 with CO, and compound 4 is obtained from the reaction of 2 with NCMe. The reaction of 2 with PMe(2)Ph yielded the tetramanganese disulfide Mn(4)(CO)(15)(PMe(2)Ph)(2)(mu(3)-S)(2), 5, and S=PMe(2)Ph. The reaction of 5 with PMe(2)Ph yielded Mn(4)(CO)(14)(PMe(2)Ph)(3)(mu(3)-S)(2), 6, by ligand substitution. The reaction of 2 with AsMe(2)Ph yielded the new complexes Mn(4)(CO)(14)(AsMe(2)Ph)(2)(mu(3)-S(2))(2), 7, Mn(4)(CO)(14)(AsMe(2)Ph)(mu(3)-S(2))(mu(4)-S(2)), 8, Mn(6)(CO)(20)(AsMe(2)Ph)(2)(mu(4)-S(2))(3), 9, and Mn(2)(CO)(6)(AsMe(2)Ph)(mu-S(2)), 10. Reaction of 2 with AsPh(3) yielded the monosubstitution derivative Mn(2)(CO)(6)(AsPh(3))(mu-S(2)), 11. Reaction of 7 with PMe(2)Ph yielded Mn(4)(CO)(15)(AsMe(2)Ph)(2)(mu(3)-S)(2), 12. The phosphine analogue of 7, Mn(4)(CO)(14)(PMe(2)Ph)(2)(mu(3)-S(2))(2), 13, was prepared from the reaction of Mn(2)(CO)(9)(PMe(2)Ph) with Me(3)NO and thiirane. Compounds 2-9 and 11-13 were characterized by single-crystal X-ray diffraction. Compound 2 contains a disulfido ligand that bridges two Mn(CO)(3) groups that are joined by a Mn-Mn single bond, 2.6745(5) A in length. A carbonyl ligand bridges the Mn-Mn bond. Compounds 3 and 4 contain four manganese atoms with one triply bridging and one quadruply bridging disulfido ligand. Compounds 5 and 6 contain four manganese atoms with two triply bridging sulfido ligands. Compound 9 contains three quadruply bridging disulfido ligands imbedded in a cluster of six manganese atoms.     

Reactions of thioethers with Mn(2)(CO)(7)(mu-S(2)) proceed with CO displacement and insertion of the sulfur atom into the Mn-Mn bond

The reaction of Mn(2)(CO)(7)(mu-S(2)) (2) with SMe(2) yielded the new complexes Mn(2)(CO)(6)(mu-S(2))(mu-SMe(2)) (3) and Mn(4)(CO)(14)(SMe(2))(mu(3)-S(2))(mu(4)-S(2)) (4) in 18 and 41% yields, respectively. The reaction of 2 with the cyclic thioether thietane SCH(2)CH(2)CH(2) yielded the new complexes Mn(2)(CO)(6)(mu-S(2))(mu-SCH(2)CH(2)CH(2)) (5) and Mn(4)(CO)(14)(SCH(2)CH(2)CH(2))(mu(3)-S(2))(mu(4)-S(2)) (6) in 12 and 52% yields, respectively, and the reaction of 2 with 1,4,9-trithiacyclododecane (12S3) yielded Mn(2)(CO)(6)(mu-12S3)(mu-S(2)) (7) and Mn(4)(CO)(14)(12S3)(mu(3)-S(2))(mu(4)-S(2)) (8) in 8 and 24% yields, respectively. Compounds 3 and 5-7 were characterized crystallographically. Compounds 3, 5, and 7 have similar structures in which the thioether ligand has replaced the bridging carbonyl ligand of 2 and its sulfur atom has been inserted into the manganese-manganese bond. The two manganese atoms are not mutually bonded, and two Mn(CO)(3) groups are held together through the bridging disulfido ligand and the bridging sulfur atom of the thioether ligand. Compound 6 contains a Mn(4)(mu(3)-S(2))(mu(4)-S(2)) moiety without metal-metal bonds. On the basis of spectroscopic data, compounds 4 and 8 are believed to have similar structures.     

Dinuclear oxidative addition of N-H and S-H bonds at chromium. Reaction of (*)Cr(CO)(3)(C(5)Me(5)) with [o-(HA)C(6)H(4)S-Cr(CO)(3)(C(5)Me(5))] (A = S,NH) yielding [eta(2)-o-(mu-A)C(6)H(4)S-Cr(C(5)Me(5))](2) and H-Cr(CO)(3)(C(5)Me(5))

Reaction of the 17-electron radical (*)Cr(CO)(3)Cp* (Cp* = C(5)Me(5)) with 0.5 equiv of 2-aminophenyl disulfide [(o-H(2)NC(6)H(4))(2)S(2)] results in rapid oxidative addition to form the initial product (o-H(2)N)C(6)H(4)S-Cr(CO)(3)Cp*. Addition of a second equivalent of (*)Cr(CO)(3)Cp* to this solution results in the formation of H-Cr(CO)(3)Cp* as well as (1)/(2)[[eta(2)-o-(mu-NH)C(6)H(4)S]CrCp*](2). Spectroscopic data show that (o-H(2)N)C(6)H(4)S-Cr(CO)(3)Cp* loses CO to form [eta(2)-(o-H(2)N)C(6)H(4)S]Cr(CO)(2)Cp*. Attack on the N-H bond of the coordinated amine by (*)Cr(CO)(3)Cp* provides a reasonable mechanism consistent with the observation that both chelate formation and oxidative addition of the N-H bond are faster under argon than under CO atmosphere. The N-H bonds of uncoordinated aniline do not react with (*)Cr(CO)(3)Cp*. Reaction of the 2 mol of (*)Cr(CO)(3)Cp* with 1,2-benzene dithiol [1,2-C(6)H(4)(SH)(2)] yields the initial product (o-HS)C(6)H(4)S-Cr(CO)(3)Cp and 1 mol of H-Cr(CO)(3)Cp*. Addition of 1 equiv more of (*)Cr(CO)(3)Cp to this solution also results in the formation of 1 equiv of H-Cr(CO)(3)Cp*, as well as the dimeric product (1)/(2)[[eta(2)-o-(mu-S)C(6)H(4)S]CrCp*](2). This reaction also occurs more rapidly under Ar than under CO, consistent with intramolecular coordination of the second thiol group prior to oxidative addition. The crystal structures of [[eta(2)-o-(mu-NH)C(6)H(4)S]CrCp*](2) and [[eta(2)-o-(mu-S)C(6)H(4)S]CrCp*](2) are reported.     

Insertion of a bis(phosphine)platinum group into the S-S bond of Mn(2)(CO)(7)(mu-S(2))

The reaction of Mn(2)(CO)(7)(mu-S(2)), 1, with Pt(PPh(3))(2)(PhC(2)Ph) yielded the new complex, Mn(2)(CO)(6)Pt(PPh(3))(2)(mu(3)-S)(2), 3, by loss of CO and insertion of a Pt(PPh(3))(2) group into the S-S bond of 1. Complex 3 was characterized crystallographically and was found to consist of an open Mn(2)Pt cluster with one Mn-Mn bond, 2.8154(14) A, one Mn-Pt bond, 2.9109(10) A, and two triply bridging sulfido ligands. Compound 3 reacts with CO to form adduct Mn(2)(CO)(6)(mu-CO)Pt(PPh(3))(2)(mu(3)-S)(2), 4. Compound 4 also contains an open Mn(2)Pt cluster with two triply bridging sulfido ligands but has only one metal-metal bond, Mn-Mn = 2.638(2) A. Under nitrogen, compound 4 readily loses CO and reverts back to 3.     

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.     

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).     

Stable diplatinum complexes with functional thiolato bridges from dialkylation of [Pt2(mu-S)2(P-P)2] [P-P=2 x PPh3, Ph2P(CH2)3PPh2

The normally robust monoalkylated complexes [Pt(2)(mu-S)(mu-SR)(PPh(3))(4)](+) can be activated towards further alkylation. Dialkylated complexes [Pt(2)(mu-SR)(2)(P-P)(2)](2+) (P-P=2 x PPh(3), Ph(2)P(CH(2))(3)PPh(2)) can be stabilized and isolated by the use of electron-rich and aromatic halogenated substituents R [e.g. 3-(2-bromoethyl)indole and 2-bromo-4'-phenylacetophenone] and 1,3-bis(diphenylphosphino)propane [Ph(2)P(CH(2))(3)PPh(2) or dppp] which enhances the nucleophilicity of the {Pt(2)(mu-S)(2)} core. This strategy led to the activation of [Pt(2)(mu-S)(mu-SR)(PPh(3))(4)](+) towards R-X as well as isolation and crystallographic elucidation of [Pt(2)(mu-SC(10)H(10)N)(2)(PPh(3))(4)](PF(6))(2) (2a), [Pt(2)(mu-SCH(2)C(O)C(6)H(4)C(6)H(5))(2)(PPh(3))(4)](PF(6))(2) (2b), and a range of functionalized-thiolato bridged complexes such as [Pt(2)(mu-SR)(2)(dppp)(2)](PF(6))(2) [R= -CH(2)C(6)H(5) (8a), -CH(2)CHCH(2) (8b) and -CH(2)CN (8c)]. The stepwise alkylation process is conveniently monitored by Electrospray Ionisation Mass Spectrometry, allowing for a direct qualitative comparison of the nucleophilicity of [Pt(2)(mu-S)(2)(P-P)(2)], thereby guiding the bench-top synthesis of some products observed spectroscopically.     

Reaction products of W(CO)(6) with formamidines; electronic structure of a W(2)(mu-CO)(2) core with unsymmetric bridging carbonyls

Reactions of W(CO)(6) with formamidines contrast with those of Mo(CO)(6) and Cr(CO)(6) in that the former do not yield quadruply bonded dimetal species. From the reaction of W(CO)(6) with HDAniF (HDAniF = N,N'-di-p-anisylformamidine), several new ditungsten carbonyl compounds (W(2)(mu-CO)(2)(mu-DAniF)(2)(eta(2)-DAniF)(2) (1), W(2)(mu-CO)(2)(mu-DAniF)(2)(eta(2)-DAniF)(eta(2)-CH(2)DAniF) (2), and W(2)(mu-CO)(mu-CNC(6)H(4)OCH(3))(mu-DAniF)(2)(eta(2)-DAniF)(2) (3)) have been isolated and fully characterized. In 2, CH(2)DAniF represents a DAniF ligand in which a methylene group has been added to one of the nitrogen atoms. This ligand binds to the tungsten atom using a nitrogen and a carbon atom. Compound 1 has a tungsten-tungsten bond distance of 2.476(1) A and a planar W(2)(mu-CO)(2) core structure which has C(2)(h)() symmetry with short and long W-C bond distances (1.99(1) and 2.28(1) A, respectively). DFT calculations on a model of 1 indicate that (a) the C(2)(h)() instead of D(2)(h)() symmetry of the ditungsten core may be attributed to W --> CO pi back-bonding interactions and (b) the bond between the tungsten atoms may be formulated as a double bond. The new tetragonal paddlewheel compound W(2)(DAniF)(4) (4) and the edge-sharing bioctahedron W(2)(mu-O)(mu-NC(6)H(3)Cl(2))(mu-D(Cl)PhF)(2)(eta(2)-D(Cl)PhF)(2) (5) (D(Cl)PhF = N,N'-di-(3,5-dichlorophenyl)formamidinate) have also been prepared.     

Reaction of nido-7,8-C(2)B(9)H(13) with Dicobalt Octacarbonyl: Crystal Structures of the Complexes [Co(2)(CO)(2)(eta(5)-7,8-C(2)B(9)H(11))(2)], [Co(2)(CO)(PMe(2)Ph)(eta(5)-7,8-C(2)B(9)H(11))(2)], and [CoCl(PMe(2)Ph)(2)(eta(5)-7,8-C(2)B(9)H(11))

The compounds [Co(2)(CO)(8)] and nido-7,8-C(2)B(9)H(13) react in CH(2)Cl(2) to give a complex mixture of products consisting primarily of two isomers of the dicobalt species [Co(2)(CO)(2)(eta(5)-7,8-C(2)B(9)H(11))(2)] (1), together with small amounts of a mononuclear cobalt compound [Co(CO)(2)(eta(5)-10-CO-7,8-C(2)B(9)H(10))] (5) and a charge-compensated carborane nido-9-CO-7,8-C(2)B(9)H(11) (6). In solution, isomers 1a and 1b slowly equilibrate. However, column chromatography allows a clean separation of 1a from the mixture, and a single-crystal X-ray diffraction study revealed that each metal atom is ligated by a terminal CO molecule and in a pentahapto manner by a nido-C(2)B(9)H(11) cage framework. The two Co(CO)(eta(5)-7,8-C(2)B(9)H(11)) units are linked by a Co-Co bond [2.503(2) ?], which is supported by two three-center two-electron B-H right harpoon-up Co bonds. The latter employ B-H vertices in each cage which lie in alpha-sites with respect to the carbons in the CCBBB rings bonded to cobalt. Addition of PMe(2)Ph to a CH(2)Cl(2) solution of a mixture of the isomers 1, enriched in 1b, gave isomers of formulation [Co(2)(CO)(PMe(2)Ph)(eta(5)-7,8-C(2)B(9)H(11))(2)] (2). Crystals of one isomer were suitable for X-ray diffraction. The molecule 2a has a structure similar to that of 1a but differs in that whereas one B-H right harpoon-up Co bridge involves a boron atom in an alpha-site of a CCBBB ring coordinated to cobalt, the other uses a boron atom in the beta-site. Reaction between 1b and an excess of PMe(2)Ph in CH(2)Cl(2) gave the complex [CoCl(PMe(2)Ph)(2)(eta(5)-7,8-C(2)B(9)H(11))] (3), the structure of which was established by X-ray diffraction. Experiments indicated that 3 was formed through a paramagnetic Co(II) species of formulation [Co(PMe(2)Ph)(2)(eta(5)-7,8-C(2)B(9)H(11))]. Addition of 2 molar equiv of CNBu(t) to solutions of either 1a or 1b gave a mixture of two isomers of the complex [Co(2)(CNBu(t))(2)(eta(5)-7,8-C(2)B(9)H(11))(2)] (4). NMR data for the new compounds are reported and discussed.     

Synthesis and structure of W(eta(2)-mp)(2)(CO)(3) (mp = monoanion of 2-mercaptopyridine) and its reactions with 2,2'-pyridine disulfide and/or NO to yield W(eta(2)-mp)(4), W(eta(2)-mp)(2)(NO)(2), and W(eta(2)-mp)(3)(NO)

Oxidative addition of the sulfur-sulfur bond of 2,2'-pyridine disulfide (C(5)H(4)NS-SC(5)H(4)N) with L(3)W(CO)(3) [L = pyridine, (1)/(3)CHPT; CHPT = cycloheptatriene] in methylene chloride solution yields the seven-coordinate W(II) thiolate complex W(eta(2)-mp)(2)(CO)(3) (mp = monoanion of 2-mercaptopyridine). This complex undergoes slow further oxidative addition with additional pyridine disulfide, yielding W(eta(2)- mp)(4). Reaction of W(eta(2)-mp)(2)(CO)(3) with NO results in quantitative formation of the six-coordinate W(0) complex W(eta(2)-mp)(2)(NO)(2). Reaction of W(eta(2)-mp)(2)(CO)(3) with NO in the presence of added pyridine disulfide yields the seven-coordinate W(II) nitrosyl complex W(eta(2)-mp)(3)(NO) as well as W(eta(2)-mp)(2)(NO)(2) and trace amounts of W(eta(2)-mp)(4). The complex W(eta(2)-mp)(3)(NO) is formed during the course of the reaction and not by reaction of W(eta(2)-mp)(4) or W(eta(2)-mp)(2)(NO)(2) with NO under these conditions. The crystal structures of W(eta(2)- mp)(2)(CO)(3), W(eta(2)-mp)(2)(NO)(2), and W(eta(2)-mp)(3)(NO) are reported.     

Substitution reactions of [Ru(dppe)(CO)(H(2)O)(3)][OTf](2)

The labile nature of the coordinated water ligands in the organometallic aqua complex [Ru(dppe)(CO)(H(2)O)(3)][OTf](2) (1) (dppe = Ph(2)PCH(2)CH(2)PPh(2); OTf = OSO(2)CF(3)) has been investigated through substitution reactions with a range of incoming ligands. Dissolution of 1 in acetonitrile or dimethyl sulfoxide results in the facile displacement of all three waters to give [Ru(dppe)(CO)(CH(3)CN)(3)][OTf](2) (2) and [Ru(dppe)(CO)(DMSO)(3)][OTf](2) (3), respectively. Similarly, 1 reacts with Me(3)CNC to afford [Ru(dppe)(CO)(CNCMe(3))(3)][OTf](2) (4). Addition of 1 equiv of 2,2'-bipyridyl (bpy) or 4,4'-dimethyl-2,2'-bipyridyl (Me(2)bpy) to acetone/water solutions of 1 initially yields [Ru(dppe)(CO)(H(2)O)(bpy)][OTf](2) (5a) and [Ru(dppe)(CO)(H(2)O)(Me(2)bpy)][OTf](2) (6a), in which the coordinated water lies trans to CO. Compounds 5a and 6a rapidly rearrange to isomeric species (5b, 6b) in which the ligated water is trans to dppe. Further reactivity has been demonstrated for 6b, which, upon dissolution in CDCl(3), loses water and coordinates a triflate anion to afford [Ru(dppe)(CO)(OTf)(Me(2)bpy)][OTf] (7). Reaction of 1 with CH(3)CH(2)CH(2)SH gives the dinuclear bridging thiolate complex [[(dppe)Ru(CO)](2)(mu-SCH(2)CH(2)CH(3))(3)][OTf] (8). The reaction of 1 with CO in acetone/water is slow and yields the cationic hydride complex [Ru(dppe)(CO)(3)H][OTf] (9) via a water gas shift reaction. Moreover, the same mechanism can also be used to account for the previously reported synthesis of 1 upon reaction of Ru(dppe)(CO)(2)(OTf)(2) with water (Organometallics 1999, 18, 4068).     

Germanium-rich pentaruthenium carbonyl clusters including Ru(5)(CO)(11)(mu-GePh(2))(4)(mu(5)-C) and its reactions with hydrogen

The reaction of Ru(5)(CO)(15)(mu(5)-C), 1, with Ph(3)GeH at 150 degrees C has yielded two new germanium-rich pentaruthenium cluster complexes: Ru(5)(CO)(11)(mu-CO)(mu-GePh(2))(3)(mu(5)-C), 2; Ru(5)(CO)(11)(mu;-GePh(2))(4)(mu(5)-C), 3. Both compounds contain square pyramidal Ru(5) clusters with GePh(2) groups bridging three and four of the edges of the Ru(5) square base, respectively. When treated with 1 equiv of Ph(3)GeH at 150 degrees C compound 2 is converted to 3. Reaction of 3 with H(2) at 150 degrees C yielded Ru(5)(CO)(10)(mu-GePh(2))(4)(mu(5)-C)(mu-H)(2), 4, containing two hydride ligands and one less CO ligand. Reaction of 4 with hydrogen at 150 degrees C yielded the compound Ru(5)(CO)(10)(mu-GePh(2))(2)(mu(3)-GePh)(2)(mu(3)-H)(mu(4)-CH), 5, by loss of benzene and conversion of two of the bridging GePh(2) groups into triply bridging GePh groups. Compound 5 contains one triply bridging hydride ligand and a quadruply bridging methylidyne ligand formed by addition of one hydrogen atom to the carbido carbon atom.     

Double-stranded W/Ag/S chain structure generated from [syn-(WO(NCS)(2))(2)(mu-S)(2)] building blocks

The dimeric W(V) complex [Et(4)N](4)[syn-(O=W(NCS)(3))(2)(mu-S)(2)], 1, prepared from [Et(4)N](2)[WS(4)], SCN(-), and Cd(2+), shows interesting reactivity patterns in that the thiocyanate trans to the oxo group can in part be replaced, initiated by Mn(2+), by dimethylformamide (DMF) to form [Et(4)N](2.5)[(O=W(NCS)(2.25)(DMF)(1.25))(2)(mu-S)(2)], 2. With Ag(+), 1 undergoes partial replacement of SCN(-) by DMF and coordinates to the silver ions to generate ([Et(4)N](2.5)[(W(2)O(2)(NCS)(2)(mu-S)(2))(mu-NCS)(2)(DMF)(Ag(0.5)(SCN))])(n), 3. Compound 3 constitutes a polymeric double-stranded chain, with normal bonding interactions [via W-(mu-NCS)-Ag] between the two strands, and moderate intrastrand [W-(mu-NCS).Ag] bonding. The crystal and molecular structures of the three compounds are described.     

Diverse evolution of [[Ph(2)P(CH(2))(n)PPh(2)]Pt(mu-S)(2)Pt[Ph(2)P(CH(2))(n)PPh(2)]] (n = 2, 3) metalloligands in CH(2)Cl(2)

The nucleophilicity of the [Pt(2)S(2)] core in [[Ph(2)P(CH(2))(n)PPh(2)]Pt(mu-S)(2)Pt[Ph(2)P(CH(2))(n)PPh(2)]] (n = 3, dppp (1); n = 2, dppe (2)) metalloligands toward the CH(2)Cl(2) solvent has been thoroughly studied. Complex 1, which has been obtained and characterized by X-ray diffraction, is structurally related to 2 and consists of dinuclear molecules with a hinged [Pt(2)S(2)] central ring. The reaction of 1 and 2 with CH(2)Cl(2) has been followed by means of (31)P, (1)H, and (13)C NMR, electrospray ionization mass spectrometry, and X-ray data. Although both reactions proceed at different rates, the first steps are common and lead to a mixture of the corresponding mononuclear complexes [Pt[Ph(2)P(CH(2))(n)PPh(2)](S(2)CH(2))], n = 3 (7), 2 (8), and [Pt[Ph(2)P(CH(2))(n)PPh(2)]Cl(2)], n = 3 (9), 2 (10). Theoretical calculations give support to the proposed pathway for the disintegration process of the [Pt(2)S(2)] ring. Only in the case of 1, the reaction proceeds further yielding [Pt(2)(dppp)(2)[mu-(SCH(2)SCH(2)S)-S,S']]Cl(2) (11). To confirm the sequence of the reactions leading from 1 and 2 to the final products 9 and 11 or 8 and 10, respectively, complexes 7, 8, and 11 have been synthesized and structurally characterized. Additional experiments have allowed elucidation of the reaction mechanism involved from 7 to 11, and thus, the origin of the CH(2) groups that participate in the expansion of the (SCH(2)S)(2-) ligand in 7 to afford the bridging (SCH(2)SCH(2)S)(2-) ligand in 11 has been established. The X-ray structure of 11 is totally unprecedented and consists of a hinged [(dppp)Pt(mu-S)(2)Pt(dppp)] core capped by a CH(2)SCH(2) fragment.     

Synthesis, Characterization, and Comparative Properties of [PPN](2)[Re(6)C(CO)(18)Mo(CO)(4)] and [PPN](2)[Re(6)C(CO)(18)Ru(CO)(3)

The reaction of [PPN](2)[Re(6)C(CO)(19)] with Mo(CO)(6) and Ru(3)(CO)(12) under sunlamp irradiation provided the new mixed-metal clusters [PPN](2)[Re(6)C(CO)(18)Mo(CO)(4)] and [PPN](2)[Re(6)C(CO)(18)Ru(CO)(3)], which were isolated in yields of 85% and 61%, respectively. The compound [PPN](2)[Re(6)C(CO)(18)Mo(CO)(4)] crystallizes in the monoclinic space group P2(1)/c with a = 20.190 (7) ?, b = 16.489 (7) ?, c = 27.778 (7) ?, beta = 101.48 (2) degrees, and Z = 4 (at T = -75 degrees C). The cluster anion is composed of a Re(6)C octahedral core with a face capped by a Mo(CO)(4) fragment. There are three terminal carbonyl ligands coordinated to each rhenium atom. The four carbonyl ligands on the molybdenum center are essentially terminal, with one pair of carbonyl ligands (C72-O72 and C74-O74) subtending a relatively large angle at molybdenum (C72-Mo-C74 = 147.2(9) degrees ), whereas the remaining pair of carbonyl ligands (C71-O71 and C73-O73) subtend a much smaller angle (C71-Mo-C73 = 100.5(9) degrees ). The (13)C NMR spectrum of (13)CO-enriched [PPN](2)[Re(6)C(CO)(18)Mo(CO)(4)] shows signals for four sets of carbonyl ligands at -40 degrees C, consistent with the solid state structure, but the carbonyl ligands undergo complete scrambling at ambient temperature. The (13)C NMR spectrum of (13)CO-enriched [PPN](2)[Re(6)C(CO)(18)Ru(CO)(3)] at 20 degrees C is consistent with the expected structure of an octahedral Re(6)C(CO)(18) core capped by a Ru(CO)(3) fragment. The visible spectrum of [PPN](2)[Re(6)C(CO)(18)Mo(CO)(4)] shows a broad, strong band at 670 nm (epsilon = 8100), whereas all of the absorptions of [PPN](2)[Re(6)C(CO)(18)Ru(CO)(3)] are at higher energy. An irreversible oxidation wave with E(p) at 0.34 V is observed for [PPN](2)[Re(6)C(CO)(18)Mo(CO)(4)], whereas two quasi-reversible oxidation waves with E(1/2) values of 0.21 and 0.61 V (vs Ag/AgCl) are observed for [PPN](2)[Re(6)C(CO)(18)Ru(CO)(3)]. The molybdenum cap in [Re(6)C(CO)(18)Mo(CO(4))](2-) is cleaved by heating in donor solvents, and by treatment with H(2), to give largely [H(2)Re(6)C(CO)(18)](2-). In contrast, [Re(6)C(CO)(18)Ru(CO)(3)](2-) shows no tendency to react under similar conditions.     

Reactions of (PCP)Ru(CO)(NHPh)(PMe3) (PCP = 2,6-(CH2PtBu2)2C6H3) with substrates that possess polar bonds

The Ru(II) amido complex (PCP)Ru(CO)(PMe(3))(NHPh) (1) (PCP = 2,6-(CH(2)P(t)Bu(2))(2)C(6)H(3)) reacts with compounds that possess polar C=N, C triple bond N, or C=O bonds (e.g., nitriles, carbodiimides, or isocyanates) to produce four-membered heterometallacycles that result from nucleophilic addition of the amido nitrogen to an unsaturated carbon of the organic substrate. Based on studies of the reaction of complex 1 with acetonitrile, the transformations are suggested to proceed by dissociation of trimethylphosphine, followed by coordination of the organic substrate and then intramolecular N-C bond formation. In the presence of ROH (R = H or Me), the fluorinated amidinate complex (PCP)Ru(CO)(N(Ph)C(C(6)F(5))NH) (6) reacts with excess pentafluorobenzonitrile to produce (PCP)Ru(CO)(F)(N(H)C(C(6)F(5))NHPh) (7). The reaction with MeOH also produces o-MeOC(6)F(4)CN (>90%) and p-MeOC(6)F(4)CN (<10%). Details of the solid-state structures of (PCP)Ru(CO)(F)(N(H)C(C(6)F(5))NHPh) (7), (PCP)Ru(CO)[PhNC{NH(hx)}N(hx)] (8), (PCP)Ru(CO){N(Ph)C(NHPh)O} (9), and (PCP)Ru(CO){OC(Ph)N(Ph)} (10) are reported.     

Syntheses,reactivity, and crystal structures of molybdenum complexes with pyridine-2-thionate (pyS)-containing ligands: crystal structures of [Mo(eta(3)-C(3)H(5))(CO)(2)](2)(mu-eta(1),eta(2)-pyS)(2), exo-[Mo(eta(3)-C(3)H(5))(CO)(eta(2)-pyS)(eta(2)-dppe)], [Mo(CO)(3)(eta(1)-SC(5)H(4)NH)(eta(2)-dppm)], and [Mo(CO)(eta(2)-pyS)(2)(eta(2)-dppm)

The doubly bridged pyridine-2-thionate (pyS) dimolybdenum complex [Mo(eta(3)-C(3)H(5))(CO)(2)](2)(mu-eta(1),eta(2)-pyS)(2) (1) is accessible by the reaction of [Mo(eta(3)-C(3)H(5))(CO)(2)(CH(3)CN)(2)Br] with pySK in methanol at room temperature. Complex 1 reacts with piperidine in acetonitrile to give the complex [Mo(eta(3)-C(3)H(5))(CO)(2)(eta(2)-pyS)(C(5)H(10)NH)] (2). Treatment of 1 with 1,10-phenanthroline (phen) results in the formation of complex [Mo(eta(3)-C(3)H(5))(CO)(2)(eta(1)-pyS)(phen)] (3), in which the pyS ligand is coordinated to Mo through the sulfur atom. Four conformational isomers, endo,exo-complexes [Mo(eta(3)-C(3)H(5))(CO)(eta(2)-pyS)(eta(2)-diphos)] (diphos = dppm, 4a-4d; dppe, 5a-5d), are accessible by the reactions of 1 with dppm and dppe in refluxing acetonitrile. Homonuclear shift-correlated 2-D (31)P((1)H)-(31)P((1)H) NMR experiments of the mixtures 4a-4d have been employed to elucidate the four stereoisomers. The reaction of 4 and pySK or [Mo(CO)(3)(eta(1)-SC(5)H(4)NH)(eta(2)-dppm)] (6) and O(2) affords allyl-displaced seven-coordinate bis(pyridine-2-thionate) complex [Mo(CO)(eta(2)-pyS)(2)(eta(2)-dppm)] (7). All of the complexes are identified by spectroscopic methods, and complexes 1, 5d, 6, and 7 are determined by single-crystal X-ray diffraction. Complexes 1 and 5d crystallize in the orthorhombic space groups Pbcn and Pbca with Z = 4 and 8, respectively, whereas 6 belongs to the monoclinic space group C2/c with Z = 8 and 7 belongs to the triclinic space group Ponemacr; with Z = 2. The cell dimensions are as follows: for 1, a = 8.3128(1) A, b = 16.1704(2) A, c = 16.6140(2) A; for 5d, a = 17.8309(10) A, b = 17.3324(10) A, c = 20.3716(11) A; for 6, a = 18.618(4) A, b = 16.062(2) A, c = 27.456(6) A, beta = 96.31(3) degrees; for 7, a = 9.1660(2) A, b = 12.0854(3) A, c = 15.9478(4) A, alpha = 78.4811(10) degrees, beta = 80.3894(10) degrees, gamma = 68.7089(11) degrees.     

Coordination Chemistry of 2,2'-Dipyridyl Diselenide: X-ray Crystal Structures of PySeSePy, [Zn(PySeSePy)Cl(2)], [(PySeSePy)Hg(C(6)F(5))(2)], [Mo(SePy)(2)(CO)(3)], [W(SePy)(2)(CO)(3)], and [Fe(SePy)(2)(CO)(2)] (PySeSePy = C(5)H(4)NSeSeC(5)H(4)N; SePy = [C(5)H(4)N(2-Se)-N,Se])

The coordination chemistry of 2,2'-dipyridyl diselenide (PySeSePy) (2) (C(10)H(8)N(2)Se(2)) has been investigated and its crystal structure has been determined (monoclinic, P2(1)/c, a = 10.129(2) ?, b = 5.7332(12) ?, c = 19.173(3) ?, beta = 101.493(8) degrees, Z = 4). In metal complexes the ligand was found to coordinate in three different modes, as also confirmed by X-ray structure determination. N,N'-coordination was found in the zinc complex [Zn(PySeSePy)Cl(2)] (3) (C(10)H(8)Cl(2)N(2)Se(2)Zn, triclinic, P&onemacr;, a = 7.9430(10) ?, b = 8.147(2) ?, c = 11.999(2) ?, alpha = 93.685(10) degrees, beta = 107.763(10) degrees, gamma = 115.440(10) degrees, Z = 2) and Se,Se'-coordination in the adduct of the ligand with bis(pentafluorophenyl)mercury(II) [PySeSePyHg(C(6)F(5))(2)] (5) (C(10)H(8)F(10)HgN(2)Se(2), monoclinic, P2(1)/n, a = 7.7325(10) ?, b = 5.9974(14) ?, c = 25.573, beta = 98.037(10) degrees, Z = 2), which however displays only weak interactions between selenium and mercury. The reaction of the ligand with norbornadiene carbonyl complexes of molybdenum and tungsten leads to reductive cleavage of the selenium-selenium bond with oxidation of the metal center and concomitant addition of the resulting selenolate to the metal carbonyl fragment. Thus the 7-coordinate complexes [Mo(SePy)(2)(CO)(3)] (6) (C(13)H(8)MoN(2)O(3)Se(2), monoclinic, P2(1)/n, a = 9.319(3) ?, b = 12.886(5) ?, c = 13.231(6) ?, beta = 109.23(3) degrees, Z = 4) and [W(SePy)(2)(CO)(3)] (7) (C(13)H(8)N(2)O(3)Se(2)W, monoclinic, P2(1)/n, a = 9.303(2) ?, b = 12.853(2) ?, c = 13.232(2) ?, beta = 109.270(10) degrees, Z = 4) were obtained. The same N,Se-coordination pattern emerges from the reaction of [Fe(2)(CO)(9)] with (2) leading to [Fe(SePy)(2)(CO)(2)] (8) (C(12)H(8)FeN(2)O(2)Se(2), monoclinic, P&onemacr;, a = 8.6691(14) ?, b = 12.443(2) ?, c = 14.085(2) ?, alpha = 105.811(10) degrees, beta = 107.533(8) degrees, gamma = 92.075(10) degrees, Z = 4).     

Stoichiometric and catalytic reactivity of the N-heterocyclic carbene ruthenium hydride complexes [Ru(NHC)(L)(CO)HCl] and [Ru(NHC)(L)(CO)H(eta2-BH4)] (L=NHC, PPh3)

Thermolysis of [Ru(AsPh3)3(CO)H2] with the N-aryl heterocyclic carbenes (NHCs) IMes (1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), IPr (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) or the adduct SIPr.(C6F5)H (SIPr=1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene), followed by addition of CH2Cl2, affords the coordinatively unsaturated ruthenium hydride chloride complexes [Ru(NHC)2(CO)HCl] (NHC=IMes , IPr , SIPr ). These react with CO at room temperature to yield the corresponding 18-electron dicarbonyl complexes . Reduction of and [Ru(IMes)(PPh3)(CO)HCl] () with NaBH4 yields the isolable borohydride complexes [Ru(NHC)(L)(CO)H(eta2-BH4)] (, L=NHC, PPh3). Both the bis-IMes complex and the IMes-PPh3 species react with CO at low temperature to give the eta1-borohydride species [Ru(IMes)(L)(CO)2H(eta1-BH4)] (L=IMes , PPh3), which can be spectroscopically characterised. Upon warming to room temperature, further reaction with CO takes place to afford initially [Ru(IMes)(L)(CO)2H2] (L=IMes, L=PPh3) and, ultimately, [Ru(IMes)(L)(CO)3] (L=IMes , L=PPh3). Both and lose BH3 on addition of PMe2Ph to give [Ru(IMes)(L)(L')(CO)H2](L=L'=PMe2Ph; L=PPh3, L'=PMe2Ph). Compounds and have been tested as catalysts for the hydrogenation of aromatic ketones in the presence of (i)PrOH and H2. For the reduction of acetophenone, catalytic activity varies with the NHC present, decreasing in the order IPr>IMes>SIMes.     

Multiple reactions of triphenylstannane with Ru(5)(CO)(12)(C(6)H(6))(mu(5)-C) yield bimetallic clusters with unusually large numbers of tin ligands

The cluster complex Ru(5)(CO)(12)(C(6)H(6))(mu(5)-C), 1, undergoes multiple addition reactions with Ph(3)SnH to yield two new bimetallic cluster complexes: Ru(5)(CO)(8)(mu-SnPh(2))(4)(C(6)H(6))(mu(5)-C), 2, 2% yield, and Ru(5)(CO)(7)(mu-SnPh(2))(4)(SnPh(3))(C(6)H(6))(mu(5)-C)(mu-H), 3, 26% yield, containing four and five tin ligands, respectively. Both compounds consist of a square pyramidal Ru(5) cluster with an interstitial carbido ligand and bridging SnPh(2) groups located across each of the four edges of the base of the Ru(5) square pyramid. Compound 3 contains an additional SnPh(3) group terminally coordinated to one of the ruthenium atoms in the square base.