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Eight Schiff bases have been synthesized by conventional and three different eco-friendly methods, whereby two aromatic carbonyl compounds viz. 2-thiophenecarboxaldehyde and salicylaldehyde were reacted with S-methyl, S-benzyl, and S-n-octyl-dithiocarbazates and thiosemicarbazide. In order to evaluate the efficiency of the synthesis methods, the time to complete the reaction and the yield of the Schiff base synthezised by eco-friendly methods, such as solvent-free grinding, water as a solvent, and lemon juice as catalyst, were compared with those synthesized by the conventional method. The chemical structures of all the synthesized Schiff bases, where two of them are novel and reported for the first time, were fully characterized by a variety of physico-chemical, analytical, and spectroscopic techniques. The molecular and crystal structures of the Schiff bases especially those having 2-thiophene moiety were further elucidated by single crystal X-ray diffraction analyzes.

Reactions of the tetranuclear mixed-metal clusters ReM3(CO)13(µ3-thpymS) (1, M = Os; 2, M = Ru; thpymSH = tetrahydropyrimidine-2-thiol) with PPh3 are examined. At room temperature reaction between 1 and PPh3 in the presence Me3NO leads to the formation of mono- and bis-phosphine substituted clusters ReOs3(CO)12(PPh3)(µ3-thpymS) (3) and ReOs3(CO)11(PPh3)2(µ3-thpymS) (4). Cluster 3 also reacts with PPh3 under similar conditions to give 4. In contrast, a similar reaction between 2 and PPh3 furnishes only the mono-phosphine substituted clusters ReRu3(CO)12(PPh3)(µ3-thpymS) (3). All the new clusters have been characterized by analytical and spectroscopic data together with single crystal X-ray diffraction for 1, 3 and 5.

Mixed-valence dimolybdenum complexes Mo2(O)(CO)2{μ-κ2-S(CH2)nS}2(κ2-Ph2P(CH2)mPPh2) (n = 2, 3; m = 1, 2) (1–4) have been synthesized from one-pot reactions of fac-Mo(CO)3(NCMe)3 and dithiols, HS(CH2)nSH, in the presence of diphosphines. The dimolybdenum framework is supported by two thiolate bridges, with one molybdenum carrying a terminal oxo ligand and the second two carbonyls. The dppm (m = 1) products exist as a pair of diastereomers differing in the relative orientation of the two carbonyls (cis and trans) at the Mo(CO)2(dppm) center, while dppe (m = 2) complexes are found solely as the trans isomers. Small amounts of Mo(CO){κ3-S(CH2CH2S)2}(κ2-dppe) (5) also result from the reaction using HS(CH2)2SH and dppe. The bonding in isomers of 1–4 has been computationally explored by DFT calculations, trans diastereomers being computed to be more stable than the corresponding pair of cis diastereomers for all. The calculations confirm the existence of MoO and Mo–Mo bond orders and suggest that the new dimeric compounds are best viewed as Mo(V)–Mo(I) mixed-valence systems. The electrochemical properties of 1 have been investigated by CV and show a reversible one-electron reduction associated with the Mo(V) centre, while two closely spaced irreversible oxidation waves are tentatively assigned to oxidation of the Mo(I) centre of the two isomers as supported by DFT calculations.

The reaction of [CpMo(CO)3]2 with dicyclopentamethylenethiuram disulfide in refluxing xylene resulted a novel mono nuclear complex, cis-[(CpMo(CO)2{S2C-N(CH2)5}] as red crystals in moderate yield. The compound was formed by the oxidative cleavage of metal-metal bond in [CpMo(CO)3]2 together with a reductive sulfur-sulfur bond scission in the ligand.

Mixed-valence dimolybdenum complexes Mo2(O)(CO)2{μ-κ2-S(CH2)nS}2(κ2-Ph2P(CH2)mPPh2) (n = 2, 3; m = 1, 2) (1-4) have been synthesized from one-pot reactions of fac-Mo(CO)3(NCMe)3 and dithiols, HS(CH2)nSH, in the presence of diphosphines. The dimolybdenum framework is supported by two thiolate bridges, with one molybdenum carrying a terminal oxo ligand and the second two carbonyls. The dppm (m = 1) products exist as a pair of diastereomers differing in the relative orientation of the two carbonyls (cis and trans) at the Mo(CO)2(dppm) center, while dppe (m = 2) complexes are found solely as the trans isomers. Small amounts of Mo(CO){κ3-S(CH2CH2S)2}(κ2-dppe) (5) also result from the reaction using HS(CH2)2SH and dppe. The bonding in isomers of 1-4 has been computationally explored by DFT calculations, trans diastereomers being computed to be more stable than the corresponding pair of cis diastereomers for all. The calculations confirm the existence of Mo[triple bond, length as m-dash]O and Mo-Mo bond orders and suggest that the new dimeric compounds are best viewed as Mo(v)-Mo(i) mixed-valence systems. The electrochemical properties of 1 have been investigated by CV and show a reversible one-electron reduction associated with the Mo(v) centre, while two closely spaced irreversible oxidation waves are tentatively assigned to oxidation of the Mo(i) centre of the two isomers as supported by DFT calculations.

Thermolysis of Ru3(CO)10(μ-dppm) [dppm = bis(diphenylphosphino)methane] in boiling xylene in presence of molecular oxygen (O2) affords the trinuclear oxo-capped cluster Ru3(CO)7(μ3-CO)(μ3-O)(μ-dppm) (1). A similar reaction between Ru3(CO)9(PPh3)(μ-dppm) and O2 in refluxing benzene also furnishes the oxo-capped Ru3(CO)6(PPh3)(μ3-CO)(μ3-O)(μ-dppm) (2). Crystal structures of 1 and 2 reveal that both contain a capping oxygen at one face and a triply-bridging carbonyl on the opposite face of the triruthenium plane. In contrast, Ru3(CO)9(PHPh2)(μ-dppm) does not react with O2 under similar conditions, but undergoes thermal transformations to give Ru3(CO)7(μ-H)(μ-PPh2){μ3-PhPCH2P(C6H4)Ph} (3) and Ru3(CO)6(μ-CO)(μ-PPh2)2(μ3-CH2PPh)] (4) via C–P, P–H and C–H bond activation. All the new clusters have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.

The electronically unsaturated dimolybdenum complex [CpMo(CO)2]2 (1) reacts with the π-excessive heterocycle 2-mercapto-1-methylimidazole at 110 °C to afford the mononuclear molybdenum complex CpMo(CO)2(κ2-C4H5N2S) (2) and the trimolybdenum cluster Cp3Mo3(μ-CO)2(μ-κ2-C4H5N2)(μ-S)(μ3-S) (3) in 22% and 20% yields, respectively. A similar reaction between 1 and the benzoannulated heterocycle 2-mercaptobenzothiazole furnishes CpMo(CO)2(κ2-C7H4NS2) (4) and Cp3Mo3(μ-CO)2(μ-κ2-C7H4NS)(μ-S)(μ3-S) (5) in 17% and 20% yields, respectively. Compounds 2 and 4 consist of a single molybdenum atom with two carbonyl groups, a cyclopentadienyl ligand, and a chelating heterocyclic thiolato ligand. The trimolybdenum clusters 3 and 5 consist of three cyclopentadienyl ligands, a metalated heterocyclic ligand, edge-bridging and face-capping sulfido ligands, and a pair of semi-bridging carbonyl ligands. All new compounds have been fully characterized in solution by IR and NMR spectroscopy, and the solid-state structures of 3 and 4 have been determined by single-crystal X-ray diffraction analyses. The bonding in cluster 3 has been computationally investigated by Density Functional Theory (DFT), and the data support a cluster that is electronically saturated with 48e and where both sulfido ligands function as 4e donor groups.

The reaction between the tetranuclear compound [Mn 4 (CO) 12 (µ -pymS) 4 ] ( 1 ) and (PPh 3 ) 2 Ni(CO) 2 at room temperature resulted in the cleavage of the square to afford the dinuclear complex [Mn 2 (CO) 5 (µ -pymS) 2 (PPh 3 )] ( 2 ) (19%) along with two mononuclear complexes fac - [Mn(CO) 3 (κ 2 -pymS)(PPh 3 )] ( 3 ) (43%) and [Mn(CO) 2 (κ 2 -pymS)(PPh 3 ) 2 ] ( 4 ) (24%). In contrast, a similar reaction of [Re 4 (CO) 12 (µ-pymS) 4 ] ( 5 ) with (PPh 3 ) 2 Ni(CO) 2 at 25 o C did not afford any dinuclear compound leading instead to the monophosphine substituted mononuclear compound fac - [Re(CO) 3 (κ 2 -pymS)(PPh 3 )] ( 6 ) (72%). Compound 4 is also formed when a toluene solution of 3 is treated with PPh 3 at elevated temperature (100 o C). A similar treatment of 6 with triphenylphosphine in refluxing toluene gave [Re(CO) 2 (κ 2 -pymS)(PPh 3 ) 2 ] ( 7 ) (60%). All the new compounds have been characterized by elemental analysis, IR, 1H NMR and 31P{1H} NMR spectroscopy and mass spectrometry along with single crystal X-ray diffraction analysis for 6 . Compound 6 consists of a single rhenium atom with three carbonyls, a triphenylphosphine ligand and a chelating pyrimidinethiolate ligand. DOI: http://dx.doi.org/10.3329/jbas.v38i2.21340 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 2, 155-165, 2014

The coordination of the bifunctional liga nd 4-mercaptoaniline with aqueous tin(II) metal ion was studied. A coordination polymer was synthesized when an aqueous solution of SnCl 2 was treated with 4-MA. The crystalline material is stable under atmospheric conditions retaining its oxidation state. However, when submerged in a solution saturated with oxygen, the compound oxidi zes to a mononuclear tin(IV) complex. Both the compounds were characterized by single crystal X-ray diffraction studies. Although the structure of the tin(IV) complex was previously reported, crystal structure of this compound was redetermined. Keywords: tin(II); tin(IV); coordina tion complex; polymer; metal sulfide; 4-Aminothiophenol; mercaptoaniline; aqueous; synthesize; redox 1. Introduction Recently, we have investigated various separation techniques in order to isolate metal ions from aqueous waste streams. Methods that can yield recyclable treated material are of interest. One such technique involves the use of 4-mercaptoaniline (4-MA) as a precipitant. The precipitated material from this method can be recycled as metal sulfides.

The solid-state molecular structure determination of the bimetallic osmium-tin compound [(?-H)Os 2 (CO) 4 (SnPh 3 ) 2 (?-HSnPh 2 )(?-dppf)] (1) was carried out to determine the relative orientationof the coordinated ligands. Compound 1 crystallizes in the monoclinic space group P 2 1 /c with a =22.366(7), b = 14.217(4), c = 25.213(8) A, ? = 98.865(7)°, Z = 8 and V = 7921(4) A 3 . It is a 34-electron bimetallic cluster with the Os-Os edge concomitantly bridged by a dppf and two HSnPh 2 ligands DOI: http://dx.doi.org/10.3329/jbas.v38i1.20218 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 1, 97-101, 2014

The new clusters [Ru-3(CO)(9)(mu-dppf){P(C4H3E)(3)}] (1, E = O; 2, E = S) have been prepared from the Me3NO-induced decarbonylation of [Ru-3(CO)(10)(mu-dppf)] in the presence of PFu(3) (E = O) and PTh3 (E = S), respectively. Upon thermolysis in benzene, the major products are the cyclometalated clusters [(mu-H) Ru-3(CO)(7)(mu-dppf){mu(3)-(C4H3E)(2)P(C4H2E)}] (3, E - O; 4, E - S). This thermolytic behavior is in marked contrast to that previously noted for the analogous bis(diphenylphosphino) methane (dppm) complexes [Ru-3(CO)(9)(mu-dppm){P(C4H3E)(3)}], in which both carbon-hydrogen and carbon-phosphorus bond activation yields furyne- and thiophyne-capped clusters. The crystal structures of 1, 3 and 4 are presented and reveal that phosphine migration has occurred during the transformation of 1,2 into 3,4, respectively. The possible relation of the observed reactivity to the relative flexibilities of the diphosphine ligands is discussed. Density functional calculations have been performed on the model cluster [Ru-3(CO)(9)(mu-Me-4-dppf){ P(C4H3O)(3)]}], and these data are discussed relative to the ground-state energy differences extant between the different isomeric forms of this cluster. The dynamic NMR behavior displayed by the metalated thienyl ring in cluster 4 has also been investigated by computational methods, and the free energy of activation for the "windshield wiper" motion of the activated thienyl moiety determined. (C) 2013 Elsevier B.V. All rights reserved. (Less)

New methods for the synthesis of 1,3,4-oxadiazole and 1,3,4-thiadiazole have been described. No cyclizations took place in the absence of ZnCl 2 . 1,3,4-Thiadiazoles are formed in the presence of ZnCl 2 alone, whereas oxadiazoles are produced when a base such as Et 3 N or KOH was used along with ZnCl 2 . % Yields are optimized.

Products of the addition of Ph3SnH to the unsaturated triosmium clusters [(μ-H)2Os3(CO)8(μ-dppm)] (1) and [(μ-H)2Os3(CO)8(μ-dppf)] (2) are highly dependent on the nature of the diphosphine. With the rigid bis(diphenylphosphino)methane (dppm), the stannylene complex [H2Os3(CO)7(μ-SnPh2)2(μ-dppm)] (3) is the major cluster product (35% yield), resulting from both Sn–H and Sn–C bond activation, while two previously reported triphenyltin complexes, [(μ-H)2Os3(CO)8(SnPh3)2(μ-dppm)] (4) (10% yield) and [(μ-H)2Os3(CO)8(SnPh3){μ-Ph2PCH2P(Ph)C6H4}] (5) (11% yield) also result. Biphenyl is also a co-product of this reaction and it is postulated to be formed concomitantly with 3. A similar reaction with the highly flexible 1,1′-bis(diphenylphosphino)ferrocene (dppf) complex leads to the formation of four tin-containing complexes: two previously reported compounds [HOs(CO)4(SnPh3)] (6) (8% yield) and [Os2(CO)6(SnPh3)2(μ-SnPh2)2] (8) (5% yield), and the new triphenyltin and hydrostannylene clusters [H(μ-H)2Os3(CO)8(SnPh3)(μ-dppf)] (10) (22% yield) and [(μ-H)Os2(CO)4(SnPh3)2(μ-HSnPh2)(μ-dppf)] (9) (12% yield) respectively, together with the dihydroxy cluster [Os3(CO)8(μ-OH)2(μ-dppf)] (7). Two of these new clusters have been characterized by X-ray crystallography. Cluster 3 consists of a central Os3 triangle with two stannylene groups, each bridging one Os–Os edge, a dppm ligand that bridges the third Os-Os edge, and two terminal hydride ligands. Cluster 10 consists of an Os3 triangle with a terminal SnPh3 group, one terminal and two bridging hydride ligands, and a bridging dppf ligand. The new compounds 3, 7, 9, and 10 have been investigated by electronic structure calculations, and the computed ground-state structures are discussed relative to the X-ray crystallographic structures.

The dirhenium complexes Re2(CO)6(μ-thpymS)2 (1) and eq-Re2(CO)9{κ1-(S)-SN2C4H8} (2) are obtained from the reaction of tetrahydropyrimidine-2-thiol (thpymSH) with Re2(CO)8(NCMe)2 or Re2(CO)10. Complex 1 proves to be an excellent precursor to a range of monometallic and cluster complexes acting as a source of “Re(CO)3(thpymS)”. Thus, reactions with triphenylphosphine (PPh3) and bis(diphenylphosphino)methane (dppm) afford mononuclear fac-Re(CO)3(PPh3)(κ2-thpymS) (3) and fac-Re(CO)3(κ1-dppm)(κ2-thpymS) (4), respectively. A crystal structure of 3 reveals that the pyrimidine-2-thiolate binds in a chelating fashion. Reactions with M3(CO)12 (M = Ru, Os) at moderate temperatures afford mixed-metal clusters. With Ru3(CO)12 in boiling thf isomeric tetranuclear butterfly clusters ReRu3(CO)13(μ3-thpymS) (5–6) result which differ in the position of the capping pyrimidine-2-thiolate ligand on the cluster surface. Thus in the kinetic isomer 5, the pyrimidine-2-thiolate caps the ReRu2 face while in the thermodynamic isomer 6 it caps the Ru3 face. A similar reaction with Os3(CO)10(NCMe)2 in boiling benzene affords predominantly the ReOs2-capped tetranuclear cluster ReOs3(CO)13(μ3-thpymS) (7), together with small amounts of (μ-H)Os3(CO)9(μ3-thpymS) (8) resulting from loss of rhenium. Cluster 7 is stable in refluxing toluene but slowly converts to isomeric 9 in xylene at 140 °C but only in low yields. The crystal structures of isomeric 5–6 have been solved and show only small variations in the cluster core geometry. Density functional calculations show that clusters 6 and 9 are slightly more stable than 5 (ΔG 2.0 kcal mol−1) and 7 (ΔG 1.5 kcal mol−1), respectively, and a mechanism is proposed for these conversions in which the pyrimidine-2-thiolate becomes bidentate after release of the pyrimidine group.

Eight new Schiff bases of 5-nitro and 5-bromo-substituted 1,10-phenanthroline-2,9-dicarboxaldehydes with sulfur-containing amines, thiosemicarbazide, S-alkyl/aryl dithiocarbazates and 2-mercaptoaniline have been synthesized and characterized by a variety of spectroscopic methods. The condensation reactions of the dialdehydes with the amines were carried out both in the presence and absence of conc. sulfuric acid. A significant increase in yield of the Schiff bases was observed when the reactions were carried out in the presence of sulfuric acid.

Four new Schiff bases of 1,10-phenanthroline-2,9-dicarboxaldehyde with sulfur-containing amines such as 2-mercaptoaniline, S-alkyl/aryl dithiocarbazates and thiosemicarbazide have been synthesized and characterized by spectroscopic and X-ray crystallographic techniques. A comparative study of the methods of synthesis has been made using both traditional and microwave techniques. A significant reduction in reaction time has been observed when the microwave method was used. In some of the reactions, the yields also increased significantly.

The reaction of 2,6-bis(di-tert-butylphosphinomethyl)pyridine (PNP) with hydrated europium(III) chloride yields a novel complex, dichlorotriaqua-(2,6-bis(di-tert-butylphosphinoxidomethyl)pyridine)europium(III)chloride. The complex crystallizes as a dihydrate. IR, 1H and 31P NMR spectroscopic studies were undertaken along with X-ray diffraction studies for structural elucidation. The solid state structure of the compound reveals the insertion of oxygen atoms in the inner coordination sphere bridging phosphorus and europium atoms. The metal center is a seven coordinate system ligated by two chloride ligands, three water ligands and two oxygen atoms from the oxidized phosphine moiety of the PNP ligand. The nitrogen atom of the pyridine unit of the ligand is not coordinated to the metal center.

Addition of phenyldi(2-thienyl) phosphine (PPhTh2) to [Re-2(CO)(10-n)(NCMe)(n)] (n = 1, 2) affords the substitution products [Re-2(CO)(10-n)(PhPTh2)(n)] (1, 2) together with small amounts of fac-[ClRe(CO)(3)(PPhTh2)(2)] (3) (n = 2). Reaction of [Re-2(CO)(10)] with PPhTh2 in refluxing xylene affords a mixture which includes 2, [Re-2(CO)(7)(PPhTh2)(mu-PPhTh)(mu-H)] (4), [Re-2(CO)(7)(PPhTh2)(mu-PPhTh)(mu-eta(1), kappa(1)(S)-C4H3S)] (5) and mer[HRe(CO)(3)(PPhTh2)(2)] (6). Phosphido-bridged 4 and 5 are formed by the carbon-phosphorus bond cleavage of the coordinated PPhTh2 ligand, the cleaved thienyl group being retained in the latter. Reaction of [Mn-2(CO)(10)] with PPhTh2 in refluxing toluene affords [Mn-2(CO)(9)(PPhTh2)] (7) and the carbon-phosphorus bond cleavage products [Mn-2(CO)(6)(mu-PPhTh)(mu-eta(1),eta(5)-C4H3S)] (8) and [Mn-2(CO)(5)(PPhTh2)(mu-PPhTh)(mu-eta(1),eta(5)-C4H3S)] (9). Both 8 and 9 contain a bridging thienyl ligand which is bonded to one manganese atom in a eta(5)-fashion. (C) 2009 Elsevier B. V. All rights reserved.

Reaction of tri(2-furyl) phosphine (PFu(3)) with [Re-2(CO)(10) (n)(NCMe)(n)] (n = 1, 2) at 40 degrees C gave the substituted complexes [Re-2(CO)(10) (n)(PFu(3))(n)] (1 and 2), the phosphines occupying axial position in all cases. Heating [Re-2(CO)(10)] and PFu(3) in refluxing xylene also gives 1 and 2 together with four phosphido-bridged complexes; [Re-2(CO)(8) (n)(PFu(3))(n)(mu-PFu(2))(mu-H)] (n = 0, 1, 2) (3-5) and [Re-2(CO)(6)(PFu(3))(2)(mu-PFu(2))(mu-Cl)] (6) resulting from phosphorus-carbon bond cleavage. A series of separate thermolysis experiments has allowed a detailed reaction pathway to be unambiguously established. A similar reaction between [Re-2(CO)(10)] and PFu(3) in refluxing chlorobenzene furnishes four complexes which include 1, 2, 6 and the new binuclear complex [Re-2(CO)(6)(eta(1)-C4H3O)(2)(mu-PFu(2))(2)] (7). All new complexes have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction studies. (C) 2009 Published by Elsevier B.V. (Less)

The thermal reaction of [Os3(CO)10(μ-H)(μ-SN2C4H5)] (1) at 110 °C afforded the new compound [Os3(CO)9(μ-H)(μ 3-η 2-SN2C4H5)] (2) in 84% yield. Compound 2 exists as two isomers, which differ in the disposition of the bridging hydride ligand. Both of the isomers of 2 have been characterized by a combination of elemental analysis, infrared and 1H NMR spectroscopic data together with single crystal X-ray crystallography. The isomers crystallize together in the triclinic space group P-1 with a = 10.4775(2), b = 13.3056(3), c = 15.0325(3) A, α = 110.8890(10), β = 99.3880(10), γ = 96.1620(10)°, Z = 2 and V = 1900.31(7) A3. The synthesis and the molecular structures of the two isomers of [Os3(CO)9(μ-H)(μ 3-η 2-SN2C4H5)] are described. The isomers differ in the disposition of the hydride ligand.

Treatment of Mn2(CO)10 with 2-thiazoline-2-thiol in the presence of Me3NO at room temperature afforded the dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) in 51 and 34% yields, respectively. Compound 1 was quantitatively converted into 2 when reacted with one equiv of Me3NO. Reaction of 1 with triphenylphosphine at room temperature furnished the mononuclear complex [Mn(CO)3(PPh3)(κ 2-NS2C3H4)] (3) in 66% yield. All three new complexes have been characterized by elemental analyzes and spectroscopic data together with single crystal X-ray diffraction studies for 1 and 3. Compound 1 crystallizes in the orthorhombic space group Pbca with a = 12.4147(2), b = 16.2416(3), c = 19.0841(4) A, β = 90°, Z = 8 and V = 3848.01(12) A3 and 3 crystallizes in the monoclinic space group P 21/n with a = 10.41730(10), b = 14.7710(2), c = 14.9209(2) A, β = 91.1760(10)°, Z = 4 and V = 2295.45(5) A3. Two new dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) were formed when [Mn2(CO)10] was treated with 2-thiazoline-2-thiol in the presence of Me3NO. Compound 2 reacts with PPh3 to give the monomeric complex [Mn(CO)3(PPh3 )(κ 2-NS2C3H4)]. The structures of 1 and 3 were established by crystallography. Shishir Ghosh, Faruque Ahmed, Rafique Al-Mamun, Daniel T. Haworth, Sergey V. Lindeman, Tasneem A. Siddiquee, Dennis W. Bennett, Shariff E. Kabir Investigations of 2-thiazoline-2-thiol as a ligand: Synthesis and X-ray structures of [Mn2(CO)7(μ-NS2C3H4)2] and [Mn(CO)3 (PPh3)(κ 2-NS2C3H4)].

Reaction of [Re-2(CO)(9)(NCMe)] with tri(2-thienyl)phosphine (PTh3) in refluxing cyclohexane affords three substituted dirhenium complexes: [Re-2(CO)(9)(PTh3)] (1), [Re-2(CO)(8)(NCMe)(PTh3)] (2), and [Re-2(CO)(8)(PTh3)(2)] (3). Complex 2 was also obtained from the room-temperature reaction of [Re-2(CO)(8)(NCMe)(2)] with PTh3 and is an unusual example in which the acetonitrile and phosphine ligands are coordinated to the same rhenium atom. Thermolysis of 1 and 3 in refluxing xylene affords [Re-2(CO)(8)(mu-PTh2)(mu-eta(1):kappa(1)-C4H3S)] (4) and [Re-2(CO)(7)(PTh3)(mu-PTh2)(mu-H)] (5), respectively, both resulting from carbon-phosphorus bond cleavage of a coordinated PTh3 ligand. Reaction of [Re-2(CO)10] and PTh3 in refluxing xylene gives a complex mixture of products. These products include 3-5, two further binuclear products, [Re-2(CO)(7)(PTh3)(mu-PTh2)(mu-eta(1):kappa(1)-C4H3S)] (6) and [Re-2(CO)(7)(mu-kappa(1):kappa(2)-Th2PC4H2SPTh)(mu-eta(1):kappa(1)-C4H3S )] (7), and the mononuclear hydrides [ReH(CO)(4)(PTh3)] (8) and trans-[ReH(CO)(3)(PTh3)(2)] (9). Binuclear 6 is structurally similar to 4 and can be obtained from reaction of the latter with 1 equiv of PTh3. Formation of 7 involves a series of rearrangements resulting in the formation of a unique new diphosphine ligand, Th2PC4H2SPTh. Reaction of [Mn-2(CO)(10)] with PTh3 in refluxing toluene affords the phosphine-substituted product [Mn-2(CO)(9)(PTh3)] (10) and two carbon-phosphorus bond cleavage products, [Mn-2)(CO)(6)(mu-PTh2)(mu-eta(1):eta(5)-C4H3S)] (11) and [Mn-2(CO)(5)(PTh3)(mu-PTh2)(mu-PTh2)(mu-eta(1):eta(5)-C4H3S)] (12). Both 11 and 12 contain a bridging thienyl ligand that is bonded to one manganese atom in a eta(5)-fashion. The molecular structures of eight of these new complexes were established by single-crystal X-ray diffraction studies, allowing a detailed analysis of the disposition of the coordinated ligands.

Reaction of [Mn2(CO)10] with 2-mercapto-1-methylimidazole in the presence of Me3NO at 25 °C afforded two new dimanganese complexes [Mn2(CO)6(μ-SN2C4H5)2] (1) and [Mn2(CO)7(μ-SN2C4H5)2] (2). Compound 1 consists of two μ-SN2C4H5 ligands, each bound through the sulfur atom to two Mn atoms and through the nitrogen atom to one Mn atom forming a four-membered chelate ring. Compound 2 was found to consist of one μ-SN2C4H5 ligand in a similar bonding mode to 1 but another μ-SN2C4H5 ligand coordinates through the sulfur atom to one Mn atom and through the nitrogen atom to another Mn atom. Compound 1 was also obtained as the only product from the reaction of [Mn2(CO)8(NCMe)2] with 2-mercapto-1-methylimidazole. In contrast, a similar reaction of [Re2(CO)8(NCMe)2] with 2-mercapto-1-methylimidazole led to the formation of the di-, tri-, and tetranuclear complexes [Re3(CO)8(μ-CO)(μ3-SN2C4H5)2(μ-H)] (3), [Re4(CO)12(μ-SN2C4H5)4] (4), and [Re2(CO)6(μ-SN2C4H5)2] (5). Compound 3 provides a unique example of a hydrido trirhenium compound. The reaction of [Cr(CO)3(NCMe)3] and [Mo(CO)3(NCMe)3] with 1 in refluxing THF afforded the mixed metal complexes [CrMn2(CO)8(μ-CO)2(μ3-SN2C4H5)2] (6) and [MoMn2(CO)8(μ-CO)2(μ3-SN2C4H5)2] (7), respectively, in which two Mn–M (M = Mo, Cr) bonds were formed. In contrast, a similar treatment of [W(CO)3(NCMe)3] with 1 yielded two W-Mn complexes [Mn2W(CO)8(μ-CO)2(μ3-SN2C4H5)2] (8) and [Mn2W(CO)7(μ-CO)2(SN2C4H5)(μ3-SN2C4H5)2] (9). Treatment of 1 with [Fe3(CO)12] at 70-75 °C afforded the trinuclear mixed-metal complex [FeMn2(CO)8(μ-CO)(μ3-SN2C4H5)2] (10) and the diiron side product [Fe2(CO)6(μ-S2N2C4H5)2] (11). Compounds 6-10 have a bent open structure of three metal atoms linked by two metal-metal bonds and all, except 9 and 10, contain a noncrystallographic two-fold axis of symmetry. Compound 9 is structurally similar to 8, but it contains a SN2C4H6 ligand, mono coordinated through the exocyclic sulfur atom to the W atom and a Mn–Mn bond instead of a Mn–W bond. Compound 11 comprises two bridging S2N2C4H5 ligands, which arise from the coupling of 2-mercapto-1-methylimidazole with sulfur.

Reactions of 2-vinylpyridine with the triruthenium complexes [Ru-3(CO)(12)] and [Ru-3(CO)(10)(mu-dppm)] leads to a previously unknown double carbon-hydrogen bond activation of the P-carbon of the vinyl group to afford the pentaruthenium and triruthenium complexes [Ru-5(CO)(14)(mu(4)-C5H4CH=C)(mu-H)(2)] (1) and [Ru3Cl(CO)(5)(mu-CO)(mu-dppm)(mu(3)-NC5H4CH=C)(mu-H)] (2), respectively. Crystal structures reveal two different forms of bridging of the dimetalated 2-vinylpyridyl ligand, capping a square face in 1 and a triangular face in 2.

Treatment of the labile compound [Re 2 (CO) 8 (MeCN) 2 ] with 2-vinylpyridine in refluxing benzene affords exclusively the new compound [Re 2 (CO) 8 (μ-η 1 :η 2 -NC 5 H 4 CH CH 2 )] ( 1 ) in 39% yield in which the μ-η 1 :η 2 -vinylpyridine ligand is coordinated to one Re atom through the nitrogen and to the other Re atom via the olefinic double bond. Reaction of [Re 2 (CO) 8 (MeCN) 2 ] with morpholine in refluxing benzene furnishes two compounds, [Re 2 (CO) 9 (η 1 -NC 4 H 9 O)] ( 2) and [Re 2 (CO) 8 (η 1 -NC 4 H 9 O) 2 ] ( 3) in 5% and 29% yields, respectively. Reaction of [Re 2 (CO) 8 (MeCN) 2 ] with 1-methylimidazole gives [Re 2 (CO) 8 {η 1 -NC 3 H 3 N(CH 3 )} 2 ] ( 4) and the mononuclear compound fac -[ReCl(CO) 3 {η 1 -NC 3 H 3 N(CH 3 )} 2 ] ( 5) in 18% and 26% yields, respectively. In the disubstituted compounds 2 and 4 , the heterocyclic ligands occupy equatorial coordination sites. The mononuclear compound 5 consists of three CO groups, two N coordinated η 1 -1-methylimidazole ligands and a terminal Cl ligand. The XRD structures of complexes 1 , 3 and 5 are reported.

We report two new crystal and molecular structures of the following monomeric arylimido tungsten tetrachloride complexes, [WCl4(NC6H4I-p)(CH3CN)] (1) and [WCl4(NC6H3-2,6-i-Pr 2)(CH3CN)] (2), containing weakly coordinating acetonitrile ligands. Complex 1 crystallizes in the triclinic space group P-1 with lattice parameters a = 6.292(1) A, b = 8.251(1) A, c = 15.126(2) A, α = 78.42(1)°, β = 82.33(2)°, γ = 77.89(1)°, V = 748.7(3) A3, Z = 2. Complex 2 crystallizes in the monoclinic space group P2 1 /c with lattice parameters a = 9.629(1) A, b = 16.790(2) A, c = 24.155(2) A, β = 95.42(1)°, V = 3888.7(6) A3, Z = 8. Despite the different electronic/steric characteristics of the arylimido ligands, the structures show no significant differences in bond lengths or bond angles in the core {N–W(Cl)4–N} fragment and are similar to those reported for other arylimido tungsten tetrachloride complexes. The Synthesis, Crystal, and Molecular Structure of Two Mononuclear Arylimido Tungsten Tetrachloride Complexes, [WCl 4 (NC 6 H 4 I -p ) (CH 3 CN)] and [WCl 4 (NC 6 H 3 - 2,6- i-Pr 2 )(CH 3 CN)] Jeffrey C. Duhacek, Tasneem A. Siddiquee, Dennis W. Bennett, and Dean C. Duncan* The crystal and molecular structures of two new arylimido tungsten tetrachloride complexes are reported herein.

Reactions of [Ru3(CO)10(μ-dppm)] (1) and its ortho-metalated derivative [Ru3(CO)9{μ3-η3-P(C6H5)CH2P(C6H5)(C6H4)}] (11) with PhEEPh (E = Te, Se, S) have been investigated. Treatment of 1 with PhTeTePh at room temperature afforded the dinuclear compound [Ru2(CO)4(μ-TePh)2(μ-dppm)] (2) and the 54-electron triruthenium compounds [Ru3(CO)6(μ3-Te)2(μ-TePh)2(μ-dppm)] (3) and [Ru3(CO)6(μ3-Te)(μ-TePh)3(η1-COPh)(μ-dppm)] (4). Analogous reactions of 1 with PhEEPh (E = Se, S) led to [Ru2(CO)4(μ-EP[Ru3(CO)6(μ3-E)2(μ-EPh)2(μ-dppm)])2(μ-dppm)] (E = Se, 5; E = S, 8) and the 54-electron triruthenium compounds (E = Se, 6; E = S, 9), and [Ru3(CO)6(μ3-E)(μ-EPh)3(Ph)(μ-dppm)] (E = Se, 7; E = S, 10). Reactions of the ortho-metalated complex 11 with PhEEPh (E = Te, Se, S) in refluxing THF gave exclusively [Ru3(CO)6(μ-EPh)2{μ3-η3-P(C6H5)CH2P(C6H5)(C6H4)}] (E = Te, 12; E = Se, 13; E = S, 14). The new compounds have been characterized by a combination of analytical and spectroscopic methods, and molecular structures of 2−4, 7, 10,...

The title cations (9 and 12) were prepared by dehydration of (3-methyl-2,4-pentadien-1-ol)Fe(CO)2L+ complexes. The structure of the (CO)2PPh3-ligated 12 was determined by single-crystal X-ray analysis. Reaction of carbon and heteroatom nucleophiles to (3-methylpentadienyl)Fe(CO)3+ cations 9 and 12 proceeds either via attack at the dienyl terminus to give (3-methyl-1,3Z-diene)iron complexes or via attack at the internal carbon, followed by carbon monoxide insertion and reductive elimination to afford 3-methyl-4-substituted cyclohexenones. Cyclohexenone formation was found to be prevalent for addition of stabilized nucleophiles with strongly dissociated counterions to cation 9 (L = CO). Reaction of cation 9 with sodium bis[(−)-8-phenylmenthyl] malonate gave a single diastereomeric cyclohexenone.

Reactions of the labile compound [Re2(CO)8(MeCN)2] with thiazole and 4-methylthiazole in refluxing benzene afforded the new compounds [Re2(CO)7{μ-2,3-η2-C3H(R)NS}{η1-NC3H2(4-R)S}(μ-H)] (1, R = H; 2, R = CH3), [Re2(CO)6{μ-2,3-η2-C3H(R)NS}{η1-NC3H2(4-R)S}2(μ-H)] (3, R = H; 4, R = CH3) and fac-[Re(CO)3(Cl){η1-NC3H2(4-R)S}2] (5, R = H; 6, R = CH3). Compounds 1 and 2 contain two rhenium atoms, one bridging thiazolide ligand, coordinated through the C(2) and N atoms and a η1-thiazole ligand coordinated through the nitrogen atom to the same Re as the thiazolide nitrogen. Compounds 3 and 4 contain a Re2(CO)6 group with one bridging thiazolide ligand coordinated through the C(2) and N atoms and two N-coordinated η1-thiazole ligands, each coordinated to one Re atom. A hydride ligand, formed by oxidative-addition of C(2)–H bond of the ligand, bridges Re–Re bond opposite the thiazolide ligand in compounds 1–4. Compound 5 contains a single rhenium atom with three carbonyl ligands, two N-coordinated η1-thiazole ligands and a terminal Cl ligand. Treatment of both 1 and 2 with 5 equiv. of thiazole and 4-methylthiazole in the presence of Me3NO in refluxing benzene afforded 3 and 4, respectively. Further activation of the coordinated η1-thiazole ligands in 1–4 is, however, unsuccessful and results only nonspecific decomposition. The single-crystal XRD structures of 1–5 are reported.

The thermal reaction of [Ru3(CO)10(μ-dppm)] (1) with benzothiophene in refluxing toluene gives a complex mixture of products. These include the known compounds [Ru2(CO)6{μ-CH2PPh(C6H4)PPh}] (2), [Ru2(CO)6{μ-C6H4PPh(CH2)PPh}] (3), [Ru3(CO)9{μ3-η3-(Ph)PCH2P(Ph)C6H4}] (4) and [Ru3(CO)10{μ-η2-PPh(CH2)(C6H4)PPh}] (6), as well as the new clusters [Ru6(μ-CO)(CO)13{μ3-η2-PhP(C6H4)PPh}(μ6-C)] (5) and [Ru4(CO)9(μ3-η2-PhPCH2PPh2)(μ4-η6:η1:η1-C6H4)(μ-H)] (7). The solid-state molecular structures of 5 and 7 were confirmed by single crystal X-ray analyses. Compound 5 consists of interesting example of a hexaruthenium interstitial carbido cluster having a tetradentate diphosphine ligand derived from the activation of P–C and C–H bonds of the dppm ligand in 1. The tetranuclear compound 7 consists of a unique example of a non-planar spiked triangular metal fragment of ruthenium [Ru(1), Ru(2) and Ru(3)] unit with Ru(4) being bonded to Ru(1). The μ4-η1:η6:η1-benzyne ligand in this compound represents a previously uncharacterized bonding mode for benzyne. Compounds 5 and 7 do not contain any benzothiophene-derived ligand. The reaction of 4 with benzothiophene gives 2, 3, 5 and 6. Thermolysis of 1 in refluxing toluene gives 2, 3 and 4; none of 5 and 7 is detected in reaction mixture.

The crystal and molecular structure of Sc(CH3COCHCOCF3)3 has been determined by X-ray diffraction. The compound crystallizes as pure mer-isomer in the orthorhombic space group Pbca with lattice parameters a=15.166(8) A, b=13.560(7) A, c=19.327(10) A, α=β=γ=90°, V=3974(4) A3, Z=8. The complex at 100 K is partially disordered in the crystal structure in an approximate 5:1 ratio with 83% fluorine population at C-11 and 17% at C-15. NMR data is compared to that previously reported.

The X-ray crystal structure of the title compound, as crystallized from acetonitrile-water was determined. The relative stereochemistry of the cyclohexenone ring with respect to the 8-phenylmenthyl esters was determined. The title compound crystallizes in the noncentrosymmetric space group P21, with a=8.9850(10) A, b=15.575(3) A, c=14.478(2) A, β=94.61(2)°, and D calc=1.118 g cm−3 for Z=2.

Treatment of the electronically unsaturated 4-methylquinoline triosmium cluster \([\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu_3\hbox{-}\upeta^{2}\hbox{-}\hbox{C}_{9}\hbox{H}_{5} \hbox{(4-Me)N})(\upmu\hbox{-H})]\) (1) with tetramethylthiourea in refluxing cyclohexane at 81°C gave \([\hbox{Os}_{3}\hbox{(CO)}_{8}(\upmu\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{5} \hbox{(4-Me)N})(\upeta^2\hbox{-SC}(\hbox{NMe}_2\hbox{NCH}_2\hbox{Me})(\upmu \hbox{-H})_2]\) (2) and \([\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{5}\hbox{(4-Me)N})(\upeta^1\hbox{-SC}(\hbox{NMe}_2)_2)(\upmu\hbox{-H})]\) (3). In contrast, a similar reaction of the corresponding quinoline compound \([\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu_{3}\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{6}\hbox{N})(\upmu\hbox{-H})]\) (4) with tetramethylthiourea afforded \([\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{6}\hbox{N})(\upeta^{1}\hbox{-SC(NMe}_{2})_{2})(\upmu\hbox{-H)}]\) (5) as the only product. Compound 2 contains a cyclometallated tetramethylthiourea ligand which is chelating at the rear osmium atom and a quinolyl ligand coordinated to the Os3 triangle via the nitrogen lone pair and the C(8) atom of the carbocyclic ring. In 3 and 5, the tetramethylthiourea ligand is coordinated at an equatorial site of the osmium atom, which is also bound to the carbon atom of the quinolyl ligand. Compounds 3 and 5 react with PPh3 at room temperature to give the previously reported phosphine substituted products \([\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu \hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{5}\hbox{(4-Me)N)(PPh}_{3})(\upmu\hbox{-H)}]\) (6) and \([\hbox{Os}_{3}\hbox{(CO}_{9}(\upmu \hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{6}\hbox{N)(PPh}_{3})(\upmu\hbox{-H)}]\) (7) by the displacement of the tetramethylthiourea ligand.

The crystal and molecular structure of cis-Cu(CH3CSCHCOCH3)2 has been determined by X-ray diffraction. The complex crystallizes in the triclinic space group P $\bar 1$ with lattice parameters a = 10.588(2) A, b = 11.445(2) A, c = 11.779(2) A, α = 88.13(1)°, β = 63.73(2)°, γ = 86.57(2)°, V = 1277.6(4) A3, Z = 4. The asymmetric unit consists of two crystallographically independent molecules. The approximate cis square planar geometry of thecomplex is consistent with the relatively large dipole moment observed in solution. Density functional calculations predict that a pseudo-tetrahedral conformation of the molecule would be on the order of 40 kJ mol−1 higher in energy than the crystallographicallydetermined conformation, while a trans conformation would have approximately the same energy. This suggests that the cis conformer observed in the solidstate coexists in equilibrium with the trans conformer in solution.

The reaction of [Ru 3 (CO) 10 (μ-dppm)] ( 1 ) with dppmSe at 66 °C affords [Ru 3 (CO) 8 (μ-dppm) 2 ] ( 2 ), [Ru 3 (CO) 7 (μ 3 -CO)(μ 3 -Se)(μ-dppm)] ( 3 ), [Ru 3 (CO) 5 (μ 3 -CO)(μ 3 -Se)(μ-dppm) 2 ] ( 4 ) and [Ru 3 (CO) 6 (μ 3 -CO)(μ 3 -Se)(μ-dppm)(η 1 -Ph 2 PCH 2 P( O)Ph 2 )] ( 5 ) in 7%, 5%, 9% and 33% yields, respectively. A similar reaction between 1 with dppmS gives [Ru 3 (CO) 7 (μ 3 -S) 2 (μ-dppm)] ( 6 ), [Ru 3 (CO) 7 (μ 3 -CO)(μ 3 -S)(μ-dppm)] ( 7 ) [Ru 3 (CO) 5 (μ 3 -CO)(μ 3 -S)(μ-dppm) 2 ] ( 8 ) and [Ru 3 (CO) 6 (μ 3 -CO)(μ 3 -S)(μ-dppm)(η 1 -Ph 2 PCH 2 P( O)Ph 2 )] ( 9 ) in 8%, 7%, 14% and 35% yields, respectively. Treatment of 1 with PhSeSePh at 66 °C affords the dinuclear compound [Ru 2 (CO) 4 (μ-SePh) 2 (μ-dppm)] ( 10 ) in 14% yield. Thermolysis of 5 and 9 in refluxing toluene at 110 °C gives 4 and 8 , respectively. The molecular structures of 4 , 9 and 10 have been determined by single-crystal X-ray diffraction studies. The cores of the new clusters 4 , 5 , 8 and 9 consist of metal triangles capped by μ 3 -sulfur or selenium atoms with the bidentate ligand bridging in equatorial positions. In compounds 4 and 8 , two bidentate dppm ligands bridge the Ru 3 triangle in such a way that each ligand bridges two ruthenium atoms and one Ru–Ru edge remains unbridged. Compounds 5 and 9 contain one bridging dppm ligand and one dangling dppm mono-oxide ligand Ph 2 PCH 2 P( O)Ph 2 coordinated to the rear metal atom at an equatorial position. The molecular structure of 10 shows classical “sawhorse” structure with two bridging SePh ligands as well as the dppm ligand.

Treatment of [Os 3 (CO) 7 (μ 3 -S) 2 (μ-dppm)] ( 1 ) with Me 3 NO in toluene at 80 °C affords the trinuclear cluster [Os 3 (CO) 6 (μ 3 -S) 2 (NMe 3 )(μ-dppm)] ( 2 ) and the hexanuclear cluster [Os 6 (CO) 12 (μ 3 -S) 4 (μ-dppm) 2 ] ( 3 ) in 30% and 51% yields, respectively. The reaction of 1 with [Os 3 (CO) 10 (MeCN) 2 ] in refluxing benzene at 80 °C gives the hexanuclear cluster [Os 6 (CO) 14 (μ 3 -S) 2 (μ-dppm)] ( 4 ) in 15% yield. Compound 2 reacts with CO, PPh 3 and P(OMe) 3 at room temperature to give 1 , [Os 3 (CO) 6 (μ 3 -S) 2 (μ-dppm)(PPh 3 )] ( 5 ) and [Os 3 (CO) 6 (μ 3 -S) 2 (μ-dppm){P(OMe) 3 }] ( 6 ), respectively; in high yields indicating that the NMe 3 ligand is weakly bound. Compound 1 reacts with PPh 3 in presence of Me 3 NO to afford 5 , 2 and 3 in 53%, 6% and 18% yields, respectively, whereas with P(OMe) 3 1 gives only 6 in 84% yield. Compound 3 reacts with CO at 98 °C to regenerate 1 by the cleavage of the three unsupported osmium–osmium bonds. The molecular structures of 4 and 6 have been unambiguously determined by single crystal X-ray diffraction studies. The hexanuclear compound 3 appears to be a64-electron butterfly core with four triply bridging sulfido ligands and two bridging dppm ligands based on the spectroscopic and analytical data. The metal core of 4 can be described as a central tetrahedral array capped on two faces with two additional osmium atoms. The triply bridging sulfido ligands face cap the two tetrahedral arrays formed by metal capping of the two faces of the central tetrahedron. The dppm ligand bridges one edge of one of the external tetrahedral arrays. Compounds 5 and 6 are formed by the displacement of equatorial carbonyl group of 1 by a PPh 3 and P(OMe) 3 ligand respectively and their structures are comparable to that of 1 .

The crystal and molecular structures of Ru3(CO)6{μ 3-OPPh2C2H(C6H4)PPhCH2PPh}-(μ 3-OPPh2)Ph (1) and Ru3(CO)6{μ-OPPh2C2H(C6H4)PPhO}(μ-PPh2)(μ-PPh2O) (2) have been determined by single crystal X-ray diffraction. Both complexes contain oxygen atoms oxidatively inserted into phosphorus–ruthenium bonds, and unique σ/π multidentate ligands formed from C $$---{\text{H}}$$ H and C $$--$$ P bond cleavage in bis(diphenylphosphino)acetylene and bis(diphenylphosphino)methane. Complex 1 crystallized in the triclinic space group $${\bar 1}$$ , with lattice parameters a = 11.642(4) A, b = 15.018(5) A, c =16.587(5) A, α = 2.48(3)°, β = 76.47(2)°, γ = 70.35(3)°, V = 2651.1(15) A3, Z = 2. Complex 2 crystallized in the centered monoclinic space group, C2/c, with lattice parameters a = 34.467(4) A, b = 14.274(2) A, c = 23.258(3) A, β = 5.29(1)°, V = 11394(3) A3, Z = 8.

Tricarbonyl(1-methoxycarbonyl-5-phenylpentadienyl)iron(1+) hexafluorophosphate (7) was prepared in two steps from tricarbonyl(methyl 6-oxo-2,4-hexadienoate)iron. While addition of carbon and heteroatom nucleophiles to 7 generally occurs at the phenyl-substituted dienyl carbon to afford (2,4-dienoate)iron products, the addition of phthalimide proceeded at C2 to afford a (pentenediyl)iron product (18). Complex 18 was structurally characterized by X-ray diffraction analysis.

The reaction of [Os3(CO)10(μ-dppm)] (4) with diphenyldiselenide in refluxing toluene at 110 °C affords the dinuclear compound [Os2(CO)4(μ-SePh)2(μ-dppm)] (5), three 50 electron isomeric triosmium compounds 6, 7 and 8 with the formula [Os3(CO)8(μ-SePh)2(μ-dppm)], two triosmium benzyne compounds [Os3(CO)6(μ-CO)(μ-η2-Se)2(μ-C6H4)(μ-dppm)] (9) and [Os3(CO)9(μ-SePh)2(μ-η2-C6H4)(μ-dppm)] (10) in 11%, 19%, 15%, 5%, 18% and 6% yields, respectively. Thermolysis of both 6 and 8 in refluxing toluene gives the dinuclear compound 5 in moderate yield, whereas a similar thermolysis of 7 yields 5 and 9 in 20% and 27% yields, respectively. Compound 10 converts to 9 refluxing in octane. Treatment of the unsaturated compound [(μ-H)Os3(CO)8{Ph2PCH2P(Ph)C6H4}] (11) with diphenyldiselenide in refluxing benzene gives 5, 6, 7 and 8 in 8%, 20%, 25% and 10% yields, respectively. The molecular structures of 5, 6, 7 and 9 have been determined by single crystal X-ray diffraction studies. The molecular structure of 5 shows classical “sawhorse” structure with two bridging phenylselenido ligands as well as a dppm ligand. The solid-state structure of 6 reveals that two SePh groups span the open Os–Os edges of the Os3 triangle, while the dppm ligand bridges one of the closed Os–Os edges. In compound 7, one SePh spans the open Os–Os site, while the other spans one of the two closed Os–Os edges and the dppm ligand bridges the third Os–Os vector. Compound 9, which exists as a mixture of two isomers in solution, contains two triply bridging selenido ligands and a benzyne ligand, which are believed to have been formed by the cleavage of Se–Se bond of the PhSeSePh ligand followed by C–Se and C–H activation of the SePh group. The 54 electron compound 10 has been characterized by elemental analysis, IR, 1H NMR, 31P{1H} NMR and mass spectroscopic data.

The crystal structure of Na2S2O5, a simple and common ionic compound, is reported here for the first time. The crystals form non-merohedral twins, with the twin domains related by a twofold axis which bisects the angle between the a and c axes of each unit cell. The structure was determined from a single-crystal fragment of a twinned crystal that had undergone cleavage along the twin boundary. In addition to the problems associated with twinning, space-group determination proved difficult as well, with the structure initially determined in the P21 space group appearing to be disordered with two rotational conformers of the metabisulfite ion occupying equivalent sites in the lattice. An analysis at low temperature provided new weak reflections which were inconsistent with the original unit cell, but indexed to the correct unit cell, allowing for space group and crystal structure determination. The apparent structure, which appeared disordered in P21, seems to have resulted from an apparently fortuitous superposition of two conformationally inequivalent S2O_5^{2-} anions in the asymmetric unit of the correct structure in the P21/n space group. The metabisulfite ions in this structure do not adopt the Cs geometry observed in previously determined crystal structures containing S2O_5^{2-}. The structures of both ions in the asymmetric unit are effectively conformational mirror images of one another with two of the O atoms on each S atom in the ion approaching an eclipsed geometry. This observation provides further evidence that the structures of sulfur-oxy anions in the solid state are dictated mainly by interionic coulombic forces rather than by intraionic bonding interactions

The unsaturated cluster [(μ-H)Os 3 (CO) 8 {Ph 2 PCH 2 P(Ph)C 6 H 4 }] ( 2 ) reacts with elemental selenium at 110 °C to give two triosmium clusters [Os 3 (CO) 7 (μ 3 -Se) 2 (μ-dppm)] ( 3 ), [Os 3 (CO) 7 (μ 3 -CO)(μ 3 -Se)(μ-dppm)] ( 4 ) and the tetraosmium cubane-like cage cluster [Os 4 (CO) 10 (μ 3 -Se) 4 (μ-dppm)] ( 5 ) in 20, 47 and 5% yields, respectively. Treatment of the labile cluster [Os 3 (CO) 10 (MeCN) 2 ] with dppmSe at ambient temperature gives the dinuclear compound [Os 2 (CO) 6 (μ-Se)(μ-dppm)] ( 6 ) along with 3 and 4 in 13, 24 and 4% yields, respectively, while with dppmSe 2 at 80 °C it yields 3 and 5 in 27 and 7% yields, respectively, by oxidative transfer of selenium atoms to the metal center. The reaction of 3 with Me 3 NO at 80 °C leads to loss of 1 mol of CO and formation of the condensation derivative [Os 6 (CO) 12 (μ 3 -Se) 4 (μ-dppm) 2 ] ( 7 ), containing a central 64-electron butterfly core, in 75% yield. Compound 7 reacts with CO at 98 °C to regenerate 4 by cleavage of the three unsupported metalmetal bonds. In the disubstituted square-pyramidal selenido cluster, 3 , the dppm ligand bridges two bonded osmium atoms whereas in 7 both the dppm ligands bridge the open osmium–osmium edges. Treatment of 3 with PPh 3 in the presence of Me 3 NO at room temperature gives the phosphine-substituted compound [Os 3 (CO) 6 (μ 3 -Se) 2 (μ-dppm)(PPh 3 )] ( 8 ) and the dimer 6 in 26 and 20% yields, respectively. The structure of 8 is comparable with that of 3 from which it is derived by replacing one equatorial carbonyl group with the PPh 3 ligand. The molecular structures of the complexes 3 , 4 , 6 , 7 and 8 have been fully elucidated by single-crystal X-ray diffraction studies.

The reactions of [Ru3(CO)10(μ-dppm)] (4) with 1,2-ethanedithiol, 1,3-propanedithiol and 3,4-toluenedithiol in refluxing THF afforded the dinuclear dithiolato complexes [Ru2(CO)4(μ-SCH2CH2S)(μ-dppm)] (5), [Ru2(CO)4(μ-SCH2CH2CH2S)(μ-dppm)] (6) and [Ru2(CO)4{μ-SC6H3(CH3)S}(μ-dppm)] (7), respectively. Protonation of complexes 5 and 6 by tetrafluoroboric acid in CD2Cl2 resulted in the formation of cationic hydrido complexes [(μ-H)Ru2(CO)4(μ-SCH2CH2S)(μ-dppm)]+ (8) and [Ru2(CO)4(μ-SCH2CH2CH2S)(μ-dppm)]+ (9) isolated as their PF6 − salts. Compounds 5 and 6 are also obtained from the reactions of dppm with [Ru2(CO)6(μ-SCH2CH2S)] (10) and [Ru2(CO)6(μ-SCH2CH2CH2S)] (11), respectively. Protonation of 10 and 11 with tetrafluroboric acid gives the mono-protronated species [(μ-H)Ru2(CO)6(μ-SCH2CH2S)]+ (12) and [(μ-H)Ru2(CO)6(μ-SCH2CH2CH2S)]+ (13), respectively. All the compounds have been characterised by IR, 1H NMR, 31P{1H} and mass spectroscopic data, together with single crystal X-ray diffraction studies for 6 and 7.

The X-ray crystal structure of the title compound, as crystallized from methanol–methylene chloride was determined. The asymmetric unit contains two steroid molecules, which differ primarily in the orientation of the aromatic rings of the benzyl ethers. The title compound crystallizes in the noncentrosymmetric space group P2(1), with a = 7.558(2), b = 16.673(3), c = 18.735(4) A, β = 97.610(10)°, and D calc = 1.268 g cm−1 for Z = 4.

ZnCl2-mediated cyclization of dithiocarbamtes provides thiadiazoles whereas in the presence of a base of oxadiazole derivatives are formed.

The reaction of [Ru3(CO)10(μ-dppm)] 1 with PPhCl2 in refluxing CHCl3 results in the isolation of [(μ-H)Ru3(CO)8(μ-Cl)(μ-dppm)] 3 in 10% yield. Compound 3, which has been structurally characterized by crystallographic methods, is also formed from the reaction of 1 with H2 in refluxing CCl4. The compound crystallizes in the monoclinic space group P21/c with a = 16.814(2), b = 18.7590(12), c = 11.486(2) A, β = 97.745(11)°, V = 3589.8(8) A3, and Z = 4. The hydride and chloride ligands bridge the same edge of the triruthenium cluster as the dppm ligand.

The reactions of [Ru3(CO)10(μ-dppm)] 4 with quinolines afforded [Ru3 (μ-CO)(CO)7{μ3-η2-P(C6H5)CH2P(C6H5)2)}{μ-η2-C9H5(R)N}] (8, R = 4-Me; 9, R = H) as the major products along with small amounts of known compound [Ru3(CO)9{μ3-η3-P(C6H5)CH2P(C6H5)(C6H4)}] 5. The molecular structure of 8 has been determined by single crystal X-ray studies. The reaction of 5 with 4-methylquinoline in refluxing cyclohexane afforded 8 and two known dinuclear compounds, [Ru2(CO)6{μ-CH2P(C6H5)(C6H4)P(C6H5}] 10 and [Ru2(CO)6 {μ-(C6H4)P(C6H5)(CH2)P(C6H5}] 11, in 40, 12, and 10% yields, respectively. The compounds 10 and 11 are also formed from the thermolysis of 4 in addition to the major compound 5. The solid state structure of the previously reported [Ru3(CO)10(η-H){μ-η2-C9H6N}] 2a is also reported for comparison.

Single crystal X-ray diffraction analysis of the title compound revealed that the phthalimide substituent was endo with respect to the bicyclic ring system.