Showing papers in "Journal of Cluster Science in 1996"

The structures of europium(III)- and uranium(IV) derivatives of [P5w3oo110]15-: Evidence for “cryptohydration”

Abstract: The crystal structures of (Nh4)11.5K0.5[ Eu(OH2)P5W30O110] ·24 H2O, K5H5 [Eu(OH2)P5W30O110] ·31 H2O, and (NH4)11[U(OH2)P5Wn30O110 ·12 H2O have been determined. In each case, the anion has the overall virtual C5v symmetry previously observed for the sodium derivative, [NaP5W30 110]14- The encrypted Eu3+ and U4+cations lie on the C5 axis, but are displaced further than the Na+ from the equatorial plane defined by the five phosphorus atoms. Only minor differences are observed between the structures of the two salts of the europium derivative, although solutions of these display31P NMR spectra with chemical shifts differing by 10 ppm, provisionally attributed to the effects of protonation of the anion, The most significant feature of the three new structures is the presence of a water molecule within the central cavity and coor-dinated to the Eu3+ or U4+ cation.The coordination spheres of the central cations can therefore be described as monocapped pentagonal antiprisms.

Electron-Deficient Molybdenum/Cobalt/Sulfido Clusters: Chemistry Related to Hydrodesulfurization (HDS) Catalysis

Abstract: The author's work on the reactions of Cp2Mo2Co2S3(CO)4 (1) and Cp2Mo2 Co2S4(CO)2 (2) with organosulfur compounds is reviewed. Reaction pathways that lead to C S bond scission are proposed, and the relexance of these results to HDS reactions mer commercial “CoMoS” catalysts is discussed.

[N(PPh3)2]2[{Au3Ag2(C2Ph)6} {Au3Cu2(Cu2Ph)6}]: Co-crystallized pentanuclear bimetallic gold-silver and gold-copper clusters

Abstract: The X-ray structural study of the reaction product of equimolar amounts of [Au3Cu2(C2Ph)6]. [{Au(C2Ph)} n ], and [Ag(C2Ph)} n ] revealed two bimetallic anionic [N(PPh3)2] + [Au3Ag2(C2Ph)6]− and [N(PPh3)2]+[Au3Cu2 (C2 Pg)6] — clusters co-crystallized in one asymmetric unit. Each cluster has trigonal bipyramidal geometry with three gold atoms occupying equatorial planes and two silver or copper atoms in the apical positions. Our earlier conclusion based upon spectroscopic characterization describing the product of be above reaction as trimetallic cluster containing three coinage-metals with an overall composition [Au3CuAg(C2Ph)6]−, was erroneous.

[Cu 12 S 6 (P n Pr 3 ) 8 ] and [Cu 20 S 10 (P n Bu 1 Bu 2 ) 8 ]: Two sulfur bridged copper clusters with Cu-s cluster cores of known compositions but new structures

Abstract: The synthesis and X-ray determination of two sulfur bridged copper clusters with the known compositions of [Cu12S6(PnPr3)8] and [Cu20S10(PnBu1Bu2)8] but new molecular structures allow a comparison of these isomeric copper sulfide clusters. The Cu-S frameworks of the clusters with twelve copper atoms are highly topologically related and can both be derived flom a hypothetical “naked” [Cu12,S6] cluster that results from theoretical investigations. More dificult is the comparison of the two clusters containing 20 metal atoms. The two cluster types can be called either a “prolate” or an “oblate” isomer of [Cu20S10(pR3)8].

Redox behavior of europium in the preyssler heteropolyanion [EuP5W30O110 12-

Abstract: In aqueous, mineral-acid electrolytes, the cyclic voltammetry of the europium-exchanged Preyssler heteropolyanion, [Eu111P5W30O110]12- , is unique among all the other trivalent-lanthanide-exchanged anions. [Ln111P5W30Oll012-] for Ln≡Ce-Lu. To obtain insights about this issue, we conductedin situ Eu L3-edge XANES IX-ray absorption near edge structure) spectroelectrochemical experiments on an aqueous solution of[EuP5W30O110]12- (5.5 mM) in a sup-porting electrolyte of I M H2SO4 at two extreme potentials. The results demonstrate that the Eu111 ion in the colorless Preyssler anion solution at open circuit potential (+0.21 V vs. Ag/AgCI) is electroactive and is reduced to Eu11 in the resulting heteropoly blue solution through constant-potential bulk elec-trolysis at -0.55 V vs. Ag/AgCI. The reduction is reversible upon complete reoxidation of the reduced anion, the Eu XANES is indistinguishable from that observed at the open circuit potential before electrolysis. This unusual redox behavior of[EuP5W30Oll0]12- may be of technological importance in the area of oxidation catalysis.

CdS nanoclusters stabilized by thiolate ligands: A mini-review

Abstract: One of the most exciting frontiers in materials chemistry in recent years is the optoelectronics of “quantum-confined” semiconductor nanoclusters. These nanoclusters are ∼ 10–200 A in diameter, and in this size regime exhibit extra-ordinarily interesting quantum mechanical effects. Cadmium sulfide is a popular semiconductor for these studies, and reviewed here is the synthesis and charac-terization of such CdS nanoclusters, with emphasis on how chemical control of the surface by thiolates influences product formation and properties. Also described are the syntheses and structures of true molecular clusters of CdS capped with thiolate ligands.

Silver(I)-dithiolate chemistry: Syntheses and characterizations of three new Ag1 cluster anions containingi-MNT [i-MNT= S2CC(CN) in2 su2− ] ligands-[Ag4(i-MNT)4]4−, [Ag8(i-MNT)6(PPh3)4]4−, and [Ag9(i-MNT)6(PPh3)6]3−

Abstract: The reaction of AgNO3 with [(“Bu4N2 i-MNT)]3 in CH3CN produces a new silver cluster anion [Ag4(i-MNT)4]4− ,3, a species having a tetrahedral arrangement of silver atoms bridged by fouri-MNT ligands which has been isolated and characterized by X-ray crystallography as [Bu4N]2[(PPh3)2]2 [Ag4(i-MNT)4],4. The reaction of two or three equivalents of Ag(PPh3)2NO3 with [BzEt3N]6[Ag6(i-MNT)6] in CH3CN produces two new clusters, [BzEt3N]4[Ag8(i-MNT)6(PPh3)4],6, and [BzEt3N]3[Ag4(i-MNT)6(PPh3)6], 7, having the common structural feature of an octahedral Ag6S12 core. The octanuclear Ag8 cluster also can be synthesized from the reaction of 4 and PPh3 in CH2Ck2 and compound 5 has been structurally characterized as [Bu4N]2[(PPh3)2N]2[Ag8(i-MNT)6(PPh3)4]. The31P{1H} NMR spectrum of 6 in CD3CN at −43° shows two sets of two doublets. The corresponding chemical shift and coupling constant of each species is 9.32 ppm (354, 408.8 Hz) and 9.45 ppm (346.7, 401.7 Hz), respectively. Pertinent crystallographic data are as follows: Compound 4 crystallizes in the orthorhombic space group Cc2a, witha=18.668(3)A,b=36.793(4) A,c=17.836(3)A, Z=4, andV= 12250(3)A3. Compound 5 crystallizes in the triclinic space group P1, witha=16.506(3)A,b=17.280(3)A,c=19.144(4) A,x=98.485(14)°, β= 105.44(2)°.y=94.63(2),Z= 1, andV = 5164(2)A3. Compound6 crystallizes in the monoclinic space group C2/m, witha= 25.341(9)A,b= 25.289(9)A,c= 15.076(7)A, β= 107.19(5)°,Z=2, and V=9230(6)A3. Compound7 crystallizes in the monoclinic space group C2/c, witha=25.872(6)A,b=21.288(4) A,c=35,928(5), β=100.98(1)°,Z-4, andV=19426(6)A3.

Triosmium clusters derived from the reactions of thioureas with dodecacarbonyltriosmium: Crystal structures of [Os3(CO)11{η 1-SC(NMe2)2}], [Os3(CO)9(μ-OH)(μ-OMeOCO){η 1-SC(NMe2)2}] and [(μ-H)Os3(CO)9{μ 3-NHC(S)NH2}]

Abstract: The reaction of [Os3(CO)12] with tetramethylthiourea in the presence of a methanolic solution of Me3NO·2H2O at 60° yields the compounds [Os3(CO)11{η1-SC(NMe2)2}] (1) in 56% yield and [Os3(CO)9(μ-OH)(μ-MeOCO){η1-SC(NMe2)2}] (2) in 10% yield in which the tetramethylthiourea ligand is coordinatedvia the sulfur atom at an equatorial position. Compound2 is a 50 e− cluster with two metal-metal bonds and the hydroxy and methoxycarbonyl ligands bridging the open metal-metal edge. In contrast, the analogous reaction of [Os3(CO)12] with thiourea gives the compounts [(μ-H)Os3(CO)10{μ-NHC(S)NH2}] (3) in 8% yield and [(μ-H)Os3(CO)9{3-NHC(S)NH2}] (4) in 30% yield. In3, the thioureato ligand bridges two osmium atomsvia the sulfur atom, whereas in4 in addition to the sulfur bridge, one of the nitrogen atoms of thioureato moiety bonds to the remaining osmium atom. The decacarbonyl compounds 3 can also be obtained in 50% yield from the reaction of [Os3(CO)10(MeCN)2] with thiourea at ambient temperature. Compound3 converts to4 (65%) photochemically. Compound1 reacts with PPh3 and acetonitrile at ambient temperature to give the simple substitution products [Os3(CO)11(PPh3)] and [Os3(CO)11(MeCN)], respectively, while with pyridine, the oxidative addition product [(μ-H)Os3(CO)10(μ-NC5H4] is formed at 80°C. All the new compounds are characterized by IR,1-H-NMR and elemental analysis together with the X-ray crystal structures of1,2 and4. Compound1 crystallizes in the triclinic space group P\(P\bar 1\)with unit cell parametersa = 8.626(3) A,b = 11.639(3) A,c = 12.568(3_ A,α = 84.67(2)°,β = 75.36(2)°,γ = 79.49(3)°,V = 1199(1) A3, andZ = 2. Least-squares refinement of 4585 reflections gave a final agreement factor ofR = 0.0766 (R w = 0.0823). Compound2 crystallizes in the monoclinic space group P21/n with unit cell parametersa = 9.149(5) A,b = 17.483(5) A,c = 15.094(4) A,β = 91.75(2)°,V = 2413(2) A3, andZ = 4. Least-squares refinement of 3632 reflections gave a final agreement factor ofR = 0.0603 (R w = 0.0802). Compound4 crystallizes in the monoclinic space group C2/c with unit cell parametersa = 13.915(7) A,b = 14.718(6) A,c = 17.109(6) A,β = 100.44(3)°,V = 3446(5) A3, andZ = 8. Least-squares refinement of 2910 reflections gave a final agreement factor ofR = 0.0763 (R w = 0.0863).

Sulfide aggregates and clusters of platinum

Abstract: The homometallic and lteterometallic chemistry of platinum sulfide polynuclear complexes with or without metal-metal bonds is reviewed. The synthetic strategies, structural and bonding characteristics, and chemical properties of these materials are emphasized. Other dinuclear platinum sulfide complexes which are potential precursors to larger aggregates (non-M-M bonded) or clusters (M-M bonded) are also identified.

Studies of the oxovanadium-organophosphonate system: Formation of pyrodiphosphonate and pyrophosphophosphonate units through metal-mediated ligand condensations. The crystal and molecular structures of (Ph4P)2[VO{RP(O)2OP(O)2 R}2] (R=Me, Ph) and (Ph4P)2(n-Bu4N)[(VO)6V{t-BuP(O)2OPO3}6]

Abstract: Under solvothermal conditions and in the presence of oxovanadium species. organophosphonates undergo self-condensation reactions or condensation with phosphate to yield pyrodiphosphonate {RP(O)2OP(O)2 R}2, or organophos-phonatophosphate units {RP(O)2OPO3}3-. In this fashion, the reactions of (Ph4P)[VO2Cl2] withRPO3H2 (R=CH3,Ph) and Et3N in CH3CN at 110°C yielded (Ph4P)2 [VO{RP(O)2P(O)2 R}2](R = CH3(1), Ph (2)). However, the reaction of {Ph4P}[VO2Cl2],t-BuPO3H2 and (n-Bu4N)H2PO4 in acetonitrile at 125°C produced an unusual mixed valence V(IV)/V(III) cluster (Ph4P)2 (n-Bu4N)[(VO)6V{Me3CP(O)2OPO3}6] ⊎3CH3CN (3). Compounds1 and2 exhibit mononuclear molecular anions with the V(IV) center in the common square pyramidal coordination mode. The organodiphosphonate ligands adopt a bidentate coordination mode. The molecular anion of3 consists of a shell constructed of six V(IV) square pyramids linked by pentadentate {Me3CP(O)2OPO3}3- groups. Each organophosphonatophosphate ligand bridges four {VO5}square pyramids of the shell and directs the fifth oxygen donor toward the interior of the cluster, so as to bond to an octahedral V(III) located at the center of the cluster cavity. Crystal data:1, C26H26O5.5P3V0.5: triciinic Pl,a=10.836(2)A,b=ll.418(2)A,c=11.486(2)A,α=82.58(2)°,s=75.29(2)°,γ=75.61(2)°,V=1328.1(7)A3,Z=2, Dcalc=l.362gcm-3;2, C36H32O6.5P3V0.5: monoclinic P21/c,a=12.823(3)A,b=14.318(3)A,c=18.581(4)A,s=94.76(3)°,V=3999.7(13)A3,Z=4, Dcalc=l.342gcm-3 3, C94H139N4O42P14V7, triclinic Pl,a=13.589(3)A,b=17.835(4)A,c=38.915(8)A,α=81.64(2)°,s=81.58(2)°,γ=82.87(2)°,V=9180(3)A3,Z=3, Dcalc=l.512gcm-3.

Bis-ethanedithiolate triruthenium cluster complexes from the reaction of Ru3(CO)12 with 1,2,5, 6-tetrathiacyclooctane

Abstract: The reaction of 1,2,5,6-tetrathiacyclooctane with Ru3(CO)12 in methylene chloride solvent at 40°C has yielded two new isomericbis-thane-1,2-dithiolate triruthenium carbonyl cluster complexes:anti-Ru3(CO)7(μ-SCH2CH2S)2, 1 andsyn-Ru3(CO)7(μ-SCH2CH2S)2,2, and the previously reported diruthenium compound, Ru2(CO)6(μ-SCH2CH2S).3 in 24 %, 5 %, and 26 % yields, respectively. Compounds1 and2 were characterized by a single crystal X-ray diflraction analyses. Both compounds consist of a open triangular triruthenium clusters with seven terminal carbonyl ligands and a bridging ethanedithiolate ligand across each of the metal metal bonds in the complex. When heated to 60° C, compound1 was trans[formed into a mixture of2 and3. Crystallographic data for1: Ru3S4O7C11H8, space group, P21/a,a= ll.830(2)A,b= 10.576(1)A,c= 16.012(1)A,β= 100.53(2)°,Z=4, 1808 reflections,R= 0.029. For2: Ru3 S4O7C11H8, space group P1,a= 9.945(l)A,b= 11.323(1)A.c= 9,788(1)A,a= 108.73(1)°,β= 104,67(1)°,y= 103.59(2)°,Z = 2, 2046 rellections.R = 0.021.

Coordination chemistry of polyoxomolybdates: The versatile behavior of amidoximes

Abstract: The reactions of 2-thienylamidoxime and 2-thienylmethylamidoxime with [MoO2(acae)2] or x-(NBu4 [Mo8O26]. in alcohols or acetonitrile, yield a number of compounds with different nuclearities and various molybdenum cores, such as the compact {Mo4O10(OMe)2}2+ the cyclic {Mo4O12}, and the open {Mo11On211-1}2+ (n= 2 or 4) cores. Addition of NH2OH to the reaction mixtures results in the formation of nitrosyl complexes containing either the Mo(NO)3 or the Mo(NO)22 units. The amidoxime component may be present either as RC(NH2)NHO. RC(NHi2), RC(NH)NHO or RC(NH)NO2: ligands, or as hydrogen-bonded RC(NH2)NOH molecules. The crystal structures of [MoO(acac)RIC'(NH2)NO] {RJC(NH)NO}](1), [Mo(NO)(acae)2 {RIC(NH2)NO}] (4), (NBu4)2[Mo4O10(OMe)2{RIC(NH) NO}2] (12a),(NBu4)2(H3O)[Mo5O13(OMe)4(NO)].2R1C(NH2)NOH(13b) and [R1C(NH2)2)]3[Mo5O13(OEt)4(NO)] (14) (R1=2-thienyl) are reported. The cryslallographic data for these compounds are as follows:1, mono-clinic. P21 a.a=24.547(4)A. b=8.188(4)A. c=9.607(3)A, s=96.18(3)c, R=0.046. R10=0.050: 4. monoclinic, P21c.a=8.265(2)A, b=9.381(2)A,c=24.770(4)A, c = 24.7701(4) A, s=93.99(2). R=0.039. R=0.042;12a, monoclinic, C2/c, a= 19.570(5)A. b=16.883(4)A, c = 19.82(l)A. s= 114.36(5)°, R=0.064,R.=0.074;13b monoclinic;. P21 c.a=18.197(5)A, b=15.857(14) A, c = 23.075(17) A, β=93.20(3). R=O.050. Rw=0.057;14, trictinic PI, a = 9.871(3),b= 14.138(3).c= 14.781(8)A. α=92.67(2)c β=99.36(1)° γ=90.52(2)°. R = 0.044. Rw = 0.049. Particular attention is focused on the various coordination modes that the different ligand forms adopt: µ- κO, κ2N,O, κ2N',O, µ-κN: κ2O. and μ3- κN:κN:κ2O.

Synthesis and structure of [(OC)4Os(PbMe2)]2 and some derivatives of the type Os2(CO)7(SnMe2)2(L)

Abstract: The complexes [(OC)4Os(PbMe2)]2 (3) and [(OC)4OsSnBu 2 ′ ]2 (4) have been prepared from be reaction of Na2[Os(CO)4] with Me2PbCl2 and Bu 2 ′ SnCl2, respectively, in THF and their X-ray crystal structures determined. The red derivative,3, was light-sensitive in solution. The reactions or [(OC)4 Os(SnMe2)]2 (2), or its decarbonylated derivative [Os3(CO)7(SnMe2)2]2 (7), with olefins or phosphorus donor ligands have also been investigated, and the structures of two derivatives, viz. [Os2(CO)7(SnMe2)2(C2H4)] (5a) and [Os2(CO)7(SnMe2)2(PMe3)] (6a), have been determined; the noncarbonyl ligand occupies an equatorial site in each case. The X-ray crystal structures of all these compounds, like those of [(OC)4Os(EMe2)]2 (E=Ge (1), Sn (2)) which have been reported previously, show leaning of the axial carbonyl ligands toward the metal tetracycle, i.e., an “umbrella” effect. Crystallographic data for compound3: space group, P21/a;a=13.4404(13) A,b=10.7494(14) A,c=148967(18) A,β=98.204(9)°,R=0.035, 1983 observed reflections. For compound4: space group,P1;a=9.016(1) A,b=9.370(1),c=11.334(1) A, α=103.67(1)°,β=100.30(1)°, γ=115.03(1)°, R=0.046, 2026 observed reflections. For compound5a: space group,P1;a=9.2933(11)A,b=9.7181(3),c=12.2508(15) A, α=89.21(1)°,β=87.61(1)°, γ=86.13(1)°,R=0.038, 2770 observed reflections. For compound6a space groupP1:a=8.7244(9)A,b=10.9318(6),c=13.2560(13) A, α=87.815(6)°,β=83.655(8)°, γ=82.343(6)°, R=0.030, 3497 observed reflections.

X-ray crystal structures of Ru3(μ-H)(μ-C,N-C5H4N)(CO)10-n (P i Pr3) n ,n=0,1: A A case of the hydride following the Phosphine?

Abstract: The reaction ofRu3(μ-H)(μ-C,N-C5H4N)(CO)10 (1) with Pt(P i Pr3)(nb)2 {nb = bicyclo-[2.2.1]hept-2-ene} does not afford any Ru-Pt mixed metal clusters, but gives instead the mono-substituted phosphine derivative Ru3(μ-H) (μ-C,N-C5H4N)(CO)9(P i Pr3) (2) as the sole isolable product. Single crystal X-ray studies have been carriedout on 1 and 2. Crystal data for 1: monoclinic, space group P21/c,a = 16.9637(10) A,b = 7.6632(5) A,c = 17.4058(11) A, β = 117.214(5)°,V = 2009.0(2) A3,R(R w) = 0.022 (0.034) for 3090 independent absorption corrected data. Crystal data for 2: triclinic, space group PĪ,a = 9.3389(5) A,b = 11.4376(6) A,c = 15.1781(8) A,α = 76.454(4),β = 79.900(5),γ = 67.428(5)°,V = 1448.8(2) A3 R(R w ) = 0.024 (0.034) for 4564 independent absorption corrected data. In cluster 1 the Ru-Ru bonds are in the range 2.8462(4)-2.8986(4) A. The hydride andσ-pyridyl ligand bridge the same Ru-Ru vector, and the Ru(μ-H) bridge is symmetric, with Ru-H = 1.78(4) and 1.77(4) A. In cluster 2 the Ru-Ru distances show a greater ranger 2.7267(3)-3.0604(3) A. The phosphine ligand is bonded to the Ru atom which is not involved in theσ-pyridyl bridge. In contrast to 1, the hydride andσ-pyridyl ligands in 2 bridge different Ru-Ru vectors and the resultant Ru(μ-H)Ru bridge is asymmetric, with Ru-H = 1.70(4) and 1.89(4) A.

Effects of a vanadate-support on the reactivity of theBis(Methallyl)Rhodium Complex [{(η3-C4H7)2Rh}2(V4O12)]2−. A comparison with the acetylacetonato complex

Abstract: The methallyl moieties of [{(η3-C4H7)2Rh}2(V4O12)]2− couple to yield 2,5-dimethyl-1,5-hexadiene in a selective manner by the action of P(OEt),3, while the reaction of [(η3-C4H7)2 Rh(acac)] with P(OEt)3 produces a mixture of organic compounds. The result shows that the vanadate support has a significant influence on the reactivity of organometallic complexes.

Theoretical studies of (d-p)? bonding, electronic spectra, and reactivities in homo- and heterometallic clusters: [Mo3- n W n X4(H2O)9]4+ ( X = O, S, Se, Te;n= 0-3)

Abstract: Ab initio calculations with relativistic effective potentials have been carried out on 12 trinuclear molybdenum/tungsten cluster aqua ions [M3X4(H2O)9]4− (M3= Mo3, W3 for X = O, S, Se, Te; M3=Mo2W, MoW2 for X = O, S). The electronic structures and bonding pictures of l-12 are discussed in terms of the delocalized and localized molecular orbitals as well as the Mulliken populations, natural populations, and Mayer bond orders. It is shown that the (d-p)ρ bonding in the puckered six-membered ring of the [M3(µ-X)3] core arises from a closed continuous ring of three mutually adjacent localized (d-p-d)ρ bonds with strong interactions. It is these three-centered two-electron (d-p-d)ρ bonds that account for the unusual physicochemical properties and reactivities of these cluster compounds. The wavelengths and the assignment of electronic spectra have been given, and the relation between the wavelength shili and the (d-p)ρ bonding is discussed, The reactivities of the ligand substitution reactions and two kinds of addition reactions as weil as some kinetic and redox properties of these compounds are briefly discussed by taking advantage of this Iocalization (d-p-d)ρ a bonding picture.

Oxidative addition of 2,2′-dithiosalicylic acid to the cluster [Os3(CO)10)(CH3CN)2]

Abstract: The reaction of 2,2'-dithiosalicylic acid with two equivalents of [Os3(CO)10 (CH3CN)] in THF at −78°C yields yellow crystals of [{Os3(CO)10(μ-H)}2 (O2CC6H4S)2] 1 in moderate yield. Hydrogenetaion of 1 in refluxing CHCl3 affords [Os3(CO)1(μ-H)(O2CC6H5)] 2 in good yield. Structures of 1 and 2 have been established by single crystal X-ray structure analysis.

Tetranuclear Planar Metal Clusters with Two Capping Ligands

Abstract: Background information and current research activity dealing with tetrametal planar clusters containing two capping ligands is briefly reviewed. The synthetic methods leading to these clusters and their chemical properties are presented. The structure and bonding in lo some representative example is discussed. Their application as models of heterogeneous catalysts, homogeneous catalysts, and precursors to materials is highlighted. Such information can have important implications in the design of a more sophisticated tetranuclear cluster systems for improved process applications.

Homogeneous catalytic hydrogenation of diethyland biphenyl-acetylene and isomerization ofCis-Stilbene in the presence of [(C5H5)2Ru3(CO)3(μ-CO)(μ3-CO)(C2Ph2)]

Abstract: The title complex (1) is a good hydrogenation catalyst tar diphenylacetylene in homogeneous conditions; it comparison with the activity of other ruthenium clusters is made. Apparently cluster catalysis occurs, but fragmentation to binuclear metallacyclic products containing two alkyne molecules was also observed: these 40 not been previously described and have been characterized by elemental analyses and mass spectrometry. Complex1 contains all alkyne bound parallel to one metal-metal edge. The results obtained support the hypothesis that transition metal clusters with alkynes bound in this fashion could ad as catalysts precursors or as intermediates in the homogeneous hydrogenation of alkynes; this behavior would be an example of structure-reactivity relationship in homogeneous catalysis.

Syntheses and structures of Tetranuclear Cluster complexes of molybdenum [Mo4(μ3-S)2(μ2-S)4 X 2-(PMe3)6] (X = SH, Cl, Br, I, SCN) and [Mo4(μ3-S)2-(μ2-S)4 (dtc)2(PMe3)4] (dtc = diethyldithiocarbamate)

Abstract: A molybdenum cluster complex [Mo4(μ3-S)2(μ2-S)4)(SH)2(PMe3 6] has been synthesized by the reaction of (NH4)2Mo3S13 with trimethylphosphine. The cluster core is composed of four molybdenum atoms arranged in the rhombus bridged by two capping and four bridging sulfur atoms. Two SH and six tri-methylphosphine ligands are coordinated to the terminal positions. The mean oxidation stares of molybdenum is +3.5 and there are five Mo-Mo bonds consistent with ten metal cluster electrons. The complex has been converted into [Mo4(μ3-S)2(μ2-S)4 X 2(PMe3)6] (X=Cl, Br, I, SCN) and [Mo4μ3-S2(μ2-S)4 (die)2(PMe3)4] (dtc - diethyldithiocarbamate). In the case of the dtc complex, two terminal trimetlaylphosphine ligands are displaced and dtc ligands are coordinated in chelate fashion. The structures of the SH, Cl, Br, and dtc complexes have been determined by X-ray crystallography. Molecular orbital calculations with DV-Xα method has shown large HOMO-LUMO gaps (1.52-1.74eV) for [Mo4S6 X 2(PH3)4] (X= SH, Cl, and Br).

Cobalt (iron) thiolato complexes containing the Co-ligand phosphine and reaction products of the structural fragment ML 2 L′ (L = 1,2-bidentate thiolate,L′= tertiary phosphine)

Abstract: Mono-, di-, tri-, and tetra-nuclear cobalt (iron) complexes containing co-ligands phosphine and thiolate are presented according to the classification by combination of different dentates of the two ligands. Emphasis is being put on the triand tetranuclear cluster complexes of monodentate phosphines and 1,2-bidentate thiolates. These complexes are considered to be constructed based on the general structural fragment (or building block) ML 2L′ (L=1,2-bidentate thiolate,L′=tertiary phosphine). Structural regularities are presented in Tables I, III, IV, and V and discussed. FAB mass spectroscopic data showed the possible fragmentation patterns. Synergism of the cluster skeletons is proposed to explain the occurrence of the distinct structural modes.

The synthesis of [Fe(CO)3(η1-dppm) {Sn(n-Bu)2}]2 by silicon-tin exchange, its crystal structure and its use as a metallodiphosphine ligand

Abstract: The reaction of the siloxyl containing ferrate [Fe(CO)3(η 1-dppm){Si(OMe)3}]−,1 (dppm = Ph2PCH2PPh2) with Sn(OAc)2(n-Bu)2 has yielded the new dimeric complex [Fe(CO)3(η 1-dppm){µ-Sn(n-Bu)2}]2, 3 in 89% yield. Compound3 was characterized crystallographically and was found to be a centrosym-etrical molecule with a rhomboidal Fe2Sn2 cluster at the center. Each iron atom contains meη 1-dppm ligand. Compound3 was found to react with [Pd(dmba) (µ-Cl)]2 (dmba=dimethylbenzylamine) to yield the new complexmer-[Fe(CO)3{Sn(n-Bu)2}(µ-dppm)Pd(dmba)Cl]2, 4 by attachment of a palla-dium grouping to each of the uncoordinated phosphorus atoms in 3. Crystal data for 3: space groupP $$\bar 1$$ ,a=11.399(2) A, 6=15.98(3) A, c=10.869(3) A, α=94.10(2)°.β=100.56(2)°, γ=69.35(1)°,Z=2, 3533 reflections,R=0.034.

RuH3[P(C6H5)3]3− as a ligand in complexes withM(CO)3 Fragments (M = Cr, Mo, W)

Abstract: The reactions of RuH3[P(C6H5)3]3− with Cr(CO)3(CH3CN)3, Mo(CO)3 (diglyme), or W(CO)3(C3H2CN)3 resulted in the formation of the appropriate [(H5C6)3P]3Ru(μ-H)3M(CO)3− complexes, which have been characterized analytically, spectroscopically, and in one case (M = Cr) by an X-ray diffraction study of the K [N(C2H4OC2H4OCH3)3]+ salt. This complex crystallizes in the triclinic space group Pl witha = 13.666(6),b= 13.7901(7),c = 18.147(8) A,a = 93.23(3)°, β = 94.07(4)° γ = 90.43(4)°, andV = 3405.6 A3 for Z = 2. Final discrepancy indices ofR = 0.048 and Ru = 0.056 were obtained. The hydride ligands, all of which could be located and their positional coordinates refined, completed local pseudo-octahedral coordination about both the ruthenium and thechromium centers. The Ru-H bonds are significantly shorter than the Cr-H ones, 1.65(4) vs. 1.92(4) A, and the Ru-Cr bond distance is 2.5474(9) A.

Reactions of the dirhenium(II) complexes Re2X4(dppm)2 (X= Cl, Br; dppm = Ph2PCH2PPh2) with isocyanides. Part IX. New isomeric forms of the mixed carbonyl-isocyanide dirhenium(II) Complexes Re2 Cl4(dppm)2(CO)(CNxyl) and [Re2Cl3(dppm)2(CO)(CNxyl)2]O3SCF3 The X-ray crystal structure of [(xyl NC)2ClRe(μ-dppm)2ReCl2(CO)] O3SCF3

Abstract: The monocarbonyl complex Re2Cl4(µ-dppm)2(CO) reacts with xylyl isocyanide in acetonitrile to afford the bioctahedral complex (CO)Cl2Re(µ-dppm)2 ReCl2(CNxyl), 2b. This is a different structural isomer from the edge-sharing bioctahedral complex Cl2Re(µ-Cl)(µ-dppm)2ReCl(CNxyl) or this same stoichiometry which A formed when acetone is be reaction solvent. The complex2b reacts with a further equivalent of xylNC in the presence of TlO3SCF3 in dichloromethane to form a red complex of composition [Re2Cl3(µ-dppm)2 (CO)(CNxyl)2]O3SCF3. 3, which has the open bioctahedral structure [(xylNC)2ClRe(µ-dppm)2ReCl2(CO)]O3SCF3. This is a third isomeric form of this dirhenium cation: the previously isolated green and yellow forms have edge-sharing bioctahedral structures. Crystal data for3 at 295 K: orthorhombic space group Pbca (No. 61) witha=22.654(5) A,b=22.717(4) A,c=27.324(4) A,V= 14061(7) A3, andZ = 8. The structure was refined to R = 0.059 (R, = 0.134 ) for 14164 data. The Re-Re distance is 2.3833(8) A.

Group 6-group 10 heterobimetallic complexes with sulfur ligands

Abstract: Complexes that contain both a group 6 group 10 metal combination and a sulfur bound ligand form a growing set of species. Their chemistry is discussed and reviewed. Ligands that bind to such heterobimetallic molecules most commonly are S2− and SR− species. Metal-metal bonded complexes, and compounds where metal-metal interactions are minimal are both discussed. The structural parameters for many of the crystallographically characterized complexes are tabulated.

Triosmium carbonyl clusters of sulfur and oxygen mixed donor ligands

Abstract: The reaction of the lightly stablized cluster [Os3(CO)10(NCMe)2] with thiosalicylic acid affords two products [{Os3(CO)10(µ-H}]2SC6H4CO2],1 and [Os3H(CO)10SC6,H4C(O)OOs3H(CO)11],2. Complex 2 undergoes CO dissociation to give1 or fragmentation to give [Os3H(CO)10SC6H4 COOH], 3 in solution. Reaction of phthalic acid and [ Os3(CO)10(NCMc)2] gives two products [{Os3(CO)10(µ-H)}2O2CC6H4CO2], 4 and [Os3H(CO)10O2CC6 H4C(O)OOs3H(CO)11], 5. 5 also undergoes CO dissociation to give4, but no such conversion is observed in the preparation of [{Os3(CO)10(µH)}2 (SC6H4S)],6 from the reaction betweeno-dithiobenzene and [Os3(CO)10 (NCMe)2]. Unlike thiosalicylic acid, treatment of [Os3(CO)10(NCMe)2] with 1 equivalent 2,2'-dithiosalicylaldehyde in dichloromethane produces the compounds [Os3(CO)10(SC6H4CHO)2],7 and [Os3(CO)10µ-H)(SC6H4CHO)].8 in moderate yields which are stable in both the solid state and solution. The mechanism for the formation of1-5 is also proposed. All the clusters1-8 have been fully characterized by conventional spectroscopic methods and the structures of1, 3, 4, 7, and8 have been established by X-ray, crystallography.

Cleavage of 1,4-diphenylbuta-1,3-diyne on a ruthenium-cobalt cluster: Synthesis and molecular structure of Co2Ru3(μ4−C2Ph)(μ3−C2Ph)(μ-dppm)(μ-CO)2(CO)9

Abstract: The reaction between Ru3(μ3-ν2-PhC2C=CPh)(μ-dppm)(CO)8 and Co2(CO)8 afforded dark red Co2Ru3(μ4-C2Ph)(μ3-C2Ph)(μ-dppm)(μ-CO)2(CO)9, shown by an X-ray structure determination to contain a strongly twisted Co2Ru3 bow-tie cluster (central Co), to which two PhC2 units derived from cleavage of the original diyne are attached. One a these is strongly interacting with four metal atoms, the other being attached in the familiar ν1,2ν2-mode. The dppm ligand remains bridging two of the Ru atoms.

A structural variability of copper(I) chloride-tetrahydrothiophene adducts crystallizing in polymeric forms and exhibiting polymorphism: The role of the solvent

Abstract: The function of the solvent in the self-assembling mode of [CuCl] with tetrahydrothiophene is reported. Copper(l) chloride has been used in the form of [CuCOCl] n , which is slightly soluble in the most common solvents, and to allow an homogeneous phase reaction. The reaction of [CuCOCl] n with THT gave [(CuCl)2(THT)3] x ,1, in CH3OH, [(CuCl)(THT)2] x ,2 in THF [(CuCl)(THT)] x ,3, in CH2Cl2, and [(CuCl)3(THT)2] x ,4, in DME. Compound1 consists of polymeric chains of centrosymmetric Cu2Cl2 dinuclear units bridged by THIT molecules running parallel to the [101] axis. In the structure of2 we found polymeric layers generated from the [(CuCl)(THT)] asymmetric unit by the center of symmetry and by the twofold axis. In compound3 the structure consists of layers generated through the center of symmetry by the [(Cu2Cl2)(THT)2] asymmetric unit, while4 consists of layers generated through the center of symmetry by the [(Cu3Cl3)(THT)2] asymmetric unit. Crystallographic details are as [ollows:2 is monoclinic, space group P21/c.a=9.657(3) A,b=6.441(2) A,c=11.459(3) A,\=111.96(2)°,V=661.0(4) A3. andR=0.075;3 is monoclinic, space group P21/n,a=19.327(7) A,b=6.703(2) A,c=10.116(3) A,s=103.04(3)°,V=1276.7(7) A3 andR=0.043:4 is triclinic, space group Pl,a=12.513(2) A,b=6.698(1) A,c=9.651(1) A,α=91.98(1)°,\=107.86(1)°,γ=74.59(1)°,V=741.2(2) A3, andR=0.044.

Reaction of group 13 sulfido cubanes with dimethylzirconocene

Abstract: The reaction of Cp2ZrMe2 with the aluminum- and gallium-sulfido cubane compounds [(1Bu)M(μ3-S)]4 (M = Al, Ga), has been followed by NMR spectroscopy. Cleavage of the M4S4 core occurs resulting in abstraction of a monomeric “(1Bu)M(S)” moiety and yielding Cp2Zr(μ-S)(μ-Me)Al(1Bu)Me (1) and [Cp2Zr(/gm-S)]2,[Ga(1Bu)Me2]2 (3), respectively. The remaining “(1Bu)3M3S3” fragment reacts further with Cp2ZrMe2 to give [(Cp2Zr)M3(μ3-S)3 (1Bu)3Me2], M = Al (2), Ga (4). The molecular structure of [(Cp2Zr)Ga3,(μ3-S)3('Bu)3Me2] (4) has been confirmed by X-ray crystallography. All these compounds subsequently decompose to [Cp2Zr(μ-S)]2 and M(1Bu)Me2. The structure of compound 3 is discussed with respect to the decreased propensity of gallium, as compared to aluminum, to form 3-center 2-electron bridging bonds. Crystal data for [(Cp2Zr)Ga3(μ3-S)3(1Bu)3Me2] (4): monoclinic, P21/n,a = 10.585(2),b = 17.970(4),c = 16.418(3) A,β = 101.00(3)°, R = 0.0402, Rw = 0.0402.