On the preparation of binuclear S,S bridged molybdenum(V) complexes crystal and molecular structure of [Mo2S4(Et2dtc)2]

MoO₄^2? is reduced by diethyldithiocarbamate (Et₂dtc^?) on prolonged digestion in aqueous medium whereby the complex [Mo₂^VO₂S₂(Et₂dtc)₂] is formed. The central moiety Mo₂O₂S₂²⁺ has a high formation tendency. When [Mo₂^V(S₂)₆]^2? is refluxed with Et₂dtc^? in ethanol, [Mo₂^VS (Et₂dtc)₂] is formed, the X-ray crystal structure of which has been determined (space group P2₁2₁2₁, a = 10.550(2) Å, b = 13.820(5) Å, c = 14.723(12) Å, d_c = 1.90 g · cm^3?, Z = 4). The Mo? Mo distance of the diamagnetic compound is 2.817(2) Å and the average Mo=S_t distance 2.099(4) Å.     

Reaktion von cyclopentadienyl-substituierten Molybdän(V)-tetrachloriden mit LiPH(2,4,6-BuC6H2) und KPPh2(Dioxan)2. Molekülstrukturen von [Cp0Mo(μ-Cl)2]2 und [CpMo2(μ-Cl)3(μ-PPh2)] (Cp0 = C5Me4Et)

Reaction of Cyclopentadienyl Substituted Molybdenum(V) Tetrachlorides with LiPH(2,4,6-Bu C₆H₂) and KPPh₂(Dioxane)₂. Crystal Structures of [Cp⁰Mo(μ? Cl)₂]₂ and [Cp Mo₂(μ? Cl)₃(μ? PPh₂)] (Cp⁰ = C₅Me₄Et) The reaction of [Cp⁰Mo(CO)₃]₂ (Cp⁰ = C₅Me₄Et) and [Cp′Mo(CO)₃]₂ (Cp′ = C₅H₄Me) with PCl₅ in CH₃CN furnishes the Mo(V) complexes Cp⁰MoCl₄(CH₃CN) 1 and Cp′MoCl₄(CH₃CN) 2 in good yields. While 1 and 2 are reduced by LiPH(2,4,6-BuC₆H₂) to the Mo(III) complexes [Cp⁰Mo(μ? Cl)₂]₂ 3 and [Cp′Mo(μ? Cl)₂]₂ 4 , the reaction of 1 with KPPh₂(dioxane)₂ yields the reduction/substitution product [CpMo₂(μ? Cl)₃(μ? PPh)] 5 in low yield. 1 – 4 were characterized spectroscopically (i.r., mass, 3 and 4 also n.m.r.). An X-ray crystal structure determination was carried out on 3 and 5. 3 crystallizes in the triclinic space group P1 (No. 2) with a = 8.278(4), b = 12.508(7), c = 12.826(7) Å, α = 86.78(5), β = 81.55(2), γ = 75.65(4)°, V = 1 272.4 ų and two formula units in the unit cell (data collection at ? 67°C, 4 255 independent observed reflections, R = 2.9%); 5 crystallizes in the triclinic space group P1 (No. 2) with a = 11.536(8), b = 12.307(9), c = 13.157(9) Å, α = 91.41(6), β = 100.42(5), γ = 112.26(6)°, V = 1 688.7 ų and two formula units in the unit cell (data collection at ? 60°C, 6 147 independent observed reflections, R = 4.9%). The crystal structure of 3 shows the presence of centrosymmetric dimeric molecules with four bridging chloro ligands. In 5, two Mo atoms are bridged by three chloro ligands and one PPh₂ ligand. The Mo? Mo bond length in 3 and 5 (2.600(2), 2.596(2) Å and 2.6388(8) Å) is in agreement with a Mo? Mo bond.     

Periphere Anbindung von Quecksilber(II)-iodid an dreikernige Molybdän-Schwefel-Dithiophosphinatocluster: [Mo3S4(R2PS2)4HgI2] (R = Et,Pr)

Peripheral Bonding of Mercury(II) Iodide to Trinuclear Molybdenum-Sulfur-Dithiophosphinato Clusters: [Mo₃S₄(R₂PS₂)₄HgI₂] (R = Et, Pr) Reaction of Mo₃S₄(R₂PS₂)₄ 1 (a : R = Et, b : R = Pr) with HgI₂ in THF yields the diamagnetic title complexes [Mo₃S₄(R₂PS₂)₄HgI₂] 3 . The crystal structure of [ 3a (H₂O)] · 2 CH₂Cl₂ shows the complexes to consist of a triangular array of Mo atoms which are bridged by μ₂? S atoms and capped by a μ₃? S atom. Each of the Mo atoms is chelated by a dithiophosphinato ligand Et₂PS₂^? and in addition two Mo atoms are bridged by a Et₂PS₂^? ligand while the H₂O molecule is bonded weakly to the third Mo atom. Thus, all Mo atoms reveal a distorted octahedral coordination sphere. HgI₂ is ?peripherally”? bonded to the cluster via two S atoms, one of which belongs to a chelating ligand and the other one to the bridging ligand. Space group P1 , lattice constants a = 12.157(2), b = 15.284(3), c = 16.049(3) Å, α = 115.56(1), β = 107.35(1), and γ = 94.62(1)°; Z = 2, d_calc = 2.23 mg/mm³; 4 236 observed reflections, R = 0.068. In organic solvents complexes 3 are strong electrolytes. VT-³¹P NMR data suggest a stepwise dissociation of 3 with formation of [Mo₃S₄(R₂PS₂)₃] ⁺[(R₂PS₂)HgI₂]^? and elimination of the bridging ligand from the cluster.     

Darstellung und Strukturen von (Et4N)2[Re(CO)3(NCS)3] und (Et4N)[Re(CO)2Br4]

Syntheses and Structures of (Et₄N)₂[Re(CO)₃(NCS)₃] and (Et₄N)[Re(CO)₂Br₄] Rhenium(I) and rhenium(III) carbonyl complexes can easily be prepared by ligand exchange reactions starting from (Et₄N)₂[Re(CO)₃Br₃]. Using nonoxidizing reagents the facial Re^I(CO)₃ unit remains and only the bromo ligands are exchanged. Following this procedure, (Et₄N)₂[Re(CO)₃(NCS)₃] can be obtained in high yield and purity using trimethylsilylisothiocyanate. The compound crystallizes in the monoclinic space group P2₁/n, a = 18.442(5), b = 17.724(3), c = 18.668(5) Å, β = 92.54(1)°, Z = 8. The NCS^? ligands are coordinated via nitrogen. The reaction of [Re(CO)₃Br₃]^2? with Br₂ yields the rhenium(III) anion [Re(CO)₂Br₄]^?. The tetraethylammonium salt of this complex crystallizes in the noncentrosymmetric, orthorhombic space group Cmc2₁, a = 8.311(1), b = 25.480(6), c = 8.624(1) Å, Z = 4. The carbonyl ligands are positioned in a cis arrangement. Their strong trans influence causes a lengthening of the Re? Br bond distances by at least 0.05 Å.     

Synthesis and Structural Characterization of a Novel Indium Mercapto Derivative [ClIn(SCH2(CO)O)2]2-[(4-MepyH)2]2+

The synthesis and structural characterization of a novel In(III) complex is described. The reaction between InCl₃ with sodium mercapto-acetic acid (NaSCH₂(CO)OH) in 4-methylpyridine (CH₃(C₅H₅N), (4-Mepy)) at 25°C affords [ClIn(SCH₂(CO)O)₂]^2-[(4-MepyH)₂]²⁺ (1). X-ray diffraction studies of (1) show it to have a distorted square-pyramidal geometry with the [(^-SCH₂(CO)CO^-)] ligands in a trans conformation. The compound crystallizes in the P1(No. 2) space group with a = 7.8624(6) Å, b = 9.950(1) Å, c = 13.793(2) Å, α = 107.60(1)°, β = 90.336(8)°, γ = 98.983(9)°, V = 1014.3(4) ų, R(F°) = 0.037 and R_w = 0.048.     

Synthesis and Structures of [Mo12E16(PEt3)10] (E = S,Se)

Dodecanuclcar cluster complexes [Mo₁₂S₁₆(PEt₃)₁₀] 1 and [Mo₁₂Se₁₆(PEt₃)₁₀] 2 have been prepared by the reactions of [Mo₆S₈(PEt₃)₆] with sulfur or [Mo₆Se₈(PEt₃)₆] with Cp₂TiSe₅, respectively, in toluene at refluxing temperature. The structures have been determined at 173 K by X-ray crystallography. The compound 1 ·3CHCl₃ crystallizes in the triclinic space group $ {\rm P}\bar 1 $, with a = 14.859(5) Å, b = 15.868(4) Å, c = 14.200(7) Å, α = 100.58(3)°, β = 117.58(3)°, γ = 79.53(2)°, V = 2899(1) ų, and Z = 1. Full-matrix least-squares refinement using 9016 observed reflections (I_o > 2σ(I_o)) gave R = 0.056, and R_w = 0.045. The data for 2 ·2CHCl₃ are: triclinic, $ {\rm P}\bar 1 $, a = 15.737(4) Å, b = 18.763(9) Å, c = 13.062(4) Å, α = 102.45(3)°, β = 128.54(2)°, γ = 69.49(3)°, V = 2825 ų, Z = 1, R = 0.096, and R_w = 0.120 for 5922 reflections (I_o > 2σ(I_o)). The cluster complexes 1 and 2 have two octahedral molybdenum cluster units linked by the rhomboidal intercluster Mo₂(μ₄-E)₂ bonding. The intercluster Mo—Mo distances in 1 are 3.419 Å and 2 3.551 Å. The cyclic voltammetry of 1 and 2 shows two oxidation and two reduction steps separated as large as 380–490 mV. The UV-Vis spectra of the dodecanuclear cluster complexes 1 and 2 have an extra weak band at around 744 nm which is absent in the starting octahedral cluster complexes.     

Selenium-capped trimolybdenum and tritungsten carbonyl clusters [Se2M3(CO)10] (M = Mo, W)

A facile synthesis of the novel selenium-capped trimolybdenum and tritungsten ring carbonyl clusters [Se₂M₃(CO)₁₀]²⁻ (M = Mo, 1; W, 4) have been achieved. The selenium-capped trimolybdenum cluster compound [Et₄N]₂[Se₂Mo₃(CO)₁₀] ([Et₄N]₂[1]) can be obtained from the reaction of the trichromium cluster compound [Et₄N]₂[Se₂Cr₃(CO)₁₀] with 4 equiv. of Mo(CO)₆ in refluxing acetone. On the other hand, when [Et₄N]₂[Se₂Cr₃(CO)₁₀] reacted with 4 equiv. of W(CO)₆ in refluxing acetone, the planar cluster compound [Et₄N]₂[Se₂W₄(CO)₁₈] ([Et₄N]₂[3]) was isolated, which could further transform to the tritungsten cluster compound [Et₄N]₂[Se₂W₃(CO)₁₀] ([Et₄N]₂[4]) in good yield. Alternatively, clusters 1 and 4 could be formed from the reactions of the monosubstituted products [Et₄N]₂[Se₂Cr₂M(CO)₁₀] (M = Mo; W, [Et₄N]₂[2]) with 3 equiv. of M(CO)₆ in acetone, respectively. Complexes 1-4 are fully characterized by IR, ⁷⁷Se NMR spectroscopy, and single-crystal X-ray analysis. Clusters 1, 2, and 4 are isostructural and each display a trigonal bipyramidal structure with a homometallic M₃ ring (M = Mo, 1; W, 4) or a heterometallic Cr₂W ring that is further capped above and below by μ₃-Se atoms. Further, the intermediate planar complex 3 exhibits a Se₂W₂ square with each Se atom externally coordinated to one W(CO)₅ group. This paper describes a systematic route to a series of selenium-capped trimetallic carbonyl clusters and the formation and the structural features of the resultant clusters are discussed.     

Synthesis amd characterization of [Et4,N]2[Mo(CO)4(SR)2] (R = Ph,Bz): New,potentially chelating bis-thiolate species

The new complexes [Et₄N]₂ [Mo(CO)₄(SR)₂] (R = Ph, Bz) have been prepared by reaction of [Et₄N] [SR] with (norbornadiene)Mo(CO)₄ at low temperature. The IR spectra and electrochemical behavior of these two species are different, perhaps implicating different conformational isomers with respect to the thiolate ligands. These complexes may prove to be valuable reagents for the synthesis of new heterometallic compounds, by virtue of their cis-monodentate thiolate ligands.     

Neue [{Cp(CO)2Mo}2ESbCl]‐Cluster mit tetraedrischem Mo2SbE‐Gerüst (E = S,Se)

Reaction of [{Cp(CO)₃Mo}₂SbCl] with S₈ or Se₈ leads to the formation of cluster compounds [{Cp(CO)₂Mo}₂ESbCl] (E = S, Se). [{Cp(CO)₂Mo}₂SSbCl] crystallizes monoclinic, space group P2₁/n with a = 812.28(3), b = 855.65(4), c = 2441.01(9) pm and β = 90.149(3)°; [{Cp(CO)₂Mo}₂SeSbCl] · CH₂Cl₂ crystallizes triclinic, space group P$\bar{1}$ with a = 828.82(9), b = 1002.8(1), c = 1340.0(2) and α = 109.24(1), β = 100.87(1), γ = 96.81(1)°. For both compounds X‐ray crystal structure analysis reveals tetrahedral Mo₂SbE cluster cores with Sb–E bond lengths of 256.8(1) pm (E = S) and 265.3(1) (E = Se). According to the 18 electron rule the [{Cp(CO)₂Mo}₂ESbCl] clusters can be regarded as complexes of the 4 electron donator ESbCl that is coordinated “side‐on” to a {Cp(CO)₂Mo}₂ fragment.     

Syntheses and structural studies of molybdenum-iron-sulfur compounds: I. The synthesis and crystal structure of (Et4N)1[Mo2Fe7S8(SPh)12]

Through the reactions of ferrous thiolates with tetrathiomolybdate, we discussed the reaction pathways and possible intermediates during the formation of double-cubane type Mo-Fe-S cluster compounds. We also reported the synthesis, crystal structure, IR and magnetic susceptibility measurements of the title compound 2. The crystal of 2 belongs to triclinic system, M_r = 2670.3; ; a = 12.755(4) Å, b = 13.076(3) Å, c = 20.576(4) Å; α = 80.00 (2)°, β = 81.39(2)°, γ = 61.51(2)°; V = 2966.3(14) ų; Z = 1; D_c = 1.495 g/cm². Final R factor is 0.077 for 4031 observed reflections. The compound was obtained through the reaction of (Et₄N)₂[Fe₄(SPh)₁₀] (1) with (Et₄N)₂MoS₄ in acetonitrile solution. The structure of anion 2 is two cubane clusters bridged by a Fe(SPh)₆ group. The Mo… Mo' distance of 7.188 Å is the longest among all double-cubane cluster compounds of known structures.     

Über verschiedene Reaktionen der CO-verbrückten Komplexe [Mo(CO)3bipy]2 und [Mo(CO)3phen]2 (bipy = 2,2′-Bipyridyl,phen = 1,10-Phenanthrolin)

The interaction of [Mo(CO)₃bipy]₂ with various monodentate ligands L (L = NH₃, pyr, P(C₆H₅)₃, P(C₆H₅)Cl₂, CN^?, SO₂) yields, according to the reaction equation in ?Inhaltsübersicht”?, mixed tricarbonyl compounds Mo(CO)₃bipyL by cleavage of the CO bridges of the dimeric starting carbonyl. Oxidation of [Mo(CO)₃D]₂ (D = bipy, phen) by means of iodine, partly in the presence of free bipy or phen, leads to the covalent and ionic, respectively, compound types [Mo^II(CO)₃DI₂]₂, [Mo^I(CO)₂DI]₂, [Mo^II(CO)₂D₂I]I and [Mo^II(CO)₂D₂I]I₃.     

Clusters containing carbene ligands. 12. The synthesis and transformations of Os3(CO)11[C(Et)NMe2], the first simple carbene derivative of Os3(CO)12

The carbonylation of Os₂(CO)₁₀[-CH₂N(Me)C(Et)](-H),1 at 110°C/1300 psi has yielded the carbene complex Os₃(CO)₁₁[C(Et)NMe₂],2, the first simple carbene derivative of Os₃(CO)₁₂, in 68% yield. Compound2 was characterized by a single crystal structure analysis which showed the position of a dimethylaminocarbene ligand in an equatorial coordination site. Compound2 is decarbonylated at 97°C to reform1 in 59% yield. Compound1 can be decarbonylated further at 125°C to yield the new compound Os₃(CO)₉ [₃-²-C(H)N(Me)C(Et)](-H)₂,3 in 94% yield. Compound3 was characterized by a crystal structure analysis and was shown to possess a triply bridging C(H)N(Me)C(Et) ligand containing two carbene centers. Compounds1 and2 can be regenerated from3 by carbonylation with CO at 110°C/800 psi. The facile activation of the N-methyl CH bonds of the carbene ligand of2 is produced by the metal atoms adjacent to the carbene coordination site, and may be a characteristic feature of the chemistry of carbene ligands in clusters. For2: space group=P ,a=11.407(2) Å,b=12.332(2) Å,c=8.602(1) Å, =103.92(1), =110.56(1)°, =82.57(1),Z=2, 2627 reflections,R=0.031; for3: space group=C2/c,a=17.160(3) Å,b=8.947(2) Å,c=27.034(6) Å, =97.82(1)°,Z=8, 2044 reflections,R=0.038.     

Photochemical reactions of M(CO)6 (M = Cr,Mo, W) with Ph2P(S)P(S)Ph2

New complexes {M(CO)₄[Ph₂P(S)P(S)Ph₂]} (M = Cr, Mo and W), (1a)–(3a), [(1a), M = Cr; (2a), M = Mo; (3a), M = W] and {M₂(CO)₁₀[-Ph₂P(S)P(S)Ph₂]} (M = Cr, Mo, W), [(1b)–(3b) [(1b), M = Cr; (2b), M = Mo; (3b), M = W]] have been prepared by the photochemical reaction of M(CO)₆ with Ph₂P(S)P(S)Ph₂ and characterized by elemental analyses, f.t.-i.r. and ³¹P-(¹H)-n.m.r. spectroscopy and by FAB-mass spectrometry. The spectra suggest cis-chelate bidentate coordination of the ligand in {M(CO)₄[Ph₂P(S)P(S)Ph₂]} and cis-bridging bidentate coordination of the ligand between two metals in (M = Cr, Mo and W).     

Investigation of single MoFe3S4 cubane cluster: I. First successful synthesis by spontaneous self-assembly reaction and structure of (Et4N) [MoFe3S4(Et2NCSS)5]CH3CN

A single MoFe₃S₄ cubane-like cluster compound has been synthesized through spontaneous self-assembly of simple inorganic salts with organosulfur ligand for the first time. (Et₄N)-(MoFe₃S₄(Et₂NCSS)₅] CH₃CN(1) is quite stable in air. The crystal of 1 is monoclinic with space group P2/c, a=22.897 (3)Å, b= 12.399 (2)Å, c=20.928 (4)Å, β=97.15 (1)°, and Z=4. A full matrix least-squares refinement with 6725 unique reflections for all nonhydrogen atoms gives R=0.068. The anion of 1 is the first isolated single MoFe₃S₄ cubane cluster with core oxidation state [MoFe₃S₄]⁴⁺. The distance between the two 6-coordinate metal atoms (Mo, Fe) is 2.624 Å, which is the shortest M-M' bond observed for Mo-Fe-S clusters so far and the only one shorter than similar distances in FeMo-cofactor. The bond orders of this anion were calculated by EHMO method and the results coincide with the general rule. The structural feature and the unusual stability of 1 can be attributed to the bidentate chelating effect of Et₂NCSS-, which leads to high coordination of metal atoms and the various ligated types.     

Synthese und Kristallstruktur von (C5H5)Mo(CO)3(AuPPh3) und [(C5H5)Mo(CO)2(AuPPh3)4]PF6

Synthesis and Crystal Structure of (C₅H₅)Mo(CO)₃(AuPPh₃) and [(C₅H₅)Mo(CO)₂(AuPPh₃)₄]PF₆ CpMo(CO)₃(AuPPh₃) is obtained by the reaction of Li[CpMo(CO)₃] with Ph₃PAuCl at ?95°C in CH₂Cl₂. It crystallizes in the monoclinic space group C2/c with a = 2625.1(7), b = 883.2(1), c = 2328.4(7) pm, β = 116.39(1)° und Z = 8. In the complex the AuPPh₃ group is coordinated to the CpMo(CO)₃ fragment with a Au? Mo bond of 271,0 pm. The Mo atom thus achieves a square pyramidal coordination with the center of the Cp ring in apical position. CpMo(CO)₃(AuPPh₃) reacts under uv irradiation with an excess of Ph₃PAuN₃ to afford the cluster cation [CpMo(CO)₂(AuPPh₃)₄]⁺. It crystallizes as [CpMo(CO)₂(AuPPh₃)₄]PF₆ · 2 CH₂Cl₂ in the orthorhombic space group P2₁2₁2₁ with a = 1553.9(1), b = 1793.8(2), c = 2809.8(7) pm und Z = 4. The five metal atoms form a trigonal bipyramidal cluster skeleton with the Mo atom in equatorial position. The Mo? Au distances range from 275.5 to 280.8 pm, and the Au? Au distances are between 281.2 and 285.6 pm.     

Organic Reactions upon Dimetalated Olefins. Reactions of the Olefinic Group in the Dirhenlum Complex (OC)4Re[E-HC?C(CO2Me)CS2]Re(CO)4 with Amines

The reaction of (OC)₄Re[μ-E-HC? C(CO₂Me)CS₂]Re(CO)₄, 1 with EtNH₂ yielded two new complexes: Re(CO)₄[C(H)? C(CO₂Me)C(NHEt)? S], 2 , (52%) and Re(CO)₃(NH₂Et)[C(H)? C(CO₂Me)C(NHEt)=S], 3a (24%) by competitive attack of the EtNH₂ at the dithiocarboxylate grouping and at the hydrogen substituted olefinic carbon atom in 1 . In both cases there is a loss of one of the rhenium groupings. The reaction of the sulfurized and oxygenated derivatives of 1, (OC)₄Re[EC(H)C(CO₂Me)CS₂]Re(CO)₄, 4a (E=S), 4b (E=O) with EtNH₂ yielded Re(CO)₄[C(H)=C(CO₂Me)C(NHEt)=S], 5a , the parent carbonyl of 3a , by exclusive attack of the amine at the hydrogen substituted olefinic carbon atom. The reaction of (OC)₄Re[μ-SC(S)C(CO₂Me)C(H)S]Re(CO)₄, 6a (an isomer of 4a ) with EtNH₂ produced a similar result. The reaction of 4a with Et₂NH yielded Re(CO)₄[μ-S₂C=C(CO₂Me)C=NEt₂], 5b an N-ethyl substituted derivative of 5a . These results indicate that the addition of certain heteroatoms can have a directing effect upon the reactivity of these compounds with amines. Compounds 2 and 5a were characterized by single crystal x-ray diffraction analyses. Crystal Data: For 2 : space group = P1, a = 10.782(1) Å, b = 14.721(2) Å, c = 9.940(2) Å, a = 91.57(1)°, β = 93.61(1)°, γ = 70.774(9)°, Z = 4, 4516 reflections, R = 0.047 and for 5a : space group = P2₁/n, a = 11.389(2) Å, b = 9.660(2) Å, c = 14.756(3) Å, β = 103.36(2)°, Z = 4, 1601 reflections, R = 0.022.     

Metal–metal bond energies in Mo2, Mo2Cl,and Mo2(O2CH)4

Previous attempts to determine the strengths of multiple metal-metal bonds are reviewed. Estimates of 73 and 97 kcal/mole for the Mo? Mo bond energies in Mo₂Cl and Mo₂(O₂CH)₄, respectively, are obtained by combining the known experimental bond energy in Mo₂ (96.5 ± 5 kcal/mole) with the results of SCF-Xα-SW calculations on Mo₂, Mo₂Cl, and Mo₂(O₂CH)₄. Possible errors in the estimates are discussed. It is noted that the quadruple bonds in the complexes are predicted stronger per component than the sextuple bond in the diatomic.     

Zur Reaktivität des Ferriophosphaalkens (Z)‐[Cp*(CO)2FeP=C(tBu)NMe2] gegenüber Propiolsäureestern HC≡C‐CO2R (R=Me,Et) und Acetylendicarbonsäureestern RO2C‐C≡C‐CO2R (R=Me,Et, tBu)

On the Reactivity of the Ferriophosphaalkene (Z)‐[Cp*(CO)₂Fe‐P=C(tBu)NMe₂] towards Propiolates HC≡C‐CO₂R (R=Me, Et) and Acetylene Dicarboxylates RO ₂C‐C≡C‐CO₂R (R=Me, Et, tBu) The reaction of equimolar amounts of (Z)‐[Cp*(CO)₂Fe‐P=C(tBu)NMe₂] 3 and methyl‐ and ethyl‐propiolate ( 2a, b ) or of 3 and dialkyl acetylene dicarboxylates 1a (R=Me), 1b (Et), 1c (tBu) afforded the five‐membered metallaheterocycles [Cp*(CO) =C(tBu)NMe₂] ( 4a, b ) and [Cp*(CO) =C(tBu)NMe₂] ( 5a—c ). The molecular structures of 4b and 5a were elucidated by single crystal X‐ray analyses. Moreover, the reactivity of 4b towards ethereal HBF₄ was investigated.     

Molybdänhalogenidcluster mit zwei terminalen Alkoholatliganden: Synthese und Kristallstrukturen von (C18H36N2O6Na)2[Mo6Cl12(OCH3)2] und (C18H36N2O6Na)2[Mo6Cl12(OC15H11)2] · 2C4H6O3

Molybdenum(II) Halide Clusters with two Alcoholate Ligands: Syntheses and Crystal Structures of (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OCH₃)₂] and (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OC₁₅H₁₁)₂] · 2C₄H₆O₃ . Reaction of Mo₆Cl₁₂ with two equivalents of sodium methoxide in the presence of 2,2,2-crypt yields (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OCH₃)₂] ( 1 ), which can be converted to (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₁₂(OC₁₅H₁₁)₂] · 2C₄H₆O₃ ( 2 ) by metathesis with 9-Anthracenemethanole in propylene carbonate. As confirmed by X-ray single crystal structure determination ( 1 : C2/m, a=25.513(8) Å, b=13.001(3) Å, c=10.128(3) Å, β=100.204(12)°; : C2/c, a=15.580(5) Å, b=22.337(5) Å, c=27.143(8) Å, β=98.756(10)°) the compounds contain anionic cluster units [Mo₆ClCl(OR^a)₂]^2? with two alcoholate ligands in terminal trans positions ( 1 : d(Mo—Mo) 2.597(2) Å to 2.610(2) Å, d(Mo—Clⁱ) 2.471(3) Å to 2.493(4) Å, d(Mo—Cl^a) 2.417(8) Å and 2.427(8) Å, d(Mo—O) 2.006(13) Å; 2 : d(Mo—Mo) 2.599(3) Å to 2.628(3), d(Mo—Clⁱ) 2.468(8) Å to 2.506(7) Å, d(Mo—Cl^a) 2.444(8) Å and 2.445(7) Å, d(Mo—O) 2.012(19) Å).     

Research on in part “loosely” coordinated trinuclear molybdenum cluster compounds — the synthesis and crystal structure of {Mo3(μ3-S)(μ-S)3[S2P(OEt)2]4 ṁ P(C6H5)3} (0.86CH2Cl2)

The synthesis and crystal structure of novel trinuclear molybdenum cluster compound with somewhat “loose” coordination site {Mo₃(μ₃-S)(μ-S)₃[S₂P(OEt)₂l₄ ? P(C₆H₅)₃} ? (0.86 CH₂C1₂) have been reported. The cluster crystallizes in the space group with two molecules in a unit cell whose parameters are a=10.472(4), b=14.375(2), c=21.695(3)Å; α=74.04(1)°, β=76.50(2)°, γ=72.22 (2)°, V=2950ų and D_o=1.693 g ? cm^?3. On the basis of 4840 independent reflections with I≥2σ(I), the structure was solved by heavy atom method and Fourier method and refined by full-matrix least-squares techniques to a final R=0.058. The distances between Mo atoms in this cluster are 2.731(1), 2.748(1) and 2.753(1)Å respectively. The meat value of Mo—Mo bond lengths is slightly shorter than those in other trinuclear Mo clusters with “loosely coordinated” site. In addition, the PPh₃ ligand is loosely coordinated to one Mo atom in direction opposite to the μ₃-S with Mo—P bond length of 2.647(3)Å. This is different from the other structurally analogous clusters, in which the loosely coordinated ligand is trans to μ₂-S. A summary of Mo—Mo and Mo—L bonding for such clusters is given.