Diastereoselective Alkylation of (Diene-Aldehyde)Fe(CO)3 Complexes with Functionalized Zinc-Copper Reagents NuCu(CN)Znl

Addition of functionalized zinc-copper reagents to the title complexes proceeds in a highly diastereoselective fashion to afford dienol complexes. The relative configurations of adducts 3d were determined by single X-ray diffraction analysis.     

Syntheses and Crystal Structures of Bis-Citrato,Bis-Citramalato and Bis-Malato Germanate(IV) Complexes

Bis-citrato 1a-d , bis-citramalato 2 and bis-malato 3 germanate(IV) complexes were synthesized from germanium dioxide and citric acid, citramalic acid and malic acid respectively and were identified with IR, NMR and elementary analysis. Crystal 1a is triclinic, space group P1 with a = 7.919(2), b = 7.968(3), c = 9.605(3) Å, α = 94.25(3), β = 108.03(2), γ= 113.05(3)°, Z = 1, and the final residue, R(F), is 0.033 for 2583 reflections. Crystal 2 is monoclinic, space group C2 with a = 10.226(4), b = 12.802(4), c = 6.141(1) Å, β = 100.75(2)°, Z = 2, and the final residue, R(F), is 0.034 for 934 reflections. Both 1a and 2 have slightly distorted octahedral structures with citrate or citramalate ions as a tridentate ligand that forms five-, six- and seven-membered rings with the central metal. There is a two-fold axis through the central atom of compound 2 instead of the inversion center of 1a . Same structures for these six complexes are indicated because the spectral patterns of the other four compounds, 1b-d and 3 , are similar to those of compounds 1a and 2 .     

Carbonylchromium derivatives of bismuth: new syntheses and relevance to cbond;o activation

We have discovered a series of novel pentacarbonylchromium derivatives of bismuth from the reactions of NaBiO(3) with [Cr(CO)(6)] in KOH/MeOH solutions. When the reaction was carried out at room temperature, the highly charged [Bi[Cr(CO)(5)](4)](3-) (1) was obtained, whose structure was shown by X-ray analysis to possess a central bismuth atom tetrahedrally coordinated to four [Cr(CO)(5)] groups. As the reaction was heated at 80 degrees C, the methyl-substituted complex [MeBi[Cr(CO)(5)](3)](2-)(2) was obtained, presumably via the CbondO activation of MeOH. Further reactions of 1 with CH(2)Cl(2) or CHtbondCCH(2)Br form the halo-substituted complexes [XBi[Cr(CO)(5)](3)](2-)(X=Cl, 3; Br, 4), respectively. On the other hand, the reactions of 1 with RI (R=Me, Et) led to the formation of the alkyl-substituted complexes [RBi[Cr(CO)(5)](3)](2-)(R=Me, 2; Et). The formation of complexes 1-4 is discussed, presumably via the intermediate bismuthinidene [Bi[Cr(CO)(5)](3)](-) or the trianion [Bi[Cr(CO)(5)](3)](3-).     

The Structure of 3-Phenyl-4-(N-Carbamyl-1,4,2-Oxathiazolimin-3-yl)Sydnone,C11H7N5O4S·0.8 CH2Cl2

The title compound (M_r = 373) crystalizes in the othorhombic space group P bna with a = 10.410(2), b = 11.658(4), c = 23.108(3) Å, V = 2804.4 Å Z = 8. The single crystal intensity data were collected using MoK∞ radiation (λ = 0.7093Å) at room temperature. The crystal and molecular structure was solved with the final agreement index R = 0.039 for 1046 observed reflections. The bond lengths N(1)- C(7) and C(7)-C(8) of the title compound are slightly longer than those of 3-substituted sydnone derivatives. This may be attributed to the steric effect arising from the interaction of the phenyl ring and the 4-substituent with the neighboring atoms of sydnone ring. Both the title compound and 4-acetyl-3-(p-tolyl)sydnone have smaller dihedral angles between the sydnone ring and the plane of the sp² orbital of the double bond of the 4-substituent and both have shorter C(7)-C(9) bond lengths than those of other similar sydnone derivatives.     

[(TeMe2)Mn(CO)4(μ5-Te)(μ4-Te)Mn4(CO)12]−: A Pentacoordinate Bridging Tellurido Ligand in a Square-Pyramidal Geometry

The first Te–Mn–CO clusters were obtained by the thermal reaction of K₂TeO₃ with [Mn₂(CO)₁₀] in MeOH. The basicity of the μ₄-Te ligand in the octahedral cluster anion [(μ₄-Te)₂Mn₄(CO)₁₂]²⁻ is demonstrated by its binding to the fragment [(TeMe₂)Mn(CO)₄]⁺ in an axial fashion to afford the novel cluster 1 .     

Deliberate design of a 3D homochiral Cu(II)/l-met/Ag(I) coordination network based on the distinct soft-hard recognition principle

A homochiral amino acid coordination network [{Ag3Cu3(l-methioninato)6(NO3)3(H2O)3}.7H2O]n, self-assembled from CuII, AgI, and l-methionine via a distinct soft-hard recognition process, shows interesting characteristics, in that it is constructed from 1D helical building blocks and contains homochiral channels in which 1D water chains are hosted. This result provides an effective and controllable strategy for the preparation of enantiopure heterometallic supramolecular structures that are relevant to biopolymers.     

Deformation Density Study of KMnO4

The electron density distribution of KMnO₄ is studied by the X-ray diffraction method. Potassium permanganate crystalizes in an orthorhombic space group Pbnm with cell parameters a=7.3661(7), b=9.0610(9), c=5.6458(3)Å, Z=4. The molecular symmetry is C_S with the Mn atom and two oxygen atoms located on the plane perpendicular to the c-axis. A set of accurate diffraction data were measured at 115K. Subsequent refinements and Fourier syntheses were performed. The electron density distribution is expressed in terms of the deformation density. The Mn-O bondings are well characterized, the lone pair electron density at the oxygen atoms is also observed. The density near the Mn nucleus seems to be very sensitive to changes of the scale factor and extinction coefficient. Several types of extinction corrections were made. The features of the Mn-O bond are comparable to the theoretical density calculated at the ab-initio level, and to the experimental density of the isoelectronic compound K₂CrO₄. However, the experimental density of KMnO₄ is not so well reproduced in the vicinity of Mn nucleus.     

The Syntheses and Crystal Structures of cis-[Bis(diphenylphosphino)methane][1,2-bis(diphenylphosphlno)ethane] dicarbonylmolybdenum(O) and cis-[1,2-Bis(diphenylphosphino)ethane] [cis-1,2-bis(diphenylphosphino) ethylene]dicarbonylmolybdenum(0)

The title compounds, Mo(CO)₂(Ph₂PCH₂PPh₂)(Ph₂PCH₂CH₂PPh₂), Mo(CO)₂(dppm)(dppe) 1, and Mo(CO)₂(Ph₂PCH₂CH₂PPh₂)(Ph₂PCH = CHPPh₂), Mo(CO)₂(dppe)(cis-vpp) 2, were prepared from Mo(CO)₆ and the corresponding bidentate diphosphine ligands in n-decane under nitrogen atomosphere. Crystals of 1 are monoclinic, space group P 2₁/c, with a = 19.072(3), b = 11.348(3), c = 23.57(1) Å, β = 99.64(3)°, Z = 4, and the final residual R(F) = 0.044 for 4810 observed reflections; data of 2 are triclinic, space group P 1, with a = 12.091(3), b = 12.186(8), c = 18.934(5) Å, α = 96.93(4),β = 108.15(2), γ = 107.08(4)deg;, Z = 2, and the final residual R(F) = 0.058 for 4570 observed reflections. The distortion of compound 1 is more pronounced than that of compound 2, The two Mo-P lengths in the same bidentate chelate ligand for both compounds are different. Among them, the two larger Mo-P bond lengths for compound 2 are similar, but significantly different for 1.     

Monosubstituted Trinuclear and Tetranuclear VIB Metal Carbonyl Complexes: Syntheses of [{M(CO)5}3(Pf-Pf-Pf)] [Pf-Pf-Pf = PhP(CH2CH2PPh2)2] and [{M(CO)5}4(P-Pf3)] [P-Pf3 = P(CH2CH2PPh2)3] (M = Cr,Mo) and Crystal Structures of the Latter Three

The triligate trimetallic complexes, [{M(CO)₅}₃(Pf-Pf-Pf)] and tetraligate tetrametallic complexes, [{M(CO)₅}₄(P-Pf₃)] (M = Cr and Mo), were prepared from [M(CO) ₆] and the corresponding ligands in MeCN/CH₂Cl₂ promoted by Me₃NO at 0 °C. Crystals of trimer lb are monoclinic, space group P 2₁/n, with a = 13.407(3), b = 15.002(5), c = 26.52(1) Å, β = 90.65(2)°, Z = 4, and R = 0.060 for 2760 observed reflections. Crystals of tetramer 2a are monoclinic, space group P 2₁/c, with a – 14.183(8), b = 29.880(4), c = 16.103(2) Å, β = 94.98(3)°, Z = 4, and R = 0.039 for 5014 observed reflections. Crystals of 2b are monoclinic, space group C 2/c, with a = 42.120(8), b = 13.679(1), c = 23.486(2) Å, β = 92.14(1)°, Z = 8, and R = 0.032 for 6897 observed reflections. Each phosphorus atom of the ligands is coordinated to the M(CO)₅ moiety in each title compounds. The geometry of the four metals is a distorted tetrahedron for the tetramers.