scholarly journals Crystal and molecular structures of some phosphane-substituted cymantrenes [(C5H4 X)Mn(CO)LL′] (X = H or Cl, L = CO, L′ = PPh3 or PCy3, and LL' = Ph2PCH2CH2PPh2)

Author(s):  
Karlheinz Sünkel ◽  
Christian Klein-Hessling

UV irradiation of tetrahydrofuran solutions of [CpMn(CO)3] (Cp = π-C5H5 or π-C5H4Cl) in the presence of the phosphanes PPh3 or PCy3 (Cy = cyclohexyl) and Ph2PCH2CH2PPh2 yields the substitution products [CpMn(CO)2PR 3] (R = Ph or Cy) and [CpMn(CO)(Ph2PCH2CH2PPh2)], namely, dicarbonyl(η5-cyclopentadienyl)(triphenylphosphane-κP)manganese(I), [Mn(C5H5)(C18H15P)(CO)2], 1a, dicarbonyl(η5-1-chlorocyclopentadienyl)(triphenylphosphane-κP)manganese(I), [Mn(C5H4Cl)(C18H15P)(CO)2], 1b, dicarbonyl(η5-cyclopentadienyl)(tricyclohexylphosphane-κP)manganese(I), [Mn(C5H5)(C18H33P)(CO)2], 2a, dicarbonyl(η5-1-chlorocyclopentadienyl)(tricyclohexylphosphane-κP)manganese(I), [Mn(C5H4Cl)(C18H33P)(CO)2], 2b, carbonyl(η5-cyclopentadienyl)[1,2-bis(diphenylphosphanyl)ethane-κ2 P,P′]manganese(I), [Mn(C5H5)(C26H24P2)(CO)], 3a, and carbonyl(η5-1-chlorocyclopentadienyl)[1,2-bis(diphenylphosphanyl)ethane-κ2 P,P′]manganese(I), [Mn(C5H4Cl)(C26H24P2)(CO)], 3b, The crystal structure determinations show a very small influence of the chlorine substitution and a moderate influence of the phosphane substitution on the bond lengths. The PR 3 groups avoid being eclipsed with the C—Cl bonds. All the compounds employ weak C—H...O interactions for intermolecular association, which are enhanced by C—H...Cl contacts in the chlorinated products.

1983 ◽  
Vol 61 (6) ◽  
pp. 1132-1141 ◽  
Author(s):  
Gordon William Bushnell ◽  
Roderick James Densmore ◽  
Keith Roger Dixon ◽  
Arthur Charles Ralfs

Synthesis and 31P nmr spectra of the complex cations, cis-[PtCl(L)(PEt3)2]+, L= theophylline, caffeine, or isocaffeine, and cis[Pt(isocaff)2(PEt3)2]2+ are reported. The crystal structure of cis-[PtCl(caffeine)(PEt3)2][BF4] is determined, space group [Formula: see text], a = 1.1766(6), b = 1.4428(5), c = 0.9002(4) nm, α = 97.28(4)°, β = 97.69(4)°, γ = 100.96(5)°, Dm = 1.649 g cm−1, the bond lengths are Pt—Cl= 233.4(4) pm, Pt—N = 215(1) pm, Pt—P = 225.4(5) pm (mean), and the residual R = 0.071. The crystal structure of cis-[Pt(isocaffeine)2(PEt3)2][BF4]2 is orthorhombic, space group Pbca, a = 2.317(3), b = 1.717(3), c = 2.130(3) nm, Dm = 1.574 g cm−3, with an opposing isocaffeine conformation, bond lengths Pt—N = 211(2) pm, Pt—P = 227.6(9) pm (mean), and R = 0.073. Both crystal structures contain approximately square planar Pt(II) coordination with the purine coordinated via an imidazole nitrogen. The structures are discussed as models for the possible involvement of [Formula: see text] chelation of guanine to platinum when platinum drugs act as antitumour agents, but there is no evidence that isocaffeine acts as an [Formula: see text] chelate.


1998 ◽  
Vol 53 (12) ◽  
pp. 1475-1482 ◽  
Author(s):  
Prit Singh ◽  
Sudha Singh ◽  
Vishnu D. Gupta ◽  
Heinrich Nöth

Abstract Tris-thiobenzoates, Arsenic, Antimony, Bismuth Tris-thiobenzoates of arsenic, antimony and bismuth, M(SOCR)3 have been obtained from their oxides and characterized. In the X-ray crystal structure determinations of these, the group 15 atom and the three covalently bonded sulfur atoms are found to constitute a trigonal pyramid, the central atoms lie at a C3 axis. In the bismuth complex the thiobenzoate ligand tends to chelate. However, three comparatively short intermolecular M···S interactions are significant features for these molecules resulting in stacking of trigonal prisms providing an essentially six coordinate environment around arsenic and antimony and a nine-coordinate one for bismuth. The structure of PhSb(SOCPh)2 can be considered


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Dedong Wu ◽  
Faraj Atassi

AbstractThe crystal and molecular structures of vardenafil (free, unprotonated base), vardenafil dihydrate and the hydrochloride salts, vardenafil monohydrochloride trihydrate and vardenafil dihydrochloride hexahydrate, were determined by single-crystal X-ray diffraction. The crystal structure of vardenafil monohydrochloride trihydrate is in good agreement with the published crystal structure obtained by powder diffraction using synchrotron radiation. This work shows that the crystal structure of anhydrous vardenafil free base is very similar to the crystal structure of sildenafil free base.


2020 ◽  
Vol 76 (12) ◽  
pp. 1813-1817
Author(s):  
Masatoshi Mori ◽  
Takayoshi Suzuki

The crystal structures of the complexes (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]nickel(II) bis(perchlorate) nitromethane monosolvate, [Ni(C11H12NP)2](ClO4)2·CH3NO2 (1), and (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]platinum(II) bis(tetrafluoroborate) acetonitrile monosolvate, [Pt(C11H12NP)2](BF4)2·C2H3N (2), are reported. In both complex cations, two phosphanylquinolines act as bidentate P,N-donating chelate ligands and form the mutually cis configuration in the square-planar coordination geometry. The strong trans influence of the dimethylphosphanyl donor group is confirmed by the Ni—N bond lengths in 1, 1.970 (2) and 1.982 (2) Å and, the Pt—N bond lengths of 2, 2.123 (4) and 2.132 (4) Å, which are relatively long as compared to those in the analogous 8-(diphenylphosphanyl)quinoline complexes. Mutually cis-positioned quinoline donor groups would give a severe steric hindrance between their ortho-H atoms. In order to reduce such a steric congestion, the NiII complex in 1 shows a tetrahedral distortion of the coordination geometry, as parameterized by τ4 = 0.199 (1)°, while the PtII complex in 2 exhibits a typical square-planar coordination geometry [τ4 = 0.014 (1)°] with a large bending deformation of the ideally planar Me2Pqn chelate planes. In the crystal structure of 2, three F atoms of one of the BF4 − anions are disordered over two sets of positions with refined occupancies of 0.573 (10) and 0.427 (10).


1988 ◽  
Vol 43 (10) ◽  
pp. 1279-1284 ◽  
Author(s):  
Mervat El Essawi ◽  
H Gosmann ◽  
D Fenske ◽  
F Schmock ◽  
K Dehnicke

Triphenylmethylphosphonium nitrite and formate have been prepared by the reaction of [PPh3Me]I with silver nitrite, and lead formate, respectively, in aqueous solutions. [PPh3Me]NO2 (1) forms pale yellow crystals, and [PPh3Me]HCO2·H2O (2) forms white crystals. Both compounds are soluble in water, ethanol, and dichloromethane. In moist air 2 is hydrated to yield [PPh3Me]HCO2·2H2O (3). The compounds were characterized by their IR spectra, 1 and 2 also by X-ray crystal structure determinations.[PPh3Me]NO2 (1): space group P21/n, Z = 4, 2088 independent observed reflexions, R = 0.062. Lattice dimensions (20 °C): a = 914.7(3), b = 1887.5(9), c = 1080.0(4) pm, β = 110.29(3)°. The compound consists of PPh3Me+ ions and NO2- anions with bond lengths of 114.2(6) pm and a bond angle of 124.1(7)°. [PPh3Me]HCO2·H2O (2): space group P21/n, Z = 4, 2973 independent observed reflexions, R = 0.069. Lattice dimensions (-20 °C): a = 931(2), b = 1558(3), c = 1281(2) pm, β = 105.9(1)°. The compound consists of PPh3Me+ ions and formate anions which form centrosymmetric dimeric units [HCO2·H2O]22- through hydrogen bridges of the water molecules. Bond lengths CO 122.4(4) and 120.9(4) pm. bond angle OCO 129.9(4)°.


1992 ◽  
Vol 45 (2) ◽  
pp. 429 ◽  
Author(s):  
AT Baker ◽  
MT Emett

The structures of [Pt(S2CN(C2H5)2)2] (1) and [Pt(S2CN(C2H4OH)2)2] (2) have been determined by single-crystal X-ray diffractometry. Compound (1) crystallizes in the tetragonal space group P42/n, a 16.4692(10),c 6.2160(6) � (Z = 4); R was 0.029 for 1012 observed reflections. Compound (2) is monoclinic, space group Pc, a 6-0663(11), b 1.1784(15), c 12.5740(21) � ,β92.569(8)� (Z = 2); R was 0.019 for 1573 observed reflections. The presence of electron-withdrawing groups in the ligands of (2) appears to have little effect on the Pt-S distances but causes an increase in the C-N bond length, with the C-N bond lengths being significantly different at the 2 σ level.


1990 ◽  
Vol 43 (10) ◽  
pp. 1697 ◽  
Author(s):  
GA Bowmaker ◽  
PC Healy ◽  
LM Engelhardt ◽  
JD Kildea ◽  
BW Skelton ◽  
...  

The crystal structures of [Cu(Pme3)4]X (X = Cl , Br, I) and of [M(PPh3)4] [PF6] (M = Cu, Ag) have been determined by single-crystal X-ray diffraction methods at 295 K. The former compounds contain nearly tetrahedral [Cu(PMe3)4]+ ions on sites of m symmetry with mean Cu-P bond lengths of 2.270, 2.271 and 2.278 Ǻ for X = Cl , Br and I respectively. The latter compounds contain [M(PPh3)4]+ ions on sites of 3 symmetry. In the M =Ag complex the coordination environment is close to tetrahedral, but in the M =Cu complex the length of the axial Cu-P bond [2.465(2)Ǻ] is significantly shorter than that of the off-axis bonds [2.566(2)Ǻ]. Possible reasons for this are discussed.


1975 ◽  
Vol 28 (11) ◽  
pp. 2377 ◽  
Author(s):  
M Corbett ◽  
BF Hoskins ◽  
NJ McLeod ◽  
BP O'Day

The crystal and molecular structures have been determined, by single-crystal X-ray methods, for each of the isomorphous set of divalent binuclear metal derivatives of 1,3-diphenyltriazene, abbreviated as dptH, [M(dpt)2]2 where M = Ni, Pd, and Cu. The crystals are composed of discrete molecular units, of composition M2(dpt)4, which have a syn-syn structure analogous to that of copper(II) acetate monohydrate with pairs of closely separated metal atoms held together by the terminal nitrogen atoms of four ligand groups in such a way that the environment of each metal atom is almost square-planar. The interatomic distances between the pairs of metal atoms, 2.395(3), 2563(1), and 2.441(2) Ǻ for the Ni, Pd, and Cu compounds, are strongly suggestive of metal-metal bonding. The two N4-planes are almost parallel but the two sets of coordinating nitrogen atoms are twisted markedly from the eclipsed configuration, the average angle of rotation being about 15°. Crystals of each complex are triclinic with space group P 1. The unit cell parameters in the order of a, b, c, α, β, and γ are 10.335(3), 15.84(1), 13.546(3)& 100.48(5), 94.47(2), 102.57(3)° for Ni2(dpt)4; 10.486(1), 15.791(2), 13.751(1)Ǻ, 99.48(1), 93.61(1), 104.37(1)° for Pd2(dpt)4; 10.373(3), 15.916(5), 13.612(3) Ǻ, 99.51(2), 94.85(3), 102.33(2)° for Cu2(dpt)4. The structure of the nickel complex was solved by the Patterson-Fourier method and the atomic parameters found for this structure were used as the basis of the structure determinations of the isomorphous copper and palladium compounds. All three structures were refined by a block-diagonal least-squares method using 3300 (photographic data) 4065 (counter) and 2753 (counter) independent non-zero terms for the nickel(II), palladium(II) and copper(II) compounds respectively, converging with R values 0.13 (isotropic), 0.056 (anisotropic) and 0.069 (isotropic) respectively.


1977 ◽  
Vol 32 (12) ◽  
pp. 1416-1420 ◽  
Author(s):  
Omar Jabay ◽  
Hans Pritzkow ◽  
Jochen Jander

The crystal and molecular structures of N-bromobenzamide (NBB), N-bromosuccinimide (NBS), and N,N-dibromobenzenesulfonamide (NBBS) were determined by X-ray structure analysis. The nitrogen atoms in NBB and NBS have a trigonal planar coordination (sp2) and the N—Br distances lie in the same range (1.82 A, 1.84 A). The N—Br distance in NBBS, where the nitrogen atom is sp3-hybridized, is somewhat longer (1.88 A). In these structures the molecules are connected by O···H—N (NBB), O···Br—N (NBS) or N···Br—N (NBBS) intermolecular bonds forming endless chains; positivated hydrogen atoms or, in case that they are absent, positivated bromine atoms act as electron acceptors with oxygen or sp3- hybridized nitrogen atoms. These results suggest, that in solid nitrogen tribromide, the crystal structure of which cannot be determined, the nitrogen atoms will be sp3-hybridized and intermolecular contacts via N—Br···N will occur.


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