Conformational flexibility of longifolene

The flexibility of the bicyclo[2.2.1]heptane-based tricyclic bridged system in longifolene is analysed based on x-ray structural data. In this context, the molecular structure of three differently substituted longifolenes has been analysed. The highly substituentdependent conformation provides scope for the synthesis of a variety of commercially oriented products

A novel structure of secondary alcohol derived from (+)-&#916;<SUP>3</SUP>-carene with pseudo three-fold symmetry

The crystal structure of C12OH20 (lR-6R-4R-2 R-3,7,7-trimethyl-4-(2-hydroxyethyl) bicyclo [4.1.0] hept-2-ene) has been determined by X-ray diffraction. The compound crystallizes in space group P212121 witha = 5.893(1),b = 22.572(2), c = 26.164(3) &#197;,V = 3480.3 &#197;3, Z= 12. The structure was solved by modified direct methods and refined to anR value of 0.081 for 607 unique reflections. Each asymmetric unit has three molecules which are held together through intermolecular hydrogen bonds resulting in a novel spiral-type arrangement of molecules. The six-membered ring has a half-chair conformation

Solution of difficult crystal structures: new, simple, economic and time saving approaches

MULTAN is the most widely used package for structure determination. However, there are situations where even after utilizing all possible built-in routes the solution is not reached and these become "difficult structures". If such a structure (a) has one or more heavy atoms, (b) is "chicken-wire" with predominant aromatic character, (c) has weak diffraction data, the new approaches discussed will lead to a unique structure solution by introducing simple, economic and time saving ideas into the MULTAN package

Crystal and molecular structure of 3-dimethylaminobenzoic acid

The title compound C9H11NO2 is triclinic, space group P¯1, with the cell dimensionsa=7.022(1),b=7.476(2),c=8.957 (1) &#197;,&#945;=87.02(2),&#946;=110.88(1),&#947;=99.10(1)&#176;,V=433.8(4) &#197;3,Z=2,M r =165.2,Do=1.27,Dx=1.26 mg/m3,F(000)=176,T=293 K,R=0.057 for 939 observed reflections. The molecules are packed as centrosymmetric hydrogen bonded dimers with an O&#183;&#183;&#183;HO distance of 2.626(3) &#197;. The COOH group is rotated by 1.7(1)&#176; about the exocyclic C(1)-C(7) bond out of the benzene ring plane. The molecules lie on (0 2-1) plane for which thed value is found to be 3.378 &#197; which is very close to the mean separation between the parallel packed benezene rings [3.347(4) &#197;]. The entire molecule is planar except for the two methyl groups attached to the nitrogen atom. The N atom is free from any binding of either type C-H&#183;&#183;&#183;N or O&#183;&#183;&#183;HN

Structure of 1-diphenylmethyl-3-hydroxyazetidinium chloride, C<SUB>16</SUB>H<SUB>18</SUB>NO<SUP>+</SUP>.Cl<SUP>-</SUP>

M<SUB>r</SUB>=275.8, monoclinic, P2<SUB>1</SUB>/a, a=12.356 (5), b=9.054 (4), c= 14.043 (4) Å, β=100.34 (3) °, V=1545.5 Å<SUP>3</SUP>, Z=4, D<SUB>m</SUB>=1.14, D<SUB>x</SUB> = 1.185 Mg m<SUP>-3</SUP>, μ (Mo Kα, λ= 0.7107 Å ) 2.77 mm<SUP>-1</SUP>, F(000)=584.0, T=293 K, R=0.053 for 1088 reflections. The four-membered ring is buckled 13.0° (θ=167.0°). The azetidinium moiety is linked to the C1-ion through a hydrogen bond [O-H…C1=3.166 (5) Å]

ADDITION OF PHENYLACETYLENE TO THE MIXED-CHALCOGENIDE COMPOUNDS (CO)(6)FE-2(MU-SETE), (CO)(6)FE-2(MU-SSE), AND (CO)(6)FE-2(MU-STE) - STRUCTURAL CHARACTERIZATION OF (CO)(6)FE-2(MU-SEC(H)=C(PH)TE)

From the room-temperature reaction of the mixed-chalcogenide compound Fe-2(CO)(6)(mu-SeTe) with phenylacetylene two isomeric products were isolated, Fe-2(CO)(6){mu SeC(H)=C-(Ph)Te} (1) and Fe-2(CO)6{mu-SeC(Ph)=C(H)Te} (2). Fe-2(CO)(6)(mu-SSe) reacted with phenylacetylene to form Fe-2(CO)(6){mu-SC(Ph)=C(H)Se} (3). The room-temperature reaction of Fe-2(CO)(6)(mu-STe) with phenylacetylene also yielded two isomeric products, Fe-2(CO)(6)(mu-SC-(H)=C(Ph)Te) (4) and Fe-2(CO)(6)(mu-SC(Ph)=C(H)Te) (5). In ah of these reactions, the homochalcogenide compounds Fe-2(CO)(6)(mu-EC(H)=C(Ph)E) (E = Se, Te, E = S, Se, and E = S, Te, respectively) were also formed in trace amounts. The new compounds 1-5 were characterized by IR and H-1, C-13, Se-77, and Te-125 NMR spectroscopy. Compound 1 was structurally characterized by single-crystal X-ray diffraction methods. It crystallized in the triclinic space group P $($) over bar$$ 1 with a = 7.773(9) Angstrom, b = 10.635(9) Angstrom, c = 12.010(10) Angstrom, a = 104.99(10)degrees, beta = 102.86(11)degrees, gamma = 106.38(9)degrees, V = 872.1(8) Angstrom(3), Z = 2, and D(calc) = 2.241 g cm(-3).Full-matrix least-squares refinement of 1 converged to R = 0.077 and R(w) = 0.086

Molecular rearrangement of photoparthenin by BF<SUB>3</SUB>-etherate-acetic acid complex: X-ray crystal structure of a novel product

The structure of a novel compound,Iupac name: bicyclo [2.4.0]-octa-1,3-dimethyl-2,3-pentan-9-methylene-8, 10-butan-diolide, which resulted on treatment of photoparthenin with BF3-etherate acetic acid, has been established uniquely by X-ray crystallography. C15H18O4 is orthorhombic, space group P212121, with the cell dimensionsa=8.444(1),b=9.964(2),c=16.239(2) &#197;,V=1366.3(2) &#197;3,Z=4,Mr =262.3,D o=1.29,D x=1.28 g cm-3, F(000)=560,T=293K,R=0.065 for 818 observed reflections. &#948;-lactone ring has a skew-boat, &#947;-lactone ring has an envelope, and the remaining six-membered ring has a distorted chair conformation. The four-membered ring is nonplanar. There are two intramolecular and one intermolecular short C-H&#8230;O interactions 2.819, 2.834, and 3.259 &#197;, respectively, which stabilize the crystal structure

Structures of albanols a and b, two novel phenols from Morus alba bark

Structures for albanol A and B, isolated from Morus alba bark, have been proposed on the basis of X-ray analysis of albanol A methyl ether