Cheryl L. Klein

The synthesis, magnetic properties, and crystal structure of two copper(II) complexes prepared from 2-aminomethylpyridine

Abstract The structures of Cu(amp)2(ClO4)2 and [CuLCl2]2 (where L = C9H12N2O) were determined by X-ray crystallographic techniques. Cu(amp)2(ClO4)2 crystallized in space group P1 with a = 7.630(2), b = 7.980(1), c = 7.972(5) A, α = 106.67(3), β = 108.75(3), λ = 95.90(2)° and Z = 1. The structure was refined to R = 0.025 and Rw = 0.037 with 1146 reflections with I>3σ9I). [CuLCl2]2 crystallized in space group P 1 with a = 7.093(1), b = 9.412(1), c = 9.541(2) A, α = 94.25(1), β = 103.69(2) and λ = 108.32(1)°. The structure was refined to R = 0.040 and Rw = 0.051 with 1265 reflections with I>3σ(I). CuLCl2 forms a dimer through coordination of one of its chlorine atoms to the copper atom of an adjacent monomeric unit. Cu(amp)2(ClO4)2forms a monomer with an octahedral coordination sphere. The perchlorate groups are weakly coordinated to the copper atom. Cu(amp)2(ClO4)2 exhibits Curie-Weiss behavior with g = 2.11 and γ = 0.16 K. [CuLCl2]2 exhibits antiferromagnetic intra-dimer coupling with g = 2.09 and 2J = −3.50 cm−1.

Charge Density Studies of Drug Molecules

The role of single-crystal x-ray diffraction in structural studies is well recognized. Much of our understanding of the details of molecular structure, structure-activity relationships, and even chemical bonding has been drawn from the many structures which have been determined by x-ray diffraction. Parameterization of molecular mechanics models is also largely dependent on x-ray structural data.

Synthesis and crystal structures of the layered I–III–V Zintl phases, K4In4X6, where X = As, Sb

Ternary Zintl phase materials of the formula K4In4X6, where X = As or Sb, have been prepared following a high-temperature procedure. The crystal structure of K4In4As6 has been determined at low temperature and consists of [In4As64–]n sheets of ca. 5 A thickness insulated by a layer of potassium ions of ca. 3 A thickness. The crystal structure of K4In4Sb6 has been determined at room temperature and is isomorphous with the K4In4Sb6 compound. For K4In4As6, a= 14.323(3)A, b= 7.106(2)A, c= 15.795(3)A, β= 90.30(2)°, space group P21/c, Z= 4, ρc= 4.44 g cm–3 at T= 100(5) K, R= 0.035 for 2688 unique observed reflections. For K4In4Sb6, a= 15.282(5)A, b= 7.544(1)A, c= 16.788(3)A, β= 90.52(2)°, space group P21/c, Z= 4, ρc= 4.62 g cm–3 at T= 299 K, R= 0.042 for 3001 unique observed reflections.

Structure of droperidol−ethanol (1/1)

1-(1-[4-(4-Fluorophenyl)-4-oxobutyl]-1,2,-3,6-tetrahydro-4-pyridyl)-1,3- dihydro-2H-benzimidazol-2-one ethanol solvate, C22H22FN3O2.C2H6O, Mr = 426.3, triclinic, P1, a = 6.083 (3), b = 10.296 (1), c = 16.018 (2) A, alpha = 100.93 (1), beta = 92.72 (2), gamma = 96.27 (2) degrees, V = 976.7 A3, Z = 2, Dx = 1.45 g cm-3, Mo K alpha, lambda = 0.71073 A, mu = 0.97 cm-1, F(000) = 452, T = 90 (2) K, final R = 0.046 for 2261 observed reflections. The title compound crystallizes with the droperidol skeleton extended and a solvated ethanol molecule disordered about an inversion center. The ethanol molecule forms a hydrogen bond to the droperidol skeleton at ketone atom O(1) on the imidazole ring.

Crystal and molecular structures of benzophenone phenylhydrazone derivatives with anticancer activity

The X-ray crystal structures of 4,4′-dihydroxybenzophenone-2,4-dinitrophenylhydrazone (I) and 2,2′-dihydroxybenzophenone-2,4-dinitrophenylhydrazone (II) have been determined in order to study the structural characteristics of these molecules that may contribute to their antiestrogenic and cytotoxic properties. These structures have been compared to other hydrazone derivatives as well as tamoxifen, an antiestrogen drug presently used clinically for the treatment of breast cancer.Crystal data: (I) C19H14N4O6 · C4H10O; MW=468.0; monoclinic,P21;a=8.601(2), b=15.502(8), c=16.851(4) Å,β=98.58(2)°;Z=8; finalR=0.036 for 1904 observed reflections. (II C19H14N4O6 · H2O; MW=410.0; monoclinic,P21/c;a=7.603(2),b=19.552(4),c=12.493(3) Å,β=92.11(1)°;Z=4; finalR=0.045 for 1171 observed reflections.

Experimental electron density distribution of dopamine hydrochloride

Careful high-resolution x-ray diffraction measurements at 90 K have been used to map the electron density distribution in a single crystal of dopamine hydrochloride, a neurotransmitter. A least-squares refinement procedure has been used in which multipole parameters are added to describe the distortions of the atomic electron distributions from spherical symmetry. The refinement also yields improved estimates of the x-ray phases, which have been used to plot maps of the electron distribution. The most electron-rich areas of the molecule are the hydroxyl groups that show large buildups of electron density at the position of the nonbonded lone pairs. The sum of the net atomic charges for the ammonium group is +0.2(2). The net atomic charge for the chloride ion is −0.1(1).

Magnetic properties and molecular structure of complexes of substituted pyrazine ligands co-ordinated to iron(II) and copper(II) low dimensional antiferromagnetic interactions in diaquabis(pyrazinecarboxylato)iron(II)

The preparation and magnetic properties at 6–300 K are reported for the complexes [FeL2(H2O)2], [Fe(HL′)2]·3H2O, and [Cu(HL′)2]·3H2O, where HL = pyrazinecarboxylic acid and H2L′= 2,3-pyrazinedicarboxylic acid. The crystal structure of the compound [FeL2(H2O)2] is reported; it crystallizes as a monomer but the crystalline lattice contains an extensive network of hydrogen bonding with the hydrogen bonding along one direction shorter than in other directions. The magnetic data for [FeL2(H2O)2] exhibit a maximum in the temperature-dependent magnetic susceptibility at around 15 K, consistent with the Fisher linear-chain model (J/k=–1.3 K). The complex [Cu(HL′)2]·3H2O exhibits no magnetic interaction, whilst [Fe(HL′)2]·3H2O shows a low-temperature drop in the effective magnetic moment consistent with a zero-field splitting of the spin S= 2 multiplet (D/k= 12.6 K). Crystal data for [FeL2(H2O)2] : space group P21/c, Z= 2, a= 5.238(2), b= 11.198(2), c= 10.337(3)A, β= 100.74(5)°, R= 0.077 for 604 reflections.