Structure of the copper tripodal Schiff base complex {tris[4-(2-thienyl)-3-aza-κN-3-butenyl]amine-κN}copper(I) tetrafluoroborate

The copper Schiff base complex {tris[4-(2-thienyl)-3- aza-~N-3-butenyl]amine-~N} copper(I) tetrafluoroborate, [Cu{N(CTHgNS)3 }]+.BF4- (I), crystallizes with the cation residing in a general position and two disordered tetrafluoroborate anions residing on twofold axes. The cation has approximate threefold symmetry and the copper(I) geometry is distorted trigonal pyramidal with coordination from the apical tertiary amine N atom and the three azomethine N atoms but not from the S atoms of the three thiophene moieties. The principal bond lengths are Cu-- Napical 2.300 (5) ,~ and mean Cu--Nequatorial 1.994 (4) A,, with a mean Cu-..S contact of 3.270 (2) A

Intermolecular N-H...O=C hydrogen bonding in the crystal structure of 6-amino-1,3-dimethyluracil

The 6-amino- 1,3-dimethyluracil molecule [6-amino- 1,3- dimethyl-2,4(1H,3H)-pyrimidinedione], C6H9N302 (I), lies on a crystallographic mirror plane and participates in an extensive two-dimensional hydrogen-bonding network in the solid state. Each molecule is involved in N-- H...O=C hydrogen bonding involving the amino and carbonyl gr. oups, with O...N separations of 2.894 (3) and 2.904 (3) A

A lisp oriented architecture

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (p. 63-67).by John W.F. McClain.M.S

4-Methyl-2,6-bis(phosphonomethyl)phenol dihydrate

The 4-methyl-2,6-bis(phosphomethyl)phenol molecule, which crystallizes with two water molecules per asymmetric unit, has approximate twofold symmetry and is involved in extensive three-dimensional hydrogen bonding in which every available OH group participates. The principal dimensions include P--O 1.4981 (13) and 1.5015 (14) ,~, four P--OH distances in the range 1.5395(14) to 1.5688(13) A, P--C 1.7857(17) and 1.7893 (17) ~k, and O...O intramolecular and intermolecular hydro.gen-bond distances in the range 2.458 (2) to 2.866 (2) A

Twisted [(R3P)PdX] groups above dicarbaborane ligands: 4-dimethylsulfido-3-iodo-3-triphenylphosphine-closo-3-pallada-1,2-dicarbadodecaborane and 3-dimethylphenylphosphine-3-chloro-4-dimethylsulfido-closo-3-pallada-1,2-dicarbadodecaborane

The structural analyses of [3-(PPh₃)-3-I-4-(SMe₂)-closo-3,1,2-PdC₂B₉H₁₀] or [Pd(C₄H₁₆B₉S)I(C₁₈H₁₅P)], (I), and [3-(PPhMe₂)-3-Cl-4-(SMe₂)-closo-3,1,2-PdC₂B₉H₁₀] or [Pd(C₄H₁₆B₉S)Cl(C₈H₁₁P)], (II), show that in comparison with [3-(PR₃)2-closo-3,1,2-PdC₂B₉H₁₁] the presence of the 4-SMe₂ group causes the [PdX(PR₃)] unit (X = halogen) to twist about an axis passing through the Pd atom and the directly opposite B atom of the carbaborane ligand. The halogen atoms are located almost directly above a C atom in the C₂B₃ face, and the conformations of the [PdX(PR₃)] units above the C₂B₃ faces are not those predicted from molecular orbital calculations of the closo-3,1,2-PdC₂B₉ system. The fact that the variation from the predicted conformation is greater in the case of (I) than in (II) may be ascribed to the greater steric interactions induced by the I atom in (I) compared with the Cl atom in (II)

Structure of the partial cone conformer of 25,26,27,28-tetrakis[(2-pyridylmethyl)oxy]calix[4]arene

The partial cone conformer of tetrakis[(2-pyridylmethyl)- oxy]pentacyclo[ 19.3.1.13'7.19'13.115,19]octacosa- 1 (25),- 3,5,7 (28),9,11,13 (27), 15,17,19(26),21,23-dodecaene, (I), adopts a conformation in which the pendant OCH2py group of the rotated aryl ring is oriented away from the calixarene cavity produced by the other three aryl rings, with its N atom exo to the calixarene cup. The orientation of the four aromatic rings is such that two rings are almost parallel to each other and the other two are at an angle of 42 ° . This conformation precludes any solvent molecule being enclathrated within the small molecular cavity

The structure of triphenylgermanium hydroxide

C18H~6GeO, Mr = 320.9, triclinic, Pi, a = 15.408 (6), b = 19.974 (7), c = 23.264 (11) A, a = 107.78 (4), 13 = 1.03.54 (4), y= 101.51 (3) °, V = 6338 (5)/~3, Z = 16, Dx = 1.34 g cm -3, a(Mo Ka) = 0.71073A, /z = 19.1cm-1, F(000)=2624, T= 293 K, R = 0.055 for 6846 observed reflections. The eight independent molecules in the asymmetric unit form two independent O--H...O hydrogen-bonded tetramers with the O atoms in a flattened tetrahedral arrangement [hydrogen-bond distances in the range 2.609 (11) to 2.657 (11)A]. The Ge atoms are tetrahedrally coordinated with mean Gc O 1.791 (7) and Gc C 1.931 (8) A

Ligands for application in coordination chemistry: three dicarboxylic acids

Three potential ligand molecules have been investigated. 6,6'-o-Phenylenedioxybis(2,2-dimethyl-4-oxahexanoic acid), C20H3008 (I), has twofold crystallographic symmetry and adopts a conformation in which the two pendant carboxylic arms minimize any potential molecular cavity between them; zigzag polymeric chains are formed as a result of C==O .. .H--O hydrogen bonding about inversion centers. 2,2,9,9-Tetramethyl- 4,7-dioxadecanedioic acid, C12H2206 (II), also forms polymeric hydrogen-bonded chains involving the carboxylic acid moieties but differs from (I) in its molecular conformation. 2,2,6,6,10,10-Hexamethyl-4,8- dioxaundecanedioic acid, Ci5H2806 (III), forms discrete rectangular-shaped centrosymmetric dimers in which any potential molecular cavity is minimized as a result of the close proximity of two of the pendant etheral arms

Structure of 2,2,6,6-tetramethyl-4-oxaheptanedinitrile

The title molecule, C 10H 16N20 (I), has approximate mirror symmetry with the main chain fully extended. The main torsion angles defining the molecular conformation are O--Cw3--Cw3--Cw 58.9 (4) and -60.5 (4) °. The mean principal dimensions include N~Csp 1.13 (1), Csp--Cw3 1.46 (1) and Csp3--O 1.410 (6) A. The two nitrile groups are oriented cis to one another [N=Csp... Csp:--N 4.4o(5) °] and the intramolecular N.-.N separation is 4.70 (1) A

3-(Benzo[b]thien-2-yl)-5,6-dihydro-1,4,2-oxathiazine 4-Oxide

The title compound, C₁₁H₉NO₂S₂, is a potent material preservative and contains the 1,4,2-oxathiazine ring system in a half-chair conformation with the methylene C atoms 0.510 (3) and -0.367 (3) Å from the plane of the other four oxathiazine ring atoms