Kizakkekoikkal K. Chacko

Crystal structure of the 2:1 complex of mercury(II) chloride with trithiapyridino-12-crown-4 having unusual mercury coordination

The single crystal X-ray analysis of the 1:2 complex between trithiapyridino-12-crown-4 ( 1 ) and HgCl 2 is reported. Crystals of the complex are monoclinic, P 2 1 / n , with a =13.455(5), b =15.627(2), c =8.933(2) A, β=93.42(2)° and D c =2.844 g cm −3 for Z =4. The host macrocycle has an approximate non-crystallographic mirror symmetry. The structure contains Hg in two very different environments. One Hg is fivefold coordinated in distorted square pyramidal geometry using the four heteroatoms of the macroring and an additional chloro atom as ligating sites. The other Hg remains uncoordinated by the macroring but is surrounded by three chloro atoms to form a trigonal-planar geometry. This complex is an example of unique coordination mode around Hg.

The crystal structure and electronic properties of the Bis(1,3-dimethyl-5-diazophenyl-6-amino uracilato) copper(II) complex, dimethyl sulfoxide solvate - a new pseudotetrahedral CuN4 complex

Abstract The crystal structure of the title complex has been determined by X-ray diffraction technique. The crystals are monoclinic, space group P 2 1 / n , with a = 12.878(2), b = 14.791(1), c = 17.268(2) A, β = 109.79(1)°, Z = 4, R = 0.057 for 2514 reflections. There are two ligands of 1,3-dimethyl-5-diazophenyl- 6-amino uracilato anions in bidentate coordination to a copper(II) ion per asymmetric unit. The ligands are in cis -arrangement to each other. The copper environment is pseudotetrahedral, with a dihedral angle φ of 39.7° between the two CuN 4 ligand planes. This geometry seems to result from steric interaction between the ligands. The coordination of each molecule of the ligand takes place through the nitrogen atom of the deprotonated 6-amino group and a nitrogen of the azo group. The structure is stabilised by extensive stacking interactions between the phenyl rings as well as the pyrimidine rings. A pair of hydrogen-bonded interactions between the solvent molecule and the two ligands further stabilise the structure. The magnetic moment, ESR and electronic reflectance spectrum are in accordance with the observed molecular structure. A linear correlation between the highest energy d—d transition and the dihedral angle for several pseudotetrahedral N 4 complexes has been proposed.

Macro-rings designed for uncharged molecule complexation. Synthesis, complex formation, and structural studies of new pyridino crowns incorporating resorcinol and hydroquinone building blocks. X-Ray crystal and molecular structure of a 22-membered pyridino crown

The crystal structure of the pyridino crown (2) containing a resorcinol group is reported. Two crystallographically independent molecules of compound (2) with considerably different conformations are present in the crystal. Both molecules provide a potential cavity, but have other steric factors highly unfavourable for complex formation. Also, there is no free space in the crystal lattice for accommodation of a guest molecule. Based on this result, three pyridino crowns of different ring size incorporating two resorcinol units in different positions (5a–c) have been synthesized, together with the hydroquinone-group-containing analogues (6a–c). The host properties of the new macro-rings were determined. It was found that compound (6c) forms crystalline inclusion complexes with a number of dipolar aprotic and rather apolar organic guests such as nitromethane, acetonitrile, DMF, or dioxane, while the other compounds are inefficient. Host–guest relationships are discussed and conclusions for future host design are drawn.

The structure of the uncharged-molecule complex between a dinaphthopyridino-18-crown-6 host and acetonitrile (1 : 2)

Single crystal X-ray analysis of a 1 : 2 complex between the dinaphthopyridino-l8-crown-6 host (1) and acetonitrile is reported. Crystals of the complex are monoclinic,P21/c witha = 12.178(5),b = 8.186(1),c = 30.873(1) Å, β = 96.86(1)°, andDc = 1.25 g cm−3 forZ = 4. The host molecule reveals an approximate mirror symmetry and exists in a so-called ‘dentists chair’ conformation. One of the acetonitrile guest molecules is involved in possible weak interactions to two oxygen atoms of the host macroring, while the other fills free lattice space only.

Octa-coordinated environment for Ag+ involving an N2O6 donor set of two sandwiched pyridino crowns. X-ray crystal structure of the complex between tribenzopyridino-15-crown-5 and silver nitrate (2:1)

Abstract The single crystal X-ray analysis of the 2:1 complex between tribenzopyridino-15-crown-5 (1) and AgNO3 is reported. Crystals of the complex are triclinic, P 1 , with a=13.182(1), b=13.612(2), c=12.720(1) A, α=105.39(1), β=99.96(1), γ=103.04(1)° and Dc=1.54 g cm−3 for Z=2. The Ag+ cation forms a charge separated sandwich structure where Ag+ is in an octa-coordinated environment involving two nitrogen and six oxygen atoms of the macrorings. The complex has a complete hydrophobic shell.

Zn(II) and Hg(II) complexes of 4,6-diamino-2-thiopyrimidine and 4,6-diamino-2-methylthiopyrimidine. Crystal structure of 4,6-diamino-2-methylthiopyrimidinium hemitetrachlorozincate(II)

Abstract Reaction of Zn(II) and Hg(II) with 4,6-diamino-2- thiopyrimidine (DATP) and 4,6-diamino-2-methylthiopyrimidine (DAMTP) in aqueous medium gave six new compounds which have been characterized by elemental analysis, IR and 1H NMR spectroscopic techniques. The crystal structure of the Zn(II) complex of DAMTP has been determined by X-ray diffraction. It crystallizes in the trigonal space group P3121 (or P3221), a=8.725(2), c=24.288(4) A, C5H9Cl2N4SZn0.5, Z=6, Dcalc=1.616 g cm−3 and R=0.045 for 1056 unique reflections. The compound forms a salt structure composed of a 4,6- diamino-2-methylthiopyrimidinium cation with the ring nitrogen N1 protonated and a hemitetrachlorozincate anion. The crystal packing is dominated by a three-dimensional network of NH…Cl hydrogen bonds.

Crystal structure of 2,2′-diformyl 4,4′-dimethyl 6,6′-[piperazine-1,4-diyl bis-(methylene)]bis phenol

The title compund C22H26N2O4,Mr=382.46 crystallizes in the orthorhombic space group P212121 with α=8.867(1)Å,b=13.228(2)Å,c=17.029(3)Å,V=1956.7(2)Å3,Z=4, Dcal=1.30 Mgm−3,F(000)=816, μ=6.89 cm−1, λ(CuKα)=1.5418 Å andT=298 K. The structure was solved by direct methods and refined by full-matrix least-squares. The finalR=0.046 for 1995 unique reflections. The phenyl rings are coplanar (oriented at an angle of 6.4(1)o) and orients at an angle of 112.2(1)o and 115.7(1)o, respectively with the piperazine ring. The piperazine ring adopts achair conformation and the substituents at the N-atoms are in an equatiorial position.

Solid state structure of the hydrated potassium thiocyanate complex of benzodinaphthopyridino-21-crown-7, C37H31NO6.KSCN.H2O (1:1:1)

Single crystal X-ray analysis of the hydrated KSCN complex of benzodinaphthopyridino-21-crown-7 (1) (1 : 1 : 1) is reported. Crystals of the complex are orthorhombic,Pnma, withα = 16.946(4),b = 22.298(4),c = 10.390(8) Å andDc = 1.184 g cm−1,Z = 4. The host macroring (1) has a mirror symmetry and exists in a so-called ‘dentists chair’ conformation. The cation (K−) is coordinated to all the six ether oxygen atoms and also weakly to the pyridine N atom. The SCN− anion group has a statistical type of disorder with opposite orientations of S and N such that nitrogen and sulphur are coordinated to K+. Packing of the host molecules is in columns to form quasi channels with K+, SCN−, and H2O being located inside the stacks.

Crystal and molecular structure of 2:1 complex of 1,3-dimethyl violuric acid-mercury(II)

The complex (C6H6N3O4)2Hg crystallizes in space groupP¯1, witha=16.635(2),b=11.765(2)c=9.288(2),α=98.74(2),β=102.99(2),γ=108.13(1)°,V=1634.3(6) Å3 andZ=4. The structure was solved by the heavy-atom method, and refined by full-matrix least squaresR andRw values of 0.051 and 0.044, respectively, for 3108 uniquc reflections. The Hg(II) atom displays a highly distorted tetrahedral coordination geometry. It is bonded to two nitrogens and two oxygens of the two modified uracil base ligands in an unequalcis-bidentate manner. The ligand exists in the triketo form. The crystal structure is stabilized by C-H⋯O interactions.

Preparation and X-ray structures of two crystalline complexes between macrocyclic pyridino hosts and benzonitrile

Abstract The preparations of solid-state benzonitrile complexes of two oligoaryl-condensed crown hosts are described and their crystal structures are reported. Benzo-di[(2,3)naphtho]-(2,6)pyridino-21-crown-7 (1) forms a crystalline 1:3 (host:guest) complex (1a) while benzo-di[(1,4)benzeno]-(2,6)pyridino-25-crown-7 (2) forms a 2:1 crystalline complex (2a) with PhCN. Crystal data: 1a [P 1, a = 13.455(3), b = 15.313(2), c = 13.371(4) A, α = 103.75(2), β = 109.00(2), γ = 103.63(2)°, Z = 2], 2a [C2/c,a = 37.105, b = 17.410(8), c = 8.598(3) A. β = 90.89(2)°, Z = 4]. Both compounds are lattice-type complexes showing no significant host-guest contacts. The crystal structures are stabilized by dipole-dipole, stacking and van-der-Waals interactions.