tert-Butyl 4-{[2-amino-4-(2-hy-droxy-phen-yl)pyrimidin-5-yl]meth-yl}piperazine-1-carboxyl-ate.

In the title compound, C20H27N5O3, the central piperazine ring adopts a chair conformation, with the N-bound carboxyl-ate and methyl-ene substituents occupying bis-ectional and equatorial orientations, respectively. A twist is evident between the aromatic rings [dihedral angle = 25.61 (9)°] but an intra-molecular O-H⋯N hydrogen bond persists between these. Supra-molecular tapes along [1-10] are formed in the crystal packing through N(amino)-H⋯O(hydrox-yl) and N(amino)-H⋯N(pyrimidin-yl) hydrogen bonds, and these are linked into layers in the ab plane by π-π inter-actions [inter-centroid distance between pyrimidinyl rings = 3.5919 (9) Å].

4-(2H-1,3-Benzodioxol-5-yl)-1-(4-methyl-phenyl)-1H-pyrazol-5-amine.

In the title compound, C17H15N3O2, two independent mol-ecules (A and B) comprise the asymmetric unit. The major conformational difference arises in the relative orientation of the pyrazole ring amine and dioxole substituents which are anti in A and syn in B. The five-membered dioxole ring in each mol-ecule has an envelope conformation with the methyl-ene C atom as the flap. The mean plane through the benzodioxole and benzene groups make dihedral angles of 31.67 (8) and 68.22 (9)°, respectively, with the pyrazole ring in A; the equivalent values for B are 47.18 (7) and 49.08 (9)°. In the crystal, supra-molecular zigzag chains along the b-axis direction arise as a result of N-H⋯N hydrogen bonding. These are consolidated into supra-molecular double chains via C-H⋯O and C-H⋯π inter-actions.

2-(4-Methyl-phen-yl)-7-(2-methyl-prop-oxy)-4H-chromen-4-one-6-chloro-2-(4-methyl-phen-yl)-7-(2-methyl-prop-oxy)-4H-chromen-4-one (19/1).

The title co-crystal, 0.95C(20)H(20)O(3)·0.05C(20)H(19)ClO(3), arises as the chloride carried over during the synthesis shares a position with an aromatic H atom; the partial occupancies are 0.947 (2) and 0.053 (2) for H and Cl, respectively. The mol-ecular structure is stabilized by intra-molecular C-H⋯O contacts, forming pseudo five- and six-membered rings with S(5) and S(6) graph-set motifs, respectively. The crystal structure features π-π stacking inter-actions between the centroids of the central fused ring systems [centroid-centroid distance = 3.501 (2) Å].

(1E,4E)-1,5-Bis(thio-phen-3-yl)penta-1,4-dien-3-one.

The title compound, C(13)H(10)OS(2), exhibits twists between the central C(3)O and ethene residues [O-C-C-C torsion angles = -8.4 (3) and 11.8 (3)°], and between the ethene and adjacent thio-phenyl residues [C-C-C-C torsion angles = -4.2 (3) and 10.5 (3)°]. As a result, the mol-ecule is non-planar, the dihedral angle formed between the terminal thio-phenyl groups being 15.45 (10)°. The presence of C-H⋯O inter-actions involving the bifurcated carbonyl O atom leads to supra-molecular arrays in the ac plane. These are linked into a three-dimensional architecture by C-H⋯π inter-actions involving both thio-phenyl residues.

4-{[(4Z)-5-Oxo-2-phenyl-4,5-dihydro-1,3-oxazol-4-yl-idene]meth-yl}phenyl acetate.

The title mol-ecule, C(18)H(13)NO(4), shows a dihedral angle between the terminal acetyl group (r.m.s. deviation = 0.0081 Å) and remaining non-H atoms (r.m.s. = 0.0734 Å) of 53.45 (7)°. The configuration about the central olefinic bond is Z and overall the mol-ecule has a U-shaped conformation. Supra-molecular chains along the b-axis direction are found in the crystal structure. These are stabilized by (C=O)⋯π(ring centroid of the 1,3-oxazole ring) inter-actions [3.370 (2) Å].

Ethyl (2Z)-2-(3-methoxy-benzyl-idene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-1,3-thia-zolo[3,2-a]pyrimidine-6-carboxyl-ate.

In the title compound, C(24)H(22)N(2)O(4)S, the central pyrimidine ring is significantly puckered, assuming a conformation inter-mediate between a boat and a screw boat. The nearly planar thia-zole ring (r.m.s. deviation = 0.0258 Å) is fused with the pyriamidine ring, making a dihedral angle of 9.83 (7)°. The carboxyl group is in an extended conformation with an anti-periplanar orientation with respect to the dihydropyrimidine ring. The benzene ring linked at the chiral C atom is perpendicular to the pyrimidine ring [dihedral angle = 85.21 (8)°] whereas the phenyl ring is nearly coplanar, making a dihedral angle of 13.20 (8)°. An intra-molecular C-H⋯S hydrogen bond is observed. The crystal packing is influenced by weak inter-molecular C-H⋯π inter-actions and π-π stacking between the thia-zole and phenyl rings [centroid-centroid distance = 3.9656 (10) Å], which stack the mol-ecules along the c axis.

7-(4-Chloro-phen-yl)-9-phenyl-7H-pyrrolo[3,2-e]tetra-zolo[1,5-c]pyrimidine.

In the title compound, C(18)H(11)ClN(6), the pyrrole, pyrimidine and tetra-zole rings form a nearly planar fused trihetrocyclic system with an r.m.s. deviation of 0.0387 (13) Å, to which the 4-chloro-phenyl group and the phenyl group are substituted at the 7 and 9 positions, respectively. The dihedral angles between the pyrrole ring and the 4-chloro-phenyl and phenyl rings are 32.1 (4) and 7.87 (7)°, respectively. In the crystal, weak inter-molecular C-H⋯N and C-H⋯Cl hydrogen bonds link the mol-ecules into a layer parallel to the (001) plane. The layers are further connected by π-π stacking inter-actions [centroid-centroid distances: 3.8413 (8) and 3.5352 (8) Å]. Intra-molecular C-H⋯N hydrogen bonds are also present.

Ethyl 2-(2-acetoxy-benzyl-idene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-1,3-thia-zolo[3,2-a]pyrimidine-6-carboxyl-ate.

In the title mol-ecule, C(25)H(22)N(2)O(5)S, the atoms of the thia-zolopyrimidine ring system, with the exception of the phenyl-bearing C atom [deviation = 0.177 (2) Å], are essentially planar [r.m.s deviation = 0.100 (2) °] and the mean plane of these atoms forms dihedral angles of 89.86 (10) and 7.97 (8)° with the phenyl and benzene rings, respectively. In the crystal, co-operative C-H⋯O and C-H⋯π inter-actions lead to a supra-molecular chain along the a axis. These chains are connected via π-π inter-actions [centroid-centroid = 3.7523 (13) Å].

N-(2-Oxo-2H-chromen-3-yl)benzamide.

The phenyl ring in title mol-ecule, C(16)H(11)NO(3), forms a dihedral angle of 7.69 (6)° with the fused ring system. The observed conformation is stabilized by intra-molecular N-H⋯O and C-H⋯O inter-actions. In the crystal, supra-molecular chains are formed along the b axis which are mediated by π-π inter-actions [centroid-centroid distance = 3.614 (2) Å].

12-(4-Methoxy-phen-yl)-10-phenyl-3,4,5,6,8,10-hexa-azatricyclo-[7.3.0.0]dodeca-1(9),2,4,7,11-penta-ene.

In the title compound, C(19)H(14)N(6)O, the fused 12-membered tetra-zolo/pyrimidine/pyrrole ring system is almost planar (r.m.s. deviation = 0.013 Å). The 4-methoxy-phenyl and phenyl substituents on the pyrrole ring are both twisted with respect to the fused-ring system [dihedral angles = 25.39 (18) and 36.42 (18)°, respectively]. Intra-molecular C-H⋯N inter-actions occur. In the crystal, mol-ecules pack into layers in the ac plane and these are connected along the b axis via C-H⋯π and π-π [centroid-centroid separation = 3.608 (3) Å] inter-actions.

12-(4-Chloro-phen-yl)-7-methyl-10-phenyl-3,4,5,6,8,10-hexa-aza-tricyclo-[7.3.0.0]dodeca-1(9),2,4,7,11-penta-ene.

The 12 non-H atoms defining the triple-fused-ring system in the title compound, C(19)H(13)ClN(6), are almost coplanar (r.m.s. deviation = 0.023 Å). The chloro-substituted ring is almost effectively coplanar with the central atoms [dihedral angle = 6.74 (13)°], but the N-bound benzene ring is not [dihedral angle = 54.38 (13)°]. In the crystal, supra-molecular chains along the a axis sustained by C-H⋯π and π-π [centroid-centroid distance between N(4)C and C(4)N five-membered rings = 3.484 (2) Å] stacking occur. A very long C-Cl⋯π contact is also seen.

7-(4-Bromo-phen-yl)-9-phenyl-7H-pyrrolo[3,2-e]tetra-zolo[1,5-c]pyrimidine.

In the title compound, C(18)H(11)BrN(6), the phenyl ring is almost coplanar [dihedral angle 7.2 (1)°] with the planar (r.m.s. deviation 0.039 Å) tricyclic ring system while the 4-bromo-phenyl ring makes a dihedral angle of 33.98 (6)° with the ring system. Weak inter-molecular C-H⋯N and C-H⋯Br hydrogen-bonding inter-actions and π-π stacking [centroid-centroid distances = 3.7971 (17) and 3.5599 (16) Å] stabilize the crystal packing. A comparison of the structure to a MOPAC PM3 geometry optimization calculation in vacuo supports these observations.

(2E)-1-[2-Hydr-oxy-4-(2-methyl-prop-oxy)phen-yl]-3-(4-methyl-phen-yl)prop-2-en-1-one.

The benzene rings in the title compound, C(20)H(22)O(3), form a dihedral angle of 10.39 (8)°. Overall, the mol-ecule is approximately planar with the exception of one of the terminal methyl groups; excluding this group, the r.m.s. deviation for the remaining 22 non-H atoms is 0.0968 Å. The conformation about the C=C bond is E, and an intra-molecular O-H⋯O hydrogen bond leads to the formation of an S(6) motif. In the crystal, linear supra-molecular chains are formed along the a axis via C-H⋯O contacts, and these are connected into double chains via C-H⋯π inter-actions.

3,3-Bis(2-hy-droxy-eth-yl)-1-(4-nitro-benzo-yl)thio-urea: crystal structure, Hirshfeld surface analysis and computational study.

In the title compound, C12H15N3O5S, a tris-ubstituted thio-urea derivative, the central CN2S chromophore is almost planar (r.m.s. deviation = 0.018 Å) and the pendant hy-droxy-ethyl groups lie to either side of this plane. While to a first approximation the thione-S and carbonyl-O atoms lie to the same side of the mol-ecule, the S-C-N-C torsion angle of -47.8 (2)° indicates a considerable twist. As one of the hy-droxy-ethyl groups is orientated towards the thio-amide residue, an intra-molecular N-H⋯O hydrogen bond is formed which leads to an S(7) loop. A further twist in the mol-ecule is indicated by the dihedral angle of 65.87 (7)° between the planes through the CN2S chromophore and the 4-nitro-benzene ring. There is a close match between the experimental and gas-phase, geometry-optimized (DFT) mol-ecular structures. In the crystal, O-H⋯O and O-H⋯S hydrogen bonds give rise to supra-molecular layers propagating in the ab plane. The connections between layers to consolidate the three-dimensional architecture are of the type C-H⋯O, C-H⋯S and nitro-O⋯π. The nature of the supra-molecular association has been further analysed by a study of the calculated Hirshfeld surfaces, non-covalent inter-action plots and computational chemistry, all of which point to the significant influence and energy of stabilization provided by the conventional hydrogen bonds.

2-[(2,4,6-Tri-methyl-benzene)-sulfon-yl]phthalazin-1(2H)-one: crystal structure, Hirshfeld surface analysis and computational study.

The X-ray crystal structure of the title phthalazin-1-one derivative, C17H16N2O3S {systematic name: 2-[(2,4,6-tri-methyl-benzene)-sulfon-yl]-1,2-di-hydro-phthalazin-1-one}, features a tetra-hedral sulfoxide-S atom, connected to phthalazin-1-one and mesityl residues. The dihedral angle [83.26 (4)°] between the organic substituents is consistent with the mol-ecule having the shape of the letter V. In the crystal, phthalazinone-C6-C-H⋯O(sulfoxide) and π(phthalazinone-N2C4)-π(phthalazinone-C6) stacking [inter-centroid distance = 3.5474 (9) Å] contacts lead to a linear supra-molecular tape along the a-axis direction; tapes assemble without directional inter-actions between them. The analysis of the calculated Hirshfeld surfaces confirm the importance of the C-H⋯O and π-stacking inter-actions but, also H⋯H and C-H⋯C contacts. The calculation of the inter-action energies indicate the importance of dispersion terms with the greatest energies calculated for the C-H⋯O and π-stacking inter-actions.

(N,N-Di-allyl-dithio-carbamato-κ2 S,S')tri-phenyltin(IV) and bis-(N,N-di-allyl-dithio-carbamato-κ2 S,S')di-phenyl-tin(IV): crystal structure, Hirshfeld surface analysis and computational study.

The crystal and mol-ecular structures of the title organotin di-thio-carbamate compounds, [Sn(C6H5)3(C7H10NS2)] (I) and [Sn(C6H5)2(C7H10NS2)2] (II), present very distinct tin atom coordination geometries. In (I), the di-thio-carbamate ligand is asymmetrically coordinating with the resulting C3S2 donor set defining a coordination geometry inter-mediate between square-pyramidal and trigonal-bipyramidal. In (II), two independent mol-ecules comprise the asymmetric unit, which differ in the conformations of the allyl substituents and in the relative orientations of the tin-bound phenyl rings. The di-thio-carbamate ligands in (II) coordinate in an asymmetric mode but the Sn-S bonds are more symmetric than observed in (I). The resulting C2S4 donor set approximates an octa-hedral coordination geometry with a cis-disposition of the ipso-carbon atoms and with the more tightly bound sulfur atoms approximately trans. The only directional inter-molecular contacts in the crystals of (I) and (II) are of the type phenyl-C-H⋯π(phen-yl) and vinyl-idene-C-H⋯π(phen-yl), respectively, with each leading to a supra-molecular chain propagating along the a-axis direction. The calculated Hirshfeld surfaces emphasize the importance of H⋯H contacts in the crystal of (I), i.e. contributing 62.2% to the overall surface. The only other two significant contacts also involve hydrogen, i.e. C⋯H/H⋯C (28.4%) and S⋯H/H⋯S (8.6%). Similar observations pertain to the individual mol-ecules of (II), which are clearly distinguishable in their surface contacts, with H⋯H being clearly dominant (59.9 and 64.9%, respectively) along with C⋯H/H⋯C (24.3 and 20.1%) and S⋯H/H⋯S (14.4 and 13.6%) contacts. The calculations of energies of inter-action suggest dispersive forces make a significant contribution to the stabilization of the crystals. The exception is for the C-H⋯π contacts in (II) where, in addition to the dispersive contribution, significant contributions are made by the electrostatic forces.

(E)-{[(Butyl-sulfan-yl)methane-thio-yl]amino}(4-meth-oxy-benzyl-idene)amine: crystal structure and Hirshfeld surface analysis.

The title hydrazine carbodi-thio-ate, C13H18N2OS2, is constructed about a central and almost planar C2N2S2 chromophore (r.m.s. deviation = 0.0263 Å); the terminal meth-oxy-benzene group is close to coplanar with this plane [dihedral angle = 3.92 (11)°]. The n-butyl group has an extended all-trans conformation [torsion angles S-Cm-Cm-Cm = -173.2 (3)° and Cm-Cm-Cm-Cme = 180.0 (4)°; m = methyl-ene and me = meth-yl]. The most prominent feature of the mol-ecular packing is the formation of centrosymmetric eight-membered {⋯HNCS}2 synthons, as a result of thio-amide-N-H⋯S(thio-amide) hydrogen bonds; these are linked via meth-oxy-C-H⋯π(meth-oxy-benzene) inter-actions to form a linear supra-molecular chain propagating along the a-axis direction. An analysis of the calculated Hirshfeld surfaces and two-dimensional fingerprint plots point to the significance of H⋯H (58.4%), S⋯H/H⋯S (17.1%), C⋯H/H⋯C (8.2%) and O⋯H/H⋯O (4.9%) contacts in the packing. The energies of the most significant inter-actions, i.e. the N-H⋯S and C-H⋯π inter-actions have their most significant contributions from electrostatic and dispersive components, respectively. The energies of two other identified close contacts at close to van der Waals distances, i.e. a thione-sulfur and meth-oxy-benzene-hydrogen contact (occurring within the chains along the a axis) and between methyl-ene-H atoms (occurring between chains to consolidate the three-dimensional architecture), are largely dispersive in nature.

Crystal structures of two dis-symmetric di-Schiff base compounds: 2-({(E)-2-[(E)-2,6-di-chloro-benzyl-idene]hydrazin-1-yl-idene}meth-yl)-6-meth-oxy-phenol and 4-bromo-2-({(E)-2-[(E)-2,6-di-chloro-benzyl-idene]hydrazin-1-yl-idene}meth-yl)phenol.

Each of the title dis-symmetric di-Schiff base compounds, C15H12Cl2N2O2 (I) and C14H9BrCl2N2O (II), features a central azo-N-N bond connecting two imine groups, each with an E-configuration. One imine bond in each mol-ecule connects to a 2,6-di-chloro-benzene substituent while the other links a 2-hydroxyl-3-meth-oxy-substituted benzene ring in (I) or a 2-hydroxyl-4-bromo benzene ring in (II). Each mol-ecule features an intra-molecular hydroxyl-O-H⋯N(imine) hydrogen bond. The C-N-N-C torsion angles of -151.0 (3)° for (I) and 177.8 (6)° (II) indicates a significant twist in the former. The common feature of the mol-ecular packing is the formation of supra-molecular chains. In (I), the linear chains are aligned along the a-axis direction and the mol-ecules are linked by meth-oxy-C-H⋯O(meth-oxy) and chloro-benzene-C-Cl⋯π(chlorobenzene) inter-actions. The chain in (II) is also aligned along the a axis but, has a zigzag topology and is sustained by Br⋯O [3.132 (4) Å] secondary bonding inter-actions. In each crystal, the chains pack without directional inter-actions between them. The non-covalent inter-actions are delineated in the study of the calculated Hirshfeld surfaces. Dispersion forces make the most significant contributions to the identified inter-molecular inter-actions in each of (I) and (II).

Crystal structure, Hirshfeld surface analysis and computational study of bis-(2-{[(2,6-di-chloro-benzyl-idene)hydrazinyl-idene]meth-yl}phenolato)cobalt(II) and of the copper(II) analogue.

The title homoleptic Schiff base complexes, [M(C14H9Cl2N2O)2], for M = CoII, (I), and CuII, (II), present distinct coordination geometries despite the Schiff base dianion coordinating via the phenolato-O and imine-N atoms in each case. For (I), the coordination geometry is based on a trigonal bipyramid whereas for (II), a square-planar geometry is found (Cu site symmetry ). In the crystal of (I), discernible supra-molecular layers in the ac plane are sustained by chloro-benzene-C-H⋯O(coordinated), chloro-benzene-C-H⋯π(fused-benzene ring) as well as π(fused-benzene, chloro-benzene)-π(chloro-benzene) inter-actions [inter-centroid separations = 3.6460 (17) and 3.6580 (16) Å, respectively]. The layers inter-digitate along the b-axis direction and are linked by di-chloro-benzene-C-H⋯π(fused-benzene ring) and π-π inter-actions between fused-benzene rings and between chloro-benzene rings [inter-centroid separations = 3.6916 (16) and 3.7968 (19) Å, respectively] . Flat, supra-molecular layers are also found in the crystal of (II), being stabilized by π-π inter-actions formed between fused-benzene rings and between chloro-benzene rings [inter-centroid separations = 3.8889 (15) and 3.8889 (15) Å, respectively]; these stack parallel to [10] without directional inter-actions between them. The analysis of the respective calculated Hirshfeld surfaces indicate diminished roles for H⋯H contacts [26.2% (I) and 30.5% (II)] owing to significant contributions by Cl⋯H/H⋯Cl contacts [25.8% (I) and 24.9% (II)]. Minor contributions by Cl⋯Cl [2.2%] and Cu⋯Cl [1.9%] contacts are indicated in the crystals of (I) and (II), respectively. The inter-action energies largely arise from dispersion terms; the aforementioned Cu⋯Cl contact in (II) gives rise to the most stabilizing inter-action in the crystal of (II).

7-(4-Methoxy-phen-yl)-5-methyl-9-phenyl-7H-pyrrolo[2',3':4,5]pyrimido[1,6-d]tetrazole.

The title compound, C(20)H(16)N(6)O, is composed of a tetra-zolo ring and a 4-methoxy-phenyl and a benzene-substituted pyrrole ring at the 7 and 9 positions fused to a pyrimidine ring in a nearly planar fashion [maximum deviation of 0.018 (1) Šfor the fused ring system]. A methyl group at the 5 position is also in the plane of the hetero cyclic system. The dihedral angle between the mean planes of the benzene and 4-methoxy-phenyl rings is 40.4 (2)°. The dihedral angles between the mean planes of the pyrimidine and the benzene and 4-methoxy-phenyl rings are 15.6 (5)° and 52.6 (7)°, respectively. A weak intra-molecular C-H⋯N hydrogen bond inter-action, which forms an S(7) graph-set motif, helps to establish the relative conformations of the tetrazolo and benzene rings. In the crystal, weak inter-molecular C-H⋯O, C-H⋯π and π-π stacking inter-actions [centroid-centroid distances = 3.5270 (16), 3.5113 (16), 3.7275 (17) and 3.7866 (17) Å] link the mol-ecules into a two-dimensional array obliquely parallel to (101) and propagating along the b axis.