Gramicidin S hydrochloride [cyclic(–Val–Orn–Leu–d-Phe–Pro–)₂·2HCl] was crystallized in the space group P2₁2₁2 with cell parameters a = 34.988(1)Å, b = 23.381(1)Å, c = 18.8662(5)Å, V = 15433(1)ų and Z = 8. The diffraction data were collected at 1.1 Å resolution. The structure refinements converged at R = 0.165. Two independent peptide molecules were found, which formed antiparallel-sheets having intramolecular hydrogen bonds between Val and Leu residues. The peptides turned at the d-Phe–Pro moieties, and the conformations were defined as type II’ β-turn. Adjacent molecules formed an angle of 49° and were arranged side-by-side to form a β-sheet along the c-axis.

The structure of tertiarybutyl ammonium bis[naphthalene-2,3-diolato)borate] dimethyl sulfoxide solvate was determined by X-Ray crystallography. The compound crystallized in a triclinic system, and was characterized to be in the space group P-1, with cell parameters a = 9.6282(9)Å, b = 11.0221(9)Å, c = 13.0273(12)Å, α = 91.050(4)⁰, β = 109.419(4)⁰, γ = 94.574(2)⁰, Z = 2, and V = 1298.2(2)ų. The crystal packing is governed by intermolecular and intramolecular N–H···O hydrogen bonds. The B atom takes a distorted tetrahedral geometry with four O atoms of naphthalene-2,3-diolato ligands.

The structure of the dinuclear Fe(II) complex [Fe₂(OH)₂(L^Bu)]²⁺ (1) was determined by X-ray crystallography, where L^Bu is N,N,N′,N′-tetrakis(6-methyl-2-pyridylmethyl)-1,4-diaminobutane. The compound crystallizes in a monoclinic space group, P2₁/a, with a = 21.678(3), b = 16.3791(16), c = 22.447(3)Å, β = 111.522(2)°, Z = 4, V = 7414.5(14)ų. The R1 [I > 2σ(I)] and wR2 (all data) values were 0.0474 and 0.1274, respectively, for all 16779 independent reflections. The complex has a bis(μ-hydroxo)diiron core structure.

The crystal structure of 2-(4-methylimidazolin-2-yl)phenol was determined by X-ray crystallography. Single crystals were obtained from a racemic mixture of the title compound by the slow evaporation of an ethanol solution. The compound crystallizes in the orthorhombic chiral space group Pna2₁ and Z = 4 with cell parameters a = 12.595(4)Å, b = 6.2362(18)Å, c = 11.529(3)Å, V = 905.6(5)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0460 and 0.0997, respectively, for all 1953 independent reflections. In the crystal, the compound exists as zwitterionic form. An intermolecular hydrogen-bond was formed between the phenolate-O atom and N–H atom, which resulted in the formation of a 1D chain structure.

The structure of the dinuclear Fe(II) complex [Fe₂(Ph-bimp)(PhCO₂)(CH₃CN)](BF₄)₂·2CH₃CN·3CH₃CH₂OH (1) was determined by X-ray crystallography, where Ph-bimp is 2,6-bis[bis{2-(1-methyl-4,5-diphenylimidazolyl)methyl}aminomethyl]-4-methylpenolate. The compound crystallizes in a monoclinic space group Cc with a = 15.5690(10), b = 23.8260(8), c = 24.821(1)Å, β = 95.3460(3)°, Z = 4, V = 9167.2(10)ų. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0336 and 0.0850, respectively, for all 16812 independent reflections. The complex has a μ-phenoxo-μ-benzoate-bridged diiron(II) core structure.

The crystal structure of the Zn(II) complex with 2-(2-imidazolinyl)phenolate was determined by X-ray crystallography. The title compound was synthesized by reacting ZnCl₂ and 2-(2-imidazolinyl)phenolate in methanol. The compound crystallized in the monoclinic space group P2₁/n and Z = 4 with cell parameters a = 12.0318(15)Å, b = 7.6706(10)Å, c = 18.617(2)Å, β = 105.089(2)°, V = 1658.9(14)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0454 and 0.1096, respectively, for all 4047 independent reflections. The title compound was found to take a pseudo-tetrahedral coordination geometry in the bis-bidentate fashion. In the crystal, a 1D chain structure was formed by intermolecular hydrogen-bonds between the coordinating phenolate–O atom and a noncoordinating N–H bond.

The structure of the dinuclear Fe(III) complex [Fe₂(6Me₂-BPP)₂(OH)₂](NO₃)_1.9553·Br_0.0447·8H₂O (1) was determined by X-ray crystallography, where 6Me₂-BPP is N,N-bis(6-methyl-2-pyridylmethyl)-3-aminopropionate. The compound crystallizes in a triclinic space group, P1, with a = 10.3845(15), b = 11.1976(15), c = 20.389(4)Å, α = 82.119(10), β = 85.340(10), γ = 68.871(7)°, Z = 2, V = 2189.3(6)ų. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0342 and 0.0972, respectively, for all 9586 independent reflections. The complex has a bis(μ-hydroxo)diiron core structure.

A cobalt(II) complex with two 2,2′-bipyridine (bpy) and two trifluoromethanesulfonato (OTf⁻) ligands, cis-[Co^II(OTf )₂(bpy)₂], was prepared, and the crystal structure at 173 K was elucidated by the single-crystal X-ray diffraction method. The complex crystallized in the monoclinic space group C2/c with a = 9.90587(16), b = 14.2978(2), c = 18.6626(3)Å, α = 90, β = 101.6670(17), γ = 90°, Z = 4, V = 2588.61(7)ų. The R1 and wR2 values were 0.0397 and 0.1016, respectively, for 2377 reflections.

The structure of bis(2-methoxy-6-((Z)-(p-tolylimino)methyl)phenoxy)palladium crystallized in a monoclinic system and was characterized thus: P2₁/c, a = 13.0221(14), b = 11.6615(13), c = 8.4898(9)Å, β = 97.327(4)°, Z = 2, V = 1278.7(2)ų. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F² to final values of R1 = 0.0349 [I > 2σ(I)] and wR2 = 0.0824. The molecules have two-fold symmetry about the centre Pd1 atom. Two ligands were coordinated to the Pd1 atom via oxygen and nitrogen atoms in a bidentate manner to form a square-planar geometrical structure.

The structure of the dinuclear Fe(II) complex [Fe₂(OH)₂(L)₂](ClO₄)₂ (1) was determined by X-ray crystallography, where L is bis(1-methyl-2-phenyl-4-imidazolylmethyl)benzylamine. The compound crystallizes in a monoclinic space group, P1, with a = 11.007(2), b = 11.5591(12), c = 12.534(2)Å, α = 63.254(12), β = 86.458(19), γ = 79.581(7)°, Z = 1, V = 1400.4(4)ų. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.00328 and 0.0862, respectively, for all 6735 independent reflections. The complex has a bis(μ-hydroxo)diiron core structure.

A mononuclear iron(III) complex, [Fe(dmso)₆][PF₆]₃ [hexakis(dimethylsulfoxide-κO)iron(III) tris(hexafluoridophosphate)], was synthesized, and characterized by a single-crystal X-ray method. The compound crystallized in the trigonal space group R3 and Z = 3 with cell parameters a = 11.598(8)Å, c = 25.367(18)Å, V = 2955(4)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values were 0.0509 and 0.1565, respectively, for all 1630 independent reflections. The symmetry of the complex cation was found to belong to the S₆ point group, possessing a trigonally compressed octahedral coordination geometry with an O₆ donor set.

The title compound, 1,3-bis(5-chloro-3-methoxysalicylideneamino)-2-propanol trihydrate, was synthesized and the crystal structure was determined by the single-crystal X-ray diffraction method at 90 K. It crystallizes in the monoclinic space group P2/c with a = 18.098(3)Å, b = 4.3275(8)Å, c = 14.572(3)Å, β = 104.283(3)°, V = 1106.0(3)ų, D_x = 1.445 g/cm³, and Z = 2. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0734 and 0.2140, respectively, for all 2540 independent reflections. The molecule takes a bended structure at the central carbon atom with a dihedral angle between the two approximate planes of 74.71°.

The crystal structure of (2,2′-bipyridine)(N-(1-naphthyl)methyl-1,3-propanediamine)platinum(II) chloride was determined by X-ray crystallography. The title complex crystallized in the monoclinic space group C2/c and Z = 8 with cell parameters a = 23.3026(14)Å, b = 17.4118(12)Å, c = 12.3816(7)Å, β = 109.032(8)°, V = 4749.1(6)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0242 and 0.0490, respectively, for all 5435 independent reflections. In the crystal structure, disorder was observed for the N-(1-naphthyl)methyl-1,3-propanediamine moiety. Hydrogen-bond network was formed between the (2,2′-bipyridine)(N-(1-naphthyl)methyl-1,3-propanediamine)platinum(II) cations and chloride anions.

The crystal structure of tetracoordinated a zinc(II) complex with two 2-(1,4,5,6-tetrahydropyrimidin-2-yl)phenolate ligands was determined by X-ray crystallography. The title compound was synthesized by a reaction of ZnCl₂ and 2-(1,4,5,6-tetrahydropyrimidin-2-yl)phenolate in ethanol. The compound crystallizes in the monoclinic space group C2/c and Z = 4 with cell parameters a = 13.7667(14)Å, b = 11.4666(11)Å, c = 12.2213(12)Å, β = 116.242(2)°, V = 1730.4(3)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0401 and 0.1064, respectively, for all 2104 independent reflections. The crystal structure was solved as a two-component twin. The title compound was found to take a pseudo-tetrahedral geometry with the bis-bidentate coordination mode. The non-coordinating N–H bond in the ligands formed intermolecular hydrogen-bonds to construct one-dimensional chain structures.

The crystal structure of [N-(9-anthracenylmethyl)-1,3-propanediamine](2,2′-bipyridine)platinum(II) chloride was determined by X-ray crystallography. The title complex crystallized in the monoclinic space group P21/c and Z = 4 with cell parameters a = 11.2466(7)Å, b = 17.3553(10)Å, c = 13.7027(9)Å, β = 100.501(2)°, V = 2629.8(3)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0271 and 0.0619, respectively, for all 5995 independent reflections. The intramolecular π-π stacking interaction was observed between the anthracene and the bipyridine. In the crystal packing structure, the intermolecular π-π stacking interaction was observed.

The structure of β(Nprim)-[Co(aet)(trien)]Cl₂ [aet: 2-aminoethanethiolate, trien: triethylenetetramine] was synthesized and characterized by single-crystal X-ray analysis. The compound crystallizes in a triclinic space group P1 with a = 8.279(3), b = 10.673(5), c = 10.696(4)Å, α = 64.70(3), β = 95.76(3), γ = 91.17(4)°, V = 849.9(6)ų, D_calcd = 1.552 g/cm³, Z = 2. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0385 and 0.1145, respectively, for all 3913 independent reflections. Central cobalt(III) atoms have an approximate octahedral geometry and are coordinated by five nitrogen atoms and one sulfur atom. The obtained compound from the major eluate is in the β(Nprim) form in which the sulfur atom is present in the trans position to a primary nitrogen atom of the triethylenetetramine (trien).

The structure of 7-(dimethylamino)-3-phenylcoumarin (1) was determined by X-ray crystallography. It crystallizes in the space group P2₁/a (#14) with cell parameters a = 15.290(3)Å, b = 6.5298(14)Å, c = 27.551(6)Å, β = 105.054(13)°, Z = 8, and V = 2656.2(9)ų. The R1 (I > 2σ(I)) and wR2 (all data) values are 0.0591 and 0.1864, respectively. The structure of 1 contains two crystallographically independent molecules (1A and 1B). The coumarin rings make angles of 35.2(1)° for 1A and 33.4(1)° for 1B with phenyl groups. Intermolecular C–H···O, C–H···π, and π···π interactions were observed in the crystal lattice.

The structure of catena-((μ₈-benzene-1,2,4,5-tetracarboxylato)-triaqua-calcium(II)-copper(II)) (I) was determine by X-ray crystallography. There is half of one benzene-1,2,4,5-tetracar-boxylate tetra-anion (BTA⁴⁻), each half Cu(II) and Ca(II) dications, and one and a half coordinated water molecules in its asymmetric unit. The compound crystallizes in the monoclinic C2/c space group and was characterized as follows: a = 14.1365(13)Å, b = 13.2077(12)Å, c = 8.8865(8)Å, b = 126.365(3)°, V = 1336.1(2)ų, Z = 4, T = 150(2)K. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F² to final values of R₁ = 0.0779 and wR₂ = 0.1666.

The structure of a hexanuclear silver(I) complex with six quinoline-2-thiolato (2-qnt⁻) ligands [Ag₆(C₉H₆NS)₆] (1) has been synthesized and characterized. Complex 1 crystallized in a triclinic space group P-1 (No. 2) with a = 8.064(6), b = 13.480(3), c = 13.573(5)Å, α = 113.528(15)°, β = 104.24(3)°, γ = 100.46(3)°, V = 1244.5(11)ų, Z = 1, T = 150 K. The R1 [I > 2σ(I)] and wR2(all data) values are 0.032 and 0.089, respectively, for all 4437 independent reflections. The complex has a paddle-wheel-like structure with a trigonally distorted Ag₆ octahedral metal core.

The crystal structure of the title compound, 6-aza-3,9-dithiaundecane hydrochloride (N-H-ATU·HCl), was determined by X-ray crystallography. The hydrogen-bonding networks in the crystal extend along with the b and c axes to form a 2D-triple-sheet, in which the Cl⁻ ions put between two (N-H₂-ATU)⁺ sheets. The compound was crystallized in an orthorhombic system as: Pccn, a = 25.0091(4), b = 5.39364(10), c = 9.37759(19)Å, Z = 4, V = 1264.94(4)ų. The R1 and wR2 values were 0.0341 and 0.0880, respectively, for 1162 reflections.

The X-ray crystal structure of 6,7-dihydro-5a,7a,13,14-tetraaza-pentaphene-5,8-dione, a potential antiproliferative agent on A2058 melanoma cells, was established. It crystallizes in the monoclinic space group P2₁/c with cell parameters a = 24.879(3)Å, b = 6.868(2)Å, c = 26.068(4Å, α = 90, β = 110.49(2), γ = 90, V = 4172.4(15)ų and Z = 12. The crystal structure was refined to final values of R1 = 0.1353 and wR2 = 0.1936. An X-ray crystal structure analysis revealed that each molecule features intermolecular C_Arom.–H···O hydrogen bonds to form trimers.

The reaction of a methanol solution containing Co(BF₄)₂·6H₂O and (2-pyridylmethyl)bis(2-quinolylmethyl)amine (pbqa) afforded a dinuclear cobalt(II) complex, [Co₂(μ-F)₂(pbqa)₂](BF₄)₂, where the two metal centers are doubly bridged by two fluoride ions. BF₄⁻ is a fluoride source. A temperature-dependent magnetic susceptibility measurement reveal that a strong spin orbit contribution with a zero-field splitting effect of two high-spin Co(II) ions. It crystallizes in the monoclinic space group C2/c with a = 24.9600(9)Å, b = 11.1533(3)Å, c = 20.0575(6)Å, α = 90°, β = 109.439(4)°, γ = 90°, V = 5265.4(3)ų, D_calc = 1.535 g/cm³, and Z = 4. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0403 and 0.1018, respectively, for all 7897 independent reflections.

The cocrystal structure of diethyl 2,5-bis{[4-(ethoxycarbonyl)phenyl]amino}terephthalate (PDA) and diethyl (3E,6E)-3,6-bis{[4-(ethoxycarbonyl)phenyl]amino}cyclohexa-1,4-diene-1,4-dicarboxylate (QDI) was determined by X-ray crystallography. The compound crystallizes in a triclinic system and was characterized thus: P-1, a = 8.6778(3)Å, b = 13.0702(4)Å, c = 13.5152(4)Å, α = 79.1570(15)°, β = 71.8459(15)°, γ = 72.5962(16)°, Z = 1, V = 1382.28(7)ų. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.078 and 0.190, respectively, for all 4179 independent reflections. In the crystal, a polymeric alternating arrangement of PDA and QDI exists through a network of π-π interactions, wherein both components adopt an anti-conformation of the π-conjugated backbones.

A mononuclear iron(II) complex, [Fe(phen)₃][PF₆]₂ [tris(1,10-phenanthroline-κ²N, N′)iron(II) tris(hexafluoridophosphate)], was synthesized, and characterized by a single-crystal X-ray method. The compound crystallized in the monoclinic space group C2/c and Z = 8 with cell parameters a = 36.529(4)Å, b = 15.8597(16)Å, c = 11.7747(12)Å, β = 100.528(2)°, V = 6706.7(12)ų. The R₁ [I > 2σ(I)] and wR₂ (all data) values were 0.0631 and 0.1787, respectively, for all 8068 independent reflections. Despite the symmetrical tris(1,10-phenanthroline) environment, the symmetry around the iron(II) ion was rather low with a distorted octahedral coordination geometry.

One of the earliest charge-transfer complexes synthesized is dinaphtho[2,1,1′,2′]furan picrate, which was first reported in 1905. Here, we synthesized and structurally characterized this complex. This complex has a stoichiometric ratio of 1:1 and a melting point of 161.4°C. The bond distances and angles of the component molecules are within the range of those reported for structurally similar neutral compounds and picric acid. These characteristics taken together with the feature that the infrared spectra of the complex can be superimposed with those of its component molecules, it is concluded that this complex is in the neutral ground state. The component molecules are stacked alternately, producing a ···DA–DA–DA··· one-dimensional column in the b-axis direction. The compound crystallizes in a monoclinic system and was characterized thus: P2₁/c, a = 10.0912(18), b = 7.5548(11), c = 27.919(5)Å, β = 94.047(4)°, Z = 4, V = 2123.2(6)ų. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F² to final values of R1 = 0.0502 and wR2 = 0.1190.