Search

The crystal structure of the new double CuII complex salt, [Cu(L)(H2O)2][Cu(L)]Br4·2H2O (L = 3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2O)2]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent molecule. The CuII atom in the first complex exists in a tetragonally distorted octahedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitrogen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu—N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu—O bond length of 2.658 (4) Å. The crystal structure is stabilized by intermolecular hydrogen bonds involving the macrocycle N—H or C—H groups and the O—H groups of water molecules as donor groups, and the O atoms of water molecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100].

The crystal structure of 3,14-dimethyl-2,6,13,17-tetraazatricyclo(16.4.0.07,12)docosane-2-(nitric acid), C20H40N4·2(NO2OH) had been determined using synchrotron radiation at 220 K. The compound crystallized in the space group P21/n of the monoclinic system with two mononuclear formula units in a cell of dimensions a = 9.1930(18), b = 10.120(2), c = 12.979(3) Å and β = 101.06(3)º. The asymmetric unit contains half a centrosymmetric macrocycle and one nitric acid molecule. There were two molecules in the unit cell. In structure of macrocycle, C-C and N-C bond lengths were in the range 1.5198(19) to 1.5367(18) Å and 1.4744(16) to 1.4986 (16) Å, respectively. The NO2OH group has one longer N-O bond of 1.3441(18) Å and two shorter N-O bond of 1.2509(19) Å and 1.2510(19) Å, and O-N-O angles of 126.31(14)º, 117.98(14)º and 115.71(14)º. The N-H···O and N-H···N hydrogen bonds interconnect macrocycle (C20H40N4) with nitric acid molecules while two O-H···O hydrogen bonds link the nitric acid molecule to neighboring nitric acid molecule each other. The molecule was stabilized by forming intermolecular N-H···O, N-H−N and O-H···O hydrogen bonds. Hirshfeld surface analysis by 3D molecular surface contours and 2D fingerprint plots have been used to analyze intermolecular interactions present in the crystal.

In the title complex, [Cu(C22H44N4)(H2O)2][Cu(C22H44N4)]Br4·2H2O, each of the two complex cations lies about an inversion center. The two macrocyclic rings adopt the most stable trans-III configuration. In the crystal, O—H⋯Br, N—H⋯Br, N—H⋯O and C—H⋯O hydrogen bonds connect the complex cations, bromide anions, semi-coordinating H2O ligands and water solvent mol­ecules, forming a one-dimensional network extending parallel [100]., The crystal structure of the new double CuII complex salt, [Cu(L)(H2O)2][Cu(L)]Br4·2H2O (L = 3,14-diethyl-2,6,13,17-tetra­aza­tri­cyclo­[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2O)2]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent mol­ecule. The CuII atom in the first complex exists in a tetra­gonally distorted octa­hedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitro­gen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu—N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu—O bond length of 2.658 (4) Å. The crystal structure is stabilized by inter­molecular hydrogen bonds involving the macrocycle N—H or C—H groups and the O—H groups of water mol­ecules as donor groups, and the O atoms of water mol­ecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100].

The asymmetric unit of the title compound, Ag[Cr(C11H14N2O8)]·3H2O, contains one [Cr(1,3-pdta)]−anion [1,3-pdta is (propane-1,3-diyldinitrilo)tetraacetate], one Ag+cation and three water molecules. The Cr3+ion is coordinated to the four O and two N atoms of the 1,3-pdta ligand, displaying a distorted octahedral geometry. The mean Cr—N and Cr—O bond lengths are 2.0727 (17) and 1.9608 (15) Å, respectively. The conformations of the chelate rings were found to be envelope for the glycinates and twist-boat for the six-membered diamine (T) ring. The Ag+cation is surrounded by six O atoms from three non-coordinated carbonyl O atoms of neighbouring 1,3-pdta groups and three water molecules. The crystal structure is stabilized by intermolecular hydrogen bonding involving the water O—H group as donor and the carboxyl O atom as acceptor.

In the title organic–inorganic salt, [CrCl2(tn)2]2[Cr2O7] (tn is propane-1,3-di­amine), the CrIII ions are coordinated by four N atoms from two tn ligands and two chloride ions in a trans geometry, displaying a distorted octa­hedral arrangement. The crystal packing is stabilized by N—H⋯Cl and N—H⋯O hydrogen bonds., The structure of the title compound, [CrCl2(tn)2]2[Cr2O7] (tn = propane-1,3-di­amine; C3H10N2), has been determined from synchrotron data. The asymmetric unit contains one CrIII complex cation and half a [Cr2O7]2− anion. In the complex cation, the CrIII ion is coordinated by the four N atoms of two propane-1,3-di­amine (tn) ligands in the equatorial plane and by two Cl atoms in a trans configuration, displaying a distorted octa­hedral coordination sphere. The two six-membered rings in the complex cation have an anti chair–chair conformation with respect to each other. The mean Cr—N(tn) and Cr—Cl bond lengths are 2.09 (1) and 2.320 (2) Å, respectively. The slightly bent dichromate anion is disordered over two sets of sites (occupancy ratio = 0.7:0.3) and has a staggered conformation. The crystal structure is stabilized by inter­molecular hydrogen bonds involving the NH2 groups of the tn ligands as donors and the O atoms of the [Cr2O7]2− anion and chlorido ligands as acceptors.

In this study, two Cu2+-doped single crystals, [Cu0.02(H1.96L)](ClO4)2 (1) and [Cu0.91(H0.18L)](ClO4)2 (2) (L = 3,14-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.07,12)docosane), were prepared and characterized by elemental and X-ray crystal structural analyses, along with UV–visible, infrared (IR) and electron paramagnetic resonance (EPR) spectroscopies. The asymmetric units of compounds 1 and 2 contain one half of the molecular dication and one doubly disordered perchlorate anion. The macrocyclic ligand in both the Cu2+-doped compounds adopts the most stable trans-III conformation. The Cu–N bond lengths in the range 2.010 (2)–2.055 (3) A are normal, but the long axial Cu1–O3 bonds of 2.836 (3) and 2.729 (3) A for 1 and 2, respectively, may be due to a combination of the Jahn-Teller effect and strong in-plane ligand field. The crystals are stabilized by hydrogen bonds involving the secondary N–H, the N atoms of the macrocycle, and the O atoms of the perchlorate groups.

In the title complex, the Cr3+ ion is coordinated by the four O and two N atoms of the 1,3-pdta ligand, displaying a distorted octa­hedral geometry. The Ag+ cation is surrounded by six O atoms from neighboring 1,3-pdta groups and water mol­ecules., The asymmetric unit of the title compound, Ag[Cr(C11H14N2O8)]·3H2O, contains one [Cr(1,3-pdta)]− anion [1,3-pdta is (propane-1,3-diyldi­nitrilo)­tetra­acetate], one Ag+ cation and three water mol­ecules. The Cr3+ ion is coordinated to the four O and two N atoms of the 1,3-pdta ligand, displaying a distorted octa­hedral geometry. The mean Cr—N and Cr—O bond lengths are 2.0727 (17) and 1.9608 (15) Å, respectively. The conformations of the chelate rings were found to be envelope for the glycinates and twist-boat for the six-membered di­amine (T) ring. The Ag+ cation is surrounded by six O atoms from three non-coordinated carbonyl O atoms of neighbouring 1,3-pdta groups and three water mol­ecules. The crystal structure is stabilized by inter­molecular hydrogen bonding involving the water O—H group as donor and the carboxyl O atom as acceptor.

Chromium is the seventh most abundant element on earth. 1 It occurs in various oxidation states ranging from Cr(II) to Cr(VI) with trivalent and hexavalent states being the most stable and common in terrestrial environments. The coordination chemistry of chromium(III) complexes is relevant to third generation solar photoconversion scheme. 2 The geometrical isomerism and conformation in transition metal complexes with mixed ligands are very important in the medical application, and likely to be a major factor in determining the antiviral activity and its side-effect. 3,4 2,2Dimethyl-1,3-propanediamine (Me2tn, Fig. 1) is a bidentate ligand that can coordinate to the central metal ion by forming six-membered chelate ring with a chair conformation. The trans-[Cr(Me2tn)2(OH)(H2O)] 2+ can adopt either the trans or cis geometric isomer. In addition, two different kinds of conformation with respect to the chelate rings of Me2tn occur in the trans isomer, as shown in the bottom of Figure 1. The carbon atoms of the two chelate rings of the two conformers may be on the same side (syn conformer) or on the opposite side (anti conformer) of the coordination plane. In the case of trans-anti/syn-[Cr(Me2tn)2Cl2]Cl, trans-anti/ syn-[Cr(Me2tn)2Br2]2Br2·HClO4·H2O and trans-anti/syn[Cr(Me2tn)2Br2]Br, independent syn and anti conformational isomers were found within the same crystals. 5-7 However, structural analyses of trans-anti-[Cr(Me2tn)2(NCS)2]NCS·1/2H2O, trans-anti-[Cr(Me2tn)2Cl2]ClO4, and trans-anti-[Cr(Me2tn)2Cl2]2ZnCl4 indicated that two chelate rings of Me2tn ligands were only in the anti chair-chair conformation. 6-9 The different conformations of the two sixmembered chelate rings of Me2tn ligands may be dependent on the crystallographic disorder, packing forces, hydrated molecules and counter anions in the crystals. The factors which determine the stability of these geometric conformations are subtle and complicated. 5-9 X-ray crystallography is generally used to establish the presence of either conformation but the syn or anti conformer of the six-membered chelate rings cannot be readily discriminated by infrared and visible absorption spectroscopy. The elucidation of the factors that stabilize the either the syn- or anti-conformation in these complex cations continues to be of interest. Here we report the synthesis, crystal structure and spectroscopic properties of the trans-anti-[Cr(Me2tn)2(OH)(H2O)](ClO4)2 with the purpose of elucidating the influence of Odonor ligands occupying the axial positions and counter anions, on the geometry and the conformation referring to the position of the carbon atoms of the Me2tn chelate rings with respect to the equatorial coordination plane.

The CrIII atoms in the title compound show a distorted octa­hedral coordination with four N atoms of the cyclam ligand in the equatorial plane and two N-coordinated NCS− groups in axial positions. The macrocyclic ligands adopt trans-III configurations. The crystal packing is stabilized by N—H⋯S and N—H⋯Cl hydrogen bonds., The structure of the title compound, [Cr(NCS)2(cyclam)]2[ZnCl4] (cyclam = 1,4,8,11-tetra­aza­cyclo­tetra­decane, C10H24N4), has been determined from synchrotron data. The asymmetric unit contains two independent halves of the CrIII complex cations and half of a tetra­chlorido­zincate anion. In each complex cation, the CrIII atom is coordinated by the four N atoms of the cyclam ligand in the equatorial plane and by two N-bound NCS− anions in a trans axial arrangement, displaying a distorted octa­hedral geometry with crystallographic inversion symmetry. The mean Cr—N(cyclam) and Cr—N(NCS) bond lengths are 2.065 (4) and 1.995 (6) Å, respectively. The macrocyclic cyclam moieties adopt centrosymmetric trans-III configurations with six- and five-membered chelate rings in chair and gauche configurations, respectively. The [ZnCl4]2− anion, which lies about a twofold rotation axis, has a slightly distorted tetra­hedral geometry. The crystal packing is stabilized by hydrogen-bonding inter­actions between the N—H groups of the cyclam ligands, the S atoms of the NCS− groups and the Cl− ligands of the anion.

The structure of [CrF(2)([15]aneN(4))]ClO(4).H(2)O ([15]aneN(4)=1,4,8,12-tetraazacyclopentadecane) has been determined by a single-crystal X-ray diffraction study at 173 K. The complex crystallizes in the space group P1- of the triclinic system with two mononuclear formula units in a cell of dimensions a=9.6117(7) A, b=10.2882(7) A, c=11.0001(7) A and alpha=99.7570(10) degrees, beta=105.6080(10) degrees and gamma=113.7130(10) degrees. The complex cation unit has its central Cr atom in an octahedral coordination with four nitrogen atoms and two fluorine atoms in a trans position. Three six-membered and one five-membered chelate rings of the [15]aneN(4) ligand are in a chair-twist(skew)-chair-gauche conformation sequence. The gauche five-membered ring is disordered with the twist six-membered ring opposite. The four H atoms in the chiral N atoms have the trans-II (CTCg) type configuration. The mean Cr-N and Cr-F bonds are 2.095(2) and 1.8752(13) A, respectively. The IR and visible spectral properties are consistent with the result of X-ray crystallography. The resolved band maxima of the electronic d-d spectrum are fitted with secular determinant for quartet state energy of d(3) configuration in tetragonal field including configurational but neglecting spin-orbit coupling. It is confirmed that the fluoride has strong sigma- and pi-donor properties toward the chromium(III) ion and the nitrogen atoms of the [15]aneN(4) ligand also have a strong sigma-donor character.

The title salt, Na[CrF2(C5H5N)4]2[ZnCl4]ClO4, consists of two cationic CrIIIcomplexes, an Na+cation, one [ZnCl4]2−anion and one ClO4−anion. The CrIIIatoms are coordinated by four pyridine (py) N atoms and two F atoms in atransarrangement, displaying a distorted octahedral geometry. The mean Cr—N(py) and Cr—F bond lengths are 2.086 (8) and 1.864 (14) Å, respectively. The [ZnCl4]2−anion has a distorted tetrahedral geometry. The most notable feature of the crystal packing is the formation of weak pyridine–perchlorate C—H...O hydrogen bonds, resulting in supramolecular chains along theb-axis direction. The perchlorate anion was disordered over two sets of sites in a 0.868 (3):0.132 (3) ratio.

The crystal structure of [Cr(NCS)2(cyclam)]NCS (cyclam = 1,4,8,11-tetra-aza-cyclo-tetra-deca-ne, C10H24N4) has been determined by using synchrotron radiation at 98 K. The Cr(III) atom is in a slightly distorted octa-hedral environment with four N atoms of the macrocyclic ligand and two N-coordinated NCS(-) anions in cis positions. The average Cr-N(cyclam) and Cr-NCS bond lengths are 2.085 (5) and 1.996 (15) Å, respectively. In the crystal, the uncoordinating SCN(-) anion is hydrogen bonded through N-H⋯S and N-H⋯N inter-actions to neighbouring complex cations.

In the title compound, [Cu(ClO4)2(C20H40N4)], the CuII ion has a tetragonally distorted octahedral environment, with the four N atoms of the macrocyclic ligand in equatorial positions and the O atoms of two perchlorate groups in axial positions. The CuII ion is situated on an inversion centre. The macrocyclic ligand adopts its most stable trans-III conformation. The long axial Cu—O bond is the result of the Jahn–Teller effect. The crystal structure is stabilized by intramolecular hydrogen bonds between secondary N—H and the O atoms of the perchlorate groups.