Triclinic bis-(6-aminopurine)copper(II) tetrahydrate crystallizes in space group PI" with Z=2 and... more Triclinic bis-(6-aminopurine)copper(II) tetrahydrate crystallizes in space group PI" with Z=2 and a= 9-458, b = 10-452, c= 9-410 A and ~= 102-98, ,6= 116.58, y= 79.81. The crystal structure has been established by a three-dimensional single crystal X-ray analysis. The atomic parameters were refined by full-matrix least-squares; the final R is 0.053 for 2614 observed reflections measured on a manually operated diffractometer with Mo K~ radiation. The complex is a dimer and geometrically resembles copper(II) acetate monohydrate. The four atoms closest to the copper ion are situated in the basal plane of an octahedron; two of these are the N(3) atoms in the pyrimidine rings (mean Cu-N(3) distance 2.032 A) and the other two, the N(9) atoms in the imidazole rings (mean Cu-N(9) distance 2.007 A). The copper ion is displaced 0.27 A out of the equatorial plane toward an apical coordinated water molecule (Cu-O, 2.195/~.). The sixth position in the octahedron is occupied by another copper ion at 2.949 A. The structure is disordered and for this reason the geometry of the adenine ligands is less well established. The structure of the complex is discussed in relation to the magnetic properties of the compound.
[(CbHvNs)zCu.4H20]CI2.2H20 crystallizes from water in space group C2/m or C2 with a= 15-482, b=6-... more [(CbHvNs)zCu.4H20]CI2.2H20 crystallizes from water in space group C2/m or C2 with a= 15-482, b=6-894, c= 11"269 ,~, fl= 114.42 °. The structure determination is based on 1239 reflexions collected on a diffractometer with Mo Ke radiation. The structure was refined satisfactorily by full-matrix leastsquares calculations both in C2 and C2/m. Final R is 0-031 in C2/m. In the centrosymmetric space group the complex unit contains both a twofold axis and a mirror plane. The copper ion is coordinated in a (2 + 4) inverted Jahn-Teller distorted octahedral configuration. The adenine base is coordinated through N(7) with a short axial bond, Cu-N(7)=2-008 ~. In the equatorial plane four water molecules are bonded, Cu-O=2.162 ,~. The chloride ion is not coordinated to copper, but is hydrogen bonded to the purine base at C(2) and C(8). The amino group forms bifurcated hydrogen bonds to two of the water molecules in the coordination sphere. Pairs of centrosymmetrically related adenine ligands are hydrogen bonded through N(1) and the amino group.
The DNA binding of a dicationic pyridylimine‐based dicopper(I) metallosupramolecular cylinder is ... more The DNA binding of a dicationic pyridylimine‐based dicopper(I) metallosupramolecular cylinder is reported together with its ability to act as an artificial nuclease. The cylinder binds strongly to DNA; more strongly than the spherical dication [Ru(phen)3]2+ (phen=1,10‐phenanthroline), but more weakly than the corresponding tetracationic cylinders. DNA coiling effects are not observed with this dication, in contrast to the situation with the previously reported tetracationic cylinder involving a similar ligand. Linear dichroism (LD) data suggests that the dicopper cylinder binds in a different orientation from that of the tetracationic iron cylinder. Furthermore, the dicopper cylinder shows DNA‐cleavage activity in the presence of peroxide. Of particular note is that the cylinder displays a marked and unusual ability to cleave both DNA strands at the same site, probably reflecting its dinuclear nature and possibly its mode of binding to the DNA.
In the groove! A tetracationic supramolecular cylinder, [Fe L ] (L=C H N ), with a triple-helical... more In the groove! A tetracationic supramolecular cylinder, [Fe L ] (L=C H N ), with a triple-helical architecture is just the right size to fit into the major groove of DNA and too big to fit into the minor groove. NMR spectroscopic data confirm that the cylinder binds in the major groove. Linear dichroism shows that very low loadings of [Fe L ] have a dramatic bending effect on the DNA and atomic force microscopy images show that this is an intramolecular effect resulting in coils of DNA.
TETRA-~t-BENZOATO-BIS(4-METHYLQUINOLINE)DICOBALT(II) sight into these distances must await the ma... more TETRA-~t-BENZOATO-BIS(4-METHYLQUINOLINE)DICOBALT(II) sight into these distances must await the magnetic References anisotropy studies (Boyd, Davies & Gerloch, 1977).
The binding of Cu(I1) and Mn(I1) to 9-methylpurine has been examined by proton NMR and potentiome... more The binding of Cu(I1) and Mn(I1) to 9-methylpurine has been examined by proton NMR and potentiometric titration. The spin-lattice relaxation rates of ring protons H2, H6 and H8, used as input to the Solomon-Bloembergen equation, give a binding pattern which qualitatively agrees with crystallographic data. At neutral pH Cu(I1) and Mn(I1) binding occurs at both Nl and N7 with a preference for N7 (66%). At acidic pH, where Nl is the predominant protonation site, a further shift towards N7 binding is observed. These results are not in complete agreement with those based on comparison of N 1 /N7 basicity.
A deep-turquoise complex, bis-(6-hydroxypurine)copper(II) chloride trihydrate, crystallizes from ... more A deep-turquoise complex, bis-(6-hydroxypurine)copper(II) chloride trihydrate, crystallizes from an acidic solution containing hypoxanthine and cupric chloride in molar proportions 2" 1. The crystals are triclinic, space group PT, with cell dimensions a=9-858 (2), b= 10.259 (4), c=9.717 (3)/~, 0c = 102.53 (3) °, fl= 89.36 (2) °, 7 = 102"21(3) °. 2313 independent reflexions were measured on a diffractometer using Mo K~ radiation. The final R from full-matrix least-squares refinement is 0" 11. The complex is a centrosymmetric dimer, in which each copper atom has square-pyramidal coordination. Two of the ligand atoms in the basal plane are the N(9) nitrogen atoms in the imidazole rings and the other two the N(3) nitrogen atoms in the pyrimidine rings. The apical position is occupied by a chlorine atom, Cu-CI = 2-431 /~. The copper-copper distance in the dimer is 3.024/~. The molecular dimensions of the hypoxanthine ligands are not determined precisely becauseof disorder in the crystal.
[(C6H6N40)2CuC12.2H20].3H20 crystallizes as deep-blue prisms from an acidic solution. The space g... more [(C6H6N40)2CuC12.2H20].3H20 crystallizes as deep-blue prisms from an acidic solution. The space group is C2/e with a= 16.858, b=8.541, c= 14.293 /~, ,8=91.02 °, Z=4. The structure determination is based on diffractometer data measured with Nb-filtered Mo K~ radiation. Final R is 0.027 for the 2029 observed reflexions. The copper ion is located at a centre of symmetry and binds to the purine ring through nitrogen N(7); Cu-N = 2.054/~. The copper coordination is (4 + 2) with a pair of centrosymmetrically related water molecules completing the equatorial coordination, Cu-O= 1.972 A, and the axial sites occupied by chloride ions, Cu-C1=2.787 ~. The water molecules in the coordination sphere form intramolecular hydrogen bonds to the carbonyl substituent on C(6).
The reaction of I-phenyl-2,3,3-trichlorocyclopropene (2a) with KOt-Bu to give phenylhydroxycyclop... more The reaction of I-phenyl-2,3,3-trichlorocyclopropene (2a) with KOt-Bu to give phenylhydroxycyclopropenone was carried out according to the method of Farnum, Chickos, and Thurston. lo The product was obtained in yields of 1-12x as fluffy light yellow needles, mp 244-246" (crystallized from acetonitrile). The ultraviolet spectrum exhibited an absorption maximum at 248 mp in strong acid (5z HCI) and at 256 mp in strong base (5z NaOH). The infrared spectrum (Nujol mull) showed broad, rounded absorption maxima at 1610, 1350, and 1080 cm-1, along with strong peaks at 770 and 690 cm-1. All of the above properties are consistent with those reported for phenylhydroxycyclopropenone.O> lo Reaction of l-pFluorophenyl-2,3,3-trichlorocyclopropene with CF8COOAg. Eleven grams of CFsCOOAg (50 mmol) was added to 300 ml of anhydrous ether in a 2-necked, 5Wml round-bottomed flask, equipped with a stirrer and immersed in an ice-water bath. Compound 2b dissolved in 10 ml of ether, was added dropwise to the ethereal mixture with vigorous stirring. The mixture imrnediately turned milky due to the precipitation of AgCI. The ice-water bath was removed and stirring was continued for 2 hr. The AgCl was filtered from the solution by the use of a Biichner funnel with filter cell; 4.3 g (30 mmol) was collected. The ethereal solution was washed with 3 5Gml portions of water, dried over CaCI2, filtered, and concentrated by rotary evaporation, leaving an ofwhite pasty solid. Hot cyclohexane was added and the solution filtered while hot. In this manner, T.0 g of unreacted CFaCOOAg (14 mmol) was collected on the filter. Upon cooling the filtrate, a white solid crystallized. This was filtered to give 1.58 g (7.9 mmol; 4973 of 14b, mp 144-145', infrared spectrum identical with that of 14b prepared as described above.
Journal of Molecular Structure-theochem, Oct 1, 1987
SCF ab initio computations with good quality basis sets are reported for imidazole complexes of L... more SCF ab initio computations with good quality basis sets are reported for imidazole complexes of Li+ and Cu+. An energy vs. bonding angle curve is obtained and the results are compared with crystal structure data of metal-purine complexes.
Tienda online donde Comprar Metal Complexes - DNA Interactions al precio 136,08 € de Nick Hadjili... more Tienda online donde Comprar Metal Complexes - DNA Interactions al precio 136,08 € de Nick Hadjiliadis | Einar Sletten, tienda de Libros de Medicina, Libros de Quimica - Quimica
Triclinic bis-(6-aminopurine)copper(II) tetrahydrate crystallizes in space group PI" with Z=2 and... more Triclinic bis-(6-aminopurine)copper(II) tetrahydrate crystallizes in space group PI" with Z=2 and a= 9-458, b = 10-452, c= 9-410 A and ~= 102-98, ,6= 116.58, y= 79.81. The crystal structure has been established by a three-dimensional single crystal X-ray analysis. The atomic parameters were refined by full-matrix least-squares; the final R is 0.053 for 2614 observed reflections measured on a manually operated diffractometer with Mo K~ radiation. The complex is a dimer and geometrically resembles copper(II) acetate monohydrate. The four atoms closest to the copper ion are situated in the basal plane of an octahedron; two of these are the N(3) atoms in the pyrimidine rings (mean Cu-N(3) distance 2.032 A) and the other two, the N(9) atoms in the imidazole rings (mean Cu-N(9) distance 2.007 A). The copper ion is displaced 0.27 A out of the equatorial plane toward an apical coordinated water molecule (Cu-O, 2.195/~.). The sixth position in the octahedron is occupied by another copper ion at 2.949 A. The structure is disordered and for this reason the geometry of the adenine ligands is less well established. The structure of the complex is discussed in relation to the magnetic properties of the compound.
[(CbHvNs)zCu.4H20]CI2.2H20 crystallizes from water in space group C2/m or C2 with a= 15-482, b=6-... more [(CbHvNs)zCu.4H20]CI2.2H20 crystallizes from water in space group C2/m or C2 with a= 15-482, b=6-894, c= 11"269 ,~, fl= 114.42 °. The structure determination is based on 1239 reflexions collected on a diffractometer with Mo Ke radiation. The structure was refined satisfactorily by full-matrix leastsquares calculations both in C2 and C2/m. Final R is 0-031 in C2/m. In the centrosymmetric space group the complex unit contains both a twofold axis and a mirror plane. The copper ion is coordinated in a (2 + 4) inverted Jahn-Teller distorted octahedral configuration. The adenine base is coordinated through N(7) with a short axial bond, Cu-N(7)=2-008 ~. In the equatorial plane four water molecules are bonded, Cu-O=2.162 ,~. The chloride ion is not coordinated to copper, but is hydrogen bonded to the purine base at C(2) and C(8). The amino group forms bifurcated hydrogen bonds to two of the water molecules in the coordination sphere. Pairs of centrosymmetrically related adenine ligands are hydrogen bonded through N(1) and the amino group.
The DNA binding of a dicationic pyridylimine‐based dicopper(I) metallosupramolecular cylinder is ... more The DNA binding of a dicationic pyridylimine‐based dicopper(I) metallosupramolecular cylinder is reported together with its ability to act as an artificial nuclease. The cylinder binds strongly to DNA; more strongly than the spherical dication [Ru(phen)3]2+ (phen=1,10‐phenanthroline), but more weakly than the corresponding tetracationic cylinders. DNA coiling effects are not observed with this dication, in contrast to the situation with the previously reported tetracationic cylinder involving a similar ligand. Linear dichroism (LD) data suggests that the dicopper cylinder binds in a different orientation from that of the tetracationic iron cylinder. Furthermore, the dicopper cylinder shows DNA‐cleavage activity in the presence of peroxide. Of particular note is that the cylinder displays a marked and unusual ability to cleave both DNA strands at the same site, probably reflecting its dinuclear nature and possibly its mode of binding to the DNA.
In the groove! A tetracationic supramolecular cylinder, [Fe L ] (L=C H N ), with a triple-helical... more In the groove! A tetracationic supramolecular cylinder, [Fe L ] (L=C H N ), with a triple-helical architecture is just the right size to fit into the major groove of DNA and too big to fit into the minor groove. NMR spectroscopic data confirm that the cylinder binds in the major groove. Linear dichroism shows that very low loadings of [Fe L ] have a dramatic bending effect on the DNA and atomic force microscopy images show that this is an intramolecular effect resulting in coils of DNA.
TETRA-~t-BENZOATO-BIS(4-METHYLQUINOLINE)DICOBALT(II) sight into these distances must await the ma... more TETRA-~t-BENZOATO-BIS(4-METHYLQUINOLINE)DICOBALT(II) sight into these distances must await the magnetic References anisotropy studies (Boyd, Davies & Gerloch, 1977).
The binding of Cu(I1) and Mn(I1) to 9-methylpurine has been examined by proton NMR and potentiome... more The binding of Cu(I1) and Mn(I1) to 9-methylpurine has been examined by proton NMR and potentiometric titration. The spin-lattice relaxation rates of ring protons H2, H6 and H8, used as input to the Solomon-Bloembergen equation, give a binding pattern which qualitatively agrees with crystallographic data. At neutral pH Cu(I1) and Mn(I1) binding occurs at both Nl and N7 with a preference for N7 (66%). At acidic pH, where Nl is the predominant protonation site, a further shift towards N7 binding is observed. These results are not in complete agreement with those based on comparison of N 1 /N7 basicity.
A deep-turquoise complex, bis-(6-hydroxypurine)copper(II) chloride trihydrate, crystallizes from ... more A deep-turquoise complex, bis-(6-hydroxypurine)copper(II) chloride trihydrate, crystallizes from an acidic solution containing hypoxanthine and cupric chloride in molar proportions 2" 1. The crystals are triclinic, space group PT, with cell dimensions a=9-858 (2), b= 10.259 (4), c=9.717 (3)/~, 0c = 102.53 (3) °, fl= 89.36 (2) °, 7 = 102"21(3) °. 2313 independent reflexions were measured on a diffractometer using Mo K~ radiation. The final R from full-matrix least-squares refinement is 0" 11. The complex is a centrosymmetric dimer, in which each copper atom has square-pyramidal coordination. Two of the ligand atoms in the basal plane are the N(9) nitrogen atoms in the imidazole rings and the other two the N(3) nitrogen atoms in the pyrimidine rings. The apical position is occupied by a chlorine atom, Cu-CI = 2-431 /~. The copper-copper distance in the dimer is 3.024/~. The molecular dimensions of the hypoxanthine ligands are not determined precisely becauseof disorder in the crystal.
[(C6H6N40)2CuC12.2H20].3H20 crystallizes as deep-blue prisms from an acidic solution. The space g... more [(C6H6N40)2CuC12.2H20].3H20 crystallizes as deep-blue prisms from an acidic solution. The space group is C2/e with a= 16.858, b=8.541, c= 14.293 /~, ,8=91.02 °, Z=4. The structure determination is based on diffractometer data measured with Nb-filtered Mo K~ radiation. Final R is 0.027 for the 2029 observed reflexions. The copper ion is located at a centre of symmetry and binds to the purine ring through nitrogen N(7); Cu-N = 2.054/~. The copper coordination is (4 + 2) with a pair of centrosymmetrically related water molecules completing the equatorial coordination, Cu-O= 1.972 A, and the axial sites occupied by chloride ions, Cu-C1=2.787 ~. The water molecules in the coordination sphere form intramolecular hydrogen bonds to the carbonyl substituent on C(6).
The reaction of I-phenyl-2,3,3-trichlorocyclopropene (2a) with KOt-Bu to give phenylhydroxycyclop... more The reaction of I-phenyl-2,3,3-trichlorocyclopropene (2a) with KOt-Bu to give phenylhydroxycyclopropenone was carried out according to the method of Farnum, Chickos, and Thurston. lo The product was obtained in yields of 1-12x as fluffy light yellow needles, mp 244-246" (crystallized from acetonitrile). The ultraviolet spectrum exhibited an absorption maximum at 248 mp in strong acid (5z HCI) and at 256 mp in strong base (5z NaOH). The infrared spectrum (Nujol mull) showed broad, rounded absorption maxima at 1610, 1350, and 1080 cm-1, along with strong peaks at 770 and 690 cm-1. All of the above properties are consistent with those reported for phenylhydroxycyclopropenone.O> lo Reaction of l-pFluorophenyl-2,3,3-trichlorocyclopropene with CF8COOAg. Eleven grams of CFsCOOAg (50 mmol) was added to 300 ml of anhydrous ether in a 2-necked, 5Wml round-bottomed flask, equipped with a stirrer and immersed in an ice-water bath. Compound 2b dissolved in 10 ml of ether, was added dropwise to the ethereal mixture with vigorous stirring. The mixture imrnediately turned milky due to the precipitation of AgCI. The ice-water bath was removed and stirring was continued for 2 hr. The AgCl was filtered from the solution by the use of a Biichner funnel with filter cell; 4.3 g (30 mmol) was collected. The ethereal solution was washed with 3 5Gml portions of water, dried over CaCI2, filtered, and concentrated by rotary evaporation, leaving an ofwhite pasty solid. Hot cyclohexane was added and the solution filtered while hot. In this manner, T.0 g of unreacted CFaCOOAg (14 mmol) was collected on the filter. Upon cooling the filtrate, a white solid crystallized. This was filtered to give 1.58 g (7.9 mmol; 4973 of 14b, mp 144-145', infrared spectrum identical with that of 14b prepared as described above.
Journal of Molecular Structure-theochem, Oct 1, 1987
SCF ab initio computations with good quality basis sets are reported for imidazole complexes of L... more SCF ab initio computations with good quality basis sets are reported for imidazole complexes of Li+ and Cu+. An energy vs. bonding angle curve is obtained and the results are compared with crystal structure data of metal-purine complexes.
Tienda online donde Comprar Metal Complexes - DNA Interactions al precio 136,08 € de Nick Hadjili... more Tienda online donde Comprar Metal Complexes - DNA Interactions al precio 136,08 € de Nick Hadjiliadis | Einar Sletten, tienda de Libros de Medicina, Libros de Quimica - Quimica
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