COPPER(II) COMPLEXES OF IMIDAZOL-4-YL)METHYLENE)-3,3'-DIAMINODIPROPYLAMINE (2-SUBSTITUENT=H,ME) - DELTA AND DELTA-ENANTIOMORPHS OF THE PROTONATED COMPLEX AND HELICAL STRUCTURE OF THE DEPROTONATED COMPLEX FORMED BY HYDROGEN-BONDS

Copper(II) complexes with the quinquedentate ligands H2Ln (n=1, 2) of the 1:2 condensation products of 3,3'-diaminodipropylamine and each of 4-formylimidazole and 4-formyl-2-methylimidazole have been synthesize d and characterized, where the complexes have the general formula of [ Cu(H2Ln)]X-2 and are abbreviated as 1X(2), and 2X(2) (n=1, 2 for 2-sub stituent = H, Me; X = ClO4, NO3, Cl). X-ray crystal structures of 1(NO 3)(2), and 2(Cl)(2) were determined: 1(NO3)(2), monoclinic, space grou p P2(1)/c (No. 14), a=9.610(4) Angstrom, b=13.463(5) Angstrom, c=15.56 8(5) Angstrom, beta=98.12(3)degrees, and Z=4; 2(Cl)(2), monoclinic, sp ace group P2(1)/n (No. 14), a=9.884(2) Angstrom, b=15.073(3) Angstrom, c=15.295(2) Angstrom, beta=98.57(2)degrees, and Z=4. The complex assu mes Delta or Lambda enantiomorphs due to the spiral arrangement of the quinquedentate ligand around the copper(II) ion, and these Delta and Lambda enantiomorphs of the cation for 1(NO3)(2) and 2(Cl)(2) coexist as the racemic form in the crystals. When the protonated complexes wer e treated with NaOH, the mono-deprotonated complexes with the formula [CuHLn]ClO4, 1'ClO4 (n=1) and 2'ClO4 (n=2), were obtained. Crystal dat a for 1'ClO4: Pbca (No. 61) with a=13.211(3) Angstrom, b=25.387(3) Ang strom, c=10.939(3) Angstrom, and Z=8.; 2'. ClO4, Pbca (No. 61) with a= 16.554(4) Angstrom, b=20.609(4) Angstrom, c=12.423(3) Angstrom, and Z= 8. The structures consist of an electronically monopositive copper(II) complex involving a deprotonated imidazole moiety and a protonated im idazole moiety per molecular unit and a mononegative anion ClO4-, wher e an imidazolate nitrogen atom N(2) of the copper(II) complex is hydro gen bonded to the imidazole nitrogen atom N(6) (* denotes the symmetr y operation of 1/2 + x, 1/2 - y, -z) of the adjacent unit with the hyd rogen bond distance of N(2)...N(6) of 2.842(6) for 1'ClO4 and 2.815(4 ) Angstrom for 2'ClO4 to give a one-dimensional helical structure runn ing along the a-axis. Through the hydrogen bonds, the Delta isomer onl y aggregates with the Delta isomer and the Lambda isomer only aggregat es with the Lambda isomer to give an extended helical chain structure described as Delta Delta Delta Delta Delta... or Lambda Lambda Lambda Lambda Lambda..., respectively.