Cobalt(III) complexes of monobenzyl-cyclam macrocycle derivatives

Two dichlorocobalt(III) complexes of ligands L1 and L3 in which 4-R-benzyl moieties (R=NO2,NH2) are either N-bonded (1-position) or C-bonded (6-positi on) to the 1,4,8,11-tetraazacyclotetradecane (cyclam) macrocycle have been prepared and characterized: L1 = 1-(4-nitrobenzyl) cyclam; L3 = 6-(4-aminob enzyl) cyclam. The X-ray crystal structure of trans-[Co(L1)Cl-2]ClO4 {M 564 .73, monoclinic P2(1)/c (No. 14); a 13.1987(14), b 11.7701(11), c 14.9305( 4) Angstrom, beta 97.692(9)degrees; V 2298.6(4) Angstrom (3). Z 4. D-c 1.63 2 g cm(-3); final R1 0.0282, wR2 0.0671 (3438 refls F-o > 4 sigmaF(o)), [fo r all 4022 unique data R1 0.0366, wR2 0.0717]} shows a distorted octahedral stereochemistry at Co, with a Cl-Co-Cl angle of 174 degrees. The X-ray cry stal structure of trans-[Co(L3)Cl-2]Cl.H2O {M 488.77; monoclinic P2(1)/n (N o. 14); a 10.5781(12), b 13.536(2), c 15.065(3) Angstrom,beta 101.027(13)de grees; V 2117.3(6) Angstrom (3). Z4. D-c 1.207 g cm(-3); final R1 0.0284, w R2 0.0727 (5296 refls F-o > 4 sigmaF(o)), [for all 7928 data R1 0.0345, wR2 0.0762]} shows a less distorted octahedral stereochemistry. The Cl-Co-Cl a ngle is essentially linear, 179.80(14)degrees. The cyclam moieties in both structures display the trans-III conformation.