Molecular structure of dichloro(1,4,7-triazacyclononane)copper(II), a macrocyclic triamine complex with an unusually small formation constant

Abstract

The title complex, Cu ( [9]aneN3)C12 (l), behaves anomalously with regard to the well-known macrocyclic effect. Typically, macrocyclic pol amine Cu(I1) complexes exhibit polyamines.2 However, the formation constant of 1 (log K is: 16) is smaller than that of Cu(dien)z+ (log K = 18.0).*g3 larger formation constants yh t an those of corresponding linear dien 19 lane% In contrast, formation constants of Ni( [9]aneN#+ and Zn-([9]a11eN~)~' (log K = 16.2 and 11.6, respectively) are substantially larger than those of Ni(dien)2+ and Zn(dien)" (log K = 10.7 and 8.9, re~pectively).~ The anomalous behavior of 1 has been attributed2" to steric requirements of Cu(I1) which have been frustrated in part by structural constraints of the [9]aneN3 ligand. The present study was undertaken to help understand these constraint^.^ Experimental SectionPreparation of 1. 1,4,7-Triazacyclononane trihydrochloride ( [9]aneN3.3HC1) was prepared by appropriate modification of a published procedure for 1,5,9,13-tetraazacy~lohexadecane.~ Evaporation of a solution of [9]aneN3.3HC1 (5 mmol, 1.24 g), CuC12 (5 mmol, 0.85 g), and 15 mL of 1 N sodium hydroxide yielded sodium chloride crystals and large blue plates of 1 which were separated manually and recrystallized from water to yield pure 1.

DNA damage and induction of apoptosis in pancreatic cancer cells by a new dinuclear bis(triazacyclonane) copper complex

“…According to the definition by Addison (τ = (α-β)/60, where α and β are the two largest bond angles) an ideal square pyramid has a τ value of 0, while τ is 1 for a trigonal bipyramid [35]. As expected for d 9 Cu ions with square pyramidal coordination geometry, the Cu\N bond distances are shorter for equatorial nitrogens (2.001 to 2.017 Å) than for the apical nitrogen (2.198 to 2.257 Å) [36,37]. Table S2.…”

Effect of a conjugated acridine moiety on the binding and reactivity of Cu(II)[9-acridinylmethyl-1,4,7-triazacyclononane] with DNA

“…The dihedral angle of the acridine ring and the basal plane is 81.0(3), being indicative of nearly perpendicular angle. The crystal structure of 1 was previously reported [45]; the complex 1 consists of a copper core with three nitrogen atoms and two chlorine atoms. The coordination around the copper(II) ion is a square pyramidal geometry with a basal plane comprised of two nitrogen atoms from [9]aneN 3 and two chlorine atoms; the axial site is occupied by the remaining nitrogen atom from [9]aneN 3 .…”

“…The coordination around the copper(II) ion is a square pyramidal geometry with a basal plane comprised of two nitrogen atoms from [9]aneN 3 and two chlorine atoms; the axial site is occupied by the remaining nitrogen atom from [9]aneN 3 . The selected bond distance and bond angles of 2 are listed with those found in 1 of dichloride salt [45] in Table 2. Comparison of these structural parameters for 2 and 1 reveals that the two …”

Managing nickel metals in Agriculture contaminated soil into macrocyclic complex

“…Template condensation of chloro carbon such as dichloromethane with tetraamine such as diethylenetriamine in presence of Ni (II) yield the corresponding metal complex of the following macro cyclic legend -1,4,7,9,12,15-hexaazacyclohexadecane (HACH) [2]. A mixture contain nickel hydroxide (6.00 g, 64.70 mmole), diethylenetriamine (6.68 g, 64.75 mmole) and dichloromethane (5.50 g, 64.76 mmole) was prepared in 200 ml butanol.…”