Crystal structures oftrans-diaqua(3-R-1,3,5,8,12-pentaazacyclotetradecane)copper(II) isophthalate hydrates (R= benzyl or pyridin-3-ylmethyl)

Abstract

The asymmetric units of the title compounds, trans-diaqua(3-benzyl-1,3,5,8,12-pentaazacyclotetradecane-κ4 N 1,N 5,N 8,N 12)copper(II) isophthalate monohydrate, [Cu(C16H29N5)(H2O)2](C8H4O4)·H2O, (I), and trans-diaqua[3-(pyridin-3-ylmethyl)-1,3,5,8,12-pentaazacyclotetradecane-κ4 N 1,N 5,N 8,N 12]copper(II) isophthalate 0.9-hydrate, [Cu(C15H28N6)(H2O)2](C8H4O4)·0.9H2O, (II) consist of one diaqua macrocyclic cation, one dicarboxylate anion and uncoordinated water molecule(s). In each compound, the metal ion is coordinated by the four secondary N atoms of the macrocyclic ligand and the mutually trans O atoms of the water molecules in a tetragonally distorted octahedral geometry. The average equatorial Cu—N bond lengths are significantly shorter than the average axial Cu—O bond lengths [2.020 (9) versus 2.495 (12) Å and 2.015 (4) versus 2.507 (7) Å for (I) and (II), respectively]. The coordinated macrocyclic ligand in the cations of both compounds adopts the most energetically favorable trans-III conformation. In the crystals, the complex cations and counter-anions are connected via hydrogen-bonding interactions between the N—H groups of the macrocycles and the O—H groups of coordinated water molecules as the proton donors and the O atoms of the carboxylate as the proton acceptors. Additionally, as a result of O—H...O hydrogen bonding with the coordinated and water molecules of crystallization, the isophthalate dianions form layers lying parallel to the (\overline{1}01) and (100) planes in (I) and (II), respectively.

Coordination Polymers of the Macrocyclic Nickel(II) and Copper(II) Complexes with Isomeric Benzenedicarboxylates: The Case of Spatial Complementarity between the Bis-Macrocyclic Complexes and o-Phthalate

“…The sum of the C–N–C angles around these atoms (342–348°) is much larger than the canonical value for an sp 3 -hybridized N atom (ca. 327°), thus indicating their partial sp 2 character. ,, …”

“…327°), thus indicating their partial sp 2 character. 37,49,50 The dicarboxylate ligands in 1−8 are coordinated in axial positions of trans-MN 4 O 2 chromophores and counterbalance the charge of the complex cations. The C−O bond lengths in the carboxylate groups are nearly equal, thus indicating essential electron delocalization.…”

“…The axial positions in the coordination sphere of the copper(II) are occupied by water molecules, a situation which was also observed in other copper(II) azacyclam compounds with aromatic carboxylates. 49 The bis-macrocyclic ligand and dianion 1,4-bdc 2− are centrosymmetric and the metal ion lies on an inversion center; therefore, the fragment CuN 4 is strictly planar.…”

“…The equatorial Cu−N bond lengths in 9 (Table 4) are typical of the copper(II) complexes with 14-membered cyclam-like ligands. 7,49 Similarly to 8, the metal ion has tetragonally elongated trans-N 4 O 2 octahedral geometry, because the axial Cu−O bond lengths are essentially longer than the equatorial Cu−N ones.…”

The first structural characterization of the protonated azacyclam ligand incatena-poly[[[(perchlorato)copper(II)]-μ-3-(3-carboxypropyl)-1,5,8,12-tetraaza-3-azoniacyclotetradecane] bis(perchlorate)]

“…The formation of the azonia N3H + group in (I) leads to clear changes in the C-N-C angles compared to the nonprotonated ones. The sum of these angles in the latter case (345-354 ) is much larger than the canonical value for an sp 3hybridized N atom (ca 327 ), thus indicating their partial sp 2 character (Tsymbal et al, 2010;Andriichuk et al, 2019), while in (I) this parameter equals 335 (2) , demonstrating an sp 2 -tosp 3 transformation of the noncoordinated N atom upon protonation.…”