skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Interplay of Isomorphs and Polymorphs of Amidino-Copper(II) Complexes with Different Halides
To increase the number of potential materials for application as MRI contrast agents, several Cu(II) complexes were synthesized. Cu(II) complexes were chosen because they are less expensive in comparison with the presently used Gd(III), Mn(II) and other agents. Pyridine-2-carboximidamide (1), pyrimidine-2-carboximidamide (2) and pyrazole-2-carboximidamide (3) in the form of different salts along with CuCl2 and NaCl or CuBr2 and NaBr were used to obtain four Cu(II) complexes: dichloro-pyrimidine-2-carboximidamide copper(II) (4), dibromo-pyrimidine-2-carboximidamide copper(II) (5), dichloro-pirazole-2-carboximidamide copper(II) (6), and dibromo-pirazole-2-carboximidamide copper(II) (7). X-ray diffraction analysis revealed that molecular complexes 4–7 contain square planar coordinated Cu(II) atoms and their structures are very similar, as well as their packing in crystals, which allows us to consider them isomorphs. The same synthetic approach to complex preparation where NaCl or NaBr was not used brought us to the formation of dimeric complexes μ-chloro{chloro(pyridine-2-carboximidamide)copper(II)} (8) and μ-chloro{chloro(pyrimidine-2-carboximidamide)copper(II)} (9). In the dimeric complexes, two fragments which were the same as in monomeric complexes 4–7 are held together by bridging Cu-Cl bonds making the coordination of Cu equal to 5 (square pyramid). In dimeric complexes, axial Cu-Cl bonds are 2.7360 and 2.854 Å. These values are Cu-Cl bonds on the edge of existence according to statistical data from CSD. Synthesized complexes were characterized by IR spectroscopy, TGA, PXRD, EPR, and quantum chemical calculations. The higher thermal stability of monomer pyrimidine-based complexes with Cl and Br substituents makes them more prospective for further studies.  more » « less
Award ID(s):
2122108
PAR ID:
10502360
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
MDPI
Date Published:
Journal Name:
Crystals
Volume:
14
Issue:
4
ISSN:
2073-4352
Page Range / eLocation ID:
319
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; (, Acta Crystallographica Section E Crystallographic Communications)
    null (Ed.)
    Copper(I) iodide complexes are well known for displaying a diverse array of structural features even when only small changes in ligand design are made. This structural diversity is well displayed by five copper(I) iodide compounds reported here with closely related piperidine-2,6-dithione (SNS), isoindoline-1,3-dithione (SNS6), and 6-thioxopiperidin-2-one (SNO) ligands: di-μ-iodido-bis[(acetonitrile-κ N )(6-sulfanylidenepiperidin-2-one-κ S )copper(I)], [Cu 2 I 2 (CH 3 CN) 2 (C 5 H 7 NOS) 2 ] ( I ), bis(acetonitrile-κ N )tetra-μ 3 -iodido-bis(6-sulfanylidenepiperidin-2-one-κ S )- tetrahedro -tetracopper(I), [Cu 4 I 4 (CH 3 CN) 4 (C 5 H 7 NOS) 4 ] ( II ), catena -poly[[(μ-6-sulfanylidenepiperidin-2-one-κ 2 O : S )copper(I)]-μ 3 -iodido], [CuI(C 5 H 7 NOS)] n ( III ), poly[[(piperidine-2,6-dithione-κ S )copper(I)]-μ 3 -iodido], [CuI(C 5 H 7 NS 2 )] n ( IV ), and poly[[(μ-isoindoline-1,3-dithione-κ 2 S : S )copper(I)]-μ 3 -iodido], [CuI(C 8 H 5 NS 2 )] n ( V ). Compounds I and II crystallize as discrete dimeric and tetrameric complexes, whereas III , IV , and V crystallize as polymeric two-dimensional sheets. To the best of our knowledge, compound III is the first instance of an extended hexagonal [Cu 3 I 3 ] structure that is not supported by bridging ligands. Structures I , II , and IV display weak to moderately strong Cu...Cu cuprophilic interactions [Cu...Cu internuclear distances range between 2.5803 (10) and 2.8485 (14) Å]. All structures except III display weak hydrogen-bonding interactions between the N—H of the ligand and the μ 2 and μ 3 -I − atoms. Structure III contains classical N–H...O interactions between the SNO ligands that connect the molecules in a three-dimensional framework. Complex V features π–π stacking interactions between the aryl rings of the SNS6 ligands within the same polymeric sheet. In structure IV , there were three partially occupied solvent molecules of dichloromethane and one partially occupied molecule of acetonitrile present in the asymmetric unit. The SQUEEZE routine [Spek (2015). Acta Cryst . C 71 , 9–18] was used to correct the diffraction data for diffuse scattering effects and to identify the solvent molecules. The given chemical formula and other crystal data do not take into account the solvent molecules. 
    more » « less
  2. ; (, Acta Crystallographica Section E Crystallographic Communications)
    null (Ed.)
    The crystal structures of three bridged bimetallic molecular compounds, namely, triaqua-2κ 3 O -μ-fluorido-pentafluorido-1κ 5 F -(1,10-phenanthroline-2κ 2 N , N ′)copper(II)titanium(IV) monohydrate, [Cu(TiF 6 )(phen)(H 2 O) 3 ]·H 2 O (phen is 1,10-phenanthroline, C 12 H 8 N 2 ), (I), triaqua-2κ 3 O -μ-fluorido-pentafluorido-1κ 5 F -(1,10-phenanthroline-2κ 2 N , N ′)copper(II)zirconium(IV) monohydrate, [Cu(ZrF 6 )(phen)(H 2 O) 3 ]·H 2 O, (II), and triaqua-2κ 3 O -μ-fluorido-pentafluorido-1κ 5 F -(1,10-phenanthroline-2κ 2 N , N ′)copper(II)hafnium(IV) monohydrate, [Cu(HfF 6 )(phen)(H 2 O) 3 ]·H 2 O, (III), and one molecular salt, bis[diaquafluorido(1,10-phenanthroline-κ 2 N , N ′)copper(II)] hexafluoridohafnate(IV) dihydrate, [CuF(phen)(H 2 O) 2 ] 2 [HfF 6 ]·2H 2 O, (IV), are reported. The bridged bimetallic compounds adopt Λ-shaped configurations, with the octahedrally coordinated copper(II) center linked to the fluorinated early transition metal via a fluoride linkage. The extended structures of these Λ-shaped compounds are organized through both intra- and intermolecular hydrogen bonds and intermolecular π–π stacking. The salt compound [Cu(phen)(H 2 O) 2 F] 2 [HfF 6 ]·H 2 O displays an isolated square-pyramidal Cu(phen)(H 2 O) 2 F + complex linked to other cationic complexes and isolated HfF 6 2− anions through intermolecular hydrogen-bonding interactions. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; ; et al (, New Journal of Chemistry)
    Reactions of the bicompartmental bis(phenolato) compound 6,6′-methylenebis(2-((bis(pyridin-2-ylmethyl)amino)methyl)-4-chlorophenol)hemihydrate (H 2 L ½H 2 O) with 3d metal( ii ) ions afforded novel fully structurally characterized bridged acetato dinuclear complexes [Mn 2 (HL)(μ 1,2 -OAc) 2 ]PF 6 (1) [Zn 2 (HL)(μ 1,2 -OAc)(H 2 O) 0.75 (MeOH) 0.25 ](PF 6 ) 2 ·0.45(H 2 O) (5) and [Cd 2 (HL)(μ 1,1,2 -OAc)(OAc)(H 2 O)]PF 6 ·H 2 O (6) as well as the polymeric bridged-azido tetranuclear catena -[Cu 4 (HL) 2 (μ 1,1 -N 3 ) 2 (μ 1,3 -N 3 ) 2 ](NO 3 ) 2 ·5H 2 O (4). The complex [Cu 4 (HL) 2 (ClO 4 ) 3 (H 2 O) 5 ](ClO 4 ) 3 ·5H 2 O (2) was partially characterized. In addition, three more dinuclear complexes [Cu 2 (H 2 L)(NO 3 ) 2 (H 2 O) 2 ](NO 3 ) 2 (3), [Cu 2 (HL)(OAc)(CH 3 OH)](PF 6 ) 2 (7) and [Cu 2 (HL)(NCS) 2 ]NO 3 ·2H 2 O (8) were also isolated. All complexes were characterized by CHN elemental analysis, IR and UV-Vis spectroscopy, ESI-MS, conductivity measurements and X-ray single crystal crystallography for compounds 1, 4, 5 and 6, where the bis(phenolato) ligand displayed different deprotonation (H 2 L, HL − and L 2− ). The magnetic susceptibility measurements over the temperature range 2–300 K revealed very weak antiferromagnetic coupling in dimanganese( ii ) 1 ( J = −1.64(1) cm −1 ) and almost negligible magnetic interaction in dicopper( ii ) 2 ( J = 0(3) cm −1 ). In the azido catena -[Cu 4 (HL) 2 (μ 1,1 -N 3 ) 2 (μ 1,3 -N 3 ) 2 ](NO 3 ) 2 ·5H 2 O (4) complex, the J value of −133(3) cm −1 was obtained upon moderate-to-strong antiferromagnetic coupling through the di-μ 1,3 -N 3 -bridged dicopper( ii ) unit with no magnetic interaction between the two copper( ii ) ions in the di-μ 1,1 -N 3 -bridged unit. 
    more » « less
  4. ; ; ; ; ; ; ; ; (, International Journal of Molecular Sciences)
    The 3d transition metal (Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes, supported by anions of sterically demanding β-diketones, 1,3-dimesitylpropane-1,3-dione (HLMes) and 1,3-bis(3,5-bis(trifluoromethyl)phenyl)-3-hydroxyprop-2-en-1-one (HLCF3), were synthesized and evaluated for their antitumor activity. To assess the biological effects of substituents on phenyl moieties, we also synthesized and investigated the analogous metal(II) complexes of the anion of the less bulky 1,3-diphenylpropane-1,3-dione (HLPh) ligand. The compounds [Cu(LCF3)2], [Cu(LMes)2] and ([Zn(LMes)2]) were characterized by X-ray crystallography. The [Cu(LCF3)2] crystallizes with an apical molecule of solvent (THF) and features a rare square pyramidal geometry at the Cu(II) center. The copper(II) and zinc(II) complexes of diketonate ligands, derived from the deprotonated 1,3-dimesitylpropane-1,3-dione (HLMes), adopt a square planar or a tetrahedral geometry at the metal, respectively. We evaluated the antitumor properties of the newly synthesized (Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes against a series of human tumor cell lines derived from different solid tumors. Except for iron derivatives, cellular studies revealed noteworthy antitumor properties, even towards cancer cells endowed with poor sensitivity to the reference drug cisplatin. 
    more » « less
  5. ; ; (, Acta Crystallographica Section E Crystallographic Communications)
    null (Ed.)
    We report the hydrothermal syntheses and crystal structures of aquabis(2,2′-bipyridine-κ 2 N , N ′)copper(II) hexafluoridosilicate tetrahydrate, [Cu(bpy) 2 (H 2 O)][SiF 6 ]·4H 2 O (bpy is 2,2′-bipyridine, C 10 H 8 N 2 ), (I), bis(2,2′-bipyridine-3κ 2 N , N ′)-di-μ-fluorido-1:3κ 2 F : F ;2:3κ 2 F : F -decafluorido-1κ 5 F ,2κ 5 F -ditantalum(V)copper(II), [Cu(bpy) 2 (TaF 6 ) 2 ], (II), tris(2,2′-bipyridine-κ 2 N , N ′)copper(II) bis[hexafluoridotantalate(V)], [Cu(bpy) 3 ][TaF 6 ] 2 , (III), and catena -poly[[diaqua(2,2′-bipyridine-κ 2 N , N ′)copper(II)]-μ-fluorido-tetrafluoridotin-μ-fluorido], [Cu(bpy)(H 2 O) 2 SnF 6 ] n , (IV). Compounds (I), (II) and (III) contain locally chiral copper coordination complexes with C 2 , D 2 , and D 3 symmetry, respectively. The extended structures of (I) and (IV) are consolidated by O—H...F and O—H...O hydrogen bonds. The structure of (III) was found to be a merohedral (racemic) twin. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email