Synthesis, characterization, and X-ray crystal structures of cobalt(II) and cobalt(III) complexes of four topologically constrained tetraazamacrocycles

Hubin, Timothy J.; Alcock, Nathaniel W.; Clase, Howard J.; Seib, Lawrence; Busch, Daryle H.

doi:10.1016/s0020-1693(02)01080-0

Cited by 25 publications

(58 citation statements)

References 35 publications

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“…Two crystal growth methods were used in order to continue the investigation of how solvent type changed cobalt coordination. Both methods afforded X-ray quality crystals of 1 (1a and 1b) Complexes with a similar coordination environment to 1a and 1b are limited [8,16,17].…”

Section: Solid State Evaluation Of 1a and 1bmentioning

confidence: 99%

“…One particular Co(III) complex synthesized by Hubin et al (denoted 2) [17] offered connectivity parallels to 1a and 1b. 2 is a 12-membered ethylene cross-bridged macrocycle bound to Co(III) and is shown in figure 3.…”

Section: Solid State Evaluation Of 1a and 1bmentioning

confidence: 99%

“…Surprisingly, cobalt(III) complexes with 12-membered tetra-aza macrocycles are not prevalent in the literature, but there are a few examples [8,16,17]. The majority of the chemical literature is dominated by 12-membered Co(II) tetra-aza macrocyclic complexes or planar 14-membered Co(II)/Co(III) tetra-aza macrocyclic complexes [2,3,7,9,10,18,19].…”

Section: Introductionmentioning

confidence: 99%

“…The majority of the chemical literature is dominated by 12-membered Co(II) tetra-aza macrocyclic complexes or planar 14-membered Co(II)/Co(III) tetra-aza macrocyclic complexes [2,3,7,9,10,18,19]. Although examples of Co(III) tetra-aza macrocyclic complexes are sparse, there are many Co(II)/Co(III) coordination complexes derived from monodentate and open chain chelates that are historically significant and ubiquitous in chemical literature [17]. When new heterocycles are synthesized, the complexes formed with Co(II)/Co(III) ions can be compared to these more classic coordination compounds in order to delineate the observed reactivity [17].…”

Section: Introductionmentioning

confidence: 99%

“…Although examples of Co(III) tetra-aza macrocyclic complexes are sparse, there are many Co(II)/Co(III) coordination complexes derived from monodentate and open chain chelates that are historically significant and ubiquitous in chemical literature [17]. When new heterocycles are synthesized, the complexes formed with Co(II)/Co(III) ions can be compared to these more classic coordination compounds in order to delineate the observed reactivity [17]. One specific example of a classic Co(II) coordination complex is the equilibrium between pink cobalt(II) hexahydrate and blue cobalt(II) tetrachloride (scheme 1); this well-characterized demonstration is often used to illustrate Le Chatelier's Principle [20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic and solid-state evaluations of tetra-aza macrocyclic cobalt complexes with parallels to the classic cobalt(II) chloride equilibrium

Johnston

Palacios

Pierce

et al. 2016

Journal of Coordination Chemistry

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The Co(III) complex of 3, 6,9,15-tetra-azabicyclo[9.3.1]penta-deca-1,11,13-triene (L1) has been synthesized in DMF and isolated as a blue solid (1) ([L1Co III ClX] n+ , X = Cl -or DMF, n = 1 or 2). Complex 1 exhibits solution behavior similar to the classic cobalt(II) chloride equilibrium.When 1 is dissolved in water, the solution is pink and this complex exists as 1a, which consists of a cobalt(III) bound to L1 and two cis chlorides with a perchlorate counter-ion to balance the complex charge ([L1Co III Cl 2 ][ClO 4 ]). In contrast, when 1 is dissolved in DMF or other organic solvents the solution is blue and is observed as 1b. The 1b complex salt contains two cobalt centers. One cobalt(III) is bound to L1, Cl -, and DMF. Charge balance is accomplished by the second cobalt center: [Co II Cl 4 ] 2-, thus making 1b (L1Co III Cl(DMF)][Co II Cl 4 ]). This equilibrium was confirmed using UV-visible spectroscopy, EPR, and X-ray crystallography.

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Section: Solid State Evaluation Of 1a and 1bmentioning

confidence: 99%

Section: Solid State Evaluation Of 1a and 1bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Spectroscopic and solid-state evaluations of tetra-aza macrocyclic cobalt complexes with parallels to the classic cobalt(II) chloride equilibrium

Johnston

Palacios

Pierce

et al. 2016

Journal of Coordination Chemistry

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Aspartate‐Based CXCR4 Chemokine Receptor Binding of Cross‐Bridged Tetraazamacrocyclic Copper(II) and Zinc(II) Complexes

Maples

Cain

Burke

et al. 2016

Chemistry A European J

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The CXCR4 chemokine receptor is implicated in a number of diseases including HIV infection and cancer development and metastasis. Previous studies have demonstrated that configurationally restricted bis-tetraazamacrocyclic metal complexes are high-affinity CXCR4 antagonists. Here, we present the synthesis of Cu2+ and Zn2+ acetate complexes of six cross-bridged tetraazamacrocycles to mimic their coordination interaction with the aspartate side chains known to bind them to CXCR4. X-ray crystal structures for three new Cu2+ acetate complexes and two new Zn2+ acetate complexes, demonstrate metal-ion dependent differences in the mode of binding the acetate ligand concomitantly with the requisite cis-V configured cross-bridged tetraazamacrocyle. Concurrent density functional theory molecular modelling studies produced an energetic rationale for the unexpected [Zn(OAc)(H2O)]+ coordination motif present in all of the Zn2+ cross-bridged tetraazamacrocycle crystal structures, which differs from the chelating acetate [Zn(OAc)]+ structures of known unbridged and side-bridged tetraazamacrocyclic Zn2+ containing CXCR4 antagonists.

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Oxidized cobalt complexes of salicylaldehydes

Lalia‐Kantouri

Papadopoulos

Hatzidimitriou

et al. 2016

J Therm Anal Calorim

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Synthesis, characterization, and X-ray crystal structures of cobalt(II) and cobalt(III) complexes of four topologically constrained tetraazamacrocycles

Cited by 25 publications

References 35 publications

Spectroscopic and solid-state evaluations of tetra-aza macrocyclic cobalt complexes with parallels to the classic cobalt(II) chloride equilibrium

Spectroscopic and solid-state evaluations of tetra-aza macrocyclic cobalt complexes with parallels to the classic cobalt(II) chloride equilibrium

Aspartate‐Based CXCR4 Chemokine Receptor Binding of Cross‐Bridged Tetraazamacrocyclic Copper(II) and Zinc(II) Complexes

Oxidized cobalt complexes of salicylaldehydes

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