A linear potassium metalated vanadium(IV) polymeric alkoxide: Structural and spectroscopic studies

Nunes, Giovana G.; Friedermann, Geraldo R.; Hitchcock, Peter B.; Sá, Eduardo L. de; Soares, Jaı́sa F.

doi:10.1016/j.ica.2005.12.054

Cited by 4 publications

(7 citation statements)

References 48 publications

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“…Neither set of peaks for complex 3 show values of g and A similar to that of the aqua complex, which suggests there is little substitution of the 6 th ligand by solvent unlike that proposed for the cyclam complexes. The low A iso value of 84 (G) is at the lower end of those reported for other vanadium(IV) species with O-donor ligands (85 to 110 G), although not the lowest reported (71 G) 43-45. The values of g iso (1.985, 1.983) fall within reported ranges 44, 45.…”

Section: Discussionsupporting

confidence: 54%

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

Ross

Soares

Covelli³

et al. 2009

Inorg. Chem.

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Metal complexation can have a major influence on the antiviral and co-receptor binding properties of cyclam and bicyclam macrocycles. We report the synthesis of the vanadyl cyclam complexes [V (IV) O(cyclam)SO 4 ] (1) and [V (IV) O(cyclam)Cl]Cl -(2), and the analogous xylylbicyclam sulfato (3) and chlorido (4) complexes. The X-ray crystal structures of 1·1.33CH 3 OH and 2·CH 3 OH1.5H 2 O show short V=O bonds (1.6093(19) and 1.599(3) Å, respectively) with monodentate sulfate H-bonded to ring NH groups for 1, but a long V-Cl bond (2.650(12) Å) for 2. The solid-state structures of 3 and 4 were compared to those of 1 and 2 using vanadium K-edge EXAFS data. These suggested that complex 4 was oligomeric and contained bridging chlorido ligands. EPR studies suggested that the SO 4 2-(from 1) and Cl -(from 2) ligands are readily substituted by water in solution, whereas these remain partially bound for the V IV xylylbicyclam complexes 3 and 4. The vanadyl xylylbicyclam complexes were highly active against HIV-1 (III B ) and HIV-2 (ROD) strains with IC 50 values in the range 1-5 μM for 3 and 0.1-0.3 μM for 4; in contrast the vanadyl cyclam complexes 1 and 2 were inactive. The factors which contribute to the activity of these complexes are discussed. Studies of vanadyl cyclam docked into a model of the human CXCR4 coreceptor revealed that the coordination of vanadium to the carboxylate of Asp171 may be accompanied by H-bonding to the macrocycle and an attractive V=O··H interaction involving the backbone Trp195 α-carbon proton of CXCR4. In addition, hydrophobic interactions with Trp195 are present. Both ring configuration and the xylyl linker may play roles in determining the higher activity of the bicyclam complexes.

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Section: Discussionsupporting

confidence: 54%

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

Ross

Soares

Covelli³

et al. 2009

Inorg. Chem.

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“…24 The same tendency was also reported by some of us for double alkoxides of vanadium(IV) and Li + or K + . 25,26 Addition of [CrCl 3 (thf ) 3 ] to the boiling lithium alkoxide suspension was performed slowly over a period of several hours (see Experimental), to prevent polynuclear aggregation of the desired "core" product. This was accomplished by slow extraction of the chromium starting material into the alkoxide suspension by the refluxing solvent, in a way that the dissolved Cr III would be added to an excess of the lithium alkoxide.…”

Section: Paper Dalton Transactionsmentioning

confidence: 99%

A new approach to the synthesis of heteronuclear propeller-like single molecule magnets

et al. 2013

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Propeller-like [Fe(4)(L)(2)(dk)(6)] complexes, in which Hdk is a β-diketone and H(3)L is a tripodal alcohol, R-C(CH(2)OH)(3), exhibit tunable magnetic anisotropy barriers and retain their magnetic memory effect when chemically anchored on metal surfaces. Heteronuclear analogues of these M(4) complexes have been sought to afford a library of compounds with different total spin (S) values, but synthetic efforts described so far gave solid solutions containing M(4) in addition to the desired M(3)M' species. We now present a novel synthetic route to M(3)M' complexes featuring a central chromium(III) ion. The three-step preparation goes through coordination of Cr(III) by two equivalents of tripodal alkoxide (R = Et and Ph), followed by reaction of this complex "core" with the peripheral +III metal ions. Products have been characterised by chemical analyses together with (1)H-NMR, FTIR, W-band EPR, DC/AC magnetic susceptibility measurements and single crystal X-ray diffractometry. Due to the chemical inertness of Cr(III), this route yields 100% pure Fe(3)Cr complexes without metal scrambling; what is more, it is suitable for designing novel heteronuclear single molecule magnets (SMMs) with a variety of d- and f-metals and R groups.

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“…69 The synthesis of [{K 2 (VO) 2 (OPr) 6 (PrOH) 2 } N ] has been reported. 70 Amido-tethered N-heterocyclic carbene (NHC) lanthanide complexes, [Ln(L)N and [{6-Me(2-Py)}(Me 3 Si) 2 CK] N . 72 1,3-and 1,4-bis[tris(trimethylsilyl)silylethynyl]benzene and 1,3,5-tris[tris(trimethylsilyl)silylethynyl]benzene undergo di-or trimetallation with KO t Bu to afford the respective oligosilyldi-and tri-anions.…”

Section: Sodium and Potassiummentioning

confidence: 99%

Alkali and alkaline-earth metals

Hill¹

2007

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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A linear potassium metalated vanadium(IV) polymeric alkoxide: Structural and spectroscopic studies

Cited by 4 publications

References 48 publications

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

A new approach to the synthesis of heteronuclear propeller-like single molecule magnets

Alkali and alkaline-earth metals

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