Chemistry of HIV-1 Virucidal Pt Complexes Having Neglected Bidentate sp<sup>2</sup> N-Donor Carrier Ligands with Linked Triazine and Pyridine Rings. Synthesis, NMR Spectral Features, Structure, and Reaction with Guanosine

Maheshwari, Vidhi; Bhattacharyya, Debadeep; Fronczek, Frank R.; Marzilli, Patricia A.; Marzillï, Luigi G.

doi:10.1021/ic060605h

Cited by 35 publications

(42 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We attribute the greater downfield shifts in the Pt complexes to a greater electron-withdrawing inductive effect of Pt II as compared to Re I . In DMSO- d 6 for L = 3-(4′-methylpyridin-2′-yl)-5,6-dimethyl-1,2,4-triazine, 50 the pyridyl H6 signal appeared more downfield for PtLCl 2 (9.35 ppm) 50 than for [Re(CO) 3 L(CH 3 CN)]BF 4 (8.97 ppm), 49 a result indicating that Pt II does indeed have a generally greater inductive effect than Re I . This greater effect for Pt II than for Re I adds further confidence to our analysis that the small downfield shift for the Me 1 H NMR signal for Pt( N (SO 2 Me)dpa)Cl 2 compared to that for 1 indicates that the sulfonamide N binds to Re I but not to Pt II ; otherwise, the Me 1 H NMR signal for the Pt II compound would be more downfield than that for the Re I compound.…”

Section: Resultsmentioning

confidence: 99%

Formation of a Metal-to-Nitrogen Bond of Normal Length by a Neutral Sufonamide Group within a Tridentate Ligand. A New Approach to Radiopharmaceutical Bioconjugation

et al. 2013

Self Cite

View full text Add to dashboard Cite

We demonstrate that a tertiary sulfonamide group, N(SO2R)R′2, can re-hybridize to form a M–N bond of normal length even when the group is in a linear tridentate ligand, such as in the new tridentate N(SO2R)dpa ligands derived from di-(2-picolyl)amine (N(H)dpa). N(SO2R)dpa ligands were used to prepare fac-[Re(CO)3(N(SO2R)dpa)](PF6 or BF4) complexes. Structural characterization of the new complexes established that the tertiary sulfonamide nitrogen atom binds to Re with concomitant sp2-to-sp3 re-hybridization, facilitating facial coordination. The new fac-[Re(CO)3(N(SO2R)dpa)]X structures provide the only examples for any metal with the sulfonamide as part of a noncyclic linear tridentate ligand and with a normal metal-to-nitrogen(tertiary sulfonamide) bond length. Rare previous examples of such normal M–N bonds have been found only in more constrained situations, such as with tripodal tetradentate ligands. Our long-term objectives for the new tridentate N(SO2R)dpa ligands are to develop the fundamental chemistry relevant to the eventual use of the fac-[MI(CO)3]+ core (M = 99mTc, 186/188Re) in imaging and therapy. The sulfonamide group uniquely contributes to two of our goals: expanding ways to conjugate the fac-[MI(CO)3]+ core to biological molecules and also developing new symmetrical tridentate ligands that can coordinate facially to this core. Tests of our conjugation method, conducted by linking the fac-[ReI(CO)3]+ core to a new tetraarylporphyrin (T(N(SO2C6H4)dpa)P) as well as to a dansyl (5-(dimethylamino)naphthalene-1-sulfonyl) group, demonstrate that large molecular fragments can be tethered via a coordinated tertiary sulfonamide linkage to this core.

show abstract

Section: Resultsmentioning

confidence: 99%

Formation of a Metal-to-Nitrogen Bond of Normal Length by a Neutral Sufonamide Group within a Tridentate Ligand. A New Approach to Radiopharmaceutical Bioconjugation

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Evidence that is in favor of this attraction of the iminoether oxygen for the L hydrogen atoms has been found in the structure of an analogous methyl acetimidate complex, which has a pyridyltriazine ligand in place of the bipyridine ligand (unpublished work). This unsymmetrical aromatic bidentate L [32,33] has a pyridyl C6 H on one side, and a nitrogen that has no hydrogen atoms attached to it on the other side. The methyl acetimidate oxygen lies over the C6 H, and the iminoether adopts an orientation that is very close to that shown in this paper in Figures 2 and 3.…”

Section: Structural Resultsmentioning

confidence: 99%

Iminoether Complexes of the Type, fac‐[Re(CO)₃L{HNC(CH₃)OCH₃}]BF₄ (L = Bipyridine or a Substituted Bipyridine): Synthesis and Properties

et al. 2012

Self Cite

View full text Add to dashboard Cite

The methyl acetimidate (an iminoether) complexes, fac‐[Re(CO)3L{HNC(CH3)OCH3}]BF4 [where L = 2,2′‐bipyridine (bipy), 4,4′‐Me2bipy, 5,5′‐Me2bipy, or 6,6′‐Me2bipy], were formed when fac‐[Re(CO)3(CH3CN)3]BF4 in acetonitrile/methanol was treated with 2,2′‐bipyridine (bipy) or the dimethyl‐2,2′‐bipyridines (4,4′‐Me2bipy, 5,5′‐Me2bipy, or 6,6′‐Me2bipy). Structural analysis of the four fac‐[Re(CO)3L{HNC(CH3)OCH3}]BF4 complexes revealed that all of the complexes crystallize with the iminoether ligand in the Z configuration and that distortions in L that involved the two pyridyl rings are minor except for 6,6′‐Me2bipy, which is highly distorted. This distortion of the 6,6′‐Me2bipy ligand is reflected in the NMR‐spectroscopic data. Upon complex formation, the methyl group signal in the 13C NMR spectrum shifted downfield significantly for 6,6′‐Me2bipy, but this did not occur in the 13C NMR spectrum of the 5,5′‐Me2bipy complex. The reaction times for forming the respective fac‐[Re(CO)3L{HNC(CH3)OCH3}]BF4 complexes for these two ligands were comparable, which indicated that the differences in the distortion of L and the methyl substituent position have little influence on the ease of iminoether formation. However, a higher steric bulk of the alcohol (methanol, ethanol, and2‐propanol) decreases the ease of fac‐[Re(CO)3(5,5′‐Me2bipy){HNC(CH3)OR}]BF4 formation. Isopropanol did not form the iminoether complex after two days of heating the reaction mixture at reflux. The low reactivity of the alcohols tested versus the amines that were tested previously suggests that selective bioconjugation to the fac‐{99mTc(CO)3}+ core through an amidine linkage is feasible for biomolecules that have both amine and hydroxy groups. Finally, a comparison of the C≡N bond lengths that were obtained for the fac‐[Re(CO)3(CH3CN)3]BF4/PF6 complexes with those values obtained for other rhenium acetonitrile complexes revealed that there is no significant difference between the C≡N bond lengths and that there is no correlation to the acetonitrile reactivity. It is possible that the fac‐{Re(CO)3}+ core stabilizes the transition state for amine or alcohol addition.

show abstract

“…Metal complexes possess unique properties such as radioactivity [1, 2], preferential binding to certain proteins or organelles [3–7], inertness [8], lower toxicity than the purely organic molecules [9] and special photophysical properties [10–13] which make them eligible for both therapeutic and diagnostic applications [14–18]. Two-photon absorption behavior of certain transition metal complexes containing conjugated ligands show high applicability in biological imaging [19, 20].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of novel rhenium(I) complexes towards potential biological imaging applications

Ranasinghe

Handunnetti

Perera

et al. 2016

Chemistry Central Journal

View full text Add to dashboard Cite

BackgroundRe(I) tricarbonyl complexes exhibit immense potential as fluorescence imaging agents. However, only a handful of rhenium complexes have been utilized in biological imaging. The present study describes the synthesis of four novel rhenium complexes, their characterization and preliminary biological studies to assess their potential as biological imaging agents.ResultsFour facial rhenium tricarbonyl complexes containing a pyridyl triazine core, (L1 = 5,5′(3-(2-pyridyl)-1,2,4-triazine-5,6-diyl)-bis-2-furansulfonic acid disodium salt and L2 = (3-(2- pyridyl)-5,6-diphenyl-1,2,4-triazine-4′,4′′-disulfonic acid sodium salt) have been synthesized by utililzing two different Re metal precursors, Re(CO)5Br and [Re(CO)3(H2O)3]OTf in an organic solvent mixture and water, respectively. The rhenium complexes [Re(CO)3(H2O)L1]+ (1), Re(CO)3L1Br (2), [Re(CO)3(H2O)L2]+ (3), and Re(CO)3L2Br (4), were obtained in 70–85% yield and characterized by 1H NMR, IR, UV, and luminescence spectroscopy. In both H2O and acetonitrile, complexes display a weak absorption band in the visible region which can be assigned to a metal to ligand charge transfer excitation and fluorescent emission lying in the 650–710 nm range. Cytotoxicity assays of complexes 1, 3, and 4 were carried out for rat peritoneal cells. Both plant cells (Allium cepa bulb cells) and rat peritoneal cells were stained using the maximum non-toxic concentration levels of the compounds, 20.00 mg ml−1 for 1 and 3 and 5.00 mg ml−1 for 4 to observe under the epifluorescence microscope. In both cell lines, compound concentrated specifically in the nuclei region. Hence, nuclei showed red fluorescence upon excitation at 550 nm.ConclusionsFour novel rhenium complexes have been synthesized and characterized. Remarkable enhancement of fluorescence upon binding with cells and visible range excitability demonstrates the possibility of using the new complexes in biological applications.Graphical abstractMicrograph of rat peritoneal cells incubated with novel rhenium complex under epifluorescence microscope. Electronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0218-4) contains supplementary material, which is available to authorized users.

show abstract

Chemistry of HIV-1 Virucidal Pt Complexes Having Neglected Bidentate sp² N-Donor Carrier Ligands with Linked Triazine and Pyridine Rings. Synthesis, NMR Spectral Features, Structure, and Reaction with Guanosine

Cited by 35 publications

References 45 publications

Formation of a Metal-to-Nitrogen Bond of Normal Length by a Neutral Sufonamide Group within a Tridentate Ligand. A New Approach to Radiopharmaceutical Bioconjugation

Formation of a Metal-to-Nitrogen Bond of Normal Length by a Neutral Sufonamide Group within a Tridentate Ligand. A New Approach to Radiopharmaceutical Bioconjugation

Iminoether Complexes of the Type, fac‐[Re(CO)₃L{HNC(CH₃)OCH₃}]BF₄ (L = Bipyridine or a Substituted Bipyridine): Synthesis and Properties

Synthesis and characterization of novel rhenium(I) complexes towards potential biological imaging applications

Contact Info

Product

Resources

About

Chemistry of HIV-1 Virucidal Pt Complexes Having Neglected Bidentate sp2 N-Donor Carrier Ligands with Linked Triazine and Pyridine Rings. Synthesis, NMR Spectral Features, Structure, and Reaction with Guanosine

Cited by 35 publications

References 45 publications

Formation of a Metal-to-Nitrogen Bond of Normal Length by a Neutral Sufonamide Group within a Tridentate Ligand. A New Approach to Radiopharmaceutical Bioconjugation

Formation of a Metal-to-Nitrogen Bond of Normal Length by a Neutral Sufonamide Group within a Tridentate Ligand. A New Approach to Radiopharmaceutical Bioconjugation

Iminoether Complexes of the Type, fac‐[Re(CO)3L{HNC(CH3)OCH3}]BF4 (L = Bipyridine or a Substituted Bipyridine): Synthesis and Properties

Synthesis and characterization of novel rhenium(I) complexes towards potential biological imaging applications

Contact Info

Product

Resources

About

Chemistry of HIV-1 Virucidal Pt Complexes Having Neglected Bidentate sp² N-Donor Carrier Ligands with Linked Triazine and Pyridine Rings. Synthesis, NMR Spectral Features, Structure, and Reaction with Guanosine

Iminoether Complexes of the Type, fac‐[Re(CO)₃L{HNC(CH₃)OCH₃}]BF₄ (L = Bipyridine or a Substituted Bipyridine): Synthesis and Properties