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Ranasinghe K, Marzilli PA, Pakhomova S, Marzilli LG. New fac-[ReI(CO)3(Ltri)]Y complexes of linear N,N′,N′′-tridentate ligands (Ltri) with terminal imidazolyl or pyridyl ring (N and N′′) and central tertiary sulfonamide (N′) N-donors. Effects of size and substituents of the terminal N-donor rings and the rarely found direct sulfonamide N to metal bond. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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2
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Exploring the synthesis and characterization of fac-Re(CO)3L complexes using diethylenetriamine derivative functionalized at the central nitrogen. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Darshani T, Fronczek FR, Priyadarshani VV, Samarakoon SR, Perera IC, Perera T. Synthesis and characterization of novel naphthalene-derivatized tridentate ligands and their net neutral rhenium tricarbonyl complexes and cytotoxic effects on non-small cell lung cancer cells of interest. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Darshani T, Thushara N, Weerasuriya P, Fronczek FR, Perera IC, Perera T. Fluorescent di-(2-picolyl)amine based drug-like ligands and their Re(CO)3 complexes towards biological applications. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Lewis NA, Marzilli PA, Fronczek FR, Marzilli LG. Models for B12-conjugated radiopharmaceuticals. Cobaloxime binding to new fac-[Re(CO)3(Me2bipyridine)(amidine)]BF4 complexes having an exposed pyridyl nitrogen. Inorg Chem 2014; 53:11096-107. [PMID: 25285912 DOI: 10.1021/ic5016675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New mononuclear amidine complexes, fac-[Re(CO)3(Me2bipy)(HNC(CH3)(pyppz))]BF4 [(4,4'-Me2bipy (1), 5,5'-Me2bipy (2), and 6,6'-Me2bipy (3)] (bipy = 2,2'-bipyridine), were synthesized by treating the parent fac-[Re(I)(CO)3(Me2bipy)(CH3CN)]BF4 complex with the C2-symmetrical amine 1-(4-pyridyl)piperazine (pyppzH). The axial amidine ligand has an exposed, highly basic pyridyl nitrogen. The reaction of complexes 1-3 with a B12 model, (py)Co(DH)2Cl (DH = monoanion of dimethylglyoxime), in CH2Cl2 yielded the respective dinuclear complexes, namely, fac-[Re(CO)3(Me2bipy)(μ-(HNC(CH3)(pyppz)))Co(DH)2Cl]BF4 [(4,4'-Me2bipy (4), 5,5'-Me2bipy (5), and 6,6'-Me2bipy (6)]. (1)H NMR spectroscopic analysis of all compounds and single-crystal X-ray crystallographic data for 2, 3, 5, and 6 established that the amidine had only the E configuration in both the solid and solution states and that the pyridyl group is bound to Co in 4-6. Comparison of the NMR spectra of 1-3 with spectra of 4-6 reveals an unusually large "wrong-way" upfield shift for the pyridyl H2/6 signal for 4-6. The wrong-way H2/6 shift of (4-Xpy)Co(DH)2Cl (4-Xpy = 4-substituted pyridine) complexes increased with increasing basicity of the 4-Xpy derivative, a finding attributed to the influence of the magnetic anisotropy of the cobalt center on the shifts of the (1)H NMR signals of the pyridyl protons closest to Co. Our method of employing a coordinate bond for conjugating the fac-[Re(I)(CO)3] core to a vitamin B12 model could be extended to natural B12 derivatives. Because B12 compounds are known to accumulate in cancer cells, such an approach is a very attractive method for the development of (99m)Tc and (186/188)Re radiopharmaceuticals for targeted tumor imaging and therapy.
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Affiliation(s)
- Nerissa A Lewis
- Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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Abhayawardhana PL, Marzilli PA, Fronczek FR, Marzilli LG. Complexes possessing rare "tertiary" sulfonamide nitrogen-to-metal bonds of normal length: fac-[Re(CO)3(N(SO2R)dien)]PF6 complexes with hydrophilic sulfonamide ligands. Inorg Chem 2014; 53:1144-55. [PMID: 24400928 PMCID: PMC4465231 DOI: 10.1021/ic4026987] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tertiary sulfonamide nitrogen-to-metal bonds of normal length are very rare. We recently discovered such a bond in one class of fac-[Re(CO)3(N(SO2R)(CH2Z)2)](n) complexes (Z = 2-pyridyl) with N(SO2R)dpa ligands derived from di-(2-picolyl)amine (N(H)dpa). fac-[M(CO)3(N(SO2R)(CH2Z)2)](n) agents (M = (186/188)Re, (99m)Tc) could find use as radiopharmaceutical bioconjugates when R is a targeting moiety. However, the planar, electron-withdrawing 2-pyridyl groups of N(SO2R)dpa destabilize the ligand to base and create relatively rigid chelate rings, raising the possibility that the rare M-N(sulfonamide) bond is an artifact of a restricted geometry. Also, the hydrophobic 2-pyridyl groups could cause undesirable accumulation in the liver, limiting future use in radiopharmaceuticals. Our goal is to identify a robust, hydrophilic, and flexible N(CH2Z)2 chelate framework. New C2-symmetric ligands, N(SO2R)(CH2Z)2 with (Z = CH2NH2; R = Me, dmb, or tol), were prepared by treating N(H)dien(Boc)2, a protected diethylenetriamine (N(H)dien) derivative, with methanesulfonyl chloride (MeSO2Cl), 3,5-dimethylbenzenesulfonyl chloride (dmbSO2Cl), and 4-methylbenzenesulfonyl chloride (tolSO2Cl). Treatment of fac-[Re(CO)3(H2O)3](+) with these ligands, designated as N(SO2R)dien, afforded new fac-[Re(CO)3(N(SO2R)dien)]PF6 complexes. Comparing the fac-[Re(CO)3(N(SO2Me)dien)]PF6 and fac-[Re(CO)3(N(SO2Me)dpa)]PF6 complexes, we find that the Re(I)-N(sulfonamide) bonds are normal in length and statistically identical and that the methyl (13)C NMR signal has an unusually upfield shift compared to that in the free ligand. We attribute this unusual upfield shift to the fact that the sulfonamide N undergoes an sp(2)-to-sp(3) rehybridization upon coordination to Re(I) in both complexes. Thus, the sulfonamide N of N(SO2R)dien ligands is a good donor, even though the chelate rings are conformationally flexible. Addition of the strongly basic and potentially monodentate ligand, 4-dimethylaminopyridine, did not affect the fac-[Re(CO)3(N(SO2tol)dien)]PF6 complex, even after several weeks. This complex is also stable to heat in aqueous solution. These results indicate that N(SO2R)dien ligands form fac-[Re(CO)3(N(SO2R)dien)]PF6 complexes sufficiently robust to be utilized for radiopharmaceutical development.
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Affiliation(s)
| | - Patricia A. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Luigi G. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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Perera T, Abhayawardhana P, Marzilli PA, Fronczek FR, Marzilli LG. 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. Inorg Chem 2013; 52:2412-21. [PMID: 23421481 PMCID: PMC4465213 DOI: 10.1021/ic302180t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We demonstrate that a tertiary sulfonamide group, N(SO2R)R'2, can rehybridize 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 sp(2)-to-sp(3) rehybridization, 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-[M(I)(CO)3](+) core (M = (99m)Tc, (186/188)Re) in imaging and therapy. The sulfonamide group uniquely contributes to two of our goals: expanding ways to conjugate the fac-[M(I)(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-[Re(I)(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.
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Affiliation(s)
- Theshini Perera
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | | | - Patricia A. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Luigi G. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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Kannan R, Pillarsetty N, Gali H, Hoffman TJ, Barnes CL, Jurisson SS, Smith CJ, Volkert WA. Design and synthesis of a bombesin peptide-conjugated tripodal phosphino dithioether ligand topology for the stabilization of the fac-[M(CO)3]+ core (M=(99 m)Tc or Re). Inorg Chem 2011; 50:6210-9. [PMID: 21591746 DOI: 10.1021/ic200491z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A new tumor-seeking tridentate topology consisting of a phosphino dithioether ((HOCH(2))(2)PCH(2)CH(2)S(CH(2))(n)CH(2)SR; PS(2)) ligand framework for the production of kinetically inert and in vivo stable facial [(99m)Tc(CO)(3)(PS(2))](+) or [Re(CO)(3)(PS(2))](+) is described. The X-ray crystal structure of fac-Re(CO)(3)(PS(2))PF(6) is reported. The bioconjugation strategies for incorporating bombesin (BBN) peptides on to the PS(2) tripodal framework and, thereby, de novo designing of GRP receptor-seeking Tc(PS(2)-BBN)(CO)(3) are developed.
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Affiliation(s)
- Raghuraman Kannan
- Department of Radiology, University of Missouri, Columbia, Missouri 65211, USA.
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Perera T, Marzilli PA, Fronczek FR, Marzilli LG. NH NMR shifts of new structurally characterized fac-[Re(CO)3(polyamine)]n+ complexes probed via outer-sphere hydrogen-bonding interactions to anions, including the paramagnetic [Re(IV)Br6]2- anion. Inorg Chem 2010; 49:5560-72. [PMID: 20481637 PMCID: PMC2910926 DOI: 10.1021/ic100386c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
fac-[Re(I)(CO)(3)L](n) complexes serve as models for short-lived fac-[(99m)Tc(I)(CO)(3)L](n) imaging tracers (L = tridentate ligands forming two five-membered chelate rings defining the L face). Dangling groups on L, needed to achieve desirable biodistribution, complicate the NMR spectra, which are not readily understood. Using less complicated L, we found that NH groups (exo-NH) projecting toward the L face sometimes showed an upfield shift attributable to steric shielding of the exo-NH group from the solvent by the chelate rings. Our goal is to advance our ability to relate these spectral features to structure and solution properties. To investigate whether exo-NH groups in six-membered rings exhibit the same effect and whether the presence of dangling groups alters the effect, we prepared new fac-[Re(CO)(3)L](n+) complexes that allow direct comparisons of exo-NH shifts for six-membered versus five-membered chelate rings. New complexes were structurally characterized with the following L: dipn [N-3-(aminopropyl)-1,3-propanediamine], N'-Medipn (3,3'-diamino-N-methyldipropylamine), N,N-Me(2)dipn (N,N-dimethyldipropylenetriamine), aepn [N-2-(aminoethyl)-1,3-propanediamine], trpn [tris-(3-aminopropyl)amine], and tren [tris-(2-aminoethyl)amine]. In DMSO-d(6), the upfield exo-NH signals were exhibited by all complexes, indicating that the rings sterically shield the exo-NH groups from bulky solvent molecules. This interpretation was supported by exo-NH signal shift changes caused by added halide and [ReBr(6)](2-) anions, consistent with outer-sphere hydrogen-bond interactions between these anions and the exo-NH groups. For fac-[Re(CO)(3)(dipn)]PF(6) in acetonitrile-d(3), the exo-NH signal shifted further downfield in the series, Cl(-) > Br(-) > I(-), and the plateau in the shift change required a lower concentration for smaller anions. These results are consistent with steric shielding of the exo-NH groups by the chelate rings. Nevertheless, despite its size, the shape and charge of [ReBr(6)](2-) allowed the dianion to induce large upfield paramagnetic shifts of the exo-NH signal of fac-[Re(CO)(3)(dipn)]PF(6). This dianion shows promise as an outer-sphere hydrogen-bonding paramagnetic shift reagent.
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Affiliation(s)
- Theshini Perera
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Patricia A. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Luigi G. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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Perera T, Marzilli PA, Fronczek FR, Marzilli LG. Several novel N-donor tridentate ligands formed in chemical studies of new fac-Re(CO)3 complexes relevant to fac-99mTc(CO)3 radiopharmaceuticals: attack of a terminal amine on coordinated acetonitrile. Inorg Chem 2010; 49:2123-31. [PMID: 20104873 DOI: 10.1021/ic901705x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To evaluate syntheses of fac-[Re(CO)(3)L](+) complexes in organic solvents, we treated fac-[Re(CO)(3)(CH(3)CN)(3)]PF(6)/BF(4) in acetonitrile with triamine ligands (L). When L had two primary or two tertiary terminal amine groups, the expected fac-[Re(CO)(3)L](+) complexes formed. In contrast, N,N-dimethyldiethylenetriamine (N,N-Me(2)dien) formed an unusual compound, fac-[Re(CO)(3)(DAE)]BF(4) {DAE = (Z)-N'-(2-(2-(dimethylamino)ethylamino)ethyl)acetimidamide = (Me(2)NCH(2)CH(2))NH(CH(2)CH(2)N=C(NH(2))Me)}. DAE is formed by addition of acetonitrile to the N,N-Me(2)dien terminal primary amine, converting this sp(3) nitrogen to an sp(2) nitrogen with a double bond to the original acetonitrile sp carbon. The three Ns bound to Re derive from N,N-Me(2)dien. The pathway to fac-[Re(CO)(3)(DAE)]BF(4) is suggested by a second unusual compound, fac-[Re(CO)(3)(MAE)]PF(6) {MAE = N-methyl-N-(2-(methyl-(2-(methylamino)ethyl)amino)ethyl)acetimidamide = MeN(H)-CH(2)CH(2)-N(Me)-CH(2)CH(2)-N(Me)-C(Me)=NH}, isolated after treating fac-[Re(CO)(3)(CH(3)CN)(3)]PF(6) with N,N',N''-trimethyldiethylenetriamine (N,N',N''-Me(3)dien). MAE chelates via a terminal and a central sp(3) N from N,N',N''-Me(3)dien and via one sp(2) NH in a C(Me)=NH group. This group is derived from acetonitrile by addition of the other N,N',N''-Me(3)dien terminal amine to the nitrile carbon. This addition creates an endocyclic NMe group within a seven-membered chelate ring. The structure and other properties of fac-[Re(CO)(3)(MAE)]PF(6) allow us to propose a reaction scheme for the formation of the unprecedented DAE ligand. The new compounds advance our understanding of the spectral and structural properties of Re analogues of (99m)Tc radiopharmaceuticals.
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Affiliation(s)
- Theshini Perera
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Exploring water-soluble Pt(II) complexes of diethylenetriamine derivatives functionalized at the central nitrogen. Synthesis, characterization, and reaction with 5′-GMP. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.02.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Velayudham M, Rajagopal S. Synthesis, characterization, photophysics and intramolecular energy transfer process in bimetallic rhenium(I)–ruthenium(II) complexes. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2009.08.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Manono J, Marzilli PA, Fronczek FR, Marzilli LG. New Porphyrins Bearing Pyridyl Peripheral Groups Linked by Secondary or Tertiary Sulfonamide Groups: Synthesis and Structural Characterization. Inorg Chem 2009; 48:5626-35. [DOI: 10.1021/ic900600z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Janet Manono
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Patricia A. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Luigi G. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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Manono J, Marzilli PA, Marzilli LG. New Porphyrins Bearing Positively Charged Peripheral Groups Linked by a Sulfonamide Group to meso-Tetraphenylporphyrin: Interactions with Calf Thymus DNA. Inorg Chem 2009; 48:5636-47. [DOI: 10.1021/ic900385y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Janet Manono
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Patricia A. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Luigi G. Marzilli
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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