The synthesis, characterization and structures of the chromium(III) dinitrito complexes: trans-[Cr(L)(ONO)2]+ (L=1,4,8,11-tetraazacyclotetradecane or 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)

Leo, Malcolm A. De; Bu, Xianhui; Bentow, Jason; Ford, Peter C.

doi:10.1016/s0020-1693(00)00027-x

Cited by 34 publications

(17 citation statements)

References 21 publications

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“…tran s-Cr(cyclam)(Cl) 2 Cl was synthesized according to published procedures by Ferguson and Poon et al Cyclam (1,4,8,11-tetrazacycltetradecane, 98%) was purchased from Aldrich, and trichlorotris(tetrahydrofuran)chromium(III) was purchased from Sigma. The trans -Cr(cyclam)(ONO) 2 BF 4 was prepared from trans -Cr(cyclam)(Cl) 2 Cl according to a method slightly modified from that of DeLeo et al Briefly, trans -Cr(cyclam)(Cl) 2 Cl (50 mg) was dissolved in deionized H 2 O (<5 mL) to which 20 equiv of NaNO 2 was added. The purple solution was refluxed in the dark for 2 h. After reflux, the resulting orange solution was cooled slightly and NaBF 4 was added.…”

Section: Methodsmentioning

confidence: 99%

Liposome Encapsulation of a Photochemical NO Precursor for Controlled Nitric Oxide Release and Simultaneous Fluorescence Imaging

et al. 2012

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Described are photochemical studies of the nitric oxide precursors, trans-Cr(L)(ONO)(2)(+) (L = cyclam = 1,4,8,11-tetraazacyclotetradecane, CrONO, or L = mac = 5,7-dimethyl-6-anthracenylcyclam, mac-CrONO) encapsulated in phosphatidylcholine liposomes. The liposomes provide a means to maintain a localized high concentration of NO releasing complexes and are easily modified for in vivo targeting through self-assembly. Steady, controlled release of NO is seen after photolysis of the liposome-encapsulated CrONO as compared to the burst of NO release seen by the unencapsulated complex in oxygenated solutions. The quantum yields for photochemical NO release from liposome-encapsulated CrONO and mac-CrONO were determined in both oxygenated and anoxic solutions. The quantum yield for NO release in oxygenated solution for encapsulated CrONO was more than 5 times larger than that of unencapsulated CrONO, thus the net NO released after photolysis in oxygenated solutions is enhanced by encapsulation of CrONO in liposomes. Encapsulated mac-CrONO shows NO release after photolysis with low-intensity blue light. Furthermore, the fluorescence of mac-CrONO can be detected through the liposomes, thus allowing for development of theranostic NO delivery vessels where tracking and imaging can occur simultaneously with therapeutic NO release. This work provides insight into the development of multifunctional liposome constructs for disease theranostics.

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Section: Methodsmentioning

confidence: 99%

Liposome Encapsulation of a Photochemical NO Precursor for Controlled Nitric Oxide Release and Simultaneous Fluorescence Imaging

et al. 2012

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“…Synthesis of Chromium(III) Dinitrito Complexes. The dinitrito complexes were prepared by the reactions of the dichloro analogues with silver nitrite according to the procedure reported by DeLeo et al The previously reported 12 trans -[Cr(cyclam)(ONO) 2 ]BF 4 ( I ) was prepared in this manner from trans -[Cr(cyclam)Cl 2 ]Cl with 87.2% yield. ESI-MS ( m / z ): 344 (M + ).…”

Section: Methodsmentioning

confidence: 99%

Chromium(III) Complexes for Photochemical Nitric Oxide Generation from Coordinated Nitrite: Synthesis and Photochemistry of Macrocyclic Complexes with Pendant Chromophores, trans-[Cr(L)(ONO)₂]BF₄

DeRosa

Ford

2005

Inorg. Chem.

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Several new dinitritochromium(III) complexes of the type trans-[Cr(L)(ONO)(2)]BF(4), where L is a derivative of the macrocyclic ligand cyclam having pendant aromatic chromophores attached (L = 5,7-dimethyl-6-(substituted)-1,4,8,11-tetraazacyclotetradecane), have been prepared and characterized. Photoexcitation of aqueous solutions containing these complexes at wavelengths corresponding to the pendant chromophore absorption bands led to the generation of NO as detected by an electrochemical sensor. Photophysical data show that the expected fluorescence of the pendant chromophores is largely quenched when the macrocyclic ligand is coordinated to these Cr(III) centers, and this is interpreted in terms of fast energy transfer processes from the ligand-centered pipi states to the Cr(III)-centered ligand field states leading to subsequent cleavage of the Cr(III)-coordinated nitrito ligand. Thus, the chromophores tethered to the coordinated cyclam serve as light-gathering antennae for the intramolecular sensitization of the NO-generating photoreactions at the metal center.

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“…For example, the oxophilic chromium(III) center in trans-Cr(cyclam)(ONO) 2 + binds both nitrite ions as the nitrito isomers [50] while softer metal centers such as the cobalt(III) of Co(NH 3 ) 5 (NO 2 ) 2+ give the nitro-complexes. The metastable nitrito isomer Co(NH 3 ) 5 (ONO) 2+ can be prepared by photolysis, but this spontaneously reverts to the thermodynamically favored nitro form by a unimolecular pathway [51].…”

Section: The Coordination Chemistry Of Nitritementioning

confidence: 99%

Mechanistic studies of nitrite reactions with metalloproteins and models relevant to mammalian physiology

Heinecke

Ford

2010

Coordination Chemistry Reviews

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The synthesis, characterization and structures of the chromium(III) dinitrito complexes: trans-[Cr(L)(ONO)2]+ (L=1,4,8,11-tetraazacyclotetradecane or 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)

Cited by 34 publications

References 21 publications

Liposome Encapsulation of a Photochemical NO Precursor for Controlled Nitric Oxide Release and Simultaneous Fluorescence Imaging

Liposome Encapsulation of a Photochemical NO Precursor for Controlled Nitric Oxide Release and Simultaneous Fluorescence Imaging

Chromium(III) Complexes for Photochemical Nitric Oxide Generation from Coordinated Nitrite: Synthesis and Photochemistry of Macrocyclic Complexes with Pendant Chromophores, trans-[Cr(L)(ONO)₂]BF₄

Mechanistic studies of nitrite reactions with metalloproteins and models relevant to mammalian physiology

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The synthesis, characterization and structures of the chromium(III) dinitrito complexes: trans-[Cr(L)(ONO)2]+ (L=1,4,8,11-tetraazacyclotetradecane or 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)

Cited by 34 publications

References 21 publications

Liposome Encapsulation of a Photochemical NO Precursor for Controlled Nitric Oxide Release and Simultaneous Fluorescence Imaging

Liposome Encapsulation of a Photochemical NO Precursor for Controlled Nitric Oxide Release and Simultaneous Fluorescence Imaging

Chromium(III) Complexes for Photochemical Nitric Oxide Generation from Coordinated Nitrite: Synthesis and Photochemistry of Macrocyclic Complexes with Pendant Chromophores, trans-[Cr(L)(ONO)2]BF4

Mechanistic studies of nitrite reactions with metalloproteins and models relevant to mammalian physiology

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Chromium(III) Complexes for Photochemical Nitric Oxide Generation from Coordinated Nitrite: Synthesis and Photochemistry of Macrocyclic Complexes with Pendant Chromophores, trans-[Cr(L)(ONO)₂]BF₄