Formation, reactivity, photorelease, and scavenging of NO in ruthenium nitrosyl complexes

• Published in: Inorganica Chimica Acta Vol. 502; p. 119360
• Main Authors: Giri, Bishnubasu, Kumbhakar, Sadananda, Kalai Selvan, K., Muley, Arabinda, Maji, Somnath
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2020; Elsevier Science Ltd
• Subjects: Acetonitrile; Crystal structure; Deoxygenation; Electrochemistry; Ligand design; Myoglobins; Nitrogen dioxide; Photocleavage; Room temperature; Ruthenium; Scavenging; Single crystals; Spectra; Structure; Electrochemistry; Ligand design; Spectra; Ruthenium; Structure; Photocleavage
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2019.119360

The co-ligands dmdptz: (N,N-dimethyl-4,6-di(pyridin-2-yl)-1,3,5-triazin-2-amine) and phen: (1,10-phenanthroline) in the selective framework [RuII(dmdptz)(phen)(NO)]n+ stabilized both in {RuNO}6 and {RuNO}7 configurations. A sizeable shift in ν(NO) frequency (Δν = 361cm−1) has been observed on moving from [RuII(dmdptz)(phen)(NO+)](ClO4)3 [4](ClO4)3 to [RuII(dmdptz)(phen)(NO)](ClO4)2 [5](ClO4)2 primarily due to “NO” based electron transfer. On exposure to visible light both [4](ClO4)3 and [5](ClO4)2 spontaneously transform to their corresponding solvated derivative [RuII(dmdptz)(phen)(CH3CN)](ClO4)2 [2](ClO4)2 via the facile photocleavage of RuNO bond and the photoreleased “NO” can be trapped by myoglobin. [Display omitted] •Formation of newer frameworks of ruthenium nitrosyl complexes with both {Ru–NO}6 and {Ru–NO}7 configurations.•Structure elucidation of ruthenium nitrosyl complex along with precursor complexes.•Photo induced cleavage of RuNO bond in both {Ru  NO}6 and {Ru  NO}7 configurations.•Photoreleased NO trapping by myoglobin as MbsbndNO adduct. The two newly designed nitrosyl complexes with Enemark–Feltham notation {RuNO}6 and {RuNO}7 configurations have been isolated as the perchlorate salts in the molecular framework [RuII(dmdptz)(phen)(NO)]n+ (dmdptz: N,N-dimethyl-4,6-di(pyridin-2-yl)-1,3,5-triazin-2-amine and phen: 1,10-phenanthroline) [RuII(dmdptz)(phen)(NO+)](ClO4)3 [4](ClO4)3 and [RuII(dmdptz)(phen)(NO)](ClO4)2 [5](ClO4)2 respectively. The single crystal X-ray structures of complexes [RuII(dmdptz)(phen)Cl](ClO4) [1](ClO4), [RuII(dmdptz)(phen)(NO2)](ClO4) [3](ClO4) and [4](ClO4)3 have been determined. The π– acceptance of the NO+ moiety in [4](ClO4)3 is reflected from the triple bond characteristic bond length 1.131(5) Å with simultaneous trans angle of 175.3(4)° as a proof of true linear coordination mode. A sizable shift in ν (NO) frequency (Δν = 361 cm−1) on moving from [4](ClO4)3 to [5](ClO4)2 are in good agreement for largely NO centered reduction with the changes in bonding {RuNO}6 [4](ClO4)3 to {RuNO}7 [5](ClO4)2. The redox properties of [4](ClO4)3 along with the precursor complexes, have been investigated. On exposure to visible light in the deoxygenated acetonitrile solution at room temperature both [4](ClO4)3 and [5](ClO4)2 spontaneously transform to their corresponding solvated derivative [RuII(dmdptz)(phen)(CH3CN)](ClO4)2 [2](ClO4)2 via the facile photocleavage of Ru–NO bond with KNO 9.26 × 10−3 min−1 (t1/2 = 74 min) and 4.03 × 10−2 min−1 (t1/2 = 17 min) respectively. The photoreleased “NO” can be scavenged by biologically relevant target molecule myoglobin as an MbNO adduct.