Binuclear manganese(II)-thiolate complexes: Synthesis, characterization and nitrite induced structural changes

The hitherto unexplored reactivity of Mn(II) towards thiolates has been investigated. The reaction of a hydrated Mn(II) salt with HN-Et-HPTB ( N,N,N', N'-tetrakis(2-(1-ethylbenzimidazolyl))-2-hydroxy-1,3 diaminopropane) and Et3N yielded, [Mn-2(N-Et-HPTB)(DMF)(4)](3+) (1), while the use of MnCl2 yielded [Mn-2(N-Et-HPTB)(Cl)(DMF)(2) ](2+) (2). Further treatment of 2 with Et4NCl, produced [Mn-2(N-Et-HPTB)(Cl)(2)](1+) (3). Treatment of either 1 or 3 with NaSPh produces [Mn-2(N-Et-HPTB)(SPh)(2)](1+) ( 4 ). The reaction of a hydrated Mn(II) salt with HN-Et-HPTB and Et3N in the presence of (RCOSH)-C-1(R-1 = Me, Ph), (RCOOH)-C-2 (R-2 = p-SH-C6H4, HS-CH2CH2) and PhCOONa, under similar conditions yielded [Mn-2(N-Et-HPTB)(SCOR1)](2+) (R-1 = Me, 5a ; Ph, 5b ), [Mn-2(N-Et-HPTB)(mu-OOCR2)](2+) (R-2 = p-SH-C6H4, 6a ; HS-CH2CH2, 6b ) and [Mn-2(N-EtHPTB)(PhCOO)](2+) (6c), while the use of 2-mercapto pyridine (o-SH-Py) or 4-mercapto pyridine (p-SHPy) yielded [Mn-2(N-Et-HPTB)(o-S-Py)](2+) (7) and [Mn-2(N-Et-HPTB)(p-S-Py)](2+) (8). Further reaction of 1, 6c, 5b and 7 , with NO2- yielded [Mn-2(N-Et-HPTB)(kappa O-2-NO2)(2)](1+) (9), [Mn-2 (N-Et-HPTB)(kappa O-2-O2 CPh)(kappa O-2- NO2)](1+) ( 10 ), [Mn-2(N-Et-HPTB)(kappa OS-SCOPh)(kappa O-2-NO2))](1+) (11) and [Mn-2(N-Et-HPTB)(kappa OS-o-S-Py)(kappa O-2-NO2))](1+) ( 12 ), respectively. Complexes 10 -12 revealed interesting structural changes involving coordination mode shift of the carboxylate/thiocaboxylate bridges. Interestingly, further reaction of 9 with 4 equiv of PhSH (to remove the coordinated NO2- as HNO2) yielded 4 and diphenyldisulfide via formation of PhSNO upon reaction of HNO2 and PhSH.(c) 2022 Elsevier B.V. All rights reserved.