Not so elusive: [Fe(II)(CN)(5)(HNO)](3-) has been characterized spectroscopically after the two-electron reduction of nitroprusside (see scheme). The complex is stable at pH 6, slowly decomposing to [Fe(CN)(6)](4-) and N(2)O. It is deprotonated at increasing pH value with oxidation of bound NO(-) to [Fe(II)(CN)(5)(NO)](3-). [Fe(II)(CN)(5)(HNO)](3-) is the first non-heme iron-nitroxyl complex prepared in aqueous solution that is reversibly redox-active under biologically relevant conditions.

Several research efforts on cocoa have been focused on parameters for controlling the transformation process to guarantee homogeneity and quality of cocoa beans, the main raw material in the chocolate industry. The main changes that determine the final quality of cocoa—and also the product’s homogeneity—occur during fermentation, given the great number of factors that affect the process. This research seeks to identify the most relevant factors affecting quality in order to offer higher-quality and more homogeneous cocoa for the chocolate industry. The dynamics of the fermentation process were observed in three contrasting locations, monitoring different variables and evaluating the final quality of the cocoa. Results show that temperature and pH profile are the key factors to be monitored and controlled in order to achieve high-quality cocoa beans.

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[FeII(CN)5(HNO)]3−, ein Produkt der Zwei‐Elektronen‐Reduktion von Nitroprussid (siehe Schema), wurde spektroskopisch charakterisiert. Der Komplex ist in wässriger Lösung bei pH 6 stabil und zersetzt sich nur langsam zu [Fe(CN)6]4− und N2O. Bei steigendem pH‐Wert wird er unter Oxidation von NO− zu [FeII(CN)5(NO)]3− deprotoniert. [FeII(CN)5(HNO)]3− ist der erste Nichthäm‐Eisennitroxylkomplex mit reversibler Redoxaktivität unter physiologischen Bedingungen.

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