Colloids and Surfaces A: Physicochem. Eng. Aspects 236 (2004) 165–169 Interaction of ribose nucleotides with metal ferrocyanides and its relevance in chemical evolution Shah Raj Ali, Jahangeer Ahmad, Kamaluddin ∗ Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India Received 21 August 2003; accepted 4 February 2004 Abstract Interaction of ribose nucleotides with cobalt- and cadmium ferrocyanides was found maximum at neutral pH. Adsorption trend fol- lowed Langmuir isotherms. The Langmuir constants, X m and K L were calculated. Purine nucleotides adsorbed more than pyrimidine nu- cleotides on both the metal ferrocyanides. Cobalt ferrocyanide was found a better adsorbent for all the ribose nucleotides studied. In- frared spectral studies of the adsorption adducts suggested that the adsorption occurs due to interaction of ribose nucleotide molecule with outer divalent metal ion present in the lattice of metal ferrocyanides. The results of the present study suggest that the metal ferrocyanides could have concentrated and stabilised the ribose nucleotides on their surface through adsorption processes during the course of chemical evolution. © 2004 Elsevier B.V. All rights reserved. Keywords: Interaction; Adsorption; Metal ferrocyanide; Ribose nucleotides 1. Introduction During the last few decades several attempts have been made to trace out the steps involved in the formation of im- portant biomonomers such as amino acids and nucleotides from simple molecules present in the prebiotic environment [1]. However, the means through which the biomonomers were concentrated from their dilute aqueous solutions have not yet been clearly understood. It has been proposed that clays and clay minerals might have provided their surface onto which biomonomers could have concentrated [2–11]. Biomonomers thus concentrated, would have been protected from degradation and might have undergone a class of re- actions such as condensation, oligomerisation and redox re- actions to produce essential material for prebiotic synthesis [12–15]. The existence of a good correlation between the concen- tration of minor transition elements with their biological be- haviour has been proposed [16], which indicates the presence of important biotransition metals such as iron, zinc, man- ganese, copper, cobalt, etc. in primeval sea. It is generally ∗ Corresponding author. Fax: +91-1332-273560. E-mail address: kamalfcy@iitr.ernet.in (Kamaluddin). accepted that the transition metal ions abundantly present in primeval sea, might have formed complexes with simple molecules available to them [17]. Due to ease of formation of cyanide ions under prebiotic condition [18] and its strong field nature, it is reasonable to assume that cyanide ions might have formed a number of insoluble and soluble com- plexes with transition metal ions present in primeval sea. The existence of ferri-ferrocyanides on anoxic archean hy- drosphere has been recently proposed [19]. Since most of the metal ferrocyanides are water insoluble, it is, therefore, assumed that they might have locally settled at the bottom of sea or at sea shore. They might have provided the means of concentrating the biomonomers through adsorption pro- cesses on their surface. The biomonomers so concentrated might have protected from degradation and condensed into biopolymers, which might have been essential for prebiotic synthesis. In our laboratory, experimental studies on the possible role of metal ferrocyanides in chemical evolution have been carried out [20–25] during the last few years and the efforts are being made to establish the metal cyanogen complexes as prebiotic catalyst. The present investigation describes the interaction of ribose nucleotides on cobalt- and cadmium ferrocyanides. 0927-7757/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfa.2004.02.004