ORIGINAL PAPER Tailoring the properties of manganocene: formation of magnetic superalkali/superhalogen Rakesh Parida 1 & G. Naaresh Reddy 1 & Ricardo Inostroza-Rivera 2 & Arindam Chakraborty 3 & Santanab Giri 4 Received: 10 March 2019 /Accepted: 17 June 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract A new magnetic superalkali/superhalogen molecule based on the sandwich complex manganocene is reported. The hydrogen atoms of the cyclopentadienyl rings are periodically substituted with electron-donating and electron-withdrawing ligands (or both) to design substituted manganocene complexes. The substituted manganocene complexes exhibit the properties of superalkali and/or superhalogen depending on the nature of the substituents. The substituents, therefore, act as “switches” that can modify the properties of the parent manganocene moiety by keeping its magnetic nature intact. The substituted complexes also show marked nonlinear optical behavior. Keywords Superalkali . Superhalogen . NLO property . DFT . Manganocene Introduction Oxidants and reductants have a direct bearing on the mechanistic course of chemical reactions. Due to their apt electronic config- uration along with correspondingly low ionization energy (IE) and high electron affinity (EA) values, the alkali metals (ns 2 np 1 ) and halogens (ns 2 np 5 ) are well-known reductants and oxidants, respectively. The past three decades have witnessed the design and synthesis of many stable compounds whose IE or EA values are reportedly lower than the alkali metals or higher than halo- gens, respectively. Such atomic clusters are termed superalkali [1–3] (lower IE than alkali metals) and superhalogens [4–11] (higher EA than halogens), respectively. Superalkalis, with a gen- eral formula M k+1 L (where M is the alkali metal and L is an electronegative atom with valance k), and superhalogens, with a general formula MX k+1 (where M is a metal atom with maximal valence k and X is a halogen atom), are already reported in the chemical literature. Typical examples of molecules representing the class of superalkalis are Li 3 O, NLi 4 , LiF 2 , and those of superhalogens are BF 4 , BeF 3 , PF 6 . Attempts have also been made to design superalkali and superhalogen molecules that do not mimic their general formula. In this regard, two relevant studies by Miao et al. and Vikash et al. deserve special mention: Miao et al. [12] designed a special type of superhalogen Mn x Cl 2x + 1 (x = 1,2,3,4...) that exhibits magnetic character, while Vikash et al. [13] reported a new type of superparamagnetic superalkali species by ligating the Ni 9 Te 6 cluster. Although a variety of organic, inorganic, atomic, aromatic organometallic, and organo-Zintl and molecular clusters [14–25] have been re- ported so far as behaving like superalkalis and superhalogens, analogous studies based on the well-known sandwich complexes like ferrocene and manganocene are not known. In this study, we made an attempt to design superalkali and superhalogen cluster specimens based on manganocene. Manganocene (CpMnCp) (Cp: cyclopentadienyl) is a unique organometallic compound in some aspects. It shows notable paramagnetism and, in spite of being a 17-electron system, it is a stable molecule. Thus, the This paper belongs to Topical Collection QUITEL 2018 (44th Congress of Theoretical Chemists of Latin Expression) Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00894-019-4100-x) contains supplementary material, which is available to authorized users. * Ricardo Inostroza-Rivera riinostroz@unap.cl * Santanab Giri santanab.giri@gmail.com 1 Department of Chemistry, National Institute of Technology Rourkela, Rourkela, Odisha 769008, India 2 Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile 3 Faculty of Science, Jatragachi Pranabananda High School, New Town, Kolkata 700161, India 4 School of Applied Sciences and Humanities, Haldia Institute of Technology, Haldia 721657, India Journal of Molecular Modeling (2019) 25:218 https://doi.org/10.1007/s00894-019-4100-x