68 https://doi.org/10.1107/S2056989016019915 Acta Cryst. (2017). E73, 68–71 research communications Received 2 December 2016 Accepted 14 December 2016 Edited by W. T. A. Harrison, University of Aberdeen, Scotland Keywords: crystal structure; -pyridylvinyl- idene; binuclear complex; iron; palladium. CCDC reference: 1523136 Supporting information: this article has supporting information at journals.iucr.org/e Crystal structure of l-carbonyl-1:2j 2 C:C-carbonyl- 1jC-(1g 5 -cyclopentadienyl)iodido-2jI-[l-2- (pyridin-2-yl)ethene-1,1-diyl-1jC 1 :2j 2 N,C 1 ]- ironpalladium(Fe—Pd) benzene monosolvate Victor V. Verpekin, a Arkadii Z. Kreindlin, b Oleg V. Semeikin, b Alexander F. Smol’yakov, b Fedor M. Dolgushin, b * Oleg S. Chudin a and Nikolai A. Ustynyuk b a Institute of Chemistry and Chemical Technology, Krasnoyarsk Research Center, Siberian Branch of the Russian Academy of Sciences, Akademgorodok 50-24, Krasnoyarsk, 660036, Russian Federation, and b A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, Moscow 119991, Russian Federation. *Correspondence e-mail: fedya@ineos.ac.ru The reaction of Cp(CO) 2 FeI with 2-ethynylpyridine under Sonogashira conditions [5% PdCl 2 (PPh 3 ) 2 , 10% CuI, THF–NEt 3 (2:1)] afforded the title binuclear -pyridylvinylidene FePd complex (FePd1) as a benzene solvate, [FePd(C 5 H 5 )(C 7 H 5 N)I(CO) 2 ]C 6 H 6 , in a very low yield rather than the expected iron o-pyridylethynyl complex Cp(CO) 2 Fe—C C-(2-C 5 H 4 N). The Fe and Pd atoms in FePd1 are bridged by carbonyl and pyridylvinylidene ligands, the pyridyl N atom being bonded to the palladium atom. The use of equimolar amounts of PdCl 2 increases the yield of FePd1 to 12%. The reaction pathway leading to FePd1 is proposed. 1. Chemical context Transition metal -pyridylethynyl complexes attract consid- erable research interest since they can act as precursors for pyridylvinylidene complexes (Chou et al., 2008) and as buildings blocks for supramolecular assemblies in molecular electronics (Le Stang et al., 1999), as well as materials for non- linear optics (Wu et al., 1997). Since the presence of two Lewis base centres (C  and N atoms) makes pyridylethynyl complexes potential catalysts for electrochemical proton reduction (Valyaev et al. , 2007), we decided to study the CV behavior of the o-pyridylethynyl iron complex Cp(CO) 2 Fe-C C-(2-C 5 H 4 N) in acidified solutions. The efficient preparation of iron arylethynyls Cp(CO) 2 Fe- C C-Ar by Pd/Cu-catalyzed Sonogashira coupling of ISSN 2056-9890