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Controlling Ligand Substitution Reactions of Organometallic Complexes: Tuning Cancer Cell Cytotoxicity
Controlling ligand substitution reactions of organometallic complexes: Tuning cancer cell cytotoxicity Fuyi Wang*, Abraha Habtemariam*, Erwin P. L. van der Geer*, Rafael Ferna´ ndez*, Michael Melchart*, Robert J. Deeth†, Rhona Aird‡, Sylvie Guichard‡, Francesca P. A. Fabbiani*, Patricia Lozano-Casal*, Iain D. H. Oswald*, Duncan I. Jodrell‡, Simon Parsons*, and Peter J. Sadler*§ *School of Chemistry, University of Edinburgh, West Mains Road, EH9 3JJ Edinburgh, United Kingdom; †Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom; and ‡CRUK Pharmacology and Drug Development Team, University of Edinburgh Cancer Research Centre, Cancer Research UK Oncology Unit, Crewe Road South, EH4 2XR Edinburgh, United Kingdom Edited by Jack Halpern, University of Chicago, Chicago, IL, and approved October 27, 2005 (received for review July 11, 2005) Organometallic compounds offer broad scope for the design of the factors that control the aqueous chemistry of organometallic therapeutic agents, but this avenue has yet to be widely explored. complexes may therefore also allow the design of effective A key concept in the design of anticancer complexes is optimization anticancer agents. of chemical reactivity to allow facile attack on the target site (e.g., Our studies are focused on monofunctional ruthenium(II) arene DNA) yet avoid attack on other sites associated with unwanted anticancer complexes of the type [(6-arene)Ru(ethylenediamin- side effects. Here, we consider how this result can be achieved for e)(X)]nϩ, where X is a leaving group (e.g., Cl). In these pseudooc- monofunctional ‘‘piano-stool’’ ruthenium(II) arene complexes of tahedral ‘‘piano-stool’’ RuII complexes, a -bonded arene (the the type [(6-arene)Ru(ethylenediamine)(X)]n؉. -
Cyclic Voltammetry of Mono- and Diiron(II)Cyclopentadienyl Complexes of Thianthrene and Related Heterocycles R
Subscriber access provided by University of Texas Libraries Cyclic voltammetry of mono- and diiron(II)Cyclopentadienyl complexes of thianthrene and related heterocycles R. Quin Bligh, Roger Moulton, Allen J. Bard, Adam Piorko, and Ronald G. Sutherland Inorg. Chem., 1989, 28 (13), 2652-2659 • DOI: 10.1021/ic00312a030 Downloaded from http://pubs.acs.org on January 30, 2009 More About This Article The permalink http://dx.doi.org/10.1021/ic00312a030 provides access to: • Links to articles and content related to this article • Copyright permission to reproduce figures and/or text from this article Inorganic Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 2652 Inorg. Chem. 1989, 28, 2652-2659 nate-bond formation, not only for the metal-dioxygen bond but constant reported by Baker et al." For CoSALTMEN, the ox- also for the coordinate bonds between the metal ion and the ligand ygenation constant found here for diglyme solution at 0.5 "C is donor atoms. The increase in the electropositive nature of the very small, ca. -3.5, while the value reportedI2 for DMAC solution metal ion on oxygenation results in strengthening of its coordinate at 5 OC is similar, ca. -3.4. These low values, which seem to be bonds, thus contributing considerably to the exothermicity of the lower than those of any other cobalt Schiff base complexes re- reaction. All entropies of oxygenation are seen to be negative, ported, may indicate steric effects resulting from the distortion a general characteristic for all oxygenation processes. The observed from planarity of the ligand by the four methyl substituents on decrease of entropy is considered derived from two sources: (1) the ethylene bridge. -
Organometallics Study Meeting H.Mitsunuma 1
04/21/2011 Organometallics Study Meeting H.Mitsunuma 1. Crystal field theory (CFT) and ligand field theory (LFT) CFT: interaction between positively charged metal cation and negative charge on the non-bonding electrons of the ligand LFT: molecular orbital theory (back donation...etc) Octahedral (figure 9-1a) d-electrons closer to the ligands will have a higher energy than those further away which results in the d-orbitals splitting in energy. ligand field splitting parameter ( 0): energy between eg orbital and t2g orbital 1) high oxidation state 2) 3d<4d<5d 3) spectrochemical series I-< Br-< S2-< SCN-< Cl-< N -,F-< (H N) CO, OH-< ox, O2-< H O< NCS- <C H N, NH < H NCH CH NH < bpy, phen< NO - - - - 3 2 2 2 5 5 3 2 2 2 2 2 < CH3 ,C6H5 < CN <CO cf) pairing energy: energy cost of placing an electron into an already singly occupied orbital Low spin: If 0 is large, then the lower energy orbitals(t2g) are completely filled before population of the higher orbitals(eg) High spin: If 0 is small enough then it is easier to put electrons into the higher energy orbitals than it is to put two into the same low-energy orbital, because of the repulsion resulting from matching two electrons in the same orbital 3 n ex) (t2g) (eg) (n= 1,2) Tetrahedral (figure 9-1b), Square planar (figure 9-1c) LFT (figure 9-3, 9-4) - - Cl , Br : lower 0 (figure 9-4 a) CO: higher 0 (figure 9-4 b) 2. Ligand metal complex hapticity formal chargeelectron donation metal complex hapticity formal chargeelectron donation MR alkyl 1 -1 2 6-arene 6 0 6 MH hydride 1 -1 2 M MX H 1 -1 2 halogen 1 -1 2 M M -hydride M OR alkoxide 1 -1 2 X 1 -1 4 M M -halogen O R acyl 1 -1 2 O 1 -1 4 M R M M -alkoxide O 1-alkenyl 1 -1 2 C -carbonyl 1 0 2 M M M R2 C -alkylidene 1 -2 4 1-allyl 1 -1 2 M M M O C 3-carbonyl 1 0 2 M R acetylide 1 -1 2 MMM R R C 3-alkylidine 1 -3 6 M carbene 1 0 2 MMM R R M carbene 1 -2 4 R M carbyne 1 -3 6 M CO carbonyl 1 0 2 M 2-alkene 2 0 2 M 2-alkyne 2 0 2 M 3-allyl 3 -1 4 M 4-diene 4 0 4 5 -cyclo 5 -1 6 M pentadienyl 1 3. -
Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings
DOI: 10.1002/chem.200801917 Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings Rafael Fernndez,[a] Abdessamad Grirrane,[a] Irene Resa,[a] Amor Rodrguez,[a] Ernesto Carmona,*[a] Eleuterio lvarez,[a] Enrique Gutirrez-Puebla,[b] ngeles Monge,[b] Juan Miguel Lpez del Amo,[c] Hans-Heinrich Limbach,[c] Agustí Lleds,[d] Feliu Maseras,[d, e] and Diego del Ro[a, f] Abstract: New zincocenes [ZnCp’2](2– tion of 7, which yields a side-product ZnÀC bond of comparable strength to 5) with substituted cyclopentadienyl li- (C) upon attempted crystallisation. the ZnÀMe bond in ZnMe2. Zincocene gands C5Me4H, C5Me4tBu, Compounds 5 and 6 were also investi- 5 has dynamic behaviour in solution, 13 5 1 C5Me4SiMe2tBu and C5Me4SiMe3, re- gated by C CPMAS NMR spectrosco- but a rigid h /h (s) structure in the spectively, have been prepared by the py. Zincocenes 1 and 2 have infinite solid state, as revealed by 13C CPMAS reaction of ZnCl2 with the appropriate chain structures with bridging Cp’ li- NMR studies, whereas for 6 the differ- Cp’-transfer reagent. For a comparative gands, while 3 and 4 exhibit slipped- ent nature of the Cp’ ligands and of the structural study, the known sandwich geometries. Compounds 5 ring substituents of the h1-Cp’ group 5 1 [Zn(C5H4SiMe3)2](1), has also been in- and 6 have rigid, h /h (s) structures, in (Me and SiMe3) have permitted obser- 5 vestigated, along with the mixed-ring which the monohapto C5Me4SiMe3 vation for the first time of the rigid h / ACHTUNGRE 1 zincocenes [Zn(C5Me5)(C5Me4SiMe3)] ligand is bound to zinc through the h solution structure. -
Synthesis and Reactivity of Cyclopentadienyl Based Organometallic Compounds and Their Electrochemical and Biological Properties
Synthesis and reactivity of cyclopentadienyl based organometallic compounds and their electrochemical and biological properties Sasmita Mishra Department of Chemistry National Institute of Technology Rourkela Synthesis and reactivity of cyclopentadienyl based organometallic compounds and their electrochemical and biological properties Dissertation submitted to the National Institute of Technology Rourkela In partial fulfillment of the requirements of the degree of Doctor of Philosophy in Chemistry by Sasmita Mishra (Roll Number: 511CY604) Under the supervision of Prof. Saurav Chatterjee February, 2017 Department of Chemistry National Institute of Technology Rourkela Department of Chemistry National Institute of Technology Rourkela Certificate of Examination Roll Number: 511CY604 Name: Sasmita Mishra Title of Dissertation: ''Synthesis and reactivity of cyclopentadienyl based organometallic compounds and their electrochemical and biological properties We the below signed, after checking the dissertation mentioned above and the official record book(s) of the student, hereby state our approval of the dissertation submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy in Chemistry at National Institute of Technology Rourkela. We are satisfied with the volume, quality, correctness, and originality of the work. --------------------------- Prof. Saurav Chatterjee Principal Supervisor --------------------------- --------------------------- Prof. A. Sahoo. Prof. G. Hota Member (DSC) Member (DSC) --------------------------- -
Book of Abstracts-1
Volume: 3 ISMEC GROUP SERIES Year: 201 3 http:// mat520.unime.it/ismecacta/ Symposium Edition: XXI V ISSN : 2239 -2459 *Acta of the International Simposia on Metal Complex *Acta of the International Simposia on Metal Complex Begoña García , Editor Facultad de Ciencias, Universidad de Burgos, Spain President of the Scientific Committee of ISMEC201 3 Guido Crisponi, Editor University of Cagliari, Italy President of the ISMEC group ISMEC GROUP SERIES Volume: 3 Year: 201 3 ISSN: 2239-2459 Symposium Edition: XXI V Sponsors /Collaborators The following institutions and companies have supported ISMEC201 3, which we acknowledge: Sponsors : Collaborators : The Acta of the International Symposia on Metal Complexes (ISSN: 2239-2459) are published annually online by the ISMEC Group. Editors : Begoña García (President of the Scientific Committee of ISMEC 2013) Departamento de Química Facultad de Ciencias Universidad de Burgos Plaza de Missael Bañuelos s/n 09001 Burgos (Spain) [email protected] Guido Crisponi (President of the ISMEC Group) Dipartimento di Scienze Chimiche Università degli Studi di Cagliari Cittadella Universitaria 09042 Monserrato – Cagliari, ITALY [email protected] Scientific Committee of ISMEC 2013: Begoña García (University of Burgos, Spain) Guido Crisponi (University of Cagliari, Italy) Antonio Bianchi (University of Florence, Italy) Etelka Farkas (University of Debrecen, Hungary) Enrique García-España (University of Valencia, Spain) Carlos C.F. Geraldes (University of Coimbra, Portugal) Juan Niclós (University of Granada, Spain) Henryk -
1 Signature Page Biphenyl Substituted Cyclopentadienyl Ligand
Signature page Biphenyl substituted Cyclopentadienyl Ligand Complexes By Ketnavi Ramgoolam A Thesis Submitted to Saint Mary’s University, Halifax, Nova Scotia in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science Degree with Honours in Chemistry April 2019, Halifax, Nova Scotia Copyright Ketnavi Ramgoolam, 2019. Approved: Dr. Jason Masuda Supervisor Department of Chemistry Date: April 24, 2019 1 Biphenyl substituted Cyclopentadienyl Ligand Complexes By Ketnavi Ramgoolam A Thesis Submitted to Saint Mary’s University, Halifax, Nova Scotia in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science Degree with Honours in Chemistry April 2019, Halifax, Nova Scotia Copyright Ketnavi Ramgoolam, 2019. Approved: Dr. Jason Masuda Supervisor Department of Chemistry Date: April 24, 2019 2 Biphenyl substituted Cyclopentadienyl Ligand Complexes by Ketnavi Ramgoolam Abstract The synthesis of biphenyl substituted cyclopentadienyl ligands are described. The synthetic route is accomplished through the reaction of aryl lithium reagents with cobaltocenium salts, followed by oxidation of the intermediate cobalt(I) species to give the corresponding cyclopentadiene. Detailed information on their preparation, structural, and spectroscopic properties are described. A preliminary reaction towards the biphenyl substituted cyclopentadienyl ligand complexes yielding the corresponding alkali metal salt (K) is also described. Its structural and spectroscopic properties are described briefly. March 20, 2019 3 Acknowledgements First of all, I would like to express my most sincere gratitude to my supervisor, Dr. Jason Masuda, for all of his time, efforts, teachings and guidance. Thank you for being a most wonderful and understanding human being. This project helped me in discovering my potential as a chemist and I had plenty of wonderful experiences and opportunities that I personally believe will forever shape and influence my professional life as well as my personal growth. -
Progress in Inorganic Chemistry Volume 59 Advisory Board
Progress in Inorganic Chemistry Volume 59 Advisory Board JACQUELINE K. BARTON CALIFORNIA INSTITUTE OF TECHNOLOGY, PASADENA, CALIFORNIA SHUNICHI FUKUZUMI OSAKA UNIVERSITY, OSAKA, JAPAN CLARK R. LANDIS UNIVERSITY OF WISCONSIN, MADISON, WISCONSIN NATHAN S. LEWIS CALIFORNIA INSTITUTE OF TECHNOLOGY, PASADENA, CALIFORNIA STEPHEN J. LIPPARD MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE, MASSACHUSETTS JEFFREY R. LONG UNIVERSITY OF CALIFORNIA, BERKELEY, CALIFORNIA THOMAS E. MALLOUK PENNSYLVANIA STATE UNIVERSITY, UNIVERSITY PARK, PENNSYLVANIA TOBIN J. MARKS NORTHWESTERN UNIVERSITY, EVANSTON, ILLINOIS JAMES M. MAYER YALE UNIVERSITY, NEW HAVEN, CONNECTICUT DAVID MILSTEIN WEIZMANN INSTITUTE OF SCIENCE, REHOVOT, ISRAEL WONWOO NAM EWHA WOMANS UNIVERSITY, SEOUL, KOREA VIVIAN W. W. YAM UNIVERSITY OF HONG KONG, HONG KONG PROGRESS IN INORGANIC CHEMISTRY Edited by Kenneth D. Karlin DEPARTMENT OF CHEMISTRY JOHNS HOPKINS UNIVERSITY BALTIMORE,MARYLAND VOLUME 59 Cover Design: Wiley Copyright 2014 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750–8400, fax (978) 750–4470, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748–6011, fax (201) 748–6008, or online at http://www.wiley.com/go/ permission. -
Ligand David Peter Klein Iowa State University
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2004 Chemistry of ruthenium complexes incorporating the doubly-linked bis(dimethylsilylcyclopentadienyl) ligand David Peter Klein Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Inorganic Chemistry Commons Recommended Citation Klein, David Peter, "Chemistry of ruthenium complexes incorporating the doubly-linked bis(dimethylsilylcyclopentadienyl) ligand " (2004). Retrospective Theses and Dissertations. 1138. https://lib.dr.iastate.edu/rtd/1138 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Chemistry of ruthenium complexes incorporating the doubly-linked bis(dimethylsilylcyclopentadienyl) llgand by David Peter Klein A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Inorganic Chemistry Program of Study Committee: Robert J. Angel ici, Major Professor Victor Lin Gordon J. Miller Marc Porter Mark S. Gordon Iowa State University Ames, Iowa 2004 UMI Number: 3145699 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. -
Cyclopentadienyl Ruthenium Chemistry
ln+õe CV C LOPENT AOTENV L RUÍHEÑTUM CHEMTSÍRY *** bq Robu,t Cha¡Le's wa,U'U 8.Sc. lHows.) r** A The'si's pneterttød {on thø løgnøe od OocÅon o( Plvílc:.sop|tq Thø Oeytantnønf o( PLtqaLcal and InongawLe Cheni'sfnq The. UwLvetui-tq o6 Ade-La,Ldø Junø I98l I ,\ - I f l, . 1, ,-ei Jì ;.-', ,ìi I ì v'ri.t, -, i{ .f f¡. I 'i i, Ì i,.ov'ao,i.l. ¡t r i,', , j.l , il I ì:1r,'ì ' ,,1,{ ., TAßLE OF CONÍENTS SECTÍON A. CHAPTER 1. A SUMMARY OF THE CHEMISTRV OF CARB(0NYL.FREE COMPLEXES OT THE TYPE RuX(PRs) z(n-CsHs ). Røa"e-LLowt o d tltø l'le,tß..L- tla'Logøn Bond 5 Líga.nd Exelnng ø Røacfio nt 6 Ca.tionie CompX.exe's I Røaetíoyu o[ RuR(PPhs)z (n-Csfls ) t0 (A) Cqc,[.omefa'L[-a-.tion R¿ac.tiorø 10 (B) Rza.cfion¿ w,í,th EX-øcfnctn-dø(¡icLenf. )Lødiru t4 and A,Llzqne.r Aeutq[idø CompLexe's 29 CHAPTER 2, CV C L??ENT AO T ENV L-RUT HENI UMt AN, - 0SMI UI,l CHEtr {I STRV, 3)îÁPLEXES C0NTA/^JING NITRILES, IS0NITRILES, TERTIARy PÍI0SPINES ANO PHOSPHTTES F,RMEO ßY AYOTTTON ()R DTSPLACE¡,,IENT REACT/ONS. lntnoducbLon 3l ReacÍ.cowt wí.th N'í.tní,Le's 32 RearLLon wífh TnLdluonoa"ce,tovt/if)ú't-e- 38 R¿ae,LLont a$(ond"Lng l¿oru.Í¡i.(-e Comp,Lexe's 43 Røq.oLLon's wi-th Te,nLLanq Pho,sphine's a"nd Phodptuíføt 45 Oi'scu.¿¿ion 49 Expwínønta.L 53 0HATrER 3, CV C L?PENT AOI ENV L-RUT HENI Ul,tl AN, - OSM I ul'l CHEMI STRV . -
Answers to Exercises References Abbreviations
ANSWERS TO EXERCISES REFERENCES ABBREVIATIONS INDEX ATOMIC WEIGHTS OF THE ELEMENTS PERIODIC TABLE OF THE ELEMENTS ANSWERS TO EXERCISES CHAPTER 1 + + 1.1. [FeCp2] , sandwich structure with parallel rings, [FeL4X2] , 17, 5, 3, 6; [RhCl(PPh3)3], square planar, [RhL3X], 16, 8, 1, 4; [Ta(CH2CMe3)3(CHCMe3)], tetrahedral, [TaX5], 10, 0, 5, 4; [ScCp*2(CH3)], bent sandwich with CH3 in the equatorial plane, [ScL4X3], 14, 0, 3, 7; [HfCp2Cl2], bent sandwich with both Cl ligands in the equatorial plane, [HfL4X4], 16, 0, 4, 8; – – [W(H)(CO)5] , octahedral, [WL5X] , 18, 6, 0, 6; 2 2+ 2+ [Os(NH3)5( -C6H6)] , octahedral, [OsL6] , 18, 6, 2, 6; [Ir(CO)(PPh3)2(Cl)], square planar, [IrL3X], 16, 8, 1, 4; [ReCp(O)3], pseudo-octahedral, [ReL2X7], 18, 0, 7, 6; 2– 2– [PtCl4] , square planar, [PtX4] , 16, 8, 2, 4; – – [PtCl3(C2H4)] , square planar, [PtLX3] , 16, 8, 2, 4; [CoCp2], sandwich structure with parallel rings, [CoL4X2], 19, 7, 2, 6; 6 [Fe( -C6Me6)2], sandwich structure with parallel rings, [FeL6], 20, 8, 0, 6; [AuCl(PPh3)], linear, [AuLX], 14, 10, 1, 2; 4 [Fe( -C8H8)(CO)3], trigonal bipyramid (piano stool), [FeL5], 18, 8, 0, 5; 1 2+ 2+ [Ru(NH3)5( -C5H5N)] , octahedral, [RuL6] , 18, 6, 2, 6; 2 + + [Re(CO)4( -phen)] , octahedral, [(ReL6] , 18, 6, 1, 6; + + [FeCp*(CO)(PPh3)(CH2)] , pseudo-octahedral (piano stool), [(FeL4X3] , 18, 6, 4, 6; 2+ 2+ [Ru(bpy)3] , pseudo-octahedral, [RuL6] , 18, 6, 2, 6. 2 1.2. In the form [FeCp*( -dtc)2], both dithiocarbamate ligands are chelated to iron, 2 1 [FeL4X3], 19, 5, 3, 7. -
Reduction Chemistry of Neptunium Cyclopentadienide Complexes: from Structure to Cite This: Chem
Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Reduction chemistry of neptunium cyclopentadienide complexes: from structure to Cite this: Chem. Sci.,2017,8,2553 understanding† Michał S. Dutkiewicz,ab Christos Apostolidis,a Olaf Walter*a and Polly L. Arnold*b Neptunium complexes in the formal oxidation states II, III, and IV supported by cyclopentadienyl ligands are explored, and significant differences between Np and U highlighted as a result. A series of neptunium(III) cyclopentadienyl (Cp) complexes [Np(Cp)3], its bis-acetonitrile adduct [Np(Cp)3(NCMe)2], 0 0 anditsKCpadductK[Np(Cp)4]and[Np(Cp)3](Cp ¼ C5H4SiMe3) have been made and characterised III providing the first single crystal X-ray analyses of Np Cp complexes. In all NpCp3 derivatives there are 5 III three Cp rings in h -coordination around the Np centre; additionally in [Np(Cp)3] and K[Np(Cp)4]one 1 Cp ring establishes a m-h -interaction to one C atom of a neighbouring Np(Cp)3 unit. The solid state structure of K[Np(Cp)4] is unique in containing two different types of metal–Cp coordination III 5 Creative Commons Attribution 3.0 Unported Licence. geometries in the same crystal. Np (Cp)4 units are found exhibiting four units of h -coordinated Cp IV rings like in the known complex [Np (Cp)4], the structure of which is now reported. A detailed comparison of the structures gives evidence for the change of ionic radii of ca. À8pmassociatedwith change in oxidation state between NpIII and NpIV. The rich redox chemistry associated with the 0 syntheses is augmented by the reduction of [Np(Cp )3]byKC8 in the presence of 2.2.2-cryptand to II II afford a neptunium(II) complex that is thermally unstable above À10 C like the U and Th complexes Received 4th January 2017 K(2.2.2-cryptand)[Th/U(Cp0) ].