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(http://pubs.acs.org/page/vi/2012/quantum-molecular-magnets. html)], or compounds with extended three-dimensional structures: coordination polymers, metal−organic framework (MOF) molecules, supramolecular cages, and the like, with desirable electronic, optical, magnetic, or physical properties. The above list of justifications is by no means exhaustive, but it is representative of the articles by the young investigators considered here. The first group of papers considered here involve compounds that fall into the category of exploratory synthesis. These begin with the work of Professor Connie C. Lu and co-workers at the University of Minnesota (http://www.chem.umn.edu/groups/lu/), which focuses on creating compounds with bonding between first-row, earth-abundant transition metals. Such work can also be justified on the basis that the dimetal unit within the complexes may exhibit a multiplicity of oxidation states and is relevant for catalytic reduction (or oxidation) processes. Professor Lu’s work is distinct in that the multidentate ligands she has designed (generally trigonal triformamidinate or related ligands with three pairs of phosphorus and nitrogen donor atoms) can stabilize homo- or heteronuclear bonding between pairs of first-row transition-metal atoms or between first-row transition-metal and main-group-metal atoms. Professor Lu and her group have synthesized derivatives of the N{CH2CH2NC(Ph)N(Ph)}3+ ligand with metal cores such as [Co2]3+ or [FeCo]3+ with short Co−Co (2.29 Å) and Fe−Co (2.18 Å) bonds, with the latter being the shortest of their kind.16 In addition, in a more extensive systematic investigation, bimetallic complexes involving the metal pairs Cr/Mn, Cr/Fe, Cr/Co, and Cr/Ni complexed by a ligand (N{C6H4NCH2PPri2)33−), with trigonally disposed chelating arms containing phosphorus and nitrogen donor atoms, were synthesized and characterized.17 The Cr/Mn complex was found to have a very short bond distance of 1.82 Å, and the bond order was shown to decrease in a systematic way across the series, from 5 in the Cr/Mn complex to 1 in the Cr/Ni pair. The same ligands were also used to synthesize dimetal species with bonds between first-row transition metals and aluminum, where the Al−M bond strength decreases in the order Ni > Co > Fe.18 One of the research themes of Professor Joshua S. Figueroa and his group at the University of California, San Diego (http:// figueroagroup.ucsd.edu/research.htm), concerns the investigation of sterically encumbered isocyanide (RNC) metal complexes. Steric crowding is difficult to achieve because of the limitation of isocyanides to a single alkyl or aryl substituent. However, if the isocyanide ligands, which are closely related to carbonyls, have large terphenyl substituents with alkyl groups on their flanking aryl rings, as indicated by the terphenyl group −C6H3-2,6(C6H3-2,6-Pri2)2 (abbreviated ArDipp2), then unusual geometries can be stabilized, as in three-coordinate Ni(CNArDipp2)3. It was shown that the nickel atom can function as a Lewis base toward metal ions in the complex [TlNi(CNArDipp2)3][O3SCF3]− as well as undergo oxidative addition to alkyl halides to give direct addition either to the metal or across the Ni−C bond to afford
his virtual issue is devoted to the synthetic accomplishments in inorganic chemistry of 17 young investigators (who have received their Ph.D. since 2004) whose work has been selected from papers published in the American Chemical Society journals Inorganic Chemistry, Organometallics, and Journal of the American Chemical Society, mostly in 2012 and 2013. The focus on a synthetic theme can be easily justified on the basis of the immense variety of inorganic chemistry that is possible as a result of the range of chemical properties of the elements drawn from the s, p, d, and f blocks of the periodic table. We highlight young scientists whose work is leading the field in new and exciting directions. The rapid development of inorganic chemistry that began shortly after World War IIthe so-called renaissance of inorganic chemistry1continues and shows no signs of slackening. The synthesis of new compounds has played a leading role in generating many of the advances that have occurred and has led to the creation of new fields, for example, organometallic and bioinorganic chemistry. Molecules such as ferrocene, the borane cages, and quadruply bonded molecules have fundamentally changed our understanding of chemical bonding. Such advances have continued in the 21st century, whose first decade has continued to provide surprises that, in many cases, have overthrown long-held assumptions. For example, synthetic efforts in the years since 2000 have witnessed the arrival of the first stable molecular compounds with bonds between s-block elements,2 Zn−Zn bonds,3 transition-metal complexes with quintuple bonds,4 and a continuing procession of stable main-group species with new types of multiple bonds5−8 whose bonding, interpreted on the basis of pseudo Jahn-Teller effects,9 has provided the rationale for their interactions with important small molecules such as hydrogen,10,11 ammonia,12 ethylene,14 and carbon monoxide.15 Several of these reactions have been shown to be reversible under mild conditions. Much of the synthetic work has been, and continues to be, driven by curiosity (exploratory inorganic synthesis, of which several examples will be found in this issue). One of the hallmarks of such work is that no immediate practical application is readily apparent (despite what may be stated in the introductory sections of publications!), and the justification is that the new species so obtained have some new, unique structural, electronic, or bonding features. This approach underlies a large portion of both modern main-group- and transition-metal-based chemical synthesis. It is notable that several of the main-group compounds have been shown to display unanticipated reaction characteristics H2 activation,10−12 olefin complexation and elimination,13,14 CO complexation,15 and couplingthat are more usually associated with transition-metal complexes. Numerous other equally valid justifications for synthesis exist: for example, the synthesis of molecules that model the metal sites of metalloenzymes [the subject of an Inorganic Chemistry Virtual Issue (http://pubs.acs.org/page/vi/2013/models-ofmetalloenzymes.html) published earlier this year], molecules that can effect catalytic transformations or possess unique magnetic properties [also the subject of an earlier Virtual Issue © 2013 American Chemical Society
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iminoacyl complexes.19 In addition, molybdenum tris(isonitrile) complexes, for example, Mo(CNArDipp2)3(CN)3, were investigated.20 However, these differed from their nickel(0) congeners because one of the isocyanide ligands was further bound to the molybdenum atom through an η6 interaction with one of the flanking aryl rings from the terphenyl ligand. This interaction was further investigated by substitution of the flanking ring with electron-withdrawing chlorine or CF3 groups, as in the terphenyl −C6H3-2,6(C6H3-3,5-(CF3)2)2. It was demonstrated that this weakens the molybdenum−ring interaction sufficiently enough to be displaced by three molecules of acetonitrile. The preparation of a series of Mo(CO)3(CNArR)3 complexes showed that the CF3-substituted ligand displayed increased π acidity, although the CF3 substituents are quite distal to the terminal isocyanide unit. The use of sterically crowded ligands is also a major theme in the synthetic work of Professor Eric J. Schelter and co-workers at the University of Pennsylvania (http://scheltergroup.chem. upenn.edu/). An example of this is provided by the synthesis of the neutral UIV complex U{N(SiMe3)2}4.21 The discovery of this complex stemmed from the investigation of the oxidation chemistry of U{N(SiMe3)2}3,22 which can produce U{N(SiMe3)2}4 in low yield. A higher yielding synthesis was devised that involved oxidation of the known species [K(THF)6][U{N(SiMe3)2}4] (THF = tetrahydrofuran).23 It was found that the resulting U{N(SiMe3)2}4 exhibited a high degree of stabilization because of the protection afforded by four −N(SiMe3)2 ligands and displayed lower air sensitivity and no tendency to undergo cyclometalation. It is a possibility that this neutral, homoleptic UIV compound will find use as a synthon for other UIV derivatives. A related type of stabilization is observed in the paramagnetic amido complex Ce{N(C6F5)2}3,24 which was obtained by transamination from Ce{N(SiMe3)2}3. In this complex, there is an unusual pseudo-trigonal-planar geometry involving the three amido nitrogen atoms but also weaker C−F → Ce interactions. These interactions were characterized by comparing the paramagnetic 19F NMR chemical shifts with those of La{N(C6F5)2}3. It was shown that the C−F → Ce interactions could be displaced by the coordination of weak σ or π donors such as Et2O or toluene. Turning now to the p-block elements, the first example comes from the laboratory of Professor Xinping Wang at Nanjing University (http://chem.nju.edu.cn/subject/sklc/ChemLab/ viewMember_EN.asp?name=%CD%F5%D0%C2%C6%BD) and concerns the synthesis and characterization of a stable example of a new class of main-group compound: the unique dication [Trip2PPTrip2]2+ (Trip = C6H2-2,4,6-Pri3),25 which is isoelectronic to the corresponding neutral disilene Trip2SiSiTrip2. It was initially obtained by the oxidation of Trip2PPTrip2 with Ag[Al(ORMe)4] [ORMe = OC(CF3)2Me] and then crystallized with two [Al(ORF)4]+ cations [ORF = (CF3)3]. It has an essentially planar P2{C(ipso)}4 core array, with a P−P bond length of 2.021(2) Å, which is very close to that [2.034(2) Å] originally reported by Yoshifuji and co-workers in the first diphosphene in 198126 and consistent with a P−P double bond. The intermediate singly oxidized radical cation [Trip2PPTrip2]•+ was also isolated and characterized. In parallel work, the first crystal structures of triorganophosphine radical cations [PTrip3]+ and [P(Trip)2Mes]+ (Mes = −C6H2-2,4,6-Me3) were determined and shown to have relaxed pyramidal geometries.27 The parent divalent hydride derivatives of the group 14 elements (:EH2E = C−Pb) were unknown as stable species. However, Professor Eric Rivard and his group at the University of
Alberta (http://www.chem.ualberta.ca/~erivard/) have shown that, by using Lewis base and acid ligands (donor−acceptor approach), examples can be stabilized in complexes such as H2Sn(IPr)M(CO)5 [IPr = :CN(C6H3-2,6-Pri2)CHCHN(C6H32,6-Pri2].28 These hydrides were synthesized by the reduction of (THF)2Cl2SnM(CO)5 complexes (obtained by photolysis of M(CO)6 with SnCl2 in THF) with LiBH4. In a series of papers, Professor Rivard and his group (see ref 29 and references cited therein) have shown that parent heavier element analogues (e.g., H2SiGeH2 and H2SiSnH2) can be stabilized by using a similar approach. Thus, the reduction of a mixture of (THF)GeCl2· W(CO)5 and IPr·GeCl2 with LiBH4 in ether afforded (IPr)H2GeGeH2W(CO)5, (IPr)H2GeW(CO)5, and IprH2GeBH3. The related parent digermene complex (IPrCH2)H2GeCH2W(CO)5 was isolated using a similar approach. The Ge−Ge bonds [2.4212(7) and 2.4487(1) Å] in these complexes are mainly single in character. The formation of multiple bonds to heavier-main-group elements via reductive elimination or mediated additions with the use of zirconium complexes is a research theme in the group of Professor Rory Waterman at the University of Vermont (http://www.uvm.edu/~rwaterm1/). An example is provided by the trianionic tetradentate amido ligand N(CH2CH2NSiMe3)33−, abbreviated N3N3−, supported by zirconium arsenide N3NZrAs(H)Ar (Ar = Ph or Mes), which reacts with the isocyanides RNC (R = CH2Ph or Mes) to yield the arsaalkene species N3NZrN(R)CHAsAr in high yield.30 This represents a new and simple route to molecular species containing arsenic carbon double bonds and is a rare example of the synthesis of a multiple-bonded, heavier-main-group molecule mediated by a transition-metal species. The reaction proceeds by a 1,1 insertion pathway followed by rearrangement to arsaalkene. A reductive elimination pathway to form an As−As bond was observed for thermolysis of Cp2Zr(AsMes2)2, which afforded Mes2AsAsMes2. Evidence for a reductive elimination pathway involving a Cp2Zr pathway comes from the fact that if thermolysis is performed in the presence of PhCCPh, the addition complex Cp2ZrCPhCPhCPhCPh is formed.31 The use of redox-active ligands in combination with earthabundant elements to develop sustainable catalytic transformations is attracting considerable current interest. A metal− ligand cooperative pathway is an essential component of such work where the element has unsuitable redox characteristics, as is often the case in main-group elements. Professor Louise A. Berben and her group at the University of California, Davis (http://chemgroups.ucdavis.edu/~berben/index.html), have used bi- or tridentate iminopyridine ligands to generate redoxactive aluminum complexes in a straightforward manner. There are several aluminum and gallium derivatives of substituted mono- and dianionic parent iminopyridine 2,6-Pri2-N-(2pyridinylmethylene)phenylamine (denoted as IP), as indicated by the general formulas IP−MX2 and IP2−MX (M = Al or Ga).32 Spectroscopic and structural data established that reduction occurs stepwise in the ligand. With less bulky IP ligands, it is possible to make [Al(IP2−)2] salts with methyl or ammonium countercations. The oxidation of these with pyridine N-oxide afforded the product (IP−)2AlOH or [(IP−)(IP2−)Al(OH)][Na(DME)THF] via oxygen transfer and subsequent proton abstraction or C−H activation, respectively.33 In parallel work, bis(imino)pyridinylaluminum complexes containing neutral, monoanionic, and dianionic iminopyridine ligands have been characterized structurally and electronically. In effect, four 12856
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(http://astro.temple.edu/~mzdilla/). Investigation of the reaction of Mn{N(SiMe3)2}2 with various phenols afforded a variety of di- and trimanganese products, whereas the reaction with phenol in the presence of water gave the unchelated Mn8(μ5-O)2(μ-OPh)12(THF)6 with relatively five-coordinate manganese centers.41 An interesting spiroligomer cluster based on a ligand (L) containing two terpyridyl side chains on one side of a fused 5−6−5 ring system affords a binuclear [M2L2]4+ product, which has a macrocyclic square structure.42 Hexadentate and hexanionic ligands have been used by Professor Theodore Betley and his group at Harvard University (http://www.chem.harvard.edu/groups/betley/home.html) to assemble homo- and heteronuclear clusters with iron atoms. Although such clusters do not represent models for known sites in metalloenzymes, their chemical behavior affords knowledge of the factors that influence coordination modes and redox behavior of multimetallic assemblages. It was shown that a triiron(II) cluster of the MeC(CH2NPh-o-NPh)36−(PhL6−) ligand undergoes selective site oxidation of a diiron unit, while the remaining site remains divalent.43 The reaction of oxidized cluster dimer [ Ph LFe 3 (μ-Cl)] 2 with MCl 2 gives heptanuclear cluster (PhL)2Fe6In(μ-Cl)4(THF)2, in which “M” becomes incorporated in the original trimetal moieties of the starting material, indicating that metal migration occurs in this simple reaction.44 “Click” chemistry was used to synthesize porphyrin ligands that have distal superstructures containing redox-active ferrocenes by the group of Professor Abhishek Dey at the Indian Association for the Cultivation of Science, Kolkata, India (http://www.iacs.res.in/inorg/icad/). An iron porphyrin complex with four such ferrocenyls binds O2 and quantitatively reduces it to O2− in nonpolar solvents.45 However, the complex also electrocatalytically reduces O2 by four electrons to H2O in an aqueous solvent. The catalyst apparently mimics control of the catalysis by a second-sphere electron-transfer moiety, which often occurs in metalloenzymes. The same group has developed an efficient cobalt corrole catalyst for hydrogen evolution from H2O under ambient conditions. This was achieved by the use of numerous fluorine substituents on the substituted corrole framework, for which a synthesis was developed from commercially available compounds.46 Inclusion complexes, whether they involve one cavity produced by a single molecule or numerous cavities in an extended three-dimensional array such as a MOF coordination polymer, have attracted much attention from synthetic chemists. The first case is exemplified by an example from the synthetic work of Professor Guido Clever and his group at Göttingen University (http://www.clever-lab.de/page13/page13.html). A self-assembled cage compound composed of four concave, rigid bis-monodentate pyridyl ligands and two planar-coordinated PdII ions quantitatively encapsulates a [Mo6O19]2− cluster.47 However, it was found that a structural change takes place upon crystallization to yield a species that had a chiral cyclic arrangement of three ligands encapsulating the Mo6O192− cluster without the PdII ions. It was postulated that the structure was stabilized by attractive C−H---O and CF3−pyridine interaction. A different type of rigid, derivatized bis-monodentate pyridyl ligand with a bulky aryl substituent gives an interpenetrating selfassembling dimeric cage, in the presence of a templating anion. It was shown that the bulky aryl substituent greatly alters the outer pocket characteristics of the interpenetrating cages, to the extent that the templating anion in the inner pocket is limited to a small size, so that the outer cavities can now incorporate larger guest
different oxidation states of varying stability could be characterized, possibly opening the way for their use in CO2 reduction.34 Multimetallic complexes are widely used by biological systems to effect multielectron-transfer chemistry. In work by the group of Professor Christine M. Thomas at Brandeis University (http://people.brandeis.edu/~thomasc/), CO2 reduction can also be effected by the reduced multiple metal Zr/Co complex (THF)Zr(MesNPPri2)3Co, in which three phosphine amido ligands are bound through amido nitrogen atoms to ZrIII and to Co(0) through three phosphines.35 The addition of CO2 followed by one-electron reduction by Na/Hg affords Na(THF)3OZr(NMesPPri2)3CoCO. The corresponding Li+(12crown-4) salt was shown to bind CO2 reversibly. The ultimate objective is to develop a catalytic cycle for CO2 reduction facilitated by the bimetallic system. A different phosphinoamide ligand was used to synthesize the FeIIFeII diiron species Fe(μ-PriNPPh2)3Fe(μ2-N(Pri)PPh2), which can be reduced by Na/Hg in the presence of PMe3 to yield the FeIIFeI species Fe(μ-PriNPPh2)3Fe(PMe3), which upon treatment with organic azides (N3R) affords the FeIIFeIII species Fe(PriNPPh2)3FeNR.36 These complexes represent the first examples of first-row bimetallic complexes with both metal−ligand and metal−metal multiple bonds. Redox-active ligands of the type MeDABMe = ArNC(Me)C(Me)NAr (Ar = mesityl) have been shown to effect C−C bond reduction from uranium benzyl complexes.37 In work by Professor Suzanne C. Bart and co-workers at Purdue University (http://www.chem.purdue.edu/bart/), the first homoleptic uranium(IV) alkyl U(CH2Ph)4 (and several related complexes with methyl-substituted phenyl rings) was obtained by the reaction of 4 equiv of the potassium benzyl salt with UCl4 in THF. The compounds are stabilized by secondary U---C interactions with ipso-carbon atoms of the benzyl phenyl group. Whereas the reaction with DMPE [Me2P(CH2)2PMe2] produces the stable complex (DMPE)U(CH2Ph)4, the reaction with MeDABMe gives unimolecular elimination of bibenzyl and (MeDABMe)U(CH2Ph)2, in which the MeDABMe ligand maintains tetravalent uranium by its dianionic form. UIV complexes of the redox-active 4,6-But2-2-(R)-amidophenolate (RAP; R = But, 1-adamantanyl, and Dipp2) were synthesized by the addition of 2 equiv of its alkali-metal salt M2APR (M = Na or K) to yield UIV(APR)2(THF)2 (R = 1-adamantanyl). When the oxidizing agent PhICl2 is added to this complex, the dimeric complex {UIV(APR)2(μ-Cl)Cl}2 is obtained, in which the ligand, rather than the metal, is oxidized.38 Multimetallic structures found in metalloenzymes have been the inspiration of much synthetic effort in inorganic chemistry. One of the goals of the synthetic work of Professor Theodor Agapie and his group at the California Institute of Technology (http://agapie.caltech.edu/) involves the preparation of molecules containing the Mn3MOn core (M = Mn, Ca, or Sc; n = 3 or 4) arranged in a cuboidal fashion to investigate the oxygenevolving complex (OEC) of photosystem II.39 This is achieved by the use of a trinucleating, nonadentate, trianionic ligand to assemble a Mn3IIO3 array initially, which is then converted to higher oxidation state Mn3MO4 or Mn4O4 clusters by the addition of a further 1 equiv of a metal salt and KO2. Mechanistic studies supported those proposed for OEC involving oxide migration within the cluster. The effects of the redox-inactive metals on the chemistry of the clusters are discussed in greater detail in a short review in this journal.40 A manganese cluster relevant to the OEC was synthesized by the group of Professor Michael J. Zdilla at Temple University 12857
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(11) Welch, G. C.; San Juan, R. R.; Masuda, J. D.; Stephan, D. W. Science 2006, 314, 1124. (12) Frey, G. D.; Lavallo, V.; Donnadieu, B.; Schoeller, W. W.; Bertrand, G. Science 2007, 316, 439. (13) McCahill, J. S. J.; Welch, G. C.; Stephan, D. W. Angew. Chem., Int. Ed. 2007, 46, 4968. (14) Peng, Y.; Ellis, B. D.; Wang, X.; Fettinger, J. C.; Power, P. P. Science 2009, 325, 1668. (15) Fukazawa, A.; Dutton, J. L.; Fan, C.; Mercier, L. G.; Houghton, A. Y.; Wu, Q.; Piers, W. E.; Parvez, M. Chem. Sci. 2012, 3, 1814. (16) Zall, C. M.; Clouston, L. J.; Young, V. H.; Ding, K.; Kim, H. J.; Zherebetskyy, D.; Chen, Y.-S.; Bill, E.; Gagliardi, L.; Lu, C. C. Inorg. Chem. 2013, 52, 9216. (17) Clouston, L. J.; Siedschlag, R. B.; Rudd, P. A.; Planas, N.; Hu, S.; Miller, A. D.; Gagliardi, L.; Lu, C. C. J. Am. Chem. Soc. 2013, 135, 13142. (18) Rudd, P. A.; Liu, S.; Gagliardi, L.; Young, V. G.; Lu, C. C. J. Am. Chem. Soc. 2011, 133, 20724. (19) Ditri, T. B.; Carpenter, A. E.; Ripatti, D. S.; Moore, C. E.; Rheingold, A. L.; Figueroa, J. S. Inorg. Chem. 2013, DOI: DOI: 10.1021/ ic402130p. (20) Ditri, T. B.; Moore, C. E.; Rheingold, A. L.; Figueroa, J. S. Inorg. Chem. 2011, 50, 10448. (21) Lewis, A. J.; Williams, U. J.; Carroll, P. J.; Schelter, E. J. Inorg. Chem. 2013, 52, 7326. (22) Andersen, R. A. Inorg. Chem. 1979, 18, 1507. (23) Evans, W. J.; Lee, D. S.; Rego, D. B.; Perotti, J. M.; Kozimor, S. A.; Moore, E. K.; Ziller, J. W. J. Am. Chem. Soc. 2004, 126, 14574. (24) Yin, H.; Lewis, A. J.; Carroll, P.; Schelter, E. J. Inorg. Chem. 2013, 52, 8234. (25) Pan, X.; Su, Y.; Chen, X.; Zhao, Y.; Li, Y.; Zuo, J.; Wang, X. J. Am. Chem. Soc. 2013, 135, 5561. (26) Yoshifuji, M.; Shima, I.; Inamoto, N.; Hirotsu, K.; Higuchi, T. J. Am. Chem. Soc. 1981, 103, 4587. (27) Pan, X.; Chen, X.; Li, T.; Li, Y.; Wang, X. J. Am. Chem. Soc. 2013, 135, 3414. (28) Al-Rafia, S. M. I.; Shynkaruk, O.; McDonald, S. M.; Liew, S. K.; Ferguson, M. J.; McDonald, R.; Herber, R. H.; Rivard, E. Inorg. Chem. 2013, 52, 5581. (29) Al-Rafia, S. M. I.; Momeni, M. R.; Ferguson, M. J.; McDonald, R.; Brown, A.; Rivard, E. Organometallics. 2013, asap. (30) Maddox, A. F.; Davidson, J. J.; Shalumova, T.; Tanski, J. M.; Waterman, R. Inorg. Chem. 2013, 52, 7811. (31) Elrod, L. T.; Boxwala, H.; Haq, H.; Zhao, A. W.; Waterman, R. Organometallics 2012, 31, 5204. (32) Myers, T. W.; Berben, L. A. Inorg. Chem. 2012, 51, 1480. (33) Myers, T. W.; Berben, L. A. J. Am. Chem. Soc. 2011, 133, 11865. (34) Myers, T. W.; Kazem, N.; Stoll, S.; Britt, R. D.; Shanmugam, M.; Berben, L. A. J. Am. Chem. Soc. 2011, 133, 8662. (35) Krogman, J. P.; Bezpalko, M. W.; Foxman, B. M.; Thomas, C. M. Inorg. Chem. 2013, 52, 3022. (36) Kuppuswamy, S.; Powers, T. M.; Johnson, B. M.; Bezpalko, M. W.; Brozek, C. K.; Foxman, B. M.; Berben, L. A.; Thomas, C. M. Inorg. Chem. 2013, 52, 4802. (37) Kraft, S. J.; Fanwick, P. E.; Bart, S. C. J. Am. Chem. Soc. 2012, 134, 6160. (38) Matson, E. M.; Opperwall, S. R.; Fanwick, P. E.; Bart, S. C. Inorg. Chem. 2013, 52, 7295. (39) Kanady, J. S.; Mendoza-Cortes, J. L.; Tsui, E. Y.; Nielsen, R. J.; Goddard, W. A.; Agapie, T. J. Am. Chem. Soc. 2013, 135, 1073. (40) Tsui, E. Y.; Kanady, J. S.; Agapie, T. Inorg. Chem. 2013, in press. (41) Kondaveeti, S. K.; Vaddypally, S.; Lam, C.; Hirai, D.; Ni, N.; Cava, R. J.; Zdilla, M. J. Inorg. Chem. 2012, 51, 10095. (42) Vaddypally, S.; Xu, C.; Zhao, S.; Fan, Y.; Schafmeister, C. E.; Zdilla, M. J. Inorg. Chem. 2013, 52, 6457. (43) Eames, E. V.; Betley, T. A. Inorg. Chem. 2012, 51, 10274. (44) Eames, E. V.; Sańchez, R. H.; Betley, T. A. Inorg. Chem. 2013, 52, 5006. (45) Samanta, S.; Mittra, K.; Sengupta, K.; Chatterjee, S.; Dey, A. Inorg. Chem. 2013, 52, 1443.
species. This work provides an elegant illustration of template control of guest selectivity.48 Tuning the stability of MOFs and their porosities in a simple way is the theme of a paper by the group of Professor Jian Zhang49 at the Fujian Institute of Research on the Structure of Matter (http://english.fjirsm.cas.cn/pe/fas/RP/). It is shown that the isostructural MOFs {M2 (obb) 2(DMF)2 ]·2DMF [M = Zn or Cu; obb = 4,4′-oxybis(benzoic acid); DMF = N,Ndimethylformamide], which display no gas sorption, are structurally modified by the addition of 4,4′-bipyridyl (bipy) to yield [Zn 2 (obb)(bipy)·DMF] or [Cu 2 (obb)(bipy) 0.5 (DMF)]· 2DMF.49 The latter exhibits selective uptake of CO2 over N2 and CH4 under 273 K. A different aspect of MOF chemistry is illustrated by the work of Professor Jie-Peng Zhang and his group at Sun Yat-Sen University (http://www.sysu.edu.cn/2012/en/academics/ academics03/262.htm) on a two-dimensional square-grid-type porous coordination polymer, designated as [Fe(bdpt)]·guest, featuring six coordinate FeIIN6 units, which was designed as a spin-state crossover material.50 It is shown that the guest molecules, or lack thereof, exert a large effect on the temperature of a two-step spin-state crossover. Another class of MOFs is phosphine coordination materials, in which various phosphoruscontaining molecules are used in the contruction of MOFs. In work by Professor Simon Humphrey and his group at the University of Texas at Austin (http://humphrey.cm.utexas. edu/wordpress/), the reaction of the trilithium salt of tris(p-carboxylic)triphenylphosphine oxide (tctpo) with Dy(NO3)3 in DMF was shown to yield [Me2NH2][Dy2(tctpo)(O2CH)]· 3DMF·3H2O, which displays the highest CO2 Brunauer− Emmett−Teller surface area for a LnIII coordination polymer. The absorption−desorption characteristics of several organic vapors showed that aromatic and polar guest species showed high uptakes. It was also shown that the large surface area could be increased further by the use of [NH4]+, instead of [Me2NH2]+, countercations.51 Please join me in reading these fine pieces of work by emerging synthetic inorganic chemists.
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Philip P. Power
AUTHOR INFORMATION
Notes
Views expressed in this editorial are those of the author and not necessarily the views of the ACS.
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REFERENCES
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Inorganic Chemistry
Editorial
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