The coordination behavior of the bulky beta-diketiminate ligands N,N'-bis(2,6-diisopropylphenyl)pentane-2,4-diiminate (L-Me) and N,N'-bis(2,6-diisopropylphenyl)-2,2-6,6-tetramethylheptane-3,5-diiminate (L-tBu) toward ThX4(THF)(4) (X = Br, I) and UCl4 has been investigated. The reaction between K[L-Me] and ThX4(THF)(4) (X = Br, I) afforded the mono(beta-diketiminate)thorium(IV) halide complexes (L-Me)ThX3(THF) (X = Br (7), I (8)). The same reaction carried out with the more sterically demanding K[L-tBu] gave (L-tBu)ThBr3(THF) (9) and (L-tBu)ThI3 (11). All attempts to install two beta-diketirninate ligands on thorium(IV) were unsuccessful, giving the mono(beta-diketiminate)thorium(IV) halide complex and unreacted K[L-Me] or K[L-tBu]. However, complex 9 was shown to react with smaller anions such as K[C5H4Me] to give the mixed-ligand methylcyclopentadienyl beta-diketiminate complex (L-tBu)Th(C5H4Me)Br-2 (10). Complexes 7-11 represent rare examples of thorium complexes featuring only one beta-diketiminate ligand, and complexes 9-11 are the first examples of thorium and halide complexes supported by the L-tBu framework. In a similar manner, both K[L-Me] and K[L-tBu] were shown to react with UCl4 to give the corresponding mono(beta-diketiminate)uranium(IV) chloride complexes (L-Me)UCl3(THF) (12) and (L-tBu)UCl3 (13). Complex 13 represents the first example of a uranium complex featuring the L-tBu framework. Efforts to prepare the bis(beta-diketiminate)uranium(IV) complex (L-Me)(2)UCl2 by reacting 2 equiv of K[(Me)] with UCl4 led instead to the interesting cationic diuranium complex [{(L-Me)(Cl)U}(2)(mu-Cl)(3)][Cl] (14). Complexes 7-14 have been characterized by a combination of H-1 and C-13{H-1} NMR spectroscopy, elemental analysis, electrochemistry, and UV-visible-near-IR spectroscopy. Several complexes have also been characterized by X-ray crystallography, and a discussion of their structures is presented. NMR spectroscopy and the X-ray structures demonstrate that the beta-diketiminate ligand is symmetrically bound to the actinide metal in the L-Me complexes and is asymmetrically bound to the actinide metal in the L-tBu complexes. In all cases the actinide(IV) metal centers lie out of the plane of the beta-diketiminate ligand NCCCN backbone by similar to 1-2 angstrom. The electronic spectroscopy data on K[L-Me], (L-Me)ThI3(THF) (8), and (L-Me)UCl3(THF) (12) suggest relatively weak metal-(beta-diketiminate) ligand bonding interactions, although small perturbations in the characteristics of the beta-diketiminate pi-pi* bands with changes in the the metal ion are consistent with some metal-ligand orbital interactions. This new class of mono(beta-diketirninate)thorium and -uranium halide complexes promises to provide a robust platform for developing new chemistry of the actinides

The solvent-free reaction of M{N(SiMe(3))(2)}(2) (M = Ge, Sn, or Pb) with the sterically encumbered primary amine 2,6-dimesitylaniline Ar(#)NH(2) [Ar(#) = C(6)H(3)-2,6(C(6)H(2)-2,4,6-Me(3))(2)] at ca. 165-175 degrees C afforded the highly colored imido dimers {M(mu-NAr(#))}(2), where M = Ge (1), Sn (2), or Pb (3), with disilylamine elimination. The compounds were characterized by single-crystal X-ray crystallography and heteronuclear NMR spectroscopy. The structures of 1-3 were very similar and had nonplanar four-membered M(2)N(2) ring cores that are folded along the M---M axis. The nitrogen atoms are planar-coordinated, and the M-N distances are consistent with single bonding. The reaction of M{N(SiMe(3))(2)}(2) with Ar(#)NH(2) in a 2:1 ratio in solution at lower temperature afforded the relatively stable monomeric primary amido species M{N(H)Ar(#)}(2), where M = Ge (4), Sn (5), or Pb (6). Complexes 4-6 displayed V-shaped MN(2) structures, and 5 and 6 revealed close approaches between the metal atom and ipso-carbon atoms of two flanking Mes groups of the terphenyl substituents [Sn(II)---C (2.957 A) and Pb(II)---C (2.965 A)]. The secondary metal-ligand interactions exerted large effects on their electronic and NMR spectra.

Dimeric arylgallium/indium chalcogenides 7-10 of formula [Ar'ME](2) (Ar' = C6H3-2,6-(C6H3-2,6-Pr-2(i))(2); M = Ga or In, E = O or S) were synthesized by the treatment of Ar'MMAr' with N2O or elemental sulfur and characterized by NMR spectroscopy and X-ray crystallography. Their structures feature three-coordinate, +3 oxidation state metal centers with planar M2E2 cores. The cores were almost perfectly square for E = O, but for E = S, they were distorted parallelograms in 7-10. The M-E bond lengths were shorter than those in the higher aggregated species [RME](n) (n >= 4) but comparable to those in M3+ aryloxides or thiolates featuring three-coordinate metals. Short M center dot center dot center dot M separations [2.553(1) angstrom in 7, 2.8882(4) angstrom in 8, 2.8276 angstrom (avg.) in 9, and 3.1577(8) angstrom in 10] are observed. Low oxidation heavier group 13/group 16 chalcogenolate isomers 16-19 of formula [Ar'EM](2) (M = In or Tl, E = O or S) were also synthesized and characterized. In the +1 compounds [Ar'EIn](2) (O, 16; S, 19) together, with the In +3 species [Ar'InE](2) (O, 8; S, 10), represent the first structurally characterized isomeric pairs of organo group 13 metal/chalcogen derivatives. The E-M bonds in 16-19 were 2.3329 (avg.), 2.560 (avg.), 2.8189 (avg.), and 2.897 angstrom (avg.), respectively, which are 0.3-0.4 angstrom longer than the corresponding In-chalcogen distances in 8 and 10 as a result of the lower oxidation state, the large In+ ionic size, and the reduced ionic contribution to the bond strength in 16 and 19. The compounds 16-19 also displayed M-arene interactions to the flanking aryl rings of the Ar' ligands. The Tl-arene contacts in the crystal structure of 17 are preserved in solution, as evidenced by C-13-Tl coupling. Attempts to thermally interconvert the isomeric pairs 8, 10 and 16, 18 led to decomposition of the complexes.

The synthesis and structural characterization of the first homologous, molecular M-M bonded series for the group 12 metals are reported. The compounds Ar'MMAr' (M = Zn, Cd, or Hg; Ar' = C(6)H(3)-2,6-(C(6)H(3)-2,6-Pr(i)(2))(2)) were synthesized by reduction of the corresponding arylmetal halides by alkali metal/graphite (Zn or Hg) or sodium hydride (Cd). These compounds possess almost linear C-M-M-C core structures with two-coordinate metals. The observed M-M bonds distances were 2.3591(9), 2.6257(5), and 2.5738(3) A for the zinc, cadmium, and mercury species, respectively. The shorter Hg-Hg bond in comparison to that of Cd-Cd is consistent with DFT calculations which show that the strength of the Hg-Hg bond is greater. The arylmetal halides precursors (Ar'MI)(1 or 2), and the highly reactive hydrides (Ar'MH)(1 or 2), were also synthesized and fully characterized by X-ray crystallography (Zn and Cd) and multinuclear NMR spectroscopy. The arylzinc and arylcadmium iodides have iodide-bridged dimeric structures, whereas the arylmercury iodide, Ar'HgI, is monomeric. The arylzinc and arylcadmium hydrides have symmetric (Zn) or unsymmetric (Cd) mu-H-bridged structures. The Ar'HgH species was synthesized and characterized by spectroscopy, but a satisfactory refinement of the structure was precluded by the contamination of monomeric Ar'HgH by Ar'H. It was also shown that the decomposition of Ar'Cd(mu-H)(2)CdAr' at room temperature leads to the M-M bonded Ar'CdCdAr', thereby supporting the view that the reduction of the iodide proceeds via the hydride intermediate.

Unique interactions: Ar′ZnZnAr′ (1; Ar′=C6H3-2,6-(C6H3-2,6-iPr2)2), the dimer Ar′Zn(μ-H)2ZnAr′ (2), and the unprecedented species Ar′Zn(μ-H)(μ-Na)ZnAr′ (3) were synthesized and fully characterized. DFT calculations show that the ZnZn bonding interactions in 1 differ from those of other ZnZn compounds, and the calculations also indicate a new type of ZnZn bond in 3.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Reactions of the "digallene" Ar'GaGaAr'(1) (Ar' = C(6)H(3)-2,6-(C(6)H(3)-2,6-Pr(i)(2))(2)), which dissociates to green :GaAr' monomers in solution, with unsaturated N-N-bonded molecules are described. Treatment of solutions of :GaAr' with the bulky azide N(3)Ar(#) (Ar(#) = C(6)H(3)-2,6-(C(6)H(2)-2,6-Me(2)-4-Bu(t))(2)), afforded the red imide Ar'GaNAr(#) (2). Addition of the azobenzenes, ArylNNAryl (Aryl = C(6)H(4)-4-Me (p-tolyl), mesityl, and C(6)H(3)-2,6-Et(2)) yielded the 1,2-Ga(2)N(2) ring compound Ar'GaN(p-tolyl)N(p-tolyl)GaA' (3) or the products MesN=NC(6)H(2)-2,4-Me(2)-6-Ga(Me)Ar' (4) and 2,6-Et(2)C(6)H(3)N=NC(6)H(3)-2-Et-6-Ga(Et)Ar' (5). Reaction of GaAr' with N(2)CPh(2) yielded the 1,3-Ga(2)N(2) ring compound Ar'Ga(mu:eta(1)-N(2)CPh(2))(2)GaAr' (6), which is quasi-isomeric to 3. Calculations on simple model isomers showed that the Ga(I) amide GaNR(2) (R = Me) is much more stable than the isomeric Ga(III) imide RGaNR. This led to the synthesis of the first stable monomeric Ga(I) amide, GaN(SiMe(3))Ar' ' (8) (Ar' ' = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Me(3))(2) from the reaction of LiN(SiMe(3))Ar' ' (7) and "GaI". Compound 8 is also the first one-coordinate gallium species to be characterized in the solid state. The reaction of 8 with N(3)Ar' ' afforded the amido-imide derivative Ar' 'NGaN(SiMe(3))Ar' ' (9), a gallium nitrogen analogue of an allyl anion. All compounds were spectroscopically and structurally characterized. In addition, DFT calculations were performed on model compounds of the amide, imide, and cyclic 1,2- and 1,3-species to better understand their bonding. The pairs of compounds 2 and 8 as well as 3 and 6 are rare examples of quasi-isomeric heavier main group element compounds.

Ein Alkinanalogon mit Al: Das erste „Dialuminin“ mit der Formel Na2[Ar′AlAlAr′] (siehe Bild; Ar′=C6H3-2,6-(C6H3-2,6-iPr2)2) wurde synthetisiert und röntgenographisch charakterisiert. Die Struktur weist planare, trans-gebogene C-Al-Al-C-Ketten mit einer Al-Al-Bindungslänge von 2.428(1) Å und einem Biegewinkel an Al von 131.71(7)° auf. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2006/z601925_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Angewandte Chemie International EditionVolume 44, Issue 47 p. 7729-7733 Communication Tl2[Aryl2P4]: A Thallium Complexed Diaryltetraphosphabutadienediide and its Two-Electron Oxidation to a Diaryltetraphosphabicyclobutane, Aryl2P4† Alexander R. Fox, Alexander R. Fox Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this authorRobert J. Wright, Robert J. Wright Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this authorEric Rivard Dr., Eric Rivard Dr. Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this authorPhilip P. Power Prof., Philip P. Power Prof. pppower@ucdavis.edu Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this author Alexander R. Fox, Alexander R. Fox Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this authorRobert J. Wright, Robert J. Wright Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this authorEric Rivard Dr., Eric Rivard Dr. Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this authorPhilip P. Power Prof., Philip P. Power Prof. pppower@ucdavis.edu Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA, Fax: (+1) 530-752-8995Search for more papers by this author First published: 28 November 2005 https://doi.org/10.1002/anie.200502865Citations: 128 † The authors thank the National Science Foundation for financial support. E.R. thanks NSERC of Canada for a Postdoctoral Fellowship. We also thank Professor M. M. Olmstead and Dr. J. de Ropp for assistance with crystallographic and NMR spectroscopic studies. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract An analogue with P: Reaction of the “dithallene” (TlArequation/tex2gif-sup-1.gif)2 (1; Arequation/tex2gif-sup-2.gif=C6H3-2,6-(C6H2-2,6-iPr2)2) with P4 afforded Tl2[P4(Arequation/tex2gif-sup-3.gif)2] (2), a thallium complexed diaryltetraphosphabutadienediide. The negative charge in the anion of 2 is delocalized over the P4 array to afford an average PP bond order of approximately 1.33. Citing Literature Volume44, Issue47December 2, 2005Pages 7729-7733 RelatedInformation

A new series of Fe(II) complexes, FeCl2[N(R)=C(Me)C(Me)=N(R)], containing diimine ligands with hemilabile sidearms R (R = CH2(CH2)2NMe2, 1, CH2(CH2)2OMe, 2, CH2(CH2)2SMe), 3) were synthesized. The crystal structure of 1 showed 6-coordination where both amine arms were attached, whereas 2 was a 5-coordinate 16e species with one methoxy arm dangling free. Extensive attempts were made to bind CO to these species to synthesize precursors for dihydrogen complexes but were unsuccessful. Reaction of 1 with 1 or 2 equiv of AgOTf under CO atmosphere resulted in isolation of only a 6-coordinate bis(triflate)-containing product [Fe[N(R)=C(Me)C(Me)=N(R)](OTf)2] (R = CH2(CH2)2NMe2), 5. Reaction of 5-coordinate 2 with AgSbF6 under CO did not give a CO adduct but afforded instead a dicationic dinuclear complex [Fe[N(R)=C(Me)C(Me)=N(R)](mu-Cl)]2[SbF6]2 (R = CH2(CH2)2OMe), 4, containing a weakly bound SbF6. Thus coordination of hard-donor anions to iron was favored over CO binding. The unexpected rejection of binding of CO is rationalized by the iron being in a high-spin state in this system and energetically incapable of spin crossover to a low-spin state. Theoretical calculations on CO interaction with Fe(II) centers in spin states S = 0, 1, and 2 for both the 16e complexes and their CO adducts aid further understanding of this problem. They show that interaction of CO with a high-spin 5-coordinate Fe model diimine complex is essentially thermoneutral but is exergonic by about 48 kcal/mol to a comparable but low-spin diphosphine fragment. Spin crossover is thus disfavored thermodynamically rather than kinetically (e.g. a "spin block" effect); i.e., the ligand field strengths of the primarily N-donor groups are apparently insufficient to give a low-spin CO adduct.

Reaction of TlCl and [LiN(Me)Ar(Mes)2](2) [Ar(Mes)2 = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Me(3))(2)] in Et(2)O generated the thallium amide, TlN(Me)Ar(Mes)2 (1). X-ray data showed that it has a monomeric structure with an average Tl-N distance of 2.364(3) Angstroms. There was also a Tl-arene approach [Tl-centroid = 3.026(2) Angstroms (avg)] to a flanking mesityl ring from the terphenyl substituent. DFT calculations showed that this interaction is weak and supported essentially one coordination for thallium. The electronic spectrum of 1 is hypsochromically shifted in comparison to the monomeric TlAr(Trip)2 (Trip = C(6)H(2)-2,4,6-Pr(i)(3)).

The synthesis and characterization of three new organothallium(I) compounds are reported. Reaction of (Ar'Li)(2) (Ar' = C6H3-2,6-(C6H3-2,6-Pr'(2))(2)) and Ar"Li (Ar" = C6H3-2,6-(C6H3-2,6-Me-2)(2)) with TICI in Et2O afforded (Ar'TI)(2) (1) and (Ar"TI)(3) (2). The "dithallene" 1 is the heaviest group 13 dimetallene and features a planar, trails-bent structure with Ar'TI-TI = 119.74(14)degrees and TI-TI = 3.0936(8) angstrom. Compound 2 is the first structurally characterized neutral, three-membered ring species of formula c-(MR)(3) (M = AI-TI; R = organo group). The TI3 ring has TI-TI distances in the range ca. 3.21-3.37 angstrom as well as pyramidal TI geometries. The TI-TI bonds in 1 and 2 are outside the range (2.88-2.97 angstrom) of TI-TI single bonds in R2TITIR2 compounds. The weak TI-TI bonding in 1 and 2 leads to their dissociation into Ar'TI and Ar"TI monomers in hexane. The Ar'TI monomer behaves as a Lewis base and readily forms a 1:1 donor-acceptor complex with B(C6F5)(3) to give Ar'TIB(C6F5)(3), 3. Adduct 3 features an almost linear thallium C(ipso)-TI-B angle of 174.358(7)degrees and a TI-B distance of 2.311(2) angstrom, which indicates strong association. Treatment of 1 with a variety of reagents resulted in no reactions. The lower reactivity of 1 is in accord with the reluctance of TI(I) to undergo oxidation to TI(III) due to the unreactive character of the 6s(2) electrons.

Reaction between 2 equiv of K(Nacnac) (Nacnac(-) = [Ar]NC(Me)CHC(Me)N[Ar], Ar = 2,6-(Pr2C6H3)-Pr-i) and UI3(THF)(4) in toluene affords (Nacnac)(2)UI, which features a beta-diketiminate ligand bound to uranium(III) in an unusual eta(3)-(N,C,C')-1-azaallyl mode and possesses Close U...C-alkene contacts.

The reaction of PbBr(2) with the lithium reagents LiC(6)H(3)-2,6-(C(6)H(3)-2,6-Pr(i)(2))(2) (LiArPr(i)(2)) and Et(2)O.LiC(6)H(3)-2,6-(2,6-Pr(i)-4-Bu(t)C(6)H(2))(2) (Et(2)O.LiArPr(i)(2)Bu(t)) furnished the bromide bridged organolead(II) halides [Pb(mu-Br)ArPr(i)(2)](2) (1) and[Pb(mu-Br)ArPr(i)(2)Bu(t)](2) (2) as orange crystals. Treatment of 1 with a stoichiometric amount of methylmagnesium bromide resulted in the "diplumbene" Pr(i)(2)Ar(Me)PbPb(Me)ArPr(i)(2) (3). The addition of 1 equiv of 4-tert-butylphenylmagnesium bromide to 1 afforded the feebly associated, Pb-Pb bonded species [Pb(C(6)H(4)-4-Bu(t))ArPr(i)(2)](2) (4), whereas the corresponding reaction of tert-butylmagnesium chloride and 1 afforded the monomer Pb(Bu(t))ArPr(i)(2) (5). The reaction of the more crowded aryl lead(II) bromide [Pb(mu-Br)ArPr(i)(3)](2) (Ar = C(6)H(3)-2,6(C(6)H(2)-2,4,6-Pr(i)(3))(2)) with 4-isopropyl-benzylmagnesium bromide or LiSi(SiMe(3))(3) yielded the monomers 6, [Pb(CH(2)C(6)H(4)-4-Pr(i))ArPr(i)(3)], or 7, [Pb(Si(SiMe(3))(3))ArPr(i)(3)]. All compounds were characterized with use of X-ray crystallography, (1)H, (13)C, and (207)Pb NMR (3-7), and UV-vis spectroscopy. The dimeric Pb-Pb bonded (Pb-Pb = 3.1601(6) A) structure of 3 may be contrasted with the previously reported monomeric structure of Pb(Me)ArPr(i)(3), which differs from 3 only in that it has para Pr(i) substituents on the flanking aryl rings. The presence of these groups is sufficient to prevent the weak Pb-Pb bonding seen in 3. The dimer 4 displays a Pb-Pb distance of 3.947(1) A, which indicates a very weak lead-lead interaction, and it is possible that this close approach could be caused by packing effects. The monomeric structures of 6 and 7 are attributable to steric effects and, in particular, to the large size of ArPr(i)(3).

The synthesis, structure, and properties of several new organogallium(I) compounds are reported. The monovalent compounds GaAr* (Ar* = C(6)H(3)-2,6-Trip(2), Trip = C(6)H(2)-2,4,6-Pr(i)()(3), 1), GaAr# (Ar# = C(6)H(3)-2,6(Bu(t)Dipp)(2), Bu(t)Dipp = C(6)H(2)-2,6-Pr(i)(2)-4-Bu(t)(), 4), and the dimeric (GaAr')(2) (Ar' = C(6)H(3)-2,6-Dipp(2), Dipp = C(6)H(3)-2,6-Pr(i)(2), 6) were synthesized by the reaction of "GaI" with (Et(2)O)LiAr*, (Et(2)O)LiAr# (3), or (LiAr')(2). Compounds 1 and 4 were isolated as green crystals, whereas 6 was obtained as a brown-red crystalline solid. All three compounds dissolved in hydrocarbon solvents to give green solutions and almost identical UV/visible spectra. Cryoscopy of 1 and 6 showed that they were monomeric in cyclohexane. Crystals of 1 and 4 were unsuitable for X-ray crystal structure determinations, but an X-ray data set for 6 showed that it was weakly dimerized in the solid with a long Ga-Ga bond of 2.6268(7) A and a trans-bent CGaGaC core array. The 1,2-diiodo-1,2-diaryldigallane compounds [Ga(Ar*)I](2) (2), [Ga(Ar#)I](2) (5), and [Ga(Ar')I](2) (7) were isolated as byproducts of the synthesis of 1, 4, and 6. The crystal structures of 2 and 7 showed that they had planar ICGaGaCI core arrays with Ga-Ga distances near 2.49 A, consistent with Ga-Ga single bonding. Treatment of 1, 4, and 6 with B(C(6)F(5))(3) immediately afforded the 1:1 donor-acceptor complexes ArGa[B(C(6)F(5))(3)] (Ar = Ar*, 8; Ar#, 9; Ar', 10) that featured almost linear gallium coordination, Ga-B distances near the sum of the covalent radii of gallium and boron, as well as some close Ga...F contacts. Compound 1 also reacted with Fe(CO)(5) under ambient conditions to give Ar*GaFe(CO)(4) (11), which had been previously synthesized by the reaction of GaAr*Cl(2) with Na(2)Fe(CO)(4). Reaction of 1 with 2,3-dimethyl-1,3-butadiene afforded the compound [Ar*GaCH(2)C(Me)C(Me)CH(2)]2 (12) that had a 10-membered 1,5-Ga(2)C(8) ring with no Ga-Ga interaction. Stirring 1 or 6 with sodium readily gave Na(2)[Ar*GaGaAr*] (13) and Na(2)(Ar'GaGaAr') (14). The former species 13 had been synthesized previously by reduction of GaAr*Cl(2) with sodium and was described as having a Ga-Ga triple bond because of the short Ga-Ga distance and the electronic relationship between [Ar*GaGaAr*](2-) and the corresponding neutral group 14 alkyne analogues. Compound 14 has a similar structure featuring a trans-bent CGaGaC core, bridged by sodiums which were also coordinated to the flanking aryl rings of the Ar' ligands. The Ga-Ga bond length was found to be 2.347(1) A, which is slightly (ca. 0.02 A) longer than that reported for 13. Reaction of Ga[N(Dipp)C(Me)](2)CH, 15 (i.e., GaN(wedge)NDipp(2)), which is sterically related to 1, 4, and 6, with Fe(CO)(5) yielded Dipp(2)N(wedge)NGaFe(CO)(4) (16), whose Ga-Fe bond is slightly longer than that observed in 11. Reaction of the less bulky LiAr"(Ar"= C(6)H(3)-2,6-Mes(2)) with "GaI" afforded the new paramagnetic cluster Ga(11)Ar(4)" (17). The ready dissociation of 1, 4, and 6 in solution, the long Ga-Ga distance in 6, and the chemistry of these compounds showed that the Ga-Ga bonds are significantly weaker than single bonds. The reduction of 1 and 6 with sodium to give 13 and 14 supplies two electrons to the di-gallium unit to generate a single bond (in addition to the weak interaction in the neutral precursor) with retention of the trans-bent geometry. It was concluded that the stability of 13 and 14 depends on the matching size of the sodium ion, and the presence of Na-Ga and Na-Ar interactions that stabilize their Na(2)Ga(2) core structures.

Reaction of Ar'MMAr' (M = Ga or In) with N3Ar' ' (Ar' = C6H3-2,6-Dipp2, Dipp = C6H3-2,6-Pri2, Ar' ' = C6H3-2,6(Xyl-4-But)2) afforded the first monomeric imides of heavier group 13 elements with two-coordinate metals. Planar, trans-bent structures with short M-N bond distances were observed, which are consistent with lone pair character at both M and N and a bond order less than the formally expected triple one.

Reduction of Ar'AlI2 (Ar' = Ar'= C6H3-2,6-Dipp2; Dipp = C6H3-2,6-Pri2) with KC8 in diethyl ether most probably affords the first "dialuminene", Ar'AlAlAr'; it was characterized by its reaction with toluene which yielded a [2 + 4] cycloaddition product incorporating the Ar'AlAlAr' unit.