Reactivity of diaminogermylenes with ruthenium carbonyl: Ru3Ge3 and RuGe2 derivatives

The nature of the products of the reactions of [Ru(3)(CO)(12)] with diaminogermylenes depends upon the volume and the cyclic or acyclic structure of the latter. Thus, the triruthenium cluster [Ru(3){μ-Ge(NCH(2)CMe(3))(2)C(6)H(4)}(3)(CO)(9)], which has a planar Ru(3)Ge(3) core and an overall C(3h) symmetry, has been prepared in quantitative yield by treating [Ru(3)(CO)(12)] with an excess of the cyclic 1,3-bis(neo-pentyl)-2-germabenzimidazol-2-ylidene in toluene at 100 °C, but under analogous reaction conditions, the acyclic and bulkier Ge(HMDS)(2) (HMDS = N(SiMe(3))(2)) quantitatively leads to the mononuclear ruthenium(0) derivative [Ru{Ge(HMDS)(2)}(2)(CO)(3)]. Mixtures of products have been obtained from the reactions of [Ru(3)(CO)(12)] with the cyclic and very bulky 1,3-bis(tert-butyl)-2-germaimidazol-2-ylidene under various reaction conditions. The Ru(3)Ge(3) and RuGe(2) products reported in this paper are the first ruthenium complexes containing diaminogermylene ligands.     

Diaminogermylene and diaminostannylene derivatives of gold(I): novel AuM and AuM2 (M = Ge, Sn) complexes

The reactions of [AuCl(THT)] (THT = tetrahydrothiophene) with 1 equiv of the group 14 diaminometalenes M(HMDS)(2) [M = Ge, Sn; HMDS = N(SiMe(3))(2)] lead to [Au{MCl(HMDS)(2)}(THT)] [M = Ge (1), Sn (2)], which contain a metalate(II) ligand that arises from insertion of the corresponding M(HMDS)(2) reagent into the Au-Cl bond of the gold(I) reagent. While compound 1 reacts with more Ge(HMDS)(2) to give the germanate-germylene derivative [Au{GeCl(HMDS)(2)}{Ge(HMDS)(2)}] (3), which results from substitution of Ge(HMDS)(2) for the THT ligand of 1, an analogous treatment of compound 2 with Sn(HMDS)(2) gives the stannate-stannylene derivative [Au{SnCl(HMDS)(2)}{Sn(HMDS)(2)(THT)}] (4), which has a THT ligand attached to the stannylene tin atom and which, in solution at room temperature, participates in a dynamic process that makes its two Sn(HMDS)(2) fragments equivalent (on the NMR time scale). A similar dynamic process has not been observed for the AuGe(2) compound 3 or for the AuSn(2) derivatives [Au{SnR(HMDS)(2)}{Sn(HMDS)(2)(THT)}] [R = Bu (5), HMDS (6)], which have been prepared by treating complex 4 with LiR. The structures of compounds 1 and 3-6 have been determined by X-ray diffraction.     

Insight into the dinuclear {Fe(NO)2}10{Fe(NO)2}10 and mononuclear {Fe(NO)2}10 dinitrosyliron complexes

The reversible redox transformations [(NO)(2)Fe(S(t)Bu)(2)](-) ? [Fe(μ-S(t)Bu)(NO)(2)](2)(2-) ? [Fe(μ-S(t)Bu)(NO)(2)](2)(-) ? [Fe(μ-S(t)Bu)(NO)(2)](2) and [cation][(NO)(2)Fe(SEt)(2)] ? [cation](2)[(NO)(2)Fe(SEt)(2)] (cation = K(+)-18-crown-6 ether) are demonstrated. The countercation of the {Fe(NO)(2)}(9) dinitrosyliron complexes (DNICs) functions to control the formation of the {Fe(NO)(2)}(10){Fe(NO)(2)}(10) dianionic reduced Roussin's red ester (RRE) [PPN](2)[Fe(μ-SR)(NO)(2)](2) or the {Fe(NO)(2)}(10) dianionic reduced monomeric DNIC [K(+)-18-crown-6 ether](2)[(NO)(2)Fe(SR)(2)] upon reduction of the {Fe(NO)(2)}(9) DNICs [cation][(NO)(2)Fe(SR)(2)] (cation = PPN(+), K(+)-18-crown-6 ether; R = alkyl). The binding preference of ligands [OPh](-)/[SR](-) toward the {Fe(NO)(2)}(10){Fe(NO)(2)}(10) motif of dianionic reduced RRE follows the ligand-displacement series [SR](-) > [OPh](-). Compared to the Fe K-edge preedge energy falling within the range of 7113.6-7113.8 eV for the dinuclear {Fe(NO)(2)}(9){Fe(NO)(2)}(9) DNICs and 7113.4-7113.8 eV for the mononuclear {Fe(NO)(2)}(9) DNICs, the {Fe(NO)(2)}(10) dianionic reduced monomeric DNICs and the {Fe(NO)(2)}(10){Fe(NO)(2)}(10) dianionic reduced RREs containing S/O/N-ligation modes display the characteristic preedge energy 7113.1-7113.3 eV, which may be adopted to probe the formation of the EPR-silent {Fe(NO)(2)}(10)-{Fe(NO)(2)}(10) dianionic reduced RREs and {Fe(NO)(2)}(10) dianionic reduced monomeric DNICs in biology. In addition to the characteristic Fe/S K-edge preedge energy, the IR ν(NO) spectra may also be adopted to characterize and discriminate [(NO)(2)Fe(μ-S(t)Bu)](2) [IR ν(NO) 1809 vw, 1778 s, 1753 s cm(-1) (KBr)], [Fe(μ-S(t)Bu)(NO)(2)](2)(-) [IR ν(NO) 1674 s, 1651 s cm(-1) (KBr)], [Fe(μ-S(t)Bu)(NO)(2)](2)(2-) [IR ν(NO) 1637 m, 1613 s, 1578 s, 1567 s cm(-1) (KBr)], and [K-18-crown-6 ether](2)[(NO)(2)Fe(SEt)(2)] [IR ν(NO) 1604 s, 1560 s cm(-1) (KBr)].     

Cluster expansion reactions of group 6 and 8 metallaboranes using transition metal carbonyl compounds of groups 7-9

The reinvestigation of an early synthesis of heterometallic cubane-type clusters has led to the isolation of a number of new clusters which have been characterized by spectroscopic and crystallographic techniques. The thermolysis of [(Cp*Mo)(2)B(4)H(4)E(2)] (1: E = S; 2: E = Se; Cp* = η(5)-C(5)Me(5)) in presence of [Fe(2)(CO)(9)] yielded cubane-type clusters [(Cp*Mo)(2)(μ(3)-E)(2)B(2)H(μ-H){Fe(CO)(2)}(2)Fe(CO)(3)], 4 and 5 (4: E = S; 5: E = Se) together with fused clusters [(Cp*Mo)(2)B(4)H(4)E(2)Fe(CO)(2)Fe(CO)(3)] (8: E = S; 9: E = Se). In a similar fashion, reaction of [(Cp*RuCO)(2)B(2)H(6)], 3, with [Fe(2)(CO)(9)] yielded [(Cp*Ru)(2)(μ(3)-CO)(2)B(2)H(μ-H){Fe(CO)(2)}(2)Fe(CO)(3)], 6, and an incomplete cubane cluster [(μ(3)-BH)(3)(Cp*Ru)(2){Fe(CO)(3)}(2)], 7. Clusters 4-6 can be described as heterometallic cubane clusters containing a Fe(CO)(3) moiety exo-bonded to the cubane, while 7 has an incomplete cubane [Ru(2)Fe(2)B(3)] core. The geometry of both compounds 8 and 9 consist of a bicapped octahedron [Mo(2)Fe(2)B(3)E] and a trigonal bipyramidal [Mo(2)B(2)E] core, fused through a common three vertex [Mo(2)B] triangular face. In addition, thermolysis of 3 with [Mn(2)(CO)(10)] permits the isolation of arachno-[(Cp*RuCO)(2)B(3)H(7)], 10. Cluster 10 constitutes a diruthenaborane analogue of 8-sep pentaborane(11) and has a structural isomeric relationship to 1,2-[{Cp*Ru}(2)(CO)(2)B(3)H(7)].     

Effects of lanthanide metal size and amino ligand denticity on the solvothermal systems Ln/Sn/Se/en and Ln/Sn/Se/dien (Ln = lanthanide)

Two systems, Ln/Sn/Se/en and Ln/Sn/Se/dien, were investigated under solvothermal conditions, and novel lanthanide selenidostannates [{Ce(en)(4)}(2)(μ-Se(2))]Sn(2)Se(6) (1a), [{Ln(en)(3)}(2)(μ-OH)(2)]Sn(2)Se(6) (Ln = Pr(1b), Nd(1c), Gd(1d); en = ethylenediamine), [{Ln(dien)(2)}(4)(μ(4)-Sn(2)Se(9))(μ-Sn(2)Se(6))](∞) (Ln = Ce(2a), Nd(2b)), and [Hdien][Gd(dien)(2)(μ-SnSe(4))] (2c) (dien = diethylenetriamine) were prepared and characterized. Two structural types of lanthanide selenidostannates were obtained across the lanthanide series in both systems. In the Ln/Sn/Se/en system, two types of binuclear lanthanide complex cations [Ce(2)(en)(8)(μ-Se(2))](4+) and [{Ln(en)(3)}(2)(μ-OH)(2)](4+) (Ln = Pr, Nd, Gd) were formed depending on the Ln(3+) ions. The complex cations are compensated by the [Sn(2)Se(6)](4-) anions. In the Ln/Sn/Se/dien system, coordination polymer [{Ln(dien)(2)}(4)(μ(4)-Sn(2)Se(9))(μ-Sn(2)Se(6))](∞) and ionic complex [Hdien][Gd(dien)(2)(μ-SnSe(4))] are obtained along the lanthanide series, among which the μ(4)-Sn(2)Se(9), μ-Sn(2)Se(6) and μ-SnSe(4) ligands to the Ln(3+) ions were observed. The formation of title complexes shows the effects of lanthanide metal size and amino ligand denticity on the lanthanide selenidostannates. Complexes 1a-2c exhibit semiconducting properties with band gaps between 2.08 and 2.48 eV.     

Resorcinol based acyclic dimeric and cyclic di- and tetrameric cyclodiphosphazanes: synthesis, structural studies, and transition metal complexes

The condensation reaction of resorcinol with cis-[ClP(μ-N(t)Bu)(2)PN(H)(t)Bu] produced a difunctional derivative 1,3-C(6)H(4)[OP(μ-N(t)Bu)(2)PN(H)(t)Bu](2) (1), whereas the similar reaction with [ClP(μ-N(t)Bu)](2) resulted in the formation of a 1:1 mixture of dimeric and tetrameric species, [{P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (2a) and [{P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](4) (2b), which were separated by repeated fractional crystallization and column chromatography. The reaction of dimer 2a with H(2)O(2) and selenium produces tetrachalcogenides [{(O)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (3) and [{(Se)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (4), respectively. The reaction between the dimer (2a) and [Pd(μ-Cl)(η(3)-C(3)H(5))](2) or AuCl(SMe(2)) yielded the corresponding tetranuclear complexes, [{((Cl)(η(3)-C(3)H(5))Pd)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (5) and [{(ClAu)P(μ-N(t)Bu)}(2){1,3-(O)(2)-C(6)H(4)}](2) (6) in good yield. The complexes 5 and 6 are the rare examples of phosphorus macrocycles containing two or more exocyclic transition metal fragments. Treatment of 1 with copper halides in 1:1 molar ratio resulted in the formation of one-dimensional (1D) coordination polymers, [(CuX){1,3-C(6)H(4){OP(μ-N(t)Bu)(2)PN(H)(t)Bu}}(2)](n) (7, X = Cl; 8, X = Br; 9, X = I), which showed the helical structure in solid state because of intramolecular hydrogen bonding, whereas similar reactions of 1 with 4 equiv of copper halides also produced 1D-coordination polymers, [(Cu(2)X(2))(2){1,3-C(6)H(4){OP(μ-N(t)Bu)(2)PN(H)(t)Bu}(2)}](n) (10, X = Cl; 11, X = Br; 12, X = I), but containing Cu(2)X(2) rhomboids instead of CuX linkers. The crystal structures of 1, 2a, 2b, 4, 7-9, and 12 were established by X-ray diffraction studies.     

Condensed tantalaborane clusters: synthesis and structures of [(Cp*Ta)2B5H7{Fe(CO)3}2] and [(Cp*Ta)2B5H9{Fe(CO)3}4

The reaction of [(Cp*Ta)(2)B(4)H(9)(μ-BH(4))] (1; Cp* = η(5)-C(5)Me(5)) with [Fe(2)(CO)(9)] in hexane yielded [(Cp*Ta)(2)B(5)H(7){Fe(CO)(3)}(2)] (2) and [(Cp*Ta)(2)B(5)H(9){Fe(CO)(3)}(4)] (3) in moderate yield. Cluster 2 represents the first example of a bicapped pentagonal-bipyramidal metallaborane with a deformed equatorial plane, and 3 can be described as a fused cluster in which two pentagonal-bipyramidal units are fused through a common 3-vertex triangular face. Compounds 2 and 3 have been characterized by mass spectrometry and IR, (1)H, (11)B, and (13)C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis.     

Hydride mobility in trinuclear sulfido clusters with the core [Rh3(μ-H)(μ3-S)2]: molecular models for hydrogen migration on metal sulfide hydrotreating catalysts

The treatment of [{Rh(μ-SH){P(OPh)(3)}(2)}(2)] with [{M(μ-Cl)(diolef)}(2)] (diolef=diolefin) in the presence of NEt(3) affords the hydrido-sulfido clusters [Rh(3)(μ-H)(μ(3)-S)(2)(diolef){P(OPh)(3)}(4)] (diolef=1,5-cyclooctadiene (cod) for 1, 2,5-norbornadiene (nbd) for 2, and tetrafluorobenzo[5,6]bicyclo[2.2.2]octa-2,5,7-triene (tfb) for 3) and [Rh(2)Ir(μ-H)(μ(3)-S)(2)(cod){P(OPh)(3)}(4)] (4). Cluster 1 can be also obtained by treating [{Rh(μ-SH){P(OPh)(3)}(2)}(2)] with [{Rh(μ-OMe)(cod)}(2)], although the main product of the reaction with [{Ir(μ-OMe)(cod)}(2)] was [RhIr(2)(μ-H)(μ(3)-S)(2)(cod)(2){P(OPh)(3)}(2)] (5). The molecular structures of clusters 1 and 4 have been determined by X-ray diffraction methods. The deprotonation of a hydrosulfido ligand in [{Rh(μ-SH)(CO)(PPh(3))}(2)] by [M(acac)(diolef)] (acac=acetylacetonate) results in the formation of hydrido-sulfido clusters [Rh(3)(μ-H)(μ(3)-S)(2)(CO)(2) (diolef)(PPh(3))(2)] (diolef=cod for 6, nbd for 7) and [Rh(2)Ir(μ-H)(μ(3)-S)(2)(CO)(2)(cod)(PPh(3))(2)] (8). Clusters 1-3 and 5 exist in solution as two interconverting isomers with the bridging hydride ligand at different edges. Cluster 8 exists as three isomers that arise from the disposition of the PPh(3) ligands in the cluster (cis and trans) and the location of the hydride ligand. The dynamic behaviour of clusters with bulky triphenylphosphite ligands, which involves hydrogen migration from rhodium to sulfur with a switch from hydride to proton character, is significant to understand hydrogen diffusion on the surface of metal sulfide hydrotreating catalysts.     

Targeting large phosp(III)azane macrocyles [{P(mu-NR)}(2)(LL)](n) (n> or = 2)

The condensation reactions of the dimer [ClP(micro-NR)](2) with organic diacids [LL(H)(2)], possessing linear orientations of their organic groups, result in the formation of phospha(III)zane macrocyles of the type [{P(mu-NR)}(2)(LL)](n) of various sizes. The series of macrocycles [{P(mu-N(t)Bu)}(2){1,5-(NH)(2)C(10)H(6)}](3), [{P(mu-NCy)}(2)(1,5-O(2)C(10)H(6))](n) [n = 3; n = 4], [{P(mu-N(t)Bu)}(2){1,4-(NH)(2)C(6)H(4)}](4), [{P(mu-N(t)Bu)}(2)(1,4-O(2)C(6)H(4))], [{P(mu-NCy)}(2)(1,4-O(2)C(6)H(4))](3) and [{P(mu-N(t)Bu)}(2){(NH)C(6)H(4)OC(6)H(4)(NH)}](2) can be related to classical organic frameworks, like calixarenes.     

Halide, amide, cationic, manganese carbonylate, and oxide derivatives of triamidosilylamine uranium complexes

Treatment of the complex [U(Tren(TMS))(Cl)(THF)] [1, Tren(TMS) = N(CH(2)CH(2)NSiMe(3))(3)] with Me(3)SiI at room temperature afforded known crystalline [U(Tren(TMS))(I)(THF)] (2), which is reported as a new polymorph. Sublimation of 2 at 160 °C and 10(-6) mmHg afforded the solvent-free dimer complex [{U(Tren(TMS))(μ-I)}(2)] (3), which crystallizes in two polymorphic forms. During routine preparations of 1, an additional complex identified as [U(Cl)(5)(THF)][Li(THF)(4)] (4) was isolated in very low yield due to the presence of a slight excess of [U(Cl)(4)(THF)(3)] in one batch. Reaction of 1 with one equivalent of lithium dicyclohexylamide or bis(trimethylsilyl)amide gave the corresponding amide complexes [U(Tren(TMS))(NR(2))] (5, R = cyclohexyl; 6, R = trimethylsilyl), which both afforded the cationic, separated ion pair complex [U(Tren(TMS))(THF)(2)][BPh(4)] (7) following treatment of the respective amides with Et(3)NH·BPh(4). The analogous reaction of 5 with Et(3)NH·BAr(f)(4) [Ar(f) = C(6)H(3)-3,5-(CF(3))(2)] afforded, following addition of 1 to give a crystallizable compound, the cationic, separated ion pair complex [{U(Tren(TMS))(THF)}(2)(μ-Cl)][BAr(f)(4)] (8). Reaction of 7 with K[Mn(CO)(5)] or 5 or 6 with [HMn(CO)(5)] in THF afforded [U(Tren(TMS))(THF)(μ-OC)Mn(CO)(4)] (9); when these reactions were repeated in the presence of 1,2-dimethoxyethane (DME), the separated ion pair [U(Tren(TMS))(DME)][Mn(CO)(5)] (10) was isolated instead. Reaction of 5 with [HMn(CO)(5)] in toluene afforded [{U(Tren(TMS))(μ-OC)(2)Mn(CO)(3)}(2)] (11). Similarly, reaction of the cyclometalated complex [U{N(CH(2)CH(2)NSiMe(2)Bu(t))(2)(CH(2)CH(2)NSiMeBu(t)CH(2))}] with [HMn(CO)(5)] gave [{U(Tren(DMSB))(μ-OC)(2)Mn(CO)(3)}(2)] [12, Tren(DMSB) = N(CH(2)CH(2)NSiMe(2)Bu(t))(3)]. Attempts to prepare the manganocene derivative [U(Tren(TMS))MnCp(2)] from 7 and K[MnCp(2)] were unsuccessful and resulted in formation of [{U(Tren(TMS))}(2)(μ-O)] (13) and [MnCp(2)]. Complexes 3-13 have been characterized by X-ray crystallography, (1)H NMR spectroscopy, FTIR spectroscopy, Evans method magnetic moment, and CHN microanalyses.     

New star-shaped trinuclear Ru(II) polypyridine complexes of imidazo[4,5-f][1,10]phenanthroline derivatives: syntheses, characterization, photophysical and electrochemical properties

A series of new star-shaped trinuclear Ru(II) complexes of imidazo[4,5-f][1,10]phenanthroline derivatives, [{Ru(bpy)(2)}(3){μ-mes(1,4-phO-Izphen)(3)}](ClO(4))(6)·4H(2)O (6), [{Ru(phen)(2)}(3){μ-mes(1,4-phO-Izphen)(3)}](ClO(4))(6)·3H(2)O (7), [{Ru(bpy)(2)}(3){μ-mes(1,2-phO-Izphen)(3)}](ClO(4))(6)·4H(2)O (8), and [{Ru(phen)(2)}(3){μ-mes(1,2-phO-Izphen)(3)}](ClO(4))(6)·3H(2)O (9) [mes(1,4-phO-Izphen)(3) (4) = 2,4,6-tri methyl-1,3,5-tris(4-oxymethyl-1-yl(1H-imidazo-2-yl-[4,5-f][1,10]phenanthroline)phenyl)benzene and (mes(1,2-phO-Izphen)(3) (5) = 2,4,6-trimethyl-1,3,5-tris(2-oxymethyl-1-yl(1H-imidazo-2-yl[4,5-f][1,10]phenanthroline)phenyl)benzene] have been synthesized and characterized. Their photophysical and electrochemical properties have also been studied. The core molecule, 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene (1) and the trialdehyde intermediate, 2,4,6-trimethyl-1,3,5-tris(4-oxymethyl-1-formylphenyl)benzene (2) are characterized by single crystal X-ray diffraction: triclinic, P1[combining macron]. The complexes 6-9 exhibit Ru(II) metal centered emission at 618, 601, 615, and 605 nm, respectively, in fluid solution at room temperature. The emission profile and emission maxima are similar and independent of the excitation wavelength for each complex. The complexes 6-9 undergo metal centered oxidation and the E(1/2) values for the Ru(II)/Ru(III) redox couples are 1.33, 1.34, 1.35, and 1.35 V versus Ag/Ag(+), respectively, which are cathodically shifted with respect to that of the mononuclear complex [Ru(bpy)(2)(PIP)](2+) (PIP = 2-phenylimidazo[4,5-f][1,10]phenanthroline). The study demonstrates the versatility of the highly symmetric trinucleating imidazo[4,5-f][1,10]phenanthroline-based core ligands 4 and 5 in forming trinuclear Ru(II) complexes.     

Crystalline metal (Li, Mg, Ca, Sr, Ba, Sn, Pb) complexes of the new chelating N,N'-dianionic [1,2-N(R)C6H4(CH2NR)](2-) ligand (R = SiMe3, CH2Bu(t))

2-Aminomethylaniline was converted into the N,N'-bis(pivaloyl) (1) or -bis(trimethylsilyl) (2) derivative, using 2 Bu(t)C(O)Cl or 2 Me(3)SiCl (≡ RCl), respectively, with 2 NEt(3), or for 2 from successively using 2 LiBu(n) and 2 RCl. N,N'-Bis(neopentyl)-2-(aminomethyl)aniline (3) was prepared by LiAlH(4) reduction of 1. From 2 or 3 and 2 LiBu(n), the appropriate dilitiodiamide {2-[{N(Li)R}C(6)H(4){CH(2)N(Li)R}(L)](2) (L absent, 4a; or L = THF, 4b) or the N,N'-bis(neopentyl) analogue (5) of 4a was prepared. Treatment of 4a with 2 Bu(t)NC, 2 (2,6-Me(2)C(6)H(3)NC) or 2 Bu(t)CN (≡ L') furnished the corresponding adduct [2-N{Li(L')R}C(6)H(4){CH(2)N(Li)R}] (4c, 4d or 4e, respectively), whereas 4b with 2 PhCN afforded [2-{N(Li)R}C(6)H(4){CH(2)C(Ph) = NLi(NCPh)}] (6). The dimeric bis(amido)stannylene [Sn{N(R)C(6)H(4)(CH(2)NR)-1,2}](2) (7) was obtained from 4a and [Sn(μ-Cl)NR(2)](2), while the N,N'-bis(neopentyl) analogue 8 of 7 was similarly derived from [Sn(μ-Cl)NR(2)](2) and 5. Reaction of two equivalents of the diamine 2 with Pb(NR(2))(2) yielded 9, the lead homologue of 7. Oxidative addition of sulfur to 7 led to the dimeric bis(diamido)tin sulfide 10. Treatment of 2 successively with 'MgBu(2)' in C(5)H(12) and THF gave [Mg{N(R)C(6)H(4)(CH(2)NR)}(THF)](2) (11a), which by displacement of its THF by an equivalent portion of Bu(t)CN or PhCN produced [Mg{N(R)C(6)H(4)(CH(2)NR)}(CNR')(n)] [R' = Bu(t), n = 1 (11b); R' = Ph, n = 2 (11c)]. The Ca (12), Sr (13) or Ba (14) analogues of the Mg compound 11a were isolated from 2 and either the appropriate compound M(NR(2))(2) (M = Ca, Sr, Ba), or successively 2 LiBu(n) and 2 M(OTos)(2). The new compounds 1-14 were characterized by microanalysis (C, H, N; not for 1, 2, 3, 5), solution NMR spectra, ν(max) (C≡N) (IR for 4c, 4d, 4e, 6, 11b, 11c), selected EI-MS peaks (for 1, 2, 3, 7, 8, 9, 10), and single crystal X-ray diffraction (for 4a, 4b, 11a).     

Metal-centered deltahedral Zintl ions: synthesis of [Ni@Sn9]4- by direct extraction from intermetallic precursors and of the vertex-fused dimer [{Ni@Sn8(μ-Ge)(1/2)}2]4-

Ni-centered deltahedral Sn(9) clusters with a charge of 4-, i.e., [Ni@Sn(9)](4-), were extracted in ethylenediamine in high yield directly from intermetallic precursors with the nominal composition "K(4)Sn(9)Ni(3)". The new endohedral clusters were crystallized and structurally characterized in K[K(18-crown-6)](3)[Ni@Sn(9)]·3benzene (1a, triclinic, P1?, a = 10.2754(5) ?, b = 19.5442(9) ?, and c = 20.5576(13) ?, α = 73.927(3)°, β = 79.838(4)°, and γ = 84.389(3)°, V = 3899.6(4) ?(3), Z = 2) and K[K(2,2,2-crypt)](3)[Ni@Sn(9)] (1b, triclinic, P1, a = 15.8028(8) ?, b = 16.21350(9) ?, and c = 20.1760(12) ?, α = 98.71040(10)°, β = 104.4690(10)°, and γ = 118.3890(10)°, V = 4181.5(4) ?(3), Z = 2). The alternative method of a post-synthetic insertion of a Ni atom in empty Sn(9) clusters by a reaction with Ni(cod)(2) predominantly produces the more-oxidized clusters with a charge of 3-, i.e., the recently reported [Ni@Sn(9)](3-). Nonetheless, using substoichiometric amounts of 18-crown-6 as a cation sequestering agent, we also have been able to isolate the 4- clusters as a minor phase from such reactions. They were structurally characterized in K[K(en)][K(18-crown-6)](2)[Ni@Sn(9)]·0.5en (2, monoclinic, P2(1)/n, a = 10.4153(5) ?, b = 25.6788(11) ?, and c = 20.6630(9) ?, β = 102.530(2)°, V = 5394.7(4) ?(3), Z = 2). The ability of the Ni-centered clusters to exist with both 3- and 4- charges parallels the same ability of the empty clusters and is very promising for similarly rich chemistry involving electron transfer and flexible "oxidation states". We also report the synthesis and characterization of the endohedral heteroatomic dimer [{Ni@Sn(8)(μ-Ge)(1/2)}(2)](4-) composed of two [Ni@(Sn(8)Ge)]-clusters fused at the Ge-vertex. The dimer was synthesized by reacting an ethylenediamine solution of a ternary precursor with the nominal composition "K(4)Ge(4.5)Sn(4.5)", which is known to produce heteroatomic Ge(9-x)Sn(x) clusters, with Ni(cod)(2). It is isostructural with the reported [{Ni@Sn(8)(μ-Sn)(1/2)}(2)](4-) and is structurally characterized in [K-(2,2,2-crypt)](4)[{Ni@Sn(8)(μ-Ge)(1/2)}(2)]·2en (3, monoclinic, C2/c, a = 30.636(2) ?, b = 16.5548(12) ?, and c = 28.872(2) ?, β = 121.2140(10)°, V = 12523.5(15) ?(3), Z = 4).     

C-X bond formation and cleavage in the reactions of the ditungsten hydride complex [W2(η5-C5H5)2(H)(μ-PCy2)(CO)2] with small molecules having multiple C-X bonds (X = C, N, O)

Two molecules of C(2)(CO(2)Me)(2) or isocyanides could be added to the title hydride complex under mild conditions to give dienyl-[W(2)Cp(2){μ-η(1),κ:η(2)-C(CO(2)Me)=C(CO(2)Me)C(CO(2)Me)=CH(CO(2)Me)}(μ-PCy(2))(CO)(2)] (Cp = η(5)-C(5)H(5)), diazadienyl-[W(2)Cp(2){μ-κ,η:κ,η-C{CHN(4-MeO-C(6)H(4))}N(4-MeO-C(6)H(4))}(μ-PCy(2))(CO)(2)] or aminocarbyne-bridged derivatives [W(2)Cp(2){μ-CNH(2,6-Me(2)C(6)H(3))}(μ-PCy(2)){CN(2,6-Me(2)C(6)H(3))}(CO)]. In contrast, its reaction with excess (4-Me-C(6)H(4))C(O)H gave the C-O bond cleavage products [W(2)Cp(2){CH(2)(4-Me-C(6)H(4))}(O)(μ-PCy(2))(CO)(2)] and [W(2)Cp(2){μ-η:η,κ-C(O)CH(2)(4-Me-C(6)H(4))}(O)(μ-PCy(2))(CO)].     

Cationic diiron and diruthenium μ-allenyl complexes: synthesis, X-ray structures and cyclization reactions with ethyldiazoacetate/amine affording unprecedented butenolide- and furaniminium-substituted bridging carbene ligands

The novel cationic diiron μ-allenyl complexes [Fe(2)Cp(2)(CO)(2)(μ-CO){μ-η(1):η(2)(α,β)-C(α)(H)=C(β)=C(γ)(R)(2)}](+) (R = Me, 4a; R = Ph, 4b) have been obtained in good yields by a two-step reaction starting from [Fe(2)Cp(2)(CO)(4)]. The solid state structures of [4a][CF(3)SO(3)] and of the diruthenium analogues [Ru(2)Cp(2)(CO)(2)(μ-CO){μ-η(1):η(2)(α,β)-C(α)(H)=C(β)=C(γ)(R)(2)}][BPh(4)] (R = Me, [2a][BPh(4)]; R = Ph, [2c][BPh(4)]) have been ascertained by X-ray diffraction studies. The reactions of 2c and 4a with Br?nsted bases result in formation of the μ-allenylidene compound [Ru(2)Cp(2)(CO)(2)(μ-CO){μ-η(1):η(1)-C(α)=C(β)=C(γ)(Ph)(2)}] (5) and of the dimetallacyclopentenone [Fe(2)Cp(2)(CO)(μ-CO){μ-η(1):η(3)-C(α)(H)=C(β)(C(γ)(Me)CH(2))C(=O)}] (6), respectively. The nitrile adducts [Ru(2)Cp(2)(CO)(NCMe)(μ-CO){μ-η(1):η(2)-C(α)(H)=C(β)=C(γ)(R)(2)}](+) (R = Me, 7a; R = Ph, 7b), prepared by treatment of 2a,c with MeCN/Me(3)NO, react with N(2)CHCO(2)Et/NEt(3) at room temperature, affording the butenolide-substituted carbene complexes [Ru(2)Cp(2)(CO)(μ-CO){μ-η(1):η(3)-C(α)(H)[upper bond 1 start]C(β)C(γ)(R)(2)OC(=O)C[upper bond 1 end](H)] (R = Me, 10a; R = Ph, 10b). The intermediate cationic compound [Ru(2)Cp(2)(CO)(μ-CO){μ-η(1):η(3)-C(α)(H)[upper bond 1 start]C(β)C(γ)(Me)(2)OC(OEt)C[upper bond 1 end](H)](+) (9) has been detected in the course of the reaction leading to 10a. The addition of N(2)CHCO(2)Et/NHEt(2) to 7a gives the 2-furaniminium-carbene [Ru(2)Cp(2)(CO)(μ-CO){μ-η(1):η(3)-C(α)(H)[upper bond 1 start]C(β)C(γ)(Me)(2)OC(OEt)C[upper bond 1 end](H)](+) (11). The X-ray structures of 10a, 10b and [11][BF(4)] have been determined. The reactions of 4a,b with MeCN/Me(3)NO result in prevalent decomposition to mononuclear iron species.     

Diborane(4) compounds with bidentate diamino groups

The reaction between B(2)(NMe(2))(4) and 1,2-(NH(2))(2)-4-Bu(t)C(6)H(3) affords the diborane(4) compound 1,2-B(2){1,2-(NH)(2)-4-Bu(t)C(6)H(3)}(2) as the exclusive product whilst the reaction between rac-1,2-(NH(2))(2)C(6)H(10) and B(2)(NMe(2))(4) also affords only the 1,2-isomer, i.e. 1,2-B(2){1,2-(NH)(2)C(6)H(10)}(2), which is shown to be the more stable isomer by computational methods. The previously reported compounds 1,1-B(2){1,2-(NH)(2)C(6)H(4)}(2) and 1,2-B(2){1,2-(NH)(2)C(6)H(4)}(2) both react with four equivalents of Bu(n)Li to give what are presumed to be tetra-anions which react further with MeI, SnClMe(3) or SnClPh(3) to give the tetrasubstituted products 1,1-B(2){1,2-(NMe)(2)C(6)H(4)}(2), 1,1-B(2){1,2-(NSnMe(3))(2)C(6)H(4)}(2) and 1,2-B(2){1,2-(NSnPh(3))(2)C(6)H(4)}(2) respectively. The compound 1,1-B(2){1,8-(NH)(2)C(10)H(6)}(2) has also been prepared from the reaction between B(2)(NMe(2))(4) and 1,8-diaminonaphthalene. Lithiation and subsequent reaction with SnClMe(3), SnCl(2)Me(2) or SnCl(2)Ph(2) affords 1,1-B(2){1,8-(NSnMe(3))(2)C(10)H(6)}(2), 1,1-B(2){1,8-(N(2)-μ-SnMe(2))C(10)H(6)}(2) and 1,1-B(2){1,8-(N(2)-μ-SnPh(2))C(10)H(6)}(2) respectively. All new compounds have been characterised by X-ray crystallography.     

Bis[tetraruthenium(IV)]-containing polyoxometalates: [{Ru(IV)4O6(H2O)9}2Sb2W20O68(OH)2]4- and [{Ru(IV)4O6(H2O)9}2{Fe(H2O)2}2{β-TeW9O33}2H]-

The reaction of [Sb(2)W(22)O(74)(OH)(2)](12-) and [Fe(4)(H(2)O)(10)(β-TeW(9)O(33))(2)](4-) with (NH(4))(2)[RuCl(6)] in aqueous solution resulted in the novel ruthenium(IV)-containing polyanions [{Ru(IV)(4)O(6)(H(2)O)(9)}(2)Sb(2)W(20)O(68)(OH)(2)](4-) and [{Ru(IV)(4)O(6)(H(2)O)(9)}(2){Fe(H(2)O)(2)}(2){β-TeW(9)O(33)}(2)H](-), exhibiting two cationic, adamantane-like, tetraruthenium(IV) units {Ru(4)O(6)(H(2)O)(9)}(4+) bound to the respective polyanion in an external, highly accessible fashion.     

Ring Opening and Bidentate Coordination of Amidinate Germylenes and Silylenes on Carbonyl Dicobalt Complexes: The Importance of a Slight Difference in Ligand Volume

The reactions of [Co₂(CO)₈] with one equiv of the benzamidinate (R₂bzam) group‐14 tetrylenes [M(R₂bzam)(HMDS)] (HMDS=N(SiMe₃)₂; 1 : M=Ge, R=iPr; 2 : M=Si, R=tBu; 3 : M=Ge, R=tBu) at 20 °C led to the monosubstituted complexes [Co₂{κ¹M?M(R₂bzam)(HMDS)}(CO)₇] ( 4 : M=Ge, R=iPr; 5 : M=Si, R=tBu; 6 : M=Ge, R=tBu), which contain a terminal κ¹M–tetrylene ligand. Whereas the Co₂Si and Co₂Ge tert‐butyl derivatives 5 and 6 are stable at 20 °C, the Co₂Ge isopropyl derivative 4 evolved to the ligand‐bridged derivative [Co₂{μ‐κ²Ge,N‐Ge(iPr₂bzam)(HMDS)}(μ‐CO)(CO)₅] ( 7 ), in which the Ge atom spans the Co?Co bond and one arm of the amidinate fragment is attached to a Co atom. The mechanism of this reaction has been modeled with the help of DFT calculations, which have also demonstrated that the transformation of amidinate‐tetrylene ligands on the dicobalt framework is negligibly influenced by the nature of the group‐14 metal atom (Si or Ge) but is strongly dependent upon the volume of the amidinate N?R groups. The disubstituted derivatives [Co₂{κ¹M?M(R₂bzam)(HMDS)}₂(CO)₆] ( 8 : M=Ge, R=iPr; 9 : M=Si, R=tBu; 10 : M=Ge, R=tBu), which contain two terminal κ¹M–tetrylene ligands, have been prepared by treating [Co₂(CO)₈] with two equiv of 1 – 3 at 20 °C. The IR spectra of 8 – 10 have shown that the basicity of germylenes 1 and 3 is very high (comparable to that of trialkylphosphanes and 1,3‐diarylimidazol‐2‐ylidenes), whereas that of silylene 2 is even higher.     

Chromium(III) stars and butterflies: synthesis, structural and magnetic studies of tetrametallic clusters

We report the synthesis, structures and magnetic properties of a series of chromium(III) metal-centered triangle (or "star") clusters, [Cr(4){RC(CH(2)O)(3)}(2)(4,4'-R'(2)-bipy)(3)Cl(6)] [R = Et, R' = H (2); R = HOCH(2), R' = H (3); R = Et, R' = (t)Bu (4)], prepared by two-step solvothermal reactions starting from [CrCl(3)(thf)(3)]. The product of the first stage of this reaction is the salt [Cr(bipy)(2)Cl(2)](2)[Cr(2)Cl(8)(MeCN)(2)] (1). In the absence of the diimine, a different family of tetrametallics is isolated: the butterfly complexes [Cr(4){EtC(CH(2)O)(3)}(2){NH(C(R)NH)(2)}(2)Cl(6)] (R = Me (5), Et (6), Ph (7)] where the chelating N-acetimidoylacetamidine NH(C(R)=NH)(2) ligands are formed in situ via condensation of the nitrile solvents (RCN) under solvothermal conditions. Magnetic measurements show the chromium stars to have an isolated S = 3 ground state, arising from antiferromagnetic coupling between the central and peripheral metal ions, analogous to the well-known Fe(III) stars. Bulk antiferromagnetic ordering is observed at 0.6 K. The butterfly complexes have a singlet ground state, with a low-lying S = 1 first excited state, due to dominant wing-body antiferromagnetic coupling.     

Facile synthesis of rhodium and iridium complexes bearing a [PEP]-type ligand (E = Ge or Sn) via E-C bond cleavage

Rhodium and iridium complexes bearing a tridentate [PEP] type ligand ([PEP] = {o-(Ph(2)P)C(6)H(4)}(2)E(Me); E = Ge or Sn) were synthesized through the phosphine exchange reaction accompanied by selective E-C bond cleavage. The ligand precursors {o-(Ph(2)P)C(6)H(4)}(2)EMe(2) (E = Ge or Sn) were readily obtained in excellent yields by treating {o-(Ph(2)P)C(6)H(4)}(2)Li with 0.5 equivalents of Me(2)ECl(2). Tris(triphenylphosphine)rhodium(i) carbonyl hydride M(H)(CO)(PPh(3))(3) (M = Rh, Ir) cleaved one of the E-Me bonds of {o-(Ph(2)P)C(6)H(4)}(2)EMe(2) exclusively to afford the trigonal bipyramidal (TBP) complexes, [PEP]M(CO)(PPh(3)). Square-planar rhodium complexes [PEP]Rh(PPh(3)) were also prepared from the reactions of tetrakis(triphenylphosphine)rhodium(i) hydride Rh(H)(PPh(3))(4) with {o-(Ph(2)P)C(6)H(4)}(2)EMe(2). Further, the trans influence of group 14 elements E (E = Si, Ge, Sn) in [PEP]Rh(PPh(3)) is discussed in terms of the (1)J(Rh-P) coupling constants, indicating that E exhibited a stronger trans labilizing effect in the order Sn < Ge < Si.