Cube-type nitrido complexes containing titanium and zinc/copper

Several azaheterometallocubane complexes containing [MTi3N4] cores have been prepared by the reaction of [{Ti(eta5-C5Me5)(mu-NH)}3(mu3-N)] (1) with zinc(II) and copper(I) derivatives. The treatment of 1 with zinc dichloride in toluene at room temperature produces the adduct [Cl2Zn{(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)}] (2). Attempts to crystallize 2 in dichloromethane gave yellow crystals of the ammonia adduct [(H3N)Cl2Zn{(mu3-NH)Ti3(eta5-C5Me5)3(mu-NH)2(mu3-N)}] (3). The analogous reaction of 1 with alkyl, (trimethylsilyl)cyclopentadienyl, or amido zinc complexes [ZnR2] leads to the cube-type derivatives [RZn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (R = CH2SiMe3 (5), CH2Ph (6), Me (7), C5H4SiMe3 (8), N(SiMe3)2 (9)) via RH elimination. The amido complex 9 decomposes in the presence of ambient light to generate the alkyl derivative [{Me3Si(H)N(Me)2SiCH2}Zn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (10). The chloride complex 2 reacts with lithium cyclopentadienyl or lithium indenyl reagents to give the cyclopentadienyl or indenyl zinc derivatives [RZn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (R = C5H5 (11), C9H7 (12)). Treatment of 1 with copper(I) halides in toluene at room temperature leads to the adducts [XCu{(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)}] (X = Cl (13), I (14)). Complex 13 reacts with lithium bis(trimethylsilyl)amido in toluene to give the precipitation of [{Cu(mu4-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}2] (15). Complex 15 is prepared in a higher yield through the reaction of 1 with [{CuN(SiMe3)2}4] in toluene at 150 degrees C. The addition of triphenylphosphane to 15 in toluene produces the single-cube compound [(Ph3P)Cu{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (16). The X-ray crystal structures of 3, 8, 9, and 15 have been determined.     

Amido-bridged double-cube nitrido complexes containing titanium and magnesium/calcium

Treatment of the single cube nitrido complexes [(thf)x((Me3Si)2N)M((mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N))](M = Mg, x= 0; Ca, x= 1) with one equivalent of anilines NH2Ar in toluene affords the arylamido complexes [(ArHN)M((mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N))]n[M = Mg (3), n= 1, Ar = 4-MeC6H4; Ca (4), n= 2, Ar = 2,4,6-Me3C6H2]. The magnesium complex 3 has a single-cube structure whereas the X-ray crystal structure of the analogous calcium derivative 4 shows two cube-type azaheterometallocubane moieties Ca((mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)) held together by two mu-2,4,6-trimethylanilido ligands. Complexes 3 and 4 react with chloroform-d1 at room temperature to give the metal halide adducts [Cl2M((mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N))](M = Mg, Ca). A solution of 3 in n-hexane gave complex [(Mg2(mu3-N)(mu3-NH)5[Ti3(eta5-C5Me5)3(mu3-N)]2)(mu-NHAr)3] which shows three mu-4-methylanilido ligands bridging two [MgTi3N4] cube type cores according to an X-ray crystal structure determination.     

Titanium alkali metal nitrido complexes

Treatment of [(Ti(eta5-C5Me5)(mu-NH))3(mu3-N)] with alkali metal bis(trimethylsilyl)amido reagents in toluene afforded the complexes [M(mu3-N)(mu3-NH)2[Ti3(mu5-C5Me5)3(mu3-N)]]2 (M = Li (2), Na, (3), K (4)). The molecular structures of 2 and 3 have been determined by X-ray crystallographic studies and show two azaheterometallocubane cores [MTi3N4] linked by metal-nitrogen bonds. Reaction of the lithium derivative 2 with chlorotrimethylsilane or trimethyltin chloride in toluene gave the incomplete cube nitrido complexes [Ti3(eta5-C5Me5)3(mu-NH)2(mu-NMMe3)(mu3-N)] (M = Si (5), Sn (6)). A similar reaction with indium(I) or thallium(I) chlorides yielded cube-type derivatives [M(mu3-N)(mu3-NH)2[Ti(eta5-C5Me5)3(mu3-N)] (M=In (7), Tl (8)).     

Field-evaporation mass spectroscopy applied to crown ether complexes with alkali and alkaline-earth metals

Field evaporation from solution has been used to detect crown-ether 15K5 and 18K6 coordination compounds formed with Na⁺, K⁺, Cs⁺, Ba²⁺ and Ca²⁺ in aqueous solution, both hydrated and unhydrated; the Ca²⁺·18K6·(H₂O)_n (n=0, 1, 2,...) compounds have been observed before. 18K6 present in the solution greatly increases the yields of 18K6 compounds with the dissociation products from Ba(NO₃)₂. The detection limits for 15K5 and 18K6 combined with Na⁺, K⁺, and Cs⁺ are approximately the same at 10^–7 g.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 2, pp. 239–242, March–April 1988.     

Use of polysulfides of alkali and alkaline-earth metals to obtain highly dispersed sulfur

Possibilities of obtaining polysulfides of alkali and alkaline-earth metals in aqueous solutions were considered. The composition of the polysulfides and their concentration in solutions were found. The efficiencies of application of highly dispersed sulfur, produced from calcium polysulfide, and colloid sulfur as a fungicide were compared.     

Superbulky metallocene complexes of the heavier alkaline-earth metals strontium and barium

Superbulky sandwich complexes with the cyclopentadienyl ligand (4-nBu-C(6)H(4))(5)Cp (abbreviated here as Cp(BIG)) have been prepared by reaction of Cp(BIG)H with benzylic strontium or barium reagents. Both metallocenes have been structurally characterized by single crystal X-ray diffraction. Even for the larger metallocene (Cp(BIG))(2)Ba a highly symmetric sandwich complex with parallel Cp rings was isolated (Cp(center)-Ba = 2.667(1) A). Both structures show evidence for a C-HC(pi) network between the Cp ligands. These attractive forces induce an inward out-of-plane bending of the aryl substituents (Sr 3.4(2) degrees ; Ba 5.3(2) degrees ). A linear correlation between this bending angle and metal size has been found.     

Molecular design of macrocyclic extractants for extraction and separation of alkali and alkaline-earth metals

The distribution coefficients of the alkaline and alkali-earth metal nitrates are determined for the processes of extraction from nitric acid solutions with crown ethers, which differ in sizes of their cycles (from 18 to 22 atoms) and in side phenyl and cyclohexyl substituents, but have unchanged number of the O atoms in a cycle. The phenyl and cyclohexyl derivatives of 18-crown-6 are found to be more efficient extractants of alkali metals as compared with unsubstituted crown ethers. However, the selectivity of separation of a pair Cs-Na remains low. The 18-crown-6 derivatives with one and two cyclohexyl fragments selectively extract Sr, which can be used to separate it from the remaining alkali and alkaline-earth metals. An increase in the size of a macrocycle from 18 to 20 and 22 atoms leads to a reduction in the extraction efficiency for all alkali and alkaline-earth metals, insignificantly improves separation of a pair Cs-Na, but noticeably deteriorates Sr-Na separation.     

Amino-functionalised diarylphosphide complexes of the alkali metals and lanthanum

The secondary phosphines Ar(C6H4-2-CH2NMe2)PH [Ar = mes (3), Tripp (4)] may be isolated in good yields from reactions between Li(C6H4-2-CH2NMe2) and the respective dichlorophosphine, followed by reduction with LiAlH4 [mes = 2,4,6-Me3C6H2, Tripp = 2,4,6-Pri3C6H2]. Metalation of either 3 or 4 with BunLi gives the corresponding lithium compound; the lithium derivative of 3 was isolated as the separated ion pair complex [Li(12-crown-4)2][(mes)(C6H4-2-CH2NMe2)P].THF (5). The lithium complexes Ar(C6H4-2-CH2NMe2)PLi undergo metathesis reactions with either NaOBut or KOBut to give the heavier alkali metal phosphides {Ar(C6H4-2-CH2NMe2)P}M.1/2OEt2 [Ar = mes, M = Na (8), K (9); Ar = Tripp, M = K (10)]. Metathesis reactions between 9 and LaI3(THF)4 give only intractable products; in contrast, a metathesis reaction between 10 and LaI3(THF)4 yields the heteroleptic complex {(Tripp)(C6H4-2-CH2NMe2)P}2LaI (11). Compound 11 reacts cleanly with K{N(SiMe3)2} to give {(Tripp)(C6H4-2-CH2NMe2)P}2La{N(SiMe3)2} (14). Compounds 3-5, 8-11 and 14 have been characterised by multi-element NMR spectroscopy; in addition, compounds 5, 11 and 14 have been studied by X-ray crystallography.     

Microdetermination of carbon in compounds containing alkali metals

Zusammenfassung Wenn organische Verbindungen außer Alkalimetallen auch noch eine zumindest äquivalente Menge Schwefel enthalten, so besteht der Verbrennungsrückstand aus Alkalisulfat. Auf Grund dieser Beobachtung wird darauf hingewiesen, daß sich außer Kaliumdichromat und Vanadiumpentoxyd auch Kaliumpersulfat als oxydierender Zusatz zur organischen Substanz für die Verdrängung des Kohlendioxyds aus der Asche eignet.

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Résumé Quand des composés organiques, outre les métaux alcalins contiennent encore une quantité au moins équivalente de soufre, le résidu de la combustion apparaît sous la forme de sulfate alcalin. Sur la base de cette observation, on a montré, qu'à côté du bichromate de potassium et de l'anhydride vanadique, le persulfate de potassium convenait comme oxydant de la substance organique et pour débarrasser les cendres de l'anhydride carbonique.

     

Determination of stability constants for alkaline-earth and alkali metal ion complexes of glycine by spectrophotometry

The complex equilibria between alkaline-earth and alkali metal ions with glycine were studied by a spectrophotometric method. The following stability constant (concentration) values valid at 25 degrees and ionic strength 1.0M were found: K(HL) = 10(9.57), K(LiL) = 10(-1.2), K(BaL) = 10(-0.40), K(SrL) = 10(0.14), K(CaL) = 10(0.55), K(MgL) = 10(1.17).     

Structural diversity of 1,2,4-diazaphospholide complexes with alkali metals

Treatment of H[3,5-Ph2dp] (Hdp = 1H-1,2,4-diazaphosphole) with nBuLi or KH, or the reaction of K[3,5-tBu2dp] with an excess amount of O2, afforded the dimeric species [(eta2,eta1-3,5-Ph2dp)Li(THF)2]2 and the polymeric complexes [(eta2:eta4-3,5-Ph2dp)K(Et2O2]n, and [[(eta2:eta5-3,5-tBu2dp)K(THF)][eta2(N,N)-eta3(O,P,O)-3,5-tBu2dp-(O,O)O2K]]n, respectively.     

Vibrational spectra of nitrido and oxo complexes

The vibrational spectra of a number of transition-metal complexes containing terminal or bridging nitrido (N^3?) and oxo (O^2?) ligands are reported. Full assignments of fundamental modes are given for (OsO₃¹⁴N)^?, (OsO₃¹⁵N)^?, (Os¹⁴NX₄)^?, (Os¹⁵NX₄)^?, (Ru¹⁴NX₄)^?, (Os¹⁴NX₅)^2?, (Os¹⁵NX₅)^2? and (Ru¹⁴NX₅)^2? (X = Cl, Br), and also for the oxo complexes (Mo¹⁶OCl₄, (Mo¹⁸OCl₄)^?, (Mo¹⁶OCl₅)^2? and (Mo¹⁸OCl₅)^2?. Force constants have been evaluated for the four- and five-coordinate complexes. The significance of the results is discussed in terms of the metalligand bonding involved in these species.     

Studies on transition-metal nitrido and oxo complexes. Part VII(1). Substituted nitrido complexes of osmium and ruthenium

Summary Addition reactions of [MNCl₄]^– (M = Os or Ru) with ligands L or L to give [MNCl₄ · L]^– or [(MNCl₄)₂L]^2– (L = pyridine, pyridine-N-oxide,iso-quinoline or DMSO; L = hexamethylenetetramine, pyrazine or dioxan) are described. With NCO^–, [OsNCl₅]^– gives [OsN(NCO)₅]^2– but NCS^– gives a thionitrosyl complex, [Os(NS)(NCS)₅]^2–. Reactions of OsNCl₃(AsPh₃)₂ with pyridine, 1,10-phenanthroline and tertiary phosphites and phosphinites have been studied, as have reactions of triphenylphosphine with OsOCl₄ andtrans- [MO₂Cl₄]^2– (M = Os or Ru). The nitrido-iodo complexes [OsNI₄]^– and OsNI₃, (SbPh₃)₂ are also reported.     

Valence p functions for alkali and alkaline-earth atoms

Contracted Gaussian-type function (CGTF) basis sets are reported for valence p orbitals of the six alkali and alkaline-earth atoms Li, Be, Na, Mg, K, and Ca for molecular applications. These sets are constructed by Roothaan–Hartree–Fock calculations for the ns → np excited states of atoms, in which both linear and nonlinear parameters of CGTFs are variationally optimized. The present CGTF sets reproduce well the numerical Hartree–Fock ns → np excitation energies: the largest error is 0.0009 hartrees for Li. New CGTFs are tested with diatomic Li₂, Na₂, K₂, and MH molecules, where M = Li, Be, Na, Mg, K, and Ca, by self-consistent-field (SCF) and multiconfiguration SCF calculations. The resultant spectroscopic constants compare well with those of more elaborate calculations and are sufficiently close to experimental values, supporting the efficiency of the present set for the valence p orbitals. Received: 9 July 1998 / Accepted: 17 September 1998 / Published online: 1 February 1999