Hatam A. Jasim

Carbene complexes: XXII. Preparation, properties and structures of the N,N-functionalized bis(amino)carbenemolybdenum(O) carbonyls [Mo(CO)4 {CN(CH2CH:CH2)(CH2) 2N}(CH2CH:CH2)}] and Mo(CO)3{CN[(CH2)3PPh2] (CH2)2N {(CH2)3PPh2}]n☆

Treatment of 1,2-bis(γ-diphenylphosphinopropylamino)ethane [obtained from 1,2-bis(allylamino)ethane and 2PPh2H and CH(NMe2)(OMe)2] yielded the electron-rich enetetramine CN(R)(CH2)2NR]2 [R  CH2)3PPh2] [abbreviated as L2(CH2) 3PPh2]. Although L2All, the analogue in which R  CH2CH:CH2, is unknown, the carbenemolybdenum title compounds [Mo(CO)4(LAll] (3) and Mo(CO)3{L(CH2)3PPh2]n (4) have been prepared from [Mo(CO)6]: for 3 from CH(NMe2)(OMe)2 + [All(H)N(CH 2)]2 and for 4 from L2(CH2)3PPh2. In 3 only one of the R groups behaves in a ligating mode. LAll being a chelating ligand, 3 is thus a rare example of a metal complex having both carbene- and η2 -alkene-ligation and the first for molybdenum. The presumed polymeric structure of 4 is believed to arise from one of the PIII sites behaving in a chelating fashion with the other in a bridging mode. Treatment of 3 with 13CO stereoselectively gave the isotopomer in which a CO trans to a CO was displaced, the trans effect thus being parallel to the trans influence (X-ray data); a coproduct was cis-[Mo(CO)4(13CO)(LAll)]. Similarly, cis-[Mo(CO)4(LAll)(PEt3)] was the sole product of reaction between 3 and PEt3, which upon irradiation yielded fac- together with mer-[Mo CO)3(LAll)(PEt3)]. Thermolysis of 3 afforded AllC: N(CH2)2NAll as the only organic product. The X-ray structure of 3 showed that the mutually trans Mo CO bonds are significantly longer [av. 2.037(5) A] than MoCO trans to carbene [1.984(4) A] or alkene [1.975(5) A], with Mo Ccarb at 2.229(4) A.

Subvalent group 14 metal compounds-XIII. Oxidative addition reactions of germanium and tin amides M(NR2)2 (R = SiMe3, M = Ge OR Sn) with sulphur, selenium, tellurium or MeOOCCCCOOMe; X-ray structures of [Ge(NR2)2(μ-Te)]2 and

Abstract The germanium and tin divalent amide M(NR2)2 (R = SiMe3, M = Ge or Sn) readily reacts with a chalcogen (E) or MeOOCCCCOOMe to yield the appropriate metal(IV) oxidative addition product [M(NR2)2(μ-E)] n (E = S, Se or Te) (1–6) or (7), respectively. Each of the compounds 1–7 has been characterized by microanalysis and NMR spectra and two of the compounds [Ge{N(SiMe3)}22(μ-Te)]2 (3) and 7,by single crystal X-ray diffraction. Some selected geometric parameters are as follows. 3: Ge-N 1.86(1), Ge-Te 2.595(2), Si—N 1.76(2) A; TeGeTe′ 94.38(6), GeTeGe′ 85.59(6)°. 7: (MeO)C-C(OMe) 1.40(2), CC—C(OMe) 1.36(2), MeOCO-Sn 2.125(9), Sn-C 2.07(1), Sn-N 2.031(9), Si-N 1.75(1)A. Each of the compounds Sn(η-C5H4R)(NR2) (8) and Sn(η-C5H3R2-1,3)(NR2) (9) was obtained in a mixture with Sn(NR2)2 and the appropriate bis(cyclopentadienyl)tin(II) compound. 119Sn NMR chemical shifts are reported for compounds 4 and 6-9.

Bulky metal aryloxides, arylamides and sulphur and phosphorus analogues—III. Aluminium compounds derived from 2,4,6-TRI-t-butylaniline; X-ray structure of [{μ-NHC6H2But2-4,6-C(Me)2CH2-2}]2 ☆

Abstract Treatment of AlMe3 with ArNH2 (Ar = C6H2But3t-2,4,6) in C6H14 at 60°C afforded [AlMe2(μ-NHAr)]2 (1). Heating the amide 1 either at 200°C for 3 h or (NMR) in C6D6 at 80°C for 3 weeks in a sealed tube led to methane elimination and formation of the cyclometallated compound [ AlMe {μ-NHC6H2Bu2t-4,6-C(Me)2CH2-2}]2 (2); unexpectedly, the hydrogen atom abstracted from the N HAr ligand of 1 originated from the 2-t-butyl group rather than the NH. Deuterolysis of 2 yielded D2NC6H2Bu2t-4,6-C(Me)2CH2D-2. AlCl3 and ArNH2 gave the 1 : 1 adduct AlCl3(NH2Ar) (3), which upon heating either at 150°C and 10−4 torr or (NMR) in C6D6, at 80°C for 24 h gave isobutene and the retro-Friedel Crafts product AlCl3(NH2C6H3Bu2t-2,4) (4). An excess of LiNHAr did not react with AlMe3, but with AlCl3 furnished Al(NHAr)2Cl (5). The X-ray structure of the cyclo-metallated compound 2 showed it to be a pentacyclic centrosymmetric dimer, containing a central (AlN)2 square [ 1.965(6) A], with the adjacent six-membered unsaturated alumino-heterocycles in a twisted boat conformation, one below and the other above the (AlN)2 plane and the two anilido ligands in a transoid arrangement. The preparation of the metal anilides M(NHAr) [M = Li (6), SiMe3 (7) or SnMe3 (8)] is described.

Butyl metal aryloxides, arylamides, and sulphur and phosphorus analogues—II. Synthesis and characterization of novel bulky alkoxides and aryloxides of aluminium; X-ray structure of [Al(μ-OCH2Ar)Me2]2 (Ar = C6H2Bu3t-2,4,6)

Abstract The alkoxide, (2,4,6-tri-t-butylbenzoxo)dimethylaluminium, [Al (μ-OCH2Ar)-Me2]2 (Ar = C6H2Bu3t-2,4,6), (1), has been prepared from the corresponding benzyl alcohol ArCH2OH and trimethylaluminium in C6H14 at ca 25°C. Even using an excess of the alcohol, only one of the methyl groups of AlMe3 was replaceable under these conditions. By contrast, using the bulky phenol Ar′OH (Ar′= C6H3Bu2t-2,6) and an excess of AlMe3 yielded the bis-aryloxide, bis-[2,6-di(t-butyl) phenoxo]methylaluminium, AlMe(OAr′)2 (Ar′= C6H3Bu2t-2,6), (2). The less hindered phenol Ar″OH (Ar″ = C6H3Bu2t-2,4) and an excess of AlMe3 gave the expected aryloxide, (2,4-di-t-butylphenoxo)dimethylaluminium, AlMe2(OAr″) (Ar″ = C6H3Bu2t-2,4) (3). Compounds 1-3 have been characterized spectroscopically and in the case of the crystalline alkoxide 1, also by X-ray crystallography; some selected geometric parameters are: AlO 1.841(3) and 1.858(2), Al1.939(5) and 1.959(6), Al Al′ 2.84, O O2.37 A; OAlO′ 79.8(1), AlOAl′ 100.2(1)°. Complex 1 has the structure [AlMe2(μ-OCH2Ar)]2, both as the solid and at 30°C in C6D6 solution. Less complete data on the aryloxides 2 and 3 suggest that the former is a monomer, whereas the latter is a dimer, probably by virtue of OAr″-bridging.

Carbene complexes. Part 21. Synthesis and characterisation of bis(carbene)molybdenum(II) complexes and dimetal(0) complexes of the Group 6 elements containing novel bridging bis(carbene) ligands; X-ray structures of [Mo(CO)2(LEt)2(OSO2CF3)2][LEt=CN(Et)(CH2)2NEt] and [W(CO)5{C(OEt)CH2C6H4CH2C(OEt)-o}W(CO)5]

Treatment of the bis(carbene)tetracarbonylmolybdenum (0) complex cis-[Mo(CO)4(LEt)2][LEt= [graphic omitted]Et] with two equivalents of silver trifluoromethanesulphonate in tetrahydrofuran (thf) readily yields the molybdenum(II) complex [Mo(CO)2(LEt)2(OSO2CF3)2](1). Reaction of the complexes [M(CO)6](M = Cr or W) with Mg[(CH2)2C6H4-o](thf)(M = Cr) or o-C6H4(CH2MgCl)2(M = W) in thf affords the crystalline yellow µ-bis(carbene)-dimetal(0) complex [{M(CO)5[C([graphic omitted]g(thf)n][M = Cr, n= 3 (2a); M = W, n= 4 (2b)], which when extracted into water and treated with [Et3O][BF4] furnishes the appropriate orange µ-bis(carbene) bimetallic complex [[graphic omitted](OEt)CH2C6H4CH2[graphic omitted](CO)5][M = Cr (3a) or W (3b)]. Complex (3a) with an excess of PEt3 gives the red-orange complex [{[graphic omitted](OEt)CH2C6H4CH2[graphic omitted](CO)4(PEt3)}]. Reaction of [M(CO)6] with o-C6H4[CH(SiMe3)Li(tmen)]2[tmen = Me2N(CH2)2NMe2] yields [[graphic omitted]OLi(OEt2)(tmen)]CH(SiMe3)C6H4CH SiMe3)[graphic omitted](CO)5]. In the crystalline bis(carbene)-molybdenum(II) complex (1), the Mo atom resides at the centre of a severely distorted octahedron [Ccarb–Mo–Ccarb 134.9(2)°], with the two five-membered LEt rings arranged so as to be approximately parallel, and mean lengths Mo–Ccarb 2.154(5), Mo–CO 1.961(6), and Mo–O 2.177(4)A. In the crystalline ditungsten(0) complex (3b), each W is in an octahedral environment and selected mean parameters include W–Ccarb 2.155(12), W–CO 2.03(4), and Ccarb–O 1.317(14)A.

Phosphorus(III and V)– and arsenic(III)–nitrogen metallacycles derived from the bulky arylamido ligand NHAr (Ar = C6H2But3-2,4,6); X-ray structures of ArNPN(Ar)AIMe2 and PAr(NHAr)2

In its co-ordination chemistry P(NAr)(NHAr)(Ar = C6H2But3-2,4,6)(1a) behaves either as (i) a source of its conjugate base yielding Ar[graphic ommitted]Ln(2)[MLn= AIMe2, from (AIMe3)2] and (3)(MLn= Li, from LiBun), or (ii) as a neutral hydrido-PV ligand in [[graphic ommitted])2PH}], but the arsa(III)azene (1b)[the As analogue of (1a)] undergoes facile As–NHAr bond-scission with (AIMe3)2; whereas (1b) is obtained from 2Li(NHAr)+ AsCl3 in OEt2 at 20 °C, prolonged reflux in PhMe of the same reagents furnishes a cyclometallated product; in (2)[1.617(4)A] is intermediate between the PN and P–N bond lengths in (1a), and is significantly shorter than the 1.74(1)A for in PAr(NHAr)2[obtained from PArCl2+ 2Li(NHAr)].

Synthesis and characterisation of unusual tetraaminoalkenes (enetetramines)

Two general routes are described for the synthesis of the title compounds from the reaction of either (A) the dimethyl acetal of N,N-dimethylformamide and an appropriate N,N′-bis(secondary amine), or (B) sodium hydride and a 4,5-dihydroimidazolium or tetrahydropyrimidinium salt. The following new compounds have been made: trans-R[graphic omitted][graphic omitted]R [R = Et and R′= Me (1a) or CH2Ph (1b)] and R[graphic omitted][graphic omitted]R [n=m= 2 and R= Me (2a) or CH2Ph (2b); n= 3, m= 2, and R= CH2Ph (3); or n= 2, m= 3, and R= CH2Ph (4)].X-Ray data on crystalline [graphic omitted]R]2(R = CH2Ph) and (2b)[data in parentheses] show a short CC bond, 1.319(8)A[1.329(5)A], long Csp2–N bonds, av. 1.437(11)A[1.424(4)A], with each of the four nitrogen atoms in a pyramidal sp3 environment.

Unusual group 14 metal thiolates and sulphides derived from tris(trimethylsilyl)methanethiol; X-ray structures of [Pb(NR2)(µ-SCR3)]2 and cis-[Ge(CH2Ph)(NR2)(µ-S)]2, (R = SiMe3)

The reaction of tris(trimethylsilyl)menthanethiol, HSCR3(R = SiMe3), with a group 14†; metal(II) bis(trimethylsilyl)amide, M(NR2)2(M = Ge or Pb), gives unexpected products: cis- and trans-[Ge(CH2Ph)(NR2)(µ-S)]2[a rare example of a group 14 cyclodi(metalthiane), {MXX(µ-S)}2, by refluxing in PhMe]; [Pb(SCR3)(µ-SCR3)]2(the new ligand SCR3 evidently can function in both a terminal and a bridging fashion); and [Pb(NR2)(µ-SCR3)]2, the first simple prochiral group 14 metal(II) complex.

Synthesis and Properties of Chlorotris (1,3-Dibenzylimidazolidin-2-ylidene) Rhodium (I) and of Some Related Compounds

The electron-rich alkene Open image in new window (R = CH2Ph) has been used as a source of various carbenerhodium(I) complexes: [RhC](cod)(L)] (1), [RhCl(L)3] (2), [RhCl(CO)(h)3] (3), and trans-[RhCl(CO)(L)2] (4), and of the iridium(I) complex [IrCl(L)3] (5). Compounds (2) and (5) are of particular interest as they contain no other neutral ligand apart from the carbene: Open image in new window (R = CH2Ph); their chemistry is in many ways related to that of the well known complexes [MCl(PPh3)3] (M = Rh or Ir). Thus, compound (2) readily loses a carbene ligand upon treatment with either carbon monoxide [ultimately to lead to (4)], or O2 to yield a compound tentatively formulated as [RhCl(L)2(O2)] (6). The x-ray structures of complexes (2) and (4) have been determined.