NH Pr Research Articles

Mixed amido-/imido-/guanidinato niobium complexes: synthesis and the effect of ligands on insertion reactions.

The new monoguanidinato complexes [Nb(NMe2)2{N(2,6-(i)Pr2C6H3)}{(NR)(NR')C(NMe2)}] (R = R' = (i)Pr, 2; R = (t)Bu, R' = Et, 3) were obtained by the insertion reaction of either diisopropylcarbodiimide or 1-tert-butyl-3-ethylcarbodiimide with the triamido precursor [Nb(NMe2)3(N-2,6-(i)Pr2C6H3)] (1) bearing a bulky imido moiety. The μ-oxo derivative [{N(2,6-(i)Pr2C6H3)}{(N(i)Pr)2C(NMe2)}(NMe2)Nb]2(μ-O) (2a) was formed by an unexpected hydrolysis reaction of the amido niobium compound 2. Alternatively, monoguanidinato complexes [Nb(NMe2)2{N(2,6-(i)Pr2C6H3)}{(N(i)Pr)2C(NHR)}] (R = (i)Pr, 4, (n)Bu, 5) can be obtained by protonolysis of 1 with N,N',N''-alkylguanidines [(NH(i)Pr)2C(NR)] (R = (i)Pr, (n)Bu). Compound also reacts with either tert-butylisocyanide or 2,6-xylylisocyanide to give, by a migratory insertion reaction, the corresponding iminocarbamoyl compounds [Nb(NMe2)2{(NMe2)C=NR}{N(2,6-(i)Pr2C6H3)}] (R = (t)Bu, 6, Xy, 7). Addition of the neutral alkylguanidines to complex 6 results in a facile C-N bond cleavage at room temperature in a process directed by the formation of the stable chelate complex 4 or 5. Complex reacts with heterocumulenic CS2 to produce new imido dithiocarbamato complexes [Nb(NMe2){S2C(NMe2)}2{N(2,6-(i)Pr2C6H3)}] (8) and [Nb{S2C(NMe2)}3{N(2,6-(i)Pr2C6H3)}] (9). These complexes do not react with alkylguanines, although new mixed guanidinato dithiocarbamato complexes [Nb(NMe2){S2C(NMe2)}{(N(i)Pr)2C(NHiPr)}{N(2,6-(i)Pr2C6H3)}] (10) and [Nb{(S2C(NMe2)}2{(N(i)Pr)2C(NH(i)Pr)}{N(2,6-(i)Pr2C6H3)}] (11) can be obtained by reaction of complex 4 with one or two equivalents of CS2, respectively. All of the complexes were characterized spectroscopically and the dynamic behaviour of some of them was studied by variable-temperature NMR. The molecular structures of 2a, 3, 6 and 10 were also established by X-ray diffraction studies.

Intermolecular N–H Oxidative Addition of Ammonia, Alkylamines, and Arylamines to a Planar σ3-Phosphorus Compound via an Entropy-Controlled Electrophilic Mechanism

Ammonia, alkyl amines, and aryl amines are found to undergo rapid intermolecular N-H oxidative addition to a planar mononuclear σ(3)-phosphorus compound (1). The pentacoordinate phosphorane products (1·[H][NHR]) are structurally robust, permitting full characterization by multinuclear NMR spectroscopy and single-crystal X-ray diffraction. Isothermal titration calorimetry was employed to quantify the enthalpy of the N-H oxidative addition of n-propylamine to 1 ((n)PrNH2 + 1 → 1·[H][NH(n)Pr], ΔHrxn(298) = -10.6 kcal/mol). The kinetics of n-propylamine N-H oxidative addition were monitored by in situ UV absorption spectroscopy and determination of the rate law showed an unusually large molecularity (ν = k[1][(n)PrNH2](3)). Kinetic experiments conducted over the temperature range of 10-70 °C revealed that the reaction rate decreased with increasing temperature. Activation parameters extracted from an Eyring analysis (ΔH(⧧) = -0.8 ± 0.4 kcal/mol, ΔS(⧧) = -72 ± 2 cal/(mol·K)) indicate that the cleavage of strong N-H bonds by 1 is entropy controlled due to a highly ordered, high molecularity transition state. Density functional calculations indicate that a concerted oxidative addition via a classical three-center transition structure is energetically inaccessible. Rather, a stepwise heterolytic pathway is preferred, proceeding by initial amine-assisted N-H heterolysis upon complexation to the electrophilic phosphorus center followed by rate-controlling N → P proton transfer.

Novel inorganic heterocycles from dimetalated carboranylamidinates

Mono- and dianionic carboranylamidinates are readily available in one-pot reactions directly from o-carborane (1). In situ-monolithiation of 1 followed by treatment with N,N'-diisopropylcarbodiimide, (i)PrN=C=N(i)Pr, or N,N'-dicyclohexylcarbodiimide, CyN=C=NCy, provided the lithium carboranylamidinates (o-C2B10H10C(NH(i)Pr)(=N(i)Pr)-κ(2)C,N)Li(DME) (2a) and (o-C2B10H10C(NH(i)Cy)(=N(i)Cy)-κ(2)C,N)Li(THF)2 (2b). Controlled hydrolysis of 2a,b afforded the free carboranylamidines o-C2B10H11C(NH(i)R)(=N(i)R) (3a: R = (i)Pr, 3b: R = Cy). The first dimetalated carboranylamidinates, o-C2B10H10C(N(i)Pr)(=N(i)Pr)Li2(DME)2 (4a) (DME = 1,2-dimethoxyethane) and o-C2B10H10C(N(i)Pr)(=N(i)Pr)Li2(THF)4 (4b), were prepared in high yield (83% yield) directly from 1 using a simple one-pot synthetic protocol. Treatment of 4b with 2 equiv. of Me3SiCl afforded the disilylated derivative o-C2B10H10-κ(2)C,N-[C(N(i)PrSiMe3)(=N(i)Pr)]SiMe3 (5). Dianionic 4b also served as an excellent precursor for novel inorganic heterocycles incorporating the closo-1,2-C2B10H10 cage, including the unsymmetrical distannene [o-C2B10H10C(N(i)Pr)(=N(i)Pr)-κ(2)C,N]Sn=Sn[((i)PrN)2C(n)Bu]2 (6) and the azaphosphole derivative [o-C2B10H10C(N(i)Pr)(=N(i)Pr)-κ(2)C,N]PPh (7). Surprisingly, it was found that the synthesis of new inorganic ring systems from dianionic carboranylamidinates can also be achieved by employing only 1 equiv. of n-butyllithium in the generation of the anionic carboranylamidinate intermediates. Using this straightforward one-pot synthetic protocol, the Group 14 metallacycles [o-C2B10H10C(NCy)(=NCy)-κ(2)C,N]SiR2 (R = Cl (8), Me (9), Ph (10)) and [o-C2B10H10C(NCy)([=NCy)-κ(2)C,N]GeCl2 (11) have become accessible. The same synthetic strategy could be successfully adapted to prepare the corresponding Group 4 metallocene derivatives Cp2Ti[o-C2B10H10C(NCy)(=NCy)-κ(2)C,N] (12) and Cp2Zr[o-C2B10H10C(NCy)(=NCy)-κ(2)C,N] (13). The molecular structures of 2b, 3b, 4b, 5, 6, 7, 10, 12, and 13 were confirmed by single-crystal X-ray diffraction.

New azido-substituted tantalum compounds: syntheses and DFT examination of nitrogen-rich mono-, di-, and trinuclear tantalum(v) compounds

The syntheses of new tantalum compounds containing an ancillary azido ligand(s) are described. The tantalum compound with the composition Ta(NMe2)4(N3) has been synthesized in high yield from the reaction of TaCl(NMe2)4 with NaN3 in THF. The solid-state structure reveals a dimeric architecture based on Ta2(NMe2)8(μ-N3)2 (), where the eight-membered dimetallocyclic ring possesses a chair-like conformation with bridging azido ligands binding the two Ta(NMe2)4 moieties. Solution molecular weight measurements and electronic structure calculations predict to exist as a monomer at room temperature. reacts with the formamidine (i)PrNC(H)NH(i)Pr to furnish fac-Ta(NMe2)3(η(1)-N3)[(i)PrNC(H)N(i)Pr] () and Me2NH; compound has been characterized by IR and (1)H NMR spectroscopy and X-ray diffraction analysis. Treatment of with p-toluidine affords the trinuclear compound Ta3(NMe2)5(μ-NMe2)(μ-NC6H4Me-4)2(NC6H4Me-4)(μ-N3)2(η(1)-N3) (). Compound contains three non-bonded tantalum atoms that are ligated by edge-bridging imido, amido, and azido ligands. The molecular structure of has been determined by X-ray crystallography, and the unprecedented presence of terminal and bridging imido, amido, and azido ligands in a single tantalum compound confirmed. The bonding in has been examined by DFT, and these data are discussed relative to the crystallographic structure. Compounds represent the first structurally characterized examples of heteroleptic tantalum compounds that possess an all-nitrogen coordination sphere with at least one azido ligand.

Asymmetric niobium guanidinates as intermediates in the catalytic guanylation of amines

The molecular structure of the guanidinate complex {NbBz2(N(t)Bu)[(4-BrC6H4)N=C(N(i)Pr)(NH(i)Pr)]}, previously obtained by reaction of [NbBz3(N(t)Bu)] and the corresponding guanidine proligand, has been established by X-ray diffraction. The series of complexes {NbBz2(N(t)Bu)[(Ar)N=C(N(i)Pr)(NH(i)Pr)]} (Ar = 4-BrC6H4, 4-(t)BuC6H4, 4-MeOC6H4) and {[NbBz2(N(t)Bu)]2[(C6H4)(N=C(N(i)Pr)(NH(i)Pr))2]} show a preferred asymmetric coordination of the guanidinate ligand by means of one alkylamino nitrogen and the arylimino nitrogen atom. Computational studies confirm this preference and the results suggest that electronic factors prevail over steric factors. In addition, reaction of complex [NbBz3(N(t)Bu)] with {2-((n)butyl)-1,3-diisopropylguanidine} did not give rise to the regioselective asymmetrical guanidinate. Instead, the complex {NbBz2(N(t)Bu)[((n)Bu)N=C(N(i)Pr)(NH(i)Pr)]} was obtained as a mixture of three isomers with symmetrical and asymmetrical coordination modes. Finally, the complex [NbBz3(N(t)Bu)] was shown to be a suitable precatalyst for the guanylation reaction of a wide range of amines under mild conditions. Guanidinates are proposed as intermediates in the mechanism of this reaction. The molecular structure of the biguanidine {2,2'-(1,4-phenylene)bis(2',3-diisopropylguanidine)} was also established by X-ray diffraction studies.

Unprecedented reaction of bridged bis(guanidinate) lanthanide complexes: sterically induced deprotonation

Reaction of LnCl3 with a lithium salt of bridged bis(guanidinate) bearing a rigid naphthalene linker [Li2{LH2}2Li2] (LH2 = 1,8-C10H6{NC(N(i)Pr)(NH(i)Pr)}2) (1), which was synthesized by the reaction of 1,8-diaminonaphthalene with 2 equiv. of (n)BuLi, followed by treatment with 2 equiv. of N,N'-diisopropylcarbodiimide, yielded the chlorides [LnCl{LH2}] (Ln = Yb (2), Y (3)) in good yields. Metathesis reaction of 2 and 3 with NaN(SiMe3)2 did not afford the corresponding amide complexes, but the deprotonation products of [Ln{LH}]2 (LH = 1,8-C10H6{NC(N(i)Pr)(NH(i)Pr)}{NC(N(i)Pr)2}; Ln = Yb (4), Y (5)) were isolated instead. The LH in 4 and 5 both act as a bridging ligand binding to two metals in a μ-η(1):η(2):η(2) fashion, and the re-arrangement of LH occurred during the reaction. The size of the amido group was found to have a great influence on the outcome of the metathesis reaction. Reaction of 2 with bulky NaNH(C6H3(i)Pr2-2,6) afforded 4 as the only product, whereas the same reaction with less bulky LiNH(C6H4Cl-4) and LiNH(C6H4CH3-4) led to the corresponding amides, [Yb{LH2}(NHC6H4Cl-4)]2 (6) and [Yb{LH2}(NHC6H4CH3-4)]2 (7), respectively. The re-arrangement of ligands was also observed in both cases. A possible pathway for the deprotonation of LH2 was discussed. Molecular structures of 1-7 were determined by X-ray single crystal analysis.

Carbodiimide insertion reactions of homoleptic heavier alkaline earth amides and phosphides

A series of homoleptic guanidinate-type complexes of the heavier alkaline earth (Ae) metals calcium and strontium have been prepared. The six-coordinate compounds [Ae{(i)PrNC(NPh(2))CN(i)Pr}(2)(THF)(2)] (Ae = Ca and Sr) were synthesised through reactions of the appropriate THF-solvated hexamethyldisilazide [Ae{N(SiMe(3))(2)}(2)(THF)(2)] with two molar equivalents of diphenylamine and 1,3-di-iso-propylcarbodiimide. Both compounds were shown to crystallise with a cisoid arrangement of the two THF molecules at the metal centres. In contrast, the (Me(3)Si)(2)N-substituted calcium guanidinate, [Ca{CyNC{N(SiMe(3))(2)}CNCy}(2)(THF)(2)], contains two coordinated THF molecules with a trans disposition. Further reactions of the free amidine [{(2-FC(6)H(4))N}C(NH(i)Pr)(2)] with either [Ca{N(SiMe(3))(2)}(2)(THF)(2)] or its dimeric unsolvated analogue provided monomeric or dimeric derivatives respectively in which the ligands had tautomerised to an anisobidentate form. A further reaction of the phosphaguanidine [CyN=C(PPh(2))N(H)Cy] with [Sr{N(SiMe(3))(2)}(2)(THF)(2)] provided the first example of a phosphaguanidinate complex of this heavier alkaline earth metal. This compound has also been characterised in the solid state and shown to exist with a transoid configuration of the coordinated THF molecules.

Antitumour effect of polyoxomolybdates: induction of apoptotic cell death and autophagy in in vitro and in vivo models

Polyoxomolybdates (PMs) as discrete molybdenum-oxide cluster anions have been investigated in the course of study of their medical applications. Here, we show the significant antitumour potency of the polyoxomolybdate [Me3NH]6[H2MoV12O28(OH)12(MoVIO3)4]·2H2O (PM-17), which is a photo-reduced compound of [NH3Pri]6[Mo7O24]·3H2O. The effect of PM-17 on the growth of cancer cell lines and xenografts was assessed by a cell viability test and analysis of tumour expansion rate. Morphological analysis was carried out by Hoechst staining, flow-cytometric analysis of Annexin V staining, terminal deoxynucleotidyl transferase-mediated ‘nick-end’ labelling staining, and electron-microscopic analysis. Activation of autophagy was detected by western blotting and fluorescence-microscopic analysis of the localisation of GFP-LC3 in transfected tumour cells. PM-17 inhibited the growth of human pancreatic cancer (AsPC-1) xenografts in a nude mice model, and induced morphological alterations in tumour cells. Correspondingly, PM-17 repressed the proliferation of AsPC-1 cells and human gastric cancer cells (MKN45) depending on the dose in vitro. We observed apoptotic patterns as the formation of apoptotic small bodies and translocation of phosphatidylserine by Hoechst staining and flow-cytometric analysis following Annexin V staining, and in parallel, autophagic conformation by the formulation of autophagosomes and localisation of GFP-LC3 by electron- and fluorescence-microscopic analysis.

Enhancement Effect of Polyoxometalates on NGF-Induced Neurite-Outgrowth of PC12 Cells

Nerve growth factor (NGF)-induced neurite-outgrowth of PC12 cells was enhanced by polyoxometalates such as Na9[SbW(9)O(33)].19.5H(2)O (SbW(9)) and (NH(3)Pr(i))6[Mo(7)O(24)].3H(2)O (Mo(7)). Western blotting analysis of polyoxometalate/NGF-treated PC12 cells showed a strong expression of growth-associated protein 43 (GAP-43), which is associated with the neurite outgrowth. Similar effects were observed for other polyoxometalates, K(11)H[(VO)3(SbW(9)O(33))2].27H(2)O ((VO)3(SbW(9))2), K6[P(2)W(18)O(62)].14H(2)O (P(2)W(18)), and K7[PTi(2)W(10)O(40)].6H2O (PTi(2)W(10)), in contrast with little effect for monomeric tungstate and molybdate. Of the polyoxometalates tested in this study, SbW(9) and Mo(7) were the most potent.

Synthesis and structural investigation of N,N',N' '-trialkylguanidinato-supported zirconium(IV) complexes.

The addition of 2 equiv of N,N',N' '-triisopropylguanidine (guanH(2)) to Zr(CH(2)Ph)(4) produced the bis(guanidinato)bis(benzyl)zirconium complex [((i)PrNH)C(N(i)Pr)(2)](2)Zr(CH(2)Ph)(2) (1). The mono(guanidinato) complex [((i)PrN)(2)C(NH(i)Pr)]ZrCl(3) (2) was accessible by the reaction of 2 equiv of guanH(2) with ZrCl(4). Guanidinium hydrochloride, [C(NH(i)Pr)(3)]Cl, is a byproduct of this reaction. When crystallized from THF, complex 2 was isolated as the THF adduct [((i)PrNH)C(N(i)Pr)(2)]ZrCl(3)(THF) (2-THF). The mixed cyclopentadienyl guanidinato complex [eta(5)-1,3-(Me(3)Si)(2)C(5)H(3)][((i)PrNH)C(N(i)Pr)(2)]ZrCl(2) (3) was prepared by treatment of [1,3-(Me(3)Si)(2)C(5)H(3)]ZrCl(3) with the in situ generated lithium triisopropylguanidinate salt. The reaction of guanH(2) with [1,3-(Me(3)Si)(2)C(5)H(3)]ZrMe(3) affords the dimethyl derivative [eta(5)-1,3-(Me(3)Si)(2)C(5)H(3)][((i)PrNH)C(N(i)Pr)(2)]ZrMe(2) (4). Definitive evidence for the molecular structures of these products is provided through single-crystal X-ray characterization of 1, 2-THF, and 3, which are presented. The extent of pi delocalization within the guanidinato ligand is discussed in the context of the metrical parameters obtained from these structural studies.

Bis(isopropylamino)methylcarbenium tetrakis(pentafluorophenyl)gallate.

The title compound, [MeC(NH(i)Pr)(2)][Ga(C(6)F(5))(4)] crystallizes as discrete ions forming interionic hydrogen bonds of the type N-H.F.

Imido Complexes Derived from the Reactions of Niobium and Tantalum Pentachlorides with Primary Amines: Relevance to the Chemical Vapor Deposition of Metal Nitride Films.

Reactions of niobium and tantalum pentachlorides with tert-butylamine (>/=6 equiv) in benzene afford the dimeric imido complexes [NbCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2) (90%) and [TaCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2) (79%). The niobium complex exists as two isomers in solution, while the tantalum complex is composed of three major isomers and at least two minor isomers. Analogous treatments with isopropylamine (>/=7 equiv) give the monomeric complexes NbCl(2)(N(i)Pr)(NH(i)Pr)(NH(2)(i)Pr)(2) (84%) and TaCl(2)(N(i)Pr)(NH(i)Pr)(NH(2)(i)Pr)(2) (84%). The monomeric complexes are unaffected by treatment with excess isopropylamine, while the dimeric complexes are cleaved to the monomers MCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)(2) upon addition of excess tert-butylamine in chloroform solution. Treatment of niobium and tantalum pentachlorides with 2,6-diisopropylaniline affords insoluble precipitates of [NH(3)(2,6-(CH(CH(3))(2))(2)C(6)H(3))](2)[NbCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))] (100%) and [NH(3)(2,6-(CH(CH(3))(2))(2)C(6)H(3))](2)[TaCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))] (100%), which react with 4-tert-butylpyridine to afford the soluble complexes [4-t-C(4)H(9)C(5)H(4)NH](2)[NbCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))] (45%) and [4-t-C(4)H(9)C(5)H(4)NH](2)[TaCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))] (44%). Sublimation of [NbCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2), MCl(2)(N(i)Pr)(NH(i)Pr)(NH(2)(i)Pr)(2), and [NH(3)(2,6-(CH(CH(3))(2))(2)C(6)H(3))](2)[MCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))] leads to decomposition to give [MCl(3)(NR)(NH(2)R)](2) as sublimates (32-49%), leaving complexes of the proposed formulation MCl(NR)(2) as nonvolatile residues. By contrast, [TaCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2) sublimes without chemical reaction. Analysis of the organic products obtained from thermal decomposition of [NbCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2) showed isobutylene and tert-butylamine in a 2.2:1 ratio. Mass spectra of [NbCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2), [TaCl(2)(N(t)Bu)(NH(t)Bu)(NH(2)(t)Bu)](2), and [NbCl(3)(N(i)Pr)(NH(2)(i)Pr)](2) showed the presence of dimeric imido complexes, monomeric imido complexes, and nitrido complexes, implying that such species are important gas phase species in CVD processes utilizing these molecular precursors. The crystal structures of [4-t-C(4)H(9)C(5)H(4)NH](2)[NbCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))], [NbCl(3)(N(i)Pr)(NH(2)(i)Pr)](2), [NbCl(3)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))(NH(2)(2,6-(CH(CH(3))(2))(2)C(6)H(3)))](2), and [TaCl(3)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))(NH(2)(2,6-(CH(CH(3))(2))(2)C(6)H(3)))](2) were determined. [4-t-C(4)H(9)C(5)H(4)NH](2)[NbCl(5)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))] crystallizes in the space group P2(1)/c with a = 12.448(3) Å, b = 10.363(3) Å, c = 28.228(3) Å, beta = 94.92(1) degrees, V = 3628(5) Å(3), and Z = 4. [NbCl(3)(N(i)Pr)(NH(2)(i)Pr)](2) crystallizes in the space group P2(1)/c with a = 9.586(4) Å, b = 12.385(4) Å, c = 11.695(4) Å, beta = 112.89(2) degrees, V = 1279.0(6) Å(3), and Z = 2. [NbCl(3)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))(NH(2)(2,6-(CH(CH(3))(2))(2)C(6)H(3)))](2) crystallizes in the space group P2(1)/n with a = 10.285(3) Å, b = 11.208(3) Å, c = 23.867(6) Å, beta = 97.53 degrees, V = 2727(1) Å(3), and Z = 2. [TaCl(3)(N(2,6-(CH(CH(3))(2))(2)C(6)H(3)))(NH(2)(2,6-(CH(CH(3))(2))(2)C(6)H(3)))](2) crystallizes in the space group P2(1)/n with a = 10.273(1) Å, b = 11.241(2) Å, c = 23.929(7) Å, beta = 97.69(2) degrees, V = 2695(2) Å(3), and Z = 2. These findings are discussed in the context of niobium and tantalum nitride film depositions from molecular precursors.

The reaction of iron chlorides with some aliphatic primary amines

The reaction at room temperature of iron (III) chloride with excess of several primary amines has been studied. With each primary amine (NH 2R, R  Me, Et, Pr n and Bu n ) reduction to iron (II) takes place and compounds of formula FeCl 2, 2RNH 2 are obtained. Compounds with the same formula are produced by direct reaction of iron (II) chloride with the appropriate amine. Structures for the compounds are suggested on the basis of magnetic and spectroscopic studies.

The reaction of titanium(IV) halides with some aliphatic amines

The reactions at room temperature of titanium(IV) chloride, bromide, and iodide with excess of several primary and secondary aliphatic amines have been studied. Each primary amine (NH 2R, R  Me, Et, Pr n and Bu n ) gives an aminobasic titanium(IV) halide, TiX 2(NHR) 2, xNH 2 R( X  Cl, Br, I). Titanium halogen bonds are also aminolysed by the secondary amines (NHR 2, R  Me, Et, Pr n ). Structures are proposed for the aminobasic products on the basis of thermal decomposition, molecular weight, and infra-red spectra studies.

The reaction of vanadium(IV) chloride with some aliphatic amines

The reaction at room temperature of vanadium(IV) chloride with excess of several primary and secondary aliphatic amines has been studied. Each primary amine (NH 2R, R  Me, Et, Pr n , and Bu n ) gives an aminobasic vanadium(IV) chloride, VCl 2(NHR) 2, xNH 2R, which is insoluble in the usual organic solvents; the thermal decomposition of these compounds has been studied. Two vanadium-chlorine bonds are also aminolysed by the secondary amines (NHR 2, R = Me, Et, Pr n ). Structures for the compounds are proposed on the basis of spectroscopic studies.