Search

2-Aminomethylaniline was converted into the N,N′-bis(pivaloyl) (1) or -bis(trimethylsilyl) (2) derivative, using 2 ButC(O)Cl or 2 Me3SiCl ( RCl), respectively, with 2 NEt3, or for 2from successively using 2 LiBunand 2 RCl. N,N′-Bis(neopentyl)-2-(aminomethyl)aniline (3) was prepared by LiAlH4reduction of 1. From 2or 3and 2 LiBun, the appropriate dilitiodiamide {2-[{N(Li)R}C6H4{CH2N(Li)R}(L)]2(L absent, 4a; or L = THF, 4b) or the N,N′-bis(neopentyl) analogue (5) of 4awas prepared. Treatment of 4awith 2 ButNC, 2 (2,6-Me2C6H3NC) or 2 ButCN ( L′) furnished the corresponding adduct [2-N{Li(L′)R}C6H4{CH2N(Li)R}] (4c, 4dor 4e, respectively), whereas 4bwith 2 PhCN afforded [2-{N(Li)R}C6H4{CH2C(Ph) = NLi(NCPh)}] (6). The dimeric bis(amido)stannylene [Sn{N(R)C6H4(CH2NR)-1,2}]2(7) was obtained from 4aand [Sn(μ-Cl)NR2]2, while the N,N′-bis(neopentyl) analogue 8of 7was similarly derived from [Sn(μ-Cl)NR2]2and 5. Reaction of two equivalents of the diamine 2with Pb(NR2)2yielded 9, the lead homologue of 7. Oxidative addition of sulfur to 7led to the dimeric bis(diamido)tin sulfide 10. Treatment of 2successively with ‘MgBu2’ in C5H12and THF gave [Mg{N(R)C6H4(CH2NR)}(THF)]2(11a), which by displacement of its THF by an equivalent portion of ButCN or PhCN produced [Mg{N(R)C6H4(CH2NR)}(CNR')n] [R′ = But, n= 1 (11b); R′ = Ph, n= 2 (11c)]. The Ca (12), Sr (13) or Ba (14) analogues of the Mg compound 11awere isolated from 2and either the appropriate compound M(NR2)2(M = Ca, Sr, Ba), or successively 2 LiBunand 2 M(OTos)2. The new compounds 1–14were characterized by microanalysis (C, H, N; not for 1, 2, 3, 5), solution NMR spectra, νmax(CN) (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). [ABSTRACT FROM AUTHOR]

Pseudooctahedral complexes [MCl3(NtBu)L2] (M = Nb, L = py 1, ½ tmeda 3; M = Ta, L = py 2, ½ tmeda 4) have been studied by spectroscopic methods. By a VT 1H NMR experiment a mutual exchange process between the pyaxand pyfreein the complexes 1–2was observed, whereas 13C and 15N NMR studies showed in the complexes 3–4a tmeda ligand with an axial/equatorial coordination mode. The reaction of 2with 3 equiv of Grignard reagent produces the methathesis products [TaR3(NtBu)] (R = CH2CMeCH25, CH2CHCHCH36) in which 2-methylallyl and 2-butenyl groups appear with a η3- and σ-coordination mode, respectively. When, toluene solutions of the compounds 5–6were treated with 2 equiv of 2,6-dimethylphenylisocyanide the imido bisiminoacyl compounds [TaR(NtBu){C(R)NAr-κ1C}2] (Ar = 2,6-Me2C6H3; R = CH2CMeCH27, CH2CHCHCH38) can be isolated, viaan imido iminoacyl intermediate [TaR2(NtBu){C(R)NAr-κ1C}] (Ar = 2,6-Me2C6H3; R = CH2CMeCH29) as we have observed in the treatment of 5with 1 equiv of isocyanide; however, the analogous reaction between 5and COPh2leads to the formation of the trisalkoxo imido compound [Ta(OCPh2R)3(NtBu)] (R = CH2CMeCH210). All new complexes were studied by IR and multinuclear NMR spectroscopy. [ABSTRACT FROM AUTHOR]

In this paper a series of eight Ti(iv) piperazine based complexes have been prepared and fully characterised in the solid-state by X-ray crystallography and in solution viaNMR spectroscopy. In the solid-state either Ti2(L)(OiPr)6or Ti2(L)2(OiPr)4were observed depending upon the nature of the starting ligand. For complexes with less sterically demanding ligands (1H2and 2H2) an equilibrium was observed: 2 Ti2(L)(OiPr)6⇔ Ti2(L)2(OiPr)4+ 2 Ti(OiPr)4. The thermodynamic properties (ΔG, ΔHand ΔS) have been investigated viavariable temperature NMR spectroscopy. With more sterically demanding ligands (3–8H2) the Ti2(L)(OiPr)6form was the most prevalent in the solid-state and in solution. These complexes have been tested for the production of polylactide under melt and solution conditions with high conversions being obtained. [ABSTRACT FROM AUTHOR]

Earlier we reported the tendency of ferrocenylmethyl substituted amino acids to organize around Cu(ii) in a C2symmetry. In this paper we have utilized this property to form a chiral cavity using a l-tyrosine derivative. Structural characterization of [CuII(S-fTyr)2(MeCN)2] (1), where S-fTyr1−is ferrocenylmethyl-l-tyrosinate, showed that the alignment of two tyrosine aromatic rings around the fifth coordination site generates a narrow cavity. Structural characterization of [Cu(S-fTyr)2(pyrazine)] (2), [Cu(S-fTyr)2(pyridine)] (3), [Cu(S-fTyr)2(bpy)] (4) and [Cu(S-fTyr)2(H2O)] (5) revealed that planar heterocyclic N-donors as guests stabilized the cavity, while polar water molecules destroyed it. Electrochemical properties of the complexes showed a shift of CuII/CuIpotentials depending on the strength of the guest binding inside the cavity. [ABSTRACT FROM AUTHOR]