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The reaction of Zn[N(SiMe3)2]2 with N-alkyl-N-[ω- (pentafluorophenylamino)alkyl]-N-[2-(pentafluorophenylamino) ethyl]amines afforded new bicyclic zinc complexes. The complexes initiate ring-opening polymerization of ɛ-caprolactone and trimethylene carbonate to give the corresponding polymers with high molecular weight and satisfactory degree of polymerization.

The review discusses the results of the authors’ research aimed at the synthesis of stable tetrylenes (germylenes and stannylenes) and the determination of the structure of these compounds, including their oligomeric degree. Substituted dialkanolamines, dialkylenetriamines, aminobisphenols, pyridine and phenanthroline-containing dialcohols, and some other derivatives were used as the ligands for the synthesis. The reactivity of monomeric and dimeric tetrylenes in the reactions proceeding with both the change and the retention of the oxidation state of the metal atom (2+) is discussed in detail, as well as the influence of the oligomeric degree on the reactivity. The use of tetrylenes in synthetically useful reactions as ligands for catalytically active transition metal complexes, as well as initiators for ring-opening polymerization of cyclic esters, is analyzed.

The reactions of 3-benzyl-1,5-ditosyl-1,3,5-triazapentane (1) and 3-benzyl-1,5-dimesityl- 1,3,5-triazapentane (2) with one equivalent of Lappert´s germylene or stannylene (M[N(SiMe3)2]2, where M = Ge, Sn) produced germylenes and stannylenes of the general formula PhCH2N(CH2CH2NR)2M, where M = Ge, R = 4-MeC6H4SO2– (3); 2,4,6-Me3C6H2– (5); M = Sn, R = 4-MeC6H4SO2– (4); 2,4,6-Me3C6H2– (6), in satisfactory yields. According to NMR data (1H, 13C, 119Sn), stannylenes 4 and 6 are monomeric in solution, and the coordination number of tin is four. The synthesized stannylenes exhibited very high (compound 4) and moderate (compound 6) activity as initiators for bulk polymerization of e-caprolactone, resulting in the synthesis of high-molecular-weight polymers with relatively narrow molecular-weight distribution. Previously unknown triamine 2 was synthesized by benzylation of HN(CH2CH2NHMes)2 with benzyl chloride in the presence of K2CO3.

Previously unknown tetradentate ONNO-type ligands 1–5 (4,7-di(4-R´-phenoxy)-2,9- di(HOCR2CH)-1,10-phenanthrolines (R´ = Me, R–R = –(CH2)5– (1), R = Me (2), R–R = 2,2-adamantylene (3); R´ = But, R–R = –(CH2)5– (4), R = Me (5)) were synthesized by sequential treatment of 2,9-dimethyl-4,7-di(4-R´-phenoxy)-1,10-phenanthrolines 6 (R´ = Me) and 7 (R´ = But) with excess LDA and appropriate dialkyl ketone. The structure of compound 4 was determined by single-crystal X-ray diffraction. Previously uncharacterized phenanthroline 6 was synthesized by the treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with excess p-cresol in the presence of KOH. The reaction of compounds 1–5 with one equivalent of Lappert´s germylene or stannylene, M[N(SiMe3)2]2 (M = Ge, Sn), gave the corresponding germylenes 8–12 (M = Ge, R´ = Me, R–R = –(CH2)5– (8), R = Me (9), R–R = 2,2-adamantylene (10), R´ = But, R2 = –(CH2)5– (11), R = Me (12)) and stannylenes 13–17 (M = Sn, R´ = Me, R–R = –(CH2)5– (13), R = Me (14), R–R = 2,2-adamantylene (15), R´ = But, R–R = –(CH2)5– (16), R2 = Me (17)) in satisfactory yields. According to 1H, 13C, and 119Sn NMR data, the synthesized stannylenes are monomeric in solution, and the tin atom has a coordination number of 4. In the series of the compounds under consideration, stannylene 16 proved to be the most active initiator for e-caprolactone polymerization, whereas the germylenes were shown to be inactive in this process.

The linear oligogermyl amide 2, Ph3GeGeMe2NMe2, was obtained by reacting Ph3GeLi with 1, Me2Ge(Cl)NMe2. The amide 2 was used for the synthesis of molecular oligogermanes 3, Ph3GeGeMe2Ge(C6F5)3, and 4, [Ph3GeGeMe2]2Ge(C6F5)2, containing electron donor (Me, Ph) and acceptor (C6F5) groups, by using a hydrogermolysis reaction in n-hexane. The molecular structures of 3 and 4 were studied by XRD. It was shown that in a crystal 3 forms wide channels, in which the solvated nonpolar n-hexane molecule is present. The NMR (1H, 13C and 19F), optical (UV/vis absorption, luminescence) and electrochemical (cyclic voltammetry) properties of both compounds were also studied. The impact of the substitution type by the electron withdrawing groups (at the terminal position, such as in 3, or within the compound, such as in 5), on the physical properties was also studied.

Treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with two equivalents of p-tert-butylphenol in the presence of К2СО3 afforded 4,7-di(4-tert-butylphenoxy)-2,9-dimethyl-1,10-phenanthroline (1). Monolithiation of 1 with lithium diisopropylamide followed by treatment with benzophenone resulted in 1-(4,7-bis-p-tert-butylphenoxy-9-methyl-1,10- phenanthrolin-2-yl)methyl-1,1-diphenylethanol (2). 1-(4,7-Bis-p-tert-butylphenoxy-9-hydroxy (diphenyl)methyl-1,10-phenanthrolin-2-yl)-1,1-diphenylethanol (3), a tetradentate ONNO ligand, was prepared analogously from 2. The interaction of 3 with 1 eq. of Lappert’s germylene or stannylene M[N(SiMe3)2]2 (M = Ge, Sn) led to the corresponding germylene 4 and stannylene 5 in moderate yields. According to 1Н, 13С, and 119Sn NMR spectroscopy data, stannylene 5 is monomeric in solution and the coordination number of tin atom is 4. Tetrylenes 4 and 5 demonstrated high activity as initiators of bulk polymerization of e-caprolactone which leads to high-molecular-weight polymers with relatively narrow molecular weight distribution.

Formation of donor-acceptor complexes between dichlorosilylene, SiCl2, and allyl halides, AllHal(Hal= Cl, Br) was detected in Ar matrixes using matrix IR spectroscopy. In agreement with the predictions of the performed quantum chemical calculations, only broad unstructured absorption bands contributed by different conformers of the 1 : 1 complexes between SiCl2 and AllHal were observed in IR spectra of matrixes after deposition in the regions of characteristic vibrations of starting reactants. Annealing of matrixes resulted in strong narrowing the bands due to conversions of different conformers into the most stable structures. The predominantly formed conformers in both the reaction systems were those of complexes with SiCl2 coordinated to the Hal atoms of AllHal in the gauche conformations. At the same time, according to the calculations, the complexes with SiCl2 coordination to the double bonds of AllHal can be only slightly less stable than the complexes with coordination to the Hal atoms, and all these basic centers can be considered as comparable in their activity in the complexation. The only products revealed upon photolysis of complexes were the products of silylene insertion into the C–Hal bonds, viz., AllSiCl3 and AllSiCl2Br. Theoretical study of thermal transformations in the SiCl2 + AllHal systems showed that formal insertion of SiCl2 in the C–Hal bonds and its addition to the double bonds of AllHal have low activation barriers of 3–8 kcal mol–1. However, these barriers are too high for these reactions to occur under the matrix isolation conditions.

Aminobisphenol supported germylenes (1a–3a), stannylenes (1b–3b) and plumbylenes (1c–3c) were synthesized by reaction of Lappert’s tetrylenes, [(Me3Si)2N]2M (M = Ge, Sn, Pb), with corresponding aminobisphenols R1N(CH2C6H2(OH)(t-Bu)R2)2, 1–3 (1: R1 = Et, R2 = Me; 2: R1 = Et, R2 = t-Bu; 3: R1 = CH2(Py-2), R2 = t-Bu). X-ray diffraction analysis revealed different coordination mode for germylene 3a and stannylene 3b with additional nitrogen donor in the structure of the ligand. Germylene 1a was converted to the rhenium complex 1aa by the reaction with Re(CO)5Br.

A reaction of previously synthesized germylenes and stannylenes based on aminobisphenols RN{CH2[(5-R´)(3-But)C6H2(2-O—)]}2MII, M = Ge, R = CH2(2-Py), R´ = But (1); M = Ge, R = Et, R´ = Me (2); M = Sn, R = CH2(2-Py), R´ = But (3); M = Sn, R = Et, R´ = Me (4), containing (tetrylenes 1 and 3) or not containing (tetrylenes 2 and 4) a group capable of additional donation, with allyl bromide leads to the products of the insertion of tetrylenes into the C—Br bond: RN{CH2[(5-R´)(3-But)C6H2(2-O—)]}2M(Br)All, M = Ge, R = CH2(2-Py), R´ = But (5); M = Ge, R = Et, R´ = Me (6); M = Sn, R = CH2(2-Py), R´ = But (7); M = Sn, R = Et, R´ = Me (8). The structures of obtained derivatives were confirmed by NMR spectroscopy and elemental analysis. The structures of compounds 4, 5, and 7 were studied by X-ray crystallography. Stannylene 4 was found to be monomeric in the solid phase: the coordination number of the Sn atom is 3. The insertion products 5 and 7 are characterized by the coordination number 6 for the central atom.

A reaction of aminobisphenols EtN{CH2[(4-Alk)(6-But)(2-HO)C6H2]}2, Alk = Me (1); But (2) containing alkyl substituents in the phenol groups with trimethylaluminum and tetra(tert-butoxy)titanium gave two new aluminum derivatives with the Me–Al bond: EtN{CH2[(2-Alk)-(4-But)C6H2(2-O–)]}2Al–Me, Alk = Me (3); But (4), and two new titanium derivatives with the ButO–Ti bond: EtN{CH2[(2-Alk)(4-But)C6H2(2-O–)]}2Ti(O–But)2, Alk = Me (5); But (6). The structures of new compounds were confirmed by NMR spectroscopy and elemental analysis. The structures of complexes 3 and 6 were studied by X-ray crystallography. Complexes 3 and 6 are monomeric in the solid phase: a coordination number of Al atom is 4, that of Ti atom is 5, in addition to the M–O bonds the M←N interactions are also present. Complexes 3–6 were studied as initiators of the ring-opening polymerization of e-caprolactone. The resulting polymers are characterized by relatively high values of number average molecular weight, with the polydispersity being relatively low.

Substituted 2,6-bis(hydroxyalkyl)pyridines, H2L, 1–3 (2,6-Py(CH2(X)OH)(CH2(Y)OH), X = Y = cyclo-C6H10, 1; X = Y = 1-Ad, 2; X = CPh2, Y = CH2CPh2, 3), were used as ligands for the synthesis of titanium(IV) complexes, (i-PrO)2Ti(L), 1a–3a. On the contrary, application of related dialcohol based on 2,2′-bipyridine, H2L′, 5 (2,2′-bipy-6,6′-(CH2Ph2OH)2), resulted in titanyl complex, (L′)Ti O, 6. The molecular structure of 6 was investigated by X-ray analysis. Compounds 1a and 3a were tested as initiators in ring-opening polymerization of l -lactide and e-caprolactone showing moderate activity.

It is experimentally found that allyltrichlorosilane dissociates under vacuum pyrolysis (~10–2 Torr) at temperatures above 1100 K to form three labile intermediates: allyl radical, dichlorosilylene, and monoatomic chlorine. On the basis of experimental and theoretical data obtained, it is shown that the decomposition reaction proceeds in two steps. The first step is a typical reaction of homolytic decomposition to two radicals (C3H5 and SiCl3) at the weakest Si—C bond. Due to weakness of the Si—Cl bond in the SiCl3 radical, the energy of which is even somewhat lower than the dissociation energy of the Si—C bond in starting AllSiCl3, this radical undergoes further dissociation to SiCl2 and Cl, thus resulting in three intermediates of different classes of highly reactive species formed from AllSiCl3.

A series of novel heavier carbene analogs 3 – 8 , MeN(CH 2 CH 2 NTs)(CH 2 CR 2 O)M (M = Ge ( 3 , R = H; 4 , R = Ph), Sn ( 5 , R = H; 6 , R = Ph), Pb ( 7 , R = H; 8 , R = Ph)), was prepared by the interaction of M[N(SiMe 3 ) 2 ] 2 (M = Ge, Sn, Pb) with substituted N , N , O -ligands, 1 and 2 , MeN(CH 2 CH 2 NHTs)(CH 2 CR 2 OH) ( 1 , R = H; 2 , R = Ph). All the compounds were investigated by IR and multinuclear NMR spectroscopy and it was established that in a solution tin and lead compounds are agglomerated. An X-ray diffraction analysis of 3 revealed the monomeric structure with three-coordinated Ge atom. In contrast to germylenes, plumbylenes are associated in solid state. In the crystalline phase, the steric hindrance affects the degree of association. Thus, lead derivative 7 based on unsubstituted ligand, 1 , forms dimers with strong bridging Pb–O bonding which further crystallize into chains. On contrary, plumbylene 8 based on phenyl substituted ligand, 2 , is monomeric and only weak Pb⋯O SO contacts are observed is the solid state.

New tridentate N,N,O-type ligands MeN(CH2CH2NHTs)(CH2CR2OH) [Ts = tosyl ; R = H, 6, (N,N,OH)H2; R = Ph, 7 (N,N,OPh)H2] were prepared. The corresponding diisopropoxide complexes (N,N,OH)Ti(OiPr)2 (8) and [N,N,OPh]Ti(OiPr)2 (9) were obtained through the reactions of 6 and 7 with Ti(OiPr)4. These complexes are thermally unstable and transform into the bisligated complexes [N,N,OH]2Ti (10) and {[N,N,OPh]Ti(OiPr)}2O (11). The molecular structures of 10 and 11 were investigated by X-ray diffraction analysis. The synthesis of 11 from 9 as a thermal decomposition process was studied.

Two series of germanium compounds, (p-Tol)3Ge-MMe3 (M = Si (1), Ge (2), Sn (3)) and (Me3Si)3Ge-MPh3 (M = Ge (4), Sn (5)), were prepared using lithium or potassium intermediates. The changing of the reaction conditions results in trigermane Ph3Ge-Ge(SiMe3)2-GePh3 (6). The molecular structures of 1, 2, and 6 were investigated by X-ray analysis. By UV/visible spectroscopy it is established that introduction of a tin atom results in a significant bathochromic absorption shift. Furthermore, according to cyclic voltammetry, oxidation potentials decrease in the order 1 > 2 > 3. The electronic structures of 1–4 and related (Me3Si)3Ge-SiPh3 were investigated by DFT calculations. Fluorescence properties of 1–3 were studied in the solid state and in solution; for compound 3 phosphorescence (lifetime is 4.58 ms) is observed in the solid state.

A series of substituted pyridine dialcohols (2,6-bis(hydroxyalkyl)pyridines), 1-4, was used for the synthesis of various types of aluminum complexes. Aluminum methyl derivatives, 2-4a, were obtained by the reaction of AlMe3 with the corresponding ligand or transmetallation reactions of germylenes. Aluminum chloride complexes, 3-4b, were obtained by substitution of the Me group under the action of chlorinating agents. Methoxy-, 2-4c, or benzyloxy-, 2d, aluminum complexes were synthesized in transalkoxylation reaction of Me2Al(OX) (X = Me, Bn) by the corresponding ligand. All complexes obtained were thoroughly investigated by multinuclear NMR and X-ray analysis. It has been established that the structure of the ligand (number of carbon atoms) determines the nature of the complexes formed. Compounds were used as initiators of ring-opening polymerization of l-lactide and ε-caprolactone and showed moderate activity with controlled or immortal character.

Titanium complexes with dialkanolamine (1, 2) and salen ligands (3), as well as titanium alkoxide containing two fragments of an unsaturated alcohol (cis-but-2-ene-1,4-diol) ase-ligands (4), were studied in the anionic ring-opening bulk polymerization of ɛ-caprolactone (CL) at 80–130 °,C. All the catalysts involved initiate controlled polymerization and afford polyesters with a number-average molecular weight up to Mn = 20 000 g mol−1, which can be regulated by adjusting the [monomer]: [catalyst] ratio. Among the catalysts studied, complex 2 is most efficient in CL polymerization and affords polyesters with the narrowest molecular weight distribution (Mw/Mn < 1.2). In addition, complex 2 initiates the controlled polymerization of d,l-lactide (LA) and is effective in the synthesis of random and block copolymers of CL and LA.

A reaction of pyridine related ligands containing two hydroxyalkyl groups, 2,6-(HO-Z-CH2)2C5H3N (Z is 1,1-cyclohexylene, 2,2-adamantylene) with trimethylaluminum and trimethoxyaluminum leads to three new aluminum complexes with the Me-Al or MeO-Al bond: 2,6-C5H3N(CH2-Z-O)2Al-X (Z is 1,1-cyclohexylene, X = Me (5), OMe (6); Z is 2,2-adamantylene, X = Me (7)). The structures of new derivatives were confirmed by NMR spectroscopy and elemental analysis. The structure of complex 5 was studied by X-ray diffraction analysis. Complex 5 is a dimer in the solid state due to the formation of a four-membered ring...Al-O...Al-O.... Complexes 5 and 6 were studied as initiators of the ring-opening polymerization of e-caprolactone.

The optical (UV/Vis absorbance, fluorescence in the solid state and in solution) and semiconducting properties of a number of di- and trigermanes as well as related silicon- and tin-containing germanes, 1–6 ((p-Tol)3GeGeMe3 (1), Ph3SnGe(SiMe3)3 (2), (C6F5)3GeGePh3 (3), (p-Tol)3GeSiMe2SiMe3 (4), (p-Tol)3GeGeMe2Ge(p-Tol)3 (5), (p-Tol)3GeSiMe2SiMe2Ge(p-Tol)3 (6)) were investigated. Molecular structures of 5 and 6 were studied by X-ray diffraction analysis. All compounds displayed luminescence properties. In addition, a band gap (of about 3.3 eV) was measured for compounds 1–6 showing that those molecules display semiconductor properties.

The reaction of Al(O-i-Pr)3 with the SalenH2 ligand (2-(HO)C6H4CH NCH2CH2N CHC6H4 2-(OH), (1)) gave a new unexpected binuclear aluminum complex, [(Salen)Al]2(μ-Salen) (2). Complex 2 was characterized in solution by multinuclear NMR spectroscopy (including 27Al NMR) and in the solid state by X-ray analysis. The aluminum atoms in 2 possess a distorted octahedral coordination environment.

The first example of an oligogermane, N(CH2CH2O)3Ge-Ge(SiMe3)3 (1), containing a hypercoordinate germanium atom was prepared and characterized by various methods (NMR, UV/vis, and X-ray analysis). The electronic structure of compound 1 was investigated via DFT calculations.

A series of oligogermanes, (Me3Si)3GeGeCl3, (C6F5)3GeGePh3, (C6F5)3GeGe(p-Tol)3, and (C6F5)2Ge[Ge(p-Tol)3]2, containing substituents with different electronic properties at neighboring germanium atoms were synthesized. According to X-ray diffraction studies, UV/visible spectroscopy, and quantum chemical calculations, these “donor–acceptor” oligogermanes are characterized by energies of electronic transitions lower than those for other similar compounds.

Germylenes based on substituted diethylenetriamine (1), diethanolamines (2, 3) and pyridine-containing dialcohols (4, 5) were used as ligands in molybdenum and tungsten carbonyl complexes. Synthesis of new mono- and disubstituted (cis- or trans-) germanium(II) containing molybdenum (8, 9, 14, 15, 17) and tungsten (6, 7, 10–13, 16) carbonyl complexes were described. Composition of the complexes obtained was established by elemental analysis data and their structures were investigated by multinuclear NMR spectroscopy, IR and X-ray diffraction analysis (7, 13 and 17). The germylenes based on dialkanolamines and pyridine-containing dialcohols (O-ligands) give cis-digermanium complexes in contrast to the germylenes based on diethylenetriamines (N-ligands) which form trans-digermanium complexes.

Complexes of divalent tin 7–12 with diethylenetriamines 1–3 and related ligands 4–6 were prepared from Lappert's stannylene, Sn[N(SiMe3)2]2, and the corresponding ligands. Reactivity of the stannylenes in insertion, oxidation and [1+4] cycloaddition reactions were studied. Composition and structures of the products were confirmed by elemental analyses and multinuclear (1H, 13C, 19F, and 119Sn) NMR spectroscopy. Crystal structures of the diethylenetriamines 1, 2, stannylenes 7, 8 and the product of the reaction of stannylene 8 with an azide, which contains an eight-membered (SnNPO)2 ring, were determined by X-ray diffraction study.

During the synthesis of N-tosylaziridine, two unexpected products were isolated: 1-(2-(p-tolylsulfonamido)ethyl)pyridinium p-tolylsulfonate (3) and N,N,O-tri-(p-tolylsulfonyl)ethanolamine (3a). The structures of 3 and 3a were investigated in solid state by X-ray analysis. A new family of related salts was obtained using an efficient and facile one-pot synthesis consisting in the interaction between various nitrogen heterocycles and N,O-ditosylethanolamine.

A series of novel, low-valent germanium compounds 2a–2j based on four diethylenetriamines 1a–1d, (methyl)bis(pyrrol-2-ylmethyl)amine (1e), N,N′-(sulfanediyldibenzene-2,1-diyl)bis(pentafluoroaniline) (1f), N,N′-(oxydibenzene-2,1-diyl)bis(pentafluoroaniline) (1g), and (pentafluorophenyl)amines 1i and 1j have been obtained either by the reaction of Ge[N(SiMe3)2]2 with various diamines (1a–1e) or by the metathesis reaction of [GeCl2·dioxane] with lithium amides. The oxidative insertion (with halogenation reagents, MeI, disulfides), [1+4] cycloaddition, and oxidation reactions of the synthesized germylenes were investigated. The compositions and structures of the novel compounds were established by elemental analysis, 1H and 13C NMR spectroscopy, and X-ray diffraction analysis (germylenes 2b, 2i, 2j, Ge4+ compounds 5b, 7a, 7b, 8, 10, 11). All the synthesized germylenes are monomeric.

A series of novel low valent germanium compounds RN(CHR 2 CR 1 R 3 O)(CHR 4 CHR 5 O)Ge 1 – 13 ( R = Me, Ph, Bn; R 1 , R 2 , R 3 , R 4 , R 5 = H, Me, Ph, (CH 2 ) 3 , (CH 2 ) 4 , CH 2 (C 6 H 4 )) was obtained via the reaction between Ge[N(SiMe 3 ) 2 ] 2 and various dialkanolamines. All new compounds were characterized by elemental analysis, 1 H and 13 C NMR spectroscopy and in several cases by X-ray diffraction analysis ( 1 , 3 , 8 , 10 ). The compounds 1 , 3 , 8 are dimeric in the solid state due to the formation of intermolecular Ge–O bonds, the complex 10 is monomeric, all compounds possess a transannular Ge–N bond. The reactivity of the germylenes synthesized was investigated in reactions of oxidative insertion (with halogenation reagents, MeI, disulfides), [1 + 4]-cycloaddition, oxidation and in reactions with water and acetic anhydride. Some reactions were investigated by DFT calculations.

Novel germanium containing triflates were prepared from the reactions of trifluoromethanesulfonic acid with tetraphenylgermane (1) and digermanes (Ph3GeGeMe3 (4), Ph3GeGePh3 (5)). The improved procedures for synthesis of known organogermanium compounds (Ph4Ge (1), Ph3GeCl (2), Ph3GeGeMe3 (4), Ph3GeGePh3 (5)) were also presented. The crystal structure of Ph3GeOTf (6) and Ph2Ge(OTf)Ge(OTf)Ph2 (7) was studied by X-ray analysis. In 7 each germanium atom is pentacoordinated due to intramolecular interaction with O atom of the neighboring triflate group.

A study was carried out on the behavior of monomeric germylenes derived from pyridine-containing diols in reactions with diphenylphosphoryl azide and 9,10-phenanthrenequinone. It was found that the germanium atom increases its oxidation state to 4+ in these reactions. The structure of the product of the reaction with 9,10-phenanthrenequinone was confirmed by X-ray structural analysis, which showed a transannular germanium-nitrogen interaction in this product.

The titanium complexes with one (1a, 1b, 1c) and two (2a, 2b) dialkanolamine ligands were used as initiators in the ring-opening polymerization (ROP) of e-caprolactone. Titanocanes 1a and 1b initiated living ROP of e-caprolactone affording polymers whose number-average molecular weights (M n ) increased in direct proportion to monomer conversion (M n ≤ 30,000 g mol -1 ) in agreement with calculated values, and were inversely proportional to initiator concentration, while the molecular weight distribution stayed narrow throughout the polymerization (M w /M n ≤ 1.2 up to 80% monomer conversion). 1 H-NMR and MALDI-TOF-MS studies of the obtained poly(e-caprolactone)s revealed the presence of an isopropoxy group originated from the initiator at the polymer termini, indicating that the polymerization takes place exclusively at the Ti-O i Pr bond of the catalyst. The higher molecular weight polymers (M n < 70,000 g mol -1 ) with reasonable MWD (M w /M n < 1.6) were synthesized by living ROP of e-caprolactone using spirobititanocanes (2a, 2b) and titanocane 1c as initiators. The latter catalysts, according MALDI-TOF-MS data, afford poly(e-capro-lactone)s with almost equal content of α,ω-dihydroxyl- and α-hydroxyl-ω(carboxylic acid)-terminated chains arising due to monomer insertion into "Ti-O" bond of dialkanolamine ligand and from initiation via traces of water, respectively.

The reactions of [In(NEt2)3]2 and Sb(NEt2)3 with an equimolar amount of decafluorodiphenylamine (DFDPA, LH) lead to the indium or antimony amides [(C6F5)2NIn(NEt2)2]2 (1) and (C6F5)2NSb(NEt2)2 (2). Compound 2 rearranged further to give monofluoride Et2NSb(F)[N(o-Et2N–C6F4)(C6F5)] (3) and then difluoride F2Sb[N(o-Et2N–C6F4)2] (4). The hydrolysis of 4 gave free ligand HN(o-Et2N–C6F4)2 (5). Closely related HN(o-Me2N–C6F4)2 (6) was prepared from the reaction of Bi(NMe2)3 with DFDPA. The reactions of LiN(C6F5)2·THF with metal halides gave Sb[N(C6F5)2]3 (7), Me3Sb(Br)[N(C6F5)2] (8), Me3Sb(Cl)[N(C6F5)2] (9), Me3Sb[N(C6F5)2]2 (10), [Li(THF)2][In{N(C6F5)2}3Cl] (11). The X-ray structural investigations of 2 and 8 are presented.

The reactions between M[N(SiMe3)2]2 (M = Ge, Sn) and three pyridine-based dialcohols yielded germylenes and stannylenes 1–6. The composition and structures of the novel compounds were established by elemental analyses, 1H and 13C NMR spectroscopy. The structures of insoluble species were confirmed by conversion to the corresponding dibromides 7–9. The single crystal structures of stannylene 4 and germylene 5 were determined by X-ray diffraction analyses. The germanium compound was found to be monomeric whilst the tin compound is a dimer. Both compounds possess strong transannular MN interaction in the solid phase.

Geometries of 20 germylenes and 18 stannylenes based on dialkanolamines, diethylenetriamines, and related compounds were optimized by the DFT method. It was found that the most of the germylenes and stannylenes studied are more stable as dimeric structures of different types. The dimerization is possible due to either additional Ge-O(N) interactions or Ge-Ge bonding. The factors leading to the stabilzation of one or another isomer are examined.

The reaction of dialkanolamines RN(CH2CH2O)(CHR’CHR’OH) (R = Me, Ph, PhCH2; R’ = H, Ph) with tetraethoxygermane gives either 2,2-diethoxy-1,3,6,2-dioxazagermocanes RN(CH2CH2O)(CHR’CHR’O)Ge(OEt)2 or 1,7,9,15-tetraoxa-4,12-diaza-8-germaspiro[7.7]pentadecanes [RN(CH2CH2O) (CHR’CHR’O)]2Ge depending on the reactant ratio. The chemical behavior of the obtained compounds in substitution reactions at germanium was studied. The product structure was confirmed by elemental analysis data and 1H, 13C, and 19F NMR spectroscopy. The cyclotrigermanoxane [MeN(CH2CH2O)2GeO]3 was studied by X-ray diffraction.

Two compounds of a novel-type azagermatrane, N(CH2CH2NC6F5)3Ge-Hal: HalCl (1), Br (2), were prepared via a metathetical reaction of trilithium salt of tetramine, N[CH2CH2N(Li)C6F5]3, with corresponding GeHal4. A single crystal structure of 1 was determined by the X-ray diffraction study: The compound shows the strongest transannular Nax Ge interaction (2.148(7) A) among other studied azagermatranes. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:738–741, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20476

New 1,3,6,2-dioxazaborocanes R1N(CHR3CR4R2O)(CHR6CHR5O)BX (1–11, X = Ph, 4-MeC6H4, Me; R1 = Me, PhCH2; R2, R3, R4, R5, R6 = H, Ph) were synthesized by the reactions of aryl- or methylboronic acids with dialkanolamines. The treatment of (Me2NCH2CH2O)3B (15) with MeN(CH2CH2OH)(CH2CPh2OH) afforded 2-[2-(dime-thylamino)ethoxy]-1,3,6,2-dioxazaborocane (12). 2-Fluoro-1,3,6,2-dioxazaborocanes R1N(CHR3CHR2O)(CH2CH2O)BF (13: R1 = PhCH2, R2 = R3 = H; 14: R1 = Me, R2 = R3 = Ph, threo) were synthesized by the reaction of bis(trimethylsilyl) ethers of the corresponding dialkanolamines with BF3·Et2O. The new borocanes can be used for the synthesis of the corre-sponding germanium derivatives PhCH2N(CH2CH2O)2GeX2 (16, X = OEt; 17, X = Cl), as exemplified by the reaction of compound 6. The structures of erythro-MeN(CH2CH2O)(CHPhCHPhO)BPh (3), threo-MeN(CH2CH2O)(CHPhCHPhO)BPh (4), erythro-MeN(CH2CH2O)(CHPhCHPhO)B(4-MeC6H4) (8), and PhCH2N(CH2CH2O)2BF (13) were established by X-ray diffraction. The coordination polyhedra of the boron atoms in these complexes can be described as distorted tetrahedra. The boron-nitrogen distances (1.705(7)–1.723(3) A) provide unambiguous evidence for the presence of the B←N transannular interaction in these compounds. The structures of the resulting borocanes containing phenyl substituents at the carbon atoms of the ocane skeleton were studied by NMR spectroscopy and quantum chemical density functional theory calculations.

Novel substituted 2-[(2-hydroxyethyl)]aminophenols, MeN(CHR1CR2R3OH)(C6H4-o-OH) (2–5), were synthesized by the reaction of 2-methylaminophenol with corresponding oxiranes. Titano-spiro-bis(ocanes) [MeN(CHR1CR2R3O)(C6H4-o-O)]2Ti 6–9 (2, 6, R1 = H, R2 = R3 = Me; 3, 7, R1 = R2 = Ph (treo-), R3 = H; 4, 8, R1 = Ph, R2 = R3 = H; 5, 9, R1 = R2 = H, R3 = Ph) based on [ONO]-ligands have been synthesized. The obtained compounds were characterized by 1H and 13C NMR spectroscopy and elemental analysis data. The complex [Ti(μ2-O){O-o-C6H4}{μ2-CMe2CH2}NMe]6 (10) was obtained by controlled hydrolysis of 6. Molecular structure of 10 was determined by X-ray structure analysis.

The indium tris(amide)s [(Et2N)3–nIn{N(C6F5)(2-C5H4N)}n] [n = 1 (15), 2 (16) or 3 (9)] have been prepared by treatment of [In(NEt2)3]2 (3) with a stoichiometric amount of (2-C5H4N)(C6F5)NH (1). The analogous reaction of Bi(NMe2)3 (2) with 3 equiv. of amine 1 and the treatment of BiCl3 (5) with a stoichiometric amount of (2-C5H4N)(C6F5)NLi (4) both lead to [Bi{N(C6F5)(2-C5H4N)}3] (10). In contrast, only the difluoride 11 or the monofluoride 12, which are the products of intramolecular ortho-directed exchange of NMe2 and F substituents, are obtained from the reaction of 2 with 1 or 2 equiv. of 1, respectively. The reaction between Me3Sb(Hal)2 [Hal = Br (7) Cl, (8)] and 1 or 2 equiv. of lithium salt 4 gives the corresponding stable monoamides [Me3(Hal)Sb{N(C6F5)(2-C5H4N)}] [Hal = Br (17), Cl (18)] or bis(amide) [Me3Sb{N(C6F5)(2-C5H4N)}2] (19), respectively. The structure of 9 has been confirmed by an X-ray structure analysis, and density functional calculations data have been used to explain the possible reaction pathway of the ortho-directed metathetical fluoride/amide exchange.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The reactions of heteroelement-containing alkynes H3SiC≡CH and R3MC≡CPh [R3M = H3Si, Et3Si, Et3Ge, (MeO)3Si, (EtO)3Ge, N(CH2CH2O)3Si, N(CH2CH2O)3Ge, Bu3Sn] with one and two bromine molecules were studied in terms of the density functional theory. Transition states along reaction channels leading to products of both addition at the triple bond (cis- and trans-dibromoalkenes and 1,1-dibromoalkenes) and cleavage of the M-C≡ bond were localized.

Results on the synthesis of stannocanes-eight-membered heterocycles with the general formula D(CH2CH2Z)2SnXY-are reviewed and analyzed. The chemical behavior of the compounds is examined, and the nature of the transannular bond is studied.

Novel titanocanes and spirobititanocanes based on 2,6-bis[hydroxy(diphenyl)methyl]pyridine (1a) and 2,6-di(hydroxymethyl)pyridine (1b) – [2,6-C5H3N(CPh2O)2]Ti(O-i-Pr)2 (2a), [2,6-C5H3N(CPh2O)2]2Ti (3a), [2,6-C5H3N(CH2O)2]2Ti (3b), [2,6-C5H3N(CPh2O)2]TiCl2 (4) – as well as the closely related N-phenyl derivative PhN(CH2CH2O)2Ti(Cl)Cp (5) have been synthesized. Complexes 2–5 were characterized by 1H and 13C NMR spectroscopy and elemental analysis data. The molecular structure of 3a was determined by X-ray structure analysis.