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{The P, O-type phosphinophenol proligands (1 center dot H, 2-PPh2-4-Me-6-Me-C6H2OH; 2 center dot H, 2-PPh2-4-Me-6-Bu-t-C6H2OH) readily react with one equiv. of ZnEt2 to afford in high yields the corresponding Zn(II)ethyl dimers of the type {[}(kappa(2)-P, O) Zn-Et](2) (3 and 4) with two mu-O-Ph bridging oxygens connecting the two Zn(II) centers, as determined by X-ray diffraction (XRD) studies in the case of 3. Based on diffusion-ordered NMR spectroscopy (DOSY), both species 3 and 4 retain their dimeric structures in solution. The alcoholysis reaction of Zn(II) alkyls 3 and 4 with BnOH led to the high yield formation of the corresponding Zn(II) benzyloxide species {[}(kappa(2)-P, O) Zn-OBn](2) (5 and 6), isolated in a pure form as colorless solids. The centrosymmetric and dimeric nature of Zn(II) alkoxides 5 and 6 in solution was deduced from DOSY NMR experiments and multinuclear NMR data. Though the heteroleptic species 5 is stable in solution, its analogue 6 is instable in CH2Cl2 solution at room temperature to slowly decompose to the corresponding homoleptic species 8 via the transient formation of (kappa(2)-P, O)(2)Zn-2(mu-OBn)(mu-kappa(1):kappa(1)-P, O) (6'). Crystallization of compound 6 led to crystals of 6', as established by XRD analysis. The reaction of ZnEt2 with two equiv. of 1 center dot H and 2 center dot H allowed access to the corresponding homoleptic species of the type {[}Zn(P, O)(2)] (7 and 8). All gathered data are consistent with compound 7 being a dinuclear species in the solid state and in solution. Data for species 8, which bears a sterically demanding P, O-ligand, are consistent with a mononuclear species in solution. The Zn(II) alkoxide species 5 and the {[}Zn(P, O)(2)]-type compounds 7 and 8 were evaluated as initiators of the ring-opening polymerization (ROP) of lactide (LA), epsilon-caprolactone (epsilon-CL) and trimethylene carbonate (TMC). Species 5 is a well-behaved ROP initiator for the homo-, co- and terpolymerization of all three monomers with the production of narrow disperse materials under living and immortal conditions. Though species 7 and 8 are ROP inactive on their own, they readily polymerize LA in the presence of a nucleophile such as BnOH to produce narrow disperse PLA, presumably via an activated-monomer ROP mechanism.}

{The reactions of TCNE- and TCNQ-functionalized (TCNE: tetracyanoethylene and TCNQ: 7,7', 8,8'-tetra-cyanoquinodimethane) zwitterionic benzoquinonemonoimines with a Cu(I)-BIAN complex (BIAN = bis-(o, o'-bisisopropylphenyl)acenaphthenequinonediimine) have been investigated and found to follow a diversity of interesting patterns. The complexes {[}Cu(BIAN)(NCMe)(L2)]BF4 (2) and {[}Cu(BIAN)(L2)(2)]BF4 (4) were obtained by reacting {[}Cu(BIAN)(NCMe) 2] BF4 (1) with one and two equivalents of L2, respectively. Following similar procedures, the complexes {[}Cu(BIAN)(NCMe)(L3)] BF4 (6) and {[}Cu(BIAN)(L3)(2)]BF4 (7) were obtained by reaction of 1 with L3. The reaction of 2 with 0.5 equiv. of 4,4'-bipyridine afforded {[}\{Cu(BIAN)-(L2)\}(2)(mu-4,4'-bipyridine)](BF4)(2) (3). The complexes were characterized by multinuclear NMR, IR and UV-Vis spectroscopic techniques, mass spectrometry, cyclic voltammetry and elemental analysis. The molecular structures of complexes 3 center dot 4CH(2)Cl(2) and 4 center dot CH2Cl2 were determined by single crystal X-ray diffraction. An unexpected coordination polymer {[}Cu(L2(-))(2)](infinity) (5) was also structurally characterized, which contains Cu(II) centres chelated by two N, O-bound ligands resulting from the monodeprotonation of L2.}

{The present contribution comprehensively reviews the synthesis, structural characterization and current applications of group 13 metal complexes supported by heteroatom-bonded carbene ligands. Detailed structural analysis and comparison of the structure/reactivity trends of group 13 metal carbene species constitute the primary purpose of the present contribution. The current use and applications of this class of compounds are also discussed. In general, such adducts have been thoroughly characterized (both in solution or in the solid state) and structural data, frequently supported by theoretical investigations, provided insight into the stability/reactivity of the adducts formed. While essentially dominated by Arduengo-type NHC adducts, N- and P-bonded cyclic and acyclic carbene complexes of Al, Ga and In have also been recently described, including the recent use of ``carbon(0) ligands{''}. In general, recent developments in carbene group 13 species exploit the improved stability of the resulting metal complexes for either the isolation/characterization of unprecedented structural motifs or the production of robust group 13 metal reagents subsequently used for organic substrates functionalization or in catalysis. (C) 2014 Elsevier B.V. All rights reserved.}

{Four novel Zinc-NHC alkyl/alkoxide/chloride complexes (4, 5, 9 and 9) were readily prepared and fully characterized, including X-ray diffraction crystallography for 5 and 9. The reaction of N-methyl-N-butyl imidazolium chloride (3.HCl) with ZnEt2 (2 equiv.) afforded the corresponding {[}(CNHC)ZnCl(Et)] complex (4) via a protonolysis reaction, as deduced from NMR data. The alcoholysis of 4 with BnOH led to quantitative formation of the dinuclear Zn(II) alkoxide species {[}(CNHC)ZnCl(OBn)]2 (5), as confirmed by X-ray diffraction analysis. The NMR data are in agreement with species 5 retaining its dimeric structure in solution at room temperature. The protonolysis reaction of N-(2,6-diisopropylphenyl)-N-ethyl methyl ether imidazolium chloride (8.HCl) with ZnEt2 (2 equiv.) yielded the {[}(CNHC)ZnCl(Et)] species 9. The latter was found to be reactive with CH2Cl2 in solution and to cleanly convert to the corresponding Zn(II) dichloride {[}(CNHC)ZnCl2]2 (9), whose molecular structure was also elucidated using X-ray diffractometry. Unlike Zn(II)-NHC alkoxide species 1 and 2, which contain a NHC flanked with an additional N-functional group (i.e. thioether and ether, respectively), the Zn(II) alkoxide species 5 incorporates a monodentate NHC ligand. The Zn(II) complexes 1, 2 and 5 were tested in the ring-opening polymerization (ROP) of trimethylene carbonate (TMC). All three species are effective initiators for the controlled ROP of trimethylene carbonate, resulting in the production of narrow disperse PTMC material. Initiator 1 (incorporating a thioether moiety) was found to perform best in the ROP of TMC. Notably, the latter also readily undergoes the sequential ROP of TMC and rac-LA in the presence of a chain-transfer agent, leading to well-defined and high-molecular-weight PTMC/PLA block copolymers. Copyright (c) 2014 John Wiley & Sons, Ltd.}

{{Abstract A variety of N-heterocyclic carbene (NHC) zinc adducts of the type NHC-ZnMe2 {[}2a

{Reaction of {[}Co(eta(5)-C5H5)(CO)(2)], 1, with 1,1'-bis(diphenylphosphino)ferrocene (dppf) yields the new trinuclear complex {[}Co(eta(5)-C5H5)(CO)](2)(mu-dppf), 2, which was structurally characterised by single crystal X-ray diffraction and showed two Co(eta(5)-C5H5)(CO) moieties covalently linked by a dppf bridge. Electrochemical studies in dichloromethane revealed that both Co(I) and Fe(II) in the precursors were oxidized to Co(II)/Co(III) and Fe(III), respectively. On the other hand, in 2 the two first oxidation waves were assigned to Co, the Fe(II) centre requiring a higher potential than in free dppf. DFT calculations showed that the HOMOs of 2 were localised in the Co fragments, owing to the destabilisation of the Co(eta(5)-C5H5)(CO) orbitals after binding dppf. (C) 2012 Elsevier B.V. All rights reserved.}

{Zinc alkyl cations supported by N,N-BIAN-type bidentate ligands were found to be highly active in the immortal ROP of epsilon-caprolactone to yield narrowly disperse and chain length-controlled poly(epsilon-caprolactone), whether in solution or bulk polymerization conditions.}

{{A series of Ar-BIAN-based copper(I) complexes (where Ar-BIAN = bis(aryl) acenaphthenequinonediimine) were synthesised and characterised by H-1 and C-13 NMR spectroscopies, FT-IR spectroscopy, MALDI-TOF-MS spectrometry, cyclic voltammetry and single crystal X-ray diffraction. The bis-chelated complexes of general formula {[}Cu(Ar-BIAN)(2)]BF4 (where Ar = C6H5 (1), 4-iPrC(6)H(4) (3), 2-iPrC(6)H(4) (4)) were prepared by reaction of {[}Cu(NCMe)(4)]BF4 with two equivalents of the corresponding Ar-BIAN ligands, in dichloromethane, while the mono-chelated complexes of the type {[}Cu(Ar-BIAN)L2]BF4 (where Ar = 2,6-iPr(2)C(6)H(3)

The new compound [Co(eta(5)-C5H5)(dppf-P,P')I]I, 1, was synthesised by the stoichiometric reaction of the Co(III) complex [Co(eta(5)-C5H5)(CO)I-2], 2, with 1,1'-bis(diphenylphosphino)ferrocene (dppf) in CH2Cl2, and was characterised by multinuclear NMR spectroscopy. Exposure to air of THF or CH2Cl2 solutions of compound 1 gave, in an unexpected way, a polymeric chain comprising bridging 1,1'-bis(oxodiphenylphosphoranyl) ferrocene (dppfO(2)) joining tetrahedral Co(II) units [CoI2(mu-dppfO(2))](n), 3. Attempts to obtain the polymeric chain 3 by the direct reaction of dppfO(2) with CoI2, in CH2Cl2, gave instead the monomeric compound [CoI2(dppfO(2))], 4, in which dppfO2 is coordinated in a chelating mode. The structural characterisation of compounds 2, 3, and 4 was carried out by single crystal X-ray diffraction studies. The magnetic behaviour of [CoI2(dppfO(2))] and [CoI2(mu-dppfO(2))](n) was studied, and the results are consistent with tetrahedral S = 3/2 Co-II, possessing a (4)A(2) ground state, and S = 0 Fe-II. In these compounds, Co-II negative zero field splittings were determined from an analysis of the magnetic susceptibility temperature dependence, with D/k = -13 and -14 K for CoI2(dppfO(2)) and [CoI2(mu-dppfO(2))](n), respectively. DFT calculations were performed in order to understand the electronic structure of [Co(eta(5)-C5H5)(dppf-P,P')I]I, 1, as well as that of the paramagnetic specie [CoI2(dppfO(2))], 4. The [CoI2(mu-dppfO(2))](n) chain was also analysed and found to behave very similarly to the monomeric iodine derivative 4. The calculations showed the unpaired electrons to be localized on the Co(II) centre in all these species. The rather complicated electrochemical behaviour exhibited by the dppf complex [Co-III(eta(5)-C5H5)(dppf-P,P')I]I and by [Co(dppfO(2))I-2] is discussed.