A Structural, Theoretical and Coordinative Evaluation of the Bicyclic Guanidinate Dervived from 1,4,6-triazabicyclo[3.3.0]oct-4-ene

Partial deprotonation of the bicyclic guanidine 1,4,6-triazabicyclo[3.3.0]oct-4-ene (Htbo) is achieved using nBuLi. Isolation of the resulting lithium salts has resulted in the structural characterization of the mixed anion complex {[Li(tbo)( VIII)(tboH)]2} 1a (where VIII-H = 1-(2-aminoethyl)-2-imidazolidinethione) and the partially deprotonated salt Li6(tbo)6(Htbo)3, 1b. The neutral guanidine Htbo reacts cleanly with AlMe3 and ZnMe2 to afford the organometallic complexes [Al(tbo)Me2]2 [ 2]2, and Zn3(tbo)4Me2 ( 3). Structural characterization of these compounds enables comparison between the {5:5}-bicyclic system, [tbo]-, and the previously reported {6:6}-bicyclic system, [hpp]- (where hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine). Results indicate that delocalization within the [tbo]- anion is restricted to the CN2 amidinate component, with retention of electron density in the non-bonding nitrogen lone-pair. These conclusions are supported by a DFT analysis of the neutral guanidines, Htbo and hppH

The first structurally characterised -bonded organonickel(I) compound. Crystal structures of [Ni C(SiMe3)2(SiMe2C5H4N-2)(PPh3)] [Ni\{C(SiMe3)(SiMe2C5H4N-2)(SiMe2O)]2 and {Pd(m -Cl) C(SiMe3)2(SiMe2C5H4N-2)]2

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Phosphaguanidines as Scaffolds for Multimetallic Complexes Containing Metal-Functionalized Phosphines

Phospha(III)guanidines, R2PC{NR}{NHR}, have been used to synthesize multimetallic compounds containing combinations of aluminum with platinum or copper, in which the main-group metal is N,N-bound by an amidinate moiety, thereby generating a metal-functionalized phosphine that bonds to the transition metal through phosphorus

Samarium(III) Pentalene Sandwich Compounds [Sm(?8-C8H4{SiiPr3-1,4}2)(Cp*)] and [Sm(?8-C8H4{SiiPr3-1,4}2)(?5-C8H5{SiiPr3-1,4}2)] and a Mixed-Valence Hexasamarium Cluster Derived from Sm(II)-Based Solvent Activation

The reaction of the pentalene salt C8H4{(SiPr3)-Pr-i-1,4}(2)[K](2) with [SmCp*(mu-I)(THF)(2)](2) yields not the expected Sm(II) pentalene-bridged dimer but the Sm(III) sandwich complexes [Sm(eta(8)-C8H4{(SiPr3)-Pr-i-1,4}(2))(eta(5)-Cp*)] (1) and [Sm(eta(8)-C8H4{(SiPr3)-Pr-i-1,4}(2))(eta(5)-C8H5{(SiPr3)-Pr-i-1,4}(2))] (2) and the mixed-valence cluster [Cp*Sm-6(6)(OMe)(8)O][K(THF)(6)] (3) via solvent activation of THF. The samarium(III) sandwich compound 2 incorporates an eta(8)-pentalene ligand and an eta(5)-hydropentalenyl ligand. X-ray crystallography shows the Sm(II)/Sm(III) mixed-valence cluster compound 3 to contain a centrosymmetric hexanuclear array of Cp*Sm units, bridged by face-centered mu(3)-methoxy groups, with a central oxo unit

Yttrium iodide and bis(trimethylsilyl)methyl complexes of the chelating diamide [ArN(CH2)3NAr]2- (Ar = 2,6-iPr2C6H3)

Yttrium triiodide reacts with the potassium salt K2[ArN-(CH2)3NAr] (Ar = 2,6-iPr2C6H3) to yield a mono-iodide complex and, by further reaction with K[CH(SiMe3)2], the corresponding alkyl complex, which have both been characterised by NMR spectroscopy and X-ray crystallography

An Organozinc Hydride Cluster: an Encapsulated Tetrahydrozincate?

Reaction of the alkylzinc bromide Zn(C{SiMe3}2{SiMe2hpp})Br (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) with an excess of sodium hydride gives good yields of an unusual zinc hydride cluster, in which five zinc atoms are linked by (-H) bridge

A versatile bulky bidentate ligand for both main group and transition metals. Derivatives of lithium potassium magnesium chromium manganese and cobalt containing the C(SiMe3)2(SiMe2C5H4N-2)

The compound HC(SiMe3)2(SiMe2C5H4N-2), 1, reacts with methyllithium in THF to give a good yield of the lithium derivative which has been isolated as a molecular THF adduct 2. This reacts (a) with KOtBu to give 3, which crystallizes in a solvent-free ionic lattice, (b) with MgBr2 to give the Grignard reagent 4, and (c) with CrCl2 to give Cr{C(SiMe3)2(SiMe2C5H4N-2)}2, 5, along with the halide-bridged Grignard reagent analogue 6, which crystallizes in a lattice containing alternate THF-free molecules (6a) and molecules (6b) with coordinated THF. The reactions of 2 with MnCl2 and CoBr2 give the halide-bridged ate complexes 7, and 8, respectively

Hydrometalation of PCBut and Activation of the P-C Bond by a Tetrairidium Carbonyl Cluster:? Solution Characterization of [Ir4Pt(dppe)(CO)n{µ-PC(H)But}(µ-PPh2)] (n = 10 and 9) and Crystal and Molecular Structures of the Phosphinidine Complex [HIr4Pt(dppe)(µ-CO)(CO)7(µ-PCH2But)(µ-PPh2)] and of the Partially Encapsulated Phosphide Compound [Ir4Pt(dppe)(µ-CO)(CO)8(µ5-P)(µ-PPh2)]

Reaction of [HIr4(CO)10(µ-PPh2)], 1, with [Pt(dppe)(?2-PCBut)] yields four Ir4Pt clusters [Ir4Pt(dppe)(CO)n{µ-PC(H)But}(µ-PPh2)] (n = 10, 2, and 9, 3), [HIr4Pt(dppe)(µ-CO)(CO)7(µ-PCH2But)(µ-PPh2)], 4, and [Ir4Pt(dppe)(µ-CO)(CO)8(µ5-P)(µ-PPh2)], 5. These compounds contain fragments arising from hydrometalation and cleavage of the P-C triple bond of the phosphaalkyne. The structures of compounds 2 and 3, isolated as a mixture, were proposed on the basis of multinuclear NMR and mass spectrometry. To our knowledge these are the first examples of clusters containing a phosphido fragment {µ-PC(H)But} originating from hydrometalation of the phosphaalkyne. Compounds 4 and 5 were characterized in solution by multinuclear NMR spectroscopy, and their solid-state structures were determined by X-ray analyses. A remarkably low 1JP-Pt coupling constant in the Pt(dppe) fragment of the former square-based pyramidal compound is discussed

Oxidative addition to a monomeric stannylene to give four-coordinate tin compounds containing the bulky bidentate ligand C(SiMe3)2SiMe2CH2CH2Me2Si(Me3Si)2C. Crystal structures of CH2Me2Si(Me3Si)2CSnC(SiMe3)2SiMe2CH2, CH2Me2Si(Me3Si)2CSnMe(OCOCF3)C(SiMe3)2SiMe2CH2, and (CF3COO)2MeSnC(SiMe3)2SiMe2CH2CH2Me2Si- (Me3Si)2CSnMe(OCOCF3)2

Reaction of (THF)2KRRK(THF)2 (RR = C(SiMe3)2SiMe2CH2CH2Me2Si(Me3Si)2C) with SnCl2 in Et2O gave a mixture of the cyclic and linear SnII compounds RSnR 4, and ClSnRRSnCl, 9. This mixture was treated with MeI to give the corresponding SnIV compounds 5, and IClMeSnRRSnMeClI, 10. Treatment of RSnMeIR 5 and 10 with AgO2CCF3 gave the corresponding trifluoroacetates 6 and 11, which were structurally characterized

Nucleophilic activity of a linked bis{guanidine} leading to formation of a dicationic C4N4-heterocycle

The methylene-linked bis{guanidine}, H2C{hpp}2 (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), displays nucleophilic activity towards organic halides, including the activation of dichloromethane under ambient conditions to afford the heterocyclic dication, [H2C{hpp}2CH2]2+ [Cl]- 2. X-ray crystallography has been used as a probe of the bonding within the eight-membered ring of the dication, and DFT calculations have identified two stable conformations, in agreement with two different species observed in solution