Bimetallic Complexes from Amphoteric Group 13/15 Ligands: Syntheses and X-ray Crystal Structures

Thomas, F.; Schulz, Stephan; Nieger, Martin; Nättinen, Kallie

doi:10.1002/1521-3765(20020415)8:8<1915::aid-chem1915>3.0.co;2-z

Cited by 17 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The increased steric demand of the tert ‐butyl moieties lead to a minor increase of the Ga–P–Si angle from 109.1°/114.1° (Et/ i Pr) to 116.3° ( 2 ) or 118.0° ( 3 ). The similar DMAP‐stabilized monomeric compound [(dmap)GaMe 2 P(SiMe 3 ) 2 ], published by Schulz et al, shows a N–Ga bond length of 208.0 pm, which is almost identical to the value observed for 2 and 3 with 209.1(1) pm and 209.9(3) pm . The 31 P NMR spectra of 2 and 3 show doublet signals at –287 ppm and –288 ppm, with 1 J PH ‐coupling constants of 192.8 Hz and 191.6 Hz ppm.…”

Section: Resultssupporting

confidence: 58%

A Sterically Encumbered 13/15 Cycle and its Cleavage with N‐heterocyclic Carbenes and other Lewis Bases

Kapitein

Balmer

Hänisch

2016

Zeitschrift anorg allge chemie

View full text Add to dashboard Cite

Herein, the latest results on the topic of NHC-stabilized, monomeric group 13 metalsilylphosphanides, with the focus on the sterically demanding [GatBu 2 R x ]-fragment (x = 1, 2) are presented. The synthesis and characteristics of the cyclic compound [tBu 2 GaP(H)SitBuPh 2 ] 2 (1), followed by the cleavage of this cycle with different Lewis bases like pyridine, DMAP or the IiPr carbene is described for the first time. The compounds * Prof. Dr. C. von Hänisch

show abstract

Section: Resultssupporting

confidence: 58%

A Sterically Encumbered 13/15 Cycle and its Cleavage with N‐heterocyclic Carbenes and other Lewis Bases

Kapitein

Balmer

Hänisch

2016

Zeitschrift anorg allge chemie

View full text Add to dashboard Cite

show abstract

“…The self-aggregation is likely to prevent the interaction of the phosphorus compounds containing the TiCl 2 or ZrCl 2 unit with late transition metals. In fact, compounds containing Lewis acidic R 2 Al and Lewis basic R 2 P units in one molecule are known as “amphoteric ligands” . In these compounds, self-aggregations are often seen, for example, R n Cl 2 - n AlCH 2 PR 2 , in which two strong P→Al bonds provide a dimer with a six-membered ring structure 5b.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, compounds containing Lewis acidic R 2 Al and Lewis basic R 2 P units in one molecule are known as “amphoteric ligands” . In these compounds, self-aggregations are often seen, for example, R n Cl 2 - n AlCH 2 PR 2 , in which two strong P→Al bonds provide a dimer with a six-membered ring structure 5b. Although an aluminum phosphinoamide, Ph 2 P( t Bu)NAlEt 2 , was reportedly a monomer in a benzene solution,5f this was later contradicted by Labinger's NMR study 5a.…”

Section: Introductionmentioning

confidence: 99%

“…In these compounds, self-aggregations are often seen, for example, R n Cl 2 - n AlCH 2 PR 2 , in which two strong P→Al bonds provide a dimer with a six-membered ring structure 5b. Although an aluminum phosphinoamide, Ph 2 P( t Bu)NAlEt 2 , was reportedly a monomer in a benzene solution,5f this was later contradicted by Labinger's NMR study 5a. It is interesting, however, that Ph 2 P( t Bu)NAlEt 2 reacted with certain metal carbonyls to give metallacyclic products, presumably due to the mechanisms involving its dissociation to a monomeric form.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic Titanium Phosphinoamides as Unique Bidentate Phosphorus Ligands for Platinum

et al. 2006

View full text Add to dashboard Cite

Treatment of lithium phosphinoamides, Ph2PN(Li)R [R = tBu, iPr], with TiCl4 results in formation of titanium phosphinoamides, (Ph2PNR)2TiCl2 [R = tBu (1a), iPr (1b)]. Crystallographic studies show that there are covalent bonds between the titanium and two nitrogen atoms, whereas two phosphorus atoms are coordinated to the metal center intramolecularly. Variable-temperature NMR studies suggest reversible dissociation of the phosphorus moieties from the titanium in solution. The dissociated phosphorus moieties are effectively captured by Pt(II) species; reactions of 1a with either (η4-COD)PtCl2, (η4-COD)Pt(R)(Cl) (R = Me, p-Tol), or [Me2Pt(μ-SMe2)]2 afford the corresponding Ti−Pt heterobimetallic complexes. The molecular structures of these complexes reveal that they have a six-membered dimetallacycle, in which a titanium and a platinum are connected by two bridging phosphinoamide ligands; the Pt−Ti distances indicate the existence of a Pt→Ti dative bond. The conformation of the dimetallacycle is a boat form, with two metals at the bow and the stern in the crystal; however, dynamic conformational change involving cleavage and re-formation of the Pt→Ti dative bond is indicated from variable-temperature NMR studies.

show abstract

“…Despite the diverse range of both monosubstituted 231,275 and disubstituted 179,194,240,276 phosphanide ligands on gallium complexes, the reported reactivity of these gallium phosphanides is limited to their co-ordination complexes with transition metals, 277 thermolysis of P-H bonds to form (RGaPR)2 dimers, 278 and the attempted formation of a gallium-phosphorus double bond (discussed in section 3.1) through the attempted abstraction of HI with base from the mixed halo-phosphanide complex CXIV (Figure 104) which instead eliminated iodine through a single electron reduction of the ligand to give complex CXV. 231…”

Section: Reactivity Of Gallium Phosphanidesmentioning

confidence: 99%

Bonding and Reactivity of Gallium and Aluminium Coordination Complexes

Cummins¹

View full text Add to dashboard Cite

<p>This thesis describes the synthesis, structures and reactivities of gallium and aluminium complexes supported by β-diketiminato ligands ([CR{C(R)N(R’)}₂]-, abbrev. [(BDIR’)]-). Chapter 1 gives a general introduction into the trends and properties that distinguish the heavier p-block elements from their lighter counterparts. An introduction into the theory of multiple bond formation, both homonuclear and heteronuclear, in the heavy p-block elements is provided and a summary of the sterically demanding ligands required to stabilise these complexes is introduced. The β-diketiminato ligand framework utilised in this study is introduced and the methods of generation of low valent gallium and aluminium complexes supported by the BDIDIPP ligand are discussed. Chapter 2 discusses the reactivity of the complex BDIDIPPGa with diazo- compounds in the quest to isolate a complex with a formal gallium-carbon double bond. BDIDIPPGa reacts with two equivalents of both trimethylsilyldiazomethane and diazofluorene, presumably through the target gallium-carbon double bond intermediate. No reaction is observed with di-tert-butyldiazomethane, while BDIDIPPGa catalyses the decomposition of diphenyldiazomethane into tetraphenylethene. Three new β-diketiminato gallium(I) complexes were synthesised: ArBDIDIPPGa, BDIAr*Ga and BDIAr’Ga. ArBDIDIPPGa also reacted with two equivalents of trimethylsilyldiazomethane, presumably through the target gallium-carbon double bond intermediate. BDIAr*Ga and BDIAr’Ga both inserted into the C-H bond of trimethylsilyldiazomethane to give BDIAr*Ga(H)C(N2)SiMe₃ and BDIAr’Ga(H)C(N2)SiMe₃ respectively. Upon addition of diazofluorene to BDIAr*Ga, one of the aromatic protons of the BDIAr* ligand was abstracted by the diazofluorene, resulting in coordination of one of the flanking phenyl groups to the gallium centre. Chapter 3 discusses an investigation into the formation of formal double bonds between aluminium and phosphorus, and gallium and phosphorus. The proposed ‘deprotonation/elimination’ method, reacting BDIDIPPM(PHAr)Cl (M = Al, Ga Ar = Ph, Mes) with nBuLi, resulted in the formation of intractable mixtures of products. Direct synthesis by the addition of MesPLi₂ to BDIDIPPMCl₂ (M = Al, Ga) resulted in the formation of BDIDIPPM(PHMes)Cl (M = Al, Ga). Changing the elimination product to TMS-Cl, through the synthesis of BDIDIPPM(P(TMS)Ph)Cl (M = Al, Ga), resulted in the synthesis of BDIDIPPAl(P(TMS)Ph)Cl, which showed no signs of elimination occurring upon heating to 110 °C. BDIDIPPGa(P(TMS)Ph)Cl could not be isolated, potentially as the complex was undergoing the desired elimination of TMS-Cl, but the resulting complex was decomposing. Changing the elimination product to ethane, through the synthesis of BDIDIPPAl(PHMes)Et, resulted in no sign of elimination occurring upon heating to 110 °C. Reduction of BDIDIPPMCl₂ (M = Al, Ga) in the presence of bistrimethylsilylacetylene, as part of the synthesis of BDIDIPPMLi₂ (M = Al, Ga) salts, was unsuccessful, as was the reaction of BDIDIPPGa with bistrimethylsilylacetylene. Reduction of MesPCl₂ with potassium metal in the presence of BDIDIPPGa resulted in an intractable mixture of products, reduction with magnesium resulted in the formation of (MesP)₃ and (MesP)₄. Addition of MesPH₂ to BDIDIPPGa resulted in the formation of BDIDIPPGa(H)P(H)Mes, which did not undergo H₂ elimination at 110 °C. The synthesis of BDIDIPPAl was unsuccessful as the product could not be isolated cleanly. The synthesis of ArBDIDIPPAl resulted in the intramolecular rearrangement of the ligand to give a five-membered aluminium containing ring. The synthesis of BDIAr*Al stalled at the formation of BDIAr*Al(Me)I due to the steric bulk of the ligand blocking the second substitution of iodine from occurring. Chapter 4 discusses the reactivity of the primary phosphanide complexes BDIDIPPAl(PHMes)Cl, BDIDIPPAl(PHMes)Et and BDIDIPPGa(H)P(H)Mes with phenyl acetylene, 4-nitro-phenyl isocyanate, phenyl isothiocyanate, dicyclohexyl carbodiimide, cyclohexene, benzophenone, benzaldehyde, selenium, sulfur, and methyl iodide. Reactivity was not observed for phenyl acetylene, dicyclohexyl carbodiimide or benzophenone with any of the phosphanides. Reactivity with the phosphanides was observed with cyclohexene, however rapid decomposition of the products occurred and they were unable to be identified. BDIDIPPAl(PHMes)Cl and BDIDIPPGa(H)P(H)Mes showed no reactivity with benzaldehyde, however, the ethyl ligand of BDIDIPPAl(PHMes)Et reacted with the aldehyde proton, eliminating ethane and substituting the PhC(O)- ligand onto the aluminium centre. Reactivity with the phosphanides was observed with both sulfur and selenium, however multiple different products were formed, none of which were successfully isolated. Reactivity between the phosphanides and methyl iodide was observed, with the P-M bond appearing to be cleaved and formation of a M-I bond occurring. 4-nitro-phenyl isocyanate and phenyl isothiocyanate underwent insertion reactions into the M-P bond, however only BDIDIPPAl(Cl)N(4-NO₂-Ph)C(O)P(H)Mes was able to be isolated and fully characterised. Finally, chapter 5 summarises the results of this research and provides an outlook at the future direction of this field of research.</p>

show abstract

Bimetallic Complexes from Amphoteric Group 13/15 Ligands: Syntheses and X-ray Crystal Structures

Cited by 17 publications

References 13 publications

A Sterically Encumbered 13/15 Cycle and its Cleavage with N‐heterocyclic Carbenes and other Lewis Bases

A Sterically Encumbered 13/15 Cycle and its Cleavage with N‐heterocyclic Carbenes and other Lewis Bases

Dynamic Titanium Phosphinoamides as Unique Bidentate Phosphorus Ligands for Platinum

Bonding and Reactivity of Gallium and Aluminium Coordination Complexes

Contact Info

Product

Resources

About