Preparation and identification of intermediate carbonyls of nickel and tantalum by matrix isolation

The products of the cocondensation reactions of Pt atoms with N2 at 4.2–10 °K are investigated by matrix isolation infrared and Raman spectroscopy and are shown to be binary dinitrogen complexes of the form Pt(N2)n. Examination of the reaction products in pure 14N2, in 14N2/15N2, in dilute 14N2/Ar, in 14N2/15N2/Ar as well as 14N2/14N/15N/15N2/Ar matrices establishes the stoichiometries of the complexes to be n = 1–3. Structural assignments can be made for the complexes Pt(N2) and Pt(N2)3 which contain end-on bonded dinitrogen and are found to be similar to the corresponding dinitrogen and carbonyl complexes of nickel and palladium. Pt(N2)2 appears to be the exception in this series of complexes, for which side-on bonded dinitrogen is proposed.On the basis of the Cotton–Kraihanzel force field of approximation and the isotope intensity sum rules, isotopic frequencies are computed for the NN stretching modes of the individual complexes and isotopic absorption intensities for Pt(N2)3 and are found to be in close agreement with the observed values. In the case of Pt(N2), the scrambled 14N15N isotope data establish that the dinitrogen ligand is bonded to the Pt atom in an end-on fashion. On the basis of its unusual spectroscopic behavior Pt(N2)2 is proposed to have sideways bonded dinitrogen ligands. Pt(N2)3 in solid α-N2 is found to be slightly distorted from a regular triangular planar molecule but appears to be regular D3h in solid argon. Calculations show that a substitutional site symmetry of C2 for Pt(N2)3 satisfactorily accounts for all the spectral lines observed for the complex in nitrogen. Comparisons are made within the group of binary dinitrogen complexes M(N2)n where n = 1–3 and with the corresponding binary carbonyl complexes M(CO)n. The relationship between the dinitrogen complexes NiN2, PdN2, and PtN2 and nitrogen chemisorbed on those same metals is discussed.

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“…It nevertheless deviates from the behavior of both the Pd/N, and Ni/N, systems in some striking instances discussed below (5,6).…”

Section: Introductionmentioning

confidence: 65%

Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N₂)_n (where n = 1–3)

Kündig¹,

Moskovits²,

Ozin³

1973

Can. J. Chem.

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“…The observation of only one line at 2188 cm-' in I4N,/Ar matrices2 assignable to a bisdinitrogen species, suggests that the Rh(N,), molecule is probably linear, with Dm,, symmetry (analogous to other transition metal binary carbonyl and dinitrogen compounds, observed thus far, e.g. Ni(N,),, Ni(CO),, Pd(CO),, Pd(N,),) (3,5,6). The C.K.…”

mentioning

confidence: 85%

Binary Dinitrogen Complexes of Rhodium, Rh(N₂)_n (where n = 1–4), in Low Temperature Matrices

Ozin¹,

Voet²

1973

Can. J. Chem.

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The products of the cocondensation reactions of Rh atoms with N2 and N2/Ar mixtures at 10 °K are investigated by matrix isolation infrared spectroscopy and are shown to be binary dinitrogen complexes of the form Rh(N2)n. Examination of the reaction products in pure 14N2, 15N2, 14N2/15N2, and in dilute Ar/14N2, Ar/14N2/15N2, and Ar/14N2/14N15N/15N2 matrices establish the values of n to be 1–4. Isotopic frequencies are computed for the NN stretching modes of the individual dinitrogen complexes on the basis of the Cotton–Kraihanzel (C.K.) force field approximation and are found to be in close agreement with observed values. Trends in the best fit C.K. force constants for Rh(N2)n (n = 1–4) and the thermodynamic stabilities of the individual complexes as indicated by the function ΔHcn, a measure of the enthalpy of decomposition, are discussed. Comparisons are made between Ni(N2)n and Rh(N2)n (where n = 1–4). The structure of Rh(N2)4 in solid nitrogen is shown to be that of a distorted tetrahedron. Calculations show that a site symmetry of D2d for Rh(N2)4 satisfactorily accounts for all of the spectral lines observed for the complex in nitrogen. In solid argon, Rh(N2)4 appears to have an approximately regular tetrahedral structure. The relationship between RhN2 and N2 chemisorbed on Rh metal is discussed and compared with the analogous Ni–, Pd–, and Pt–nitrogen systems.

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“…Yield: 0.014 g, 0.014 mmol, 72.0%. 1 13 Organometallics ARTICLE Synthesis of NiCl(η 2 -C,N-(p-MeC 6 H 4 )CdNAr Dipp2 )(CNAr Dipp2 ) (9). To an Et 2 O solution of Ni(CNAr Dipp2 ) 3 (0.025 g, 0.019 mmol, 10 mL) was added p-chlorotoluene (0.002 g, 2.3 μL, 0.019 mmol, 1 equiv) via syringe.…”

Section: Synthesis Of [Tlni(cnar Dipp2 ) 3 ]Otf (4) To An Et 2 O Solmentioning

confidence: 99%

Protecting-Group-Free Access to a Three-Coordinate Nickel(0) Tris-isocyanide

et al. 2011

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It is well established that the active intermediate in reactions mediated by nickel tetracarbonyl (Ni(CO) 4 ) is the three-coordinate complex Ni(CO) 3 . 1À4 This coordinatively unsaturated binary carbonyl is formed by CO dissociation from its fourcoordinate, 18-electron precursor and is active toward ligand association 1À4 and oxidative addition 5À7 reactions. While too reactive to be isolated or observed in the condensed phase, pioneering gas-phase and matrix-isolation studies by Turner, DeKock, and Burdett succeeded in photolytically synthesizing and fully characterizing Ni(CO) 3 . 8À10 Along with these experiments, early theoretical predictions based on molecular orbital and angular overlap methods corroborated the fact that d 10 Ni(CO) 3 adopts a trigonal-planar coordination geometry. 11À13 This geometry is similar to three-coordinate, Ni(0) trisphosphine complexes (i.e., Ni(PR 3 ) 3 ), which are long known 14 and have been isolated when encumbering phosphines are employed. 15,16 Despite sharing three-coordinate, trigonal-planar geometries, Ni(CO) 3 is electronically distinct from Ni(PR 3 ) 3 complexes. This is a result of the stabilization of Ni-based, π-symmetry orbitals (e 0 and e 00 in D 3h symmetry) by back-donation to the CO ligands. Accordingly, the HOMO of D 3h -symmetric Ni(CO) 3 is d z 2 (a 1 0 ) in parentage, rather than the degenerate e 0 set (x 2 À y 2 , xy), as is widely accepted for Ni(PR 3 ) 3 complexes (Figure 1). 17 Indeed, stabilization of both the e 0 and e 00 orbital sets by the cylindrically symmetric CO π* orbitals serves to energetically isolate the Ni d z 2 orbital in Ni(CO) 3 (Figure 1) and renders the complex isolobal to σ-type Lewis bases such as phosphines and amines. In this respect, Ni(CO) 3 is also differentiated from the "planar" form of trisethylene Ni(0) (Ni(C 2 H 4 ) 3 ), 18 which possesses only the in-plane, e 0 -symmetry π-back-bonding interaction. However, the weaker π-acidity of ethylene relative to CO does not allow for an e 0 orbital Figure 1. (top) Qualitative molecular orbital diagrams for the D 3h -symmetric NiL 3 complexes Ni(C 2 H 4 ) 3 (left), Ni(PMe 3 ) 3 (center), and Ni(CO) 3 (right), reflecting the effect of π-back-donation on the d-orbital splitting pattern. (bottom) DFT-calculated HOMO for Ni(CO) 3 (left) and Ni(CN Me) 3ABSTRACT: Details are presented regarding a convenient synthesis of the nickel trisisocyanide complex Ni(CNAr Dipp2 ) 3 (Ar Dipp2 = 2,6-(2,6-[i-Pr] 2 C 6 H 3 ) 2 C 6 H 3 ). A previous synthesis of a Ni tris-isocyanide complex relied on a Tl(I) coordination-site protection strategy to discourage the formation of a tetrakis-isocyano complex. However, protectinggroup-free access to Ni(CNAr Dipp2 ) 3 is enabled by the encumbering m-terphenyl isocyanide CNAr Dipp2 . Treatment of Ni(COD) 2 with CNAr Dipp2 affords Ni(COD)-(CNAr Dipp2 ) 2 , which is readily oxidized to NiI 2 (CNAr Dipp2 ) 2 upon addition of I 2 . Reduction of NiI 2 (CNAr Dipp2 ) 2 with Mg metal generates Ni(CNAr Dipp2 ) 3 and does not require the addition of a third equivalent of C...

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Preparation and identification of intermediate carbonyls of nickel and tantalum by matrix isolation

Cited by 207 publications

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Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N₂)_n (where n = 1–3)

Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N₂)_n (where n = 1–3)

Binary Dinitrogen Complexes of Rhodium, Rh(N₂)_n (where n = 1–4), in Low Temperature Matrices

Protecting-Group-Free Access to a Three-Coordinate Nickel(0) Tris-isocyanide

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Preparation and identification of intermediate carbonyls of nickel and tantalum by matrix isolation

Cited by 207 publications

References 0 publications

Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N2)n (where n = 1–3)

Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N2)n (where n = 1–3)

Binary Dinitrogen Complexes of Rhodium, Rh(N2)n (where n = 1–4), in Low Temperature Matrices

Protecting-Group-Free Access to a Three-Coordinate Nickel(0) Tris-isocyanide

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Product

Resources

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Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N₂)_n (where n = 1–3)

Binary Transition Metal Dinitrogen Complexes. Part II. Matrix Infrared and Raman Spectra, Structure, and Bonding of Pt(N₂)_n (where n = 1–3)

Binary Dinitrogen Complexes of Rhodium, Rh(N₂)_n (where n = 1–4), in Low Temperature Matrices