Tantalum chloride species incorporating anionic and cationic guanidine components

Soria, Delia Beatriz; Grundy, Joanna; Coles, Martyn P.; Hitchcock, Peter B.

doi:10.1016/s0277-5387(03)00364-4

Cited by 15 publications

(13 citation statements)

References 29 publications

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“…The C–N bond lengths within the core are equivalent (within 3 σ ), indicating effective delocalization of the positive charge. Similar hydrogen bonding between [hppH 2 ] + and metal halide anions have been recorded for [CuCl 4 ] 2–[27] and [TaCl 6 ] – 28…”

Section: Resultssupporting

confidence: 70%

Neutral and Anionic Antimony(III) Species Supported by a Bicyclic Guanidinate

2012

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Bicyclic guanidine 1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidine (hppH) was investigated as a source of anionic or neutral ligand at antimony. Reaction of the in situ generated lithium guanidinate with SbCl3 in a 1:1 or 2:1 ratio forms the expected metathesis products Sb(hpp)nCl3–n (1, n = 1; 2, n = 2). The molecular structures of 1 and 2 were determined by X‐ray diffraction, which shows chelating guanidinates and suggests the presence of a stereochemically active lone pair of electrons. The reaction of two equivalents of the neutral guanidine hppH with SbCl3 proceeds via proton transfer between the hpp fragments, affording the ion pair [hppH2][Sb(hpp)Cl3] (3), where [Sb(hpp)Cl3]– is an unusual example of a monometallic antimonate(III) anion. The molecular structure of 3 shows hydrogen bonding between two of the chlorides and the NH functionalities of the guanidinium cation.

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Section: Resultssupporting

confidence: 70%

Neutral and Anionic Antimony(III) Species Supported by a Bicyclic Guanidinate

2012

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“…Research in our laboratory has been concerned with the synthesis of a number of transition metal complexes incorporating neutral guanidines, R 2 NC{NRЈ}{NHRЈ}, and their corresponding anions, [R 2 NC{NRЈ} 2 ] Ϫ , as N-based ligands. [2][3][4][5] Whilst application of the latter class of negatively charged guanidinates has become more widespread in coordination chemistry, the use of the former as neutral donors has not, to date, received similar attention. 6 We have previously found, however, that the combination of a donor-imine functionality and an NH group within the bicyclic guanidine 1,3,4,6,7,8hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH, Fig.…”

Section: Introductionmentioning

confidence: 99%

Structural diversity in the coordination of amidines and guanidines to monovalent metal halides

et al. 2004

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A series of structurally characterised, monovalent metal-halide complexes incorporating neutral amidine and guanidine ligands is reported. N,N'-diphenylbenzamidine reacted with copper(I) chloride to afford the bis-ligand complex [CuCl(PhC[NPh][NHPh])2]2 (1), that exists as a chlorine bridged dimer in the solid state, with a non-symmetrical distribution of NH...Cl interactions within the 'Cu2Cl2' metallacycle. In contrast, only one equivalent of the guanidine, Me2NC[NiPr][NHiPr] (2), is coordinated in the copper(I) iodide complex [CuI(Me2NC[NiPr][NHiPr])]2 (3), which was also isolated as the dimer with bridging halide atoms. The molecular structure of the bicyclic guanidine, 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-alpha]pyrimidine (hppH), is reported, revealing a hydrogen bridged dimer with extensive delocalisation throughout the ligand framework. Coordination of hppH to lithium chloride afforded the dimeric bis-ligand complex [LiCl(hppH)2]2 (4) in which each hppH molecule interacts with a different chlorine atom of the central 'Li2Cl2' core of the molecule via NH...Cl hydrogen bonding. In contrast the 2:1 ligand to metal complex is formed with silver(I) chloride to afford AgCl(hppH)2 (5), a unique example of a monomeric, three-coordinate silver chloride supported by nitrogen-based ligands. The series of mixed ligand complexes [CuX(hppH)(PPh3)]n (6, X = Cl, n= 1; 7, X = Br, n= 2; 8 X = I, n= 2) have also been synthesised and structurally characterised, allowing comparisons of the relative coordinating behaviour of hppH and PPh3 as neutral donors at copper(I) centres to be made.

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“…Compound 1 consists of a distorted octahedral niobium centre, with the smallest angle [64.11 (14)°] corresponding to the bite angle of the chelating ligand within the four-membered metallacycle. Of particular note is the large Cl-Nb-Cl angle located in the ligand plane [122.42(5)°] which is $35°more obtuse than the remaining intramolecular chloride angles [range 85.57(4)-86.39(5)°].…”

Section: Resultsmentioning

confidence: 99%

“…A number of different product have been isolated in addition to the target molecules, including compounds with the dianionic ligand, [(RN@)C(NR) 2 ] 2À and those containing the imido group, [NR] 2À . In an earlier study in our laboratory we sought to utilise [hpp] À in the stabilisation of high oxidation-state tantalum complexes [14]. However, rather than forming the expected molecular species Ta(hpp) n Cl 5 À n , the ionic species [Ta(hpp) 4 ][TaCl 6 ] was isolated, containing the previously reported eight-coordinate cation, [Ta(hpp) 4 ] + [15].…”

Section: Introductionmentioning

confidence: 99%