Bis(borane)-cyclenphosphorane: a stable adduct in which two phosphorus(V)-bonded nitrogen atoms display donor character

Dupart, J. M.; Pace, Simonne C.; Riess, Jean G.

doi:10.1021/ja00342a067

Cited by 19 publications

(6 citation statements)

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“…When for example the frequency of the v(C0) vibrations of M(CO),L adducts are measured-a commonly used approach to probe the a-accepting ability of a ligand L-one observes that these frequencies are significantly higher than L = 1 than with related but acyclic phosphorus ligands reputed to be strongly Ir-acid (Scheme 17). [22][23][24][25][26][27][28]29 This again is in line with the p,-d, rationale: the overlap of the orbitals concerned being expected to be less effective when nitrogen is pyramidal, the a-acid character of the phosphorus with respect to the metal should be enhanced; but the strain imposed on the angles at phosphorus is also expected to influence this character.…”

Section: Effects Of the Nitrogen Atom On The Donor Character Of The Psupporting

confidence: 57%

About the Coordination Chemistry of the Phosphorus-Nitrogen Entity

Riess

1986

Phosphorous and Sulfur and the Related Elements

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Triply coordinated trivalent nitrogen atoms are known to lose most or all of their Lewis donor capacity when bonded to a third or higher row element. It is shown here, in the case of P-bonded nitrogen atoms, that structural constraints which maintain the nitrogen atom in a pyramidal configuration can contribute much in preserving their basicity and/or nucleophilic character. In particular, nitrogen atoms apically bonded to 5-coordinated formally penta-or trivalent phosphorus atoms can display definite basicity. Examples of metal-and base-induced opening and closing of P-N bonds are also presented. The following unusual coordination modes and/or reaction issues are exemplified:where A can be-depending on the case-H+,CH~,BH,,BF, or a transition metal moiety, as for example CpMo(CO),CI or CpMo(CO),, etc. The factors that affect the rather variable P-N bond length are discussed.

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Section: Effects Of the Nitrogen Atom On The Donor Character Of The Psupporting

confidence: 57%

About the Coordination Chemistry of the Phosphorus-Nitrogen Entity

Riess

1986

Phosphorous and Sulfur and the Related Elements

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“…Crystals of C8H23B2N4P ( , = 227.9) were found to be orthorhombic, with cell dimensions a = 6.217 (2) Á, b = 12.557 (4) Á, and c = 16.519 (6) Á and V = 1289.6 Á3. The space group is P2{2{1\ with Z = 4 and a calculated density of 1.17 g-cnT3.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and molecular and crystal structure of bis(borane)cyclenphosphorane. First stable compound with a bipyramidally surrounded element having two quaternized apical nitrogen atoms

Dupart¹,

Borgne²,

Pace³

et al. 1985

J. Am. Chem. Soc.

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Cyclenphosphorane reacts with diborane at 0 °C to afford bis(borane)cyclenphosphorane, (C8H17N4P)(BH3)2 (2), in close to quantitative yield. No evidence for the formation of an adduct of the open-form tautomer, as from cyclamphosphorane, was found. 2 provides the first example of a stable H3B-N-P-N-BH3 sequence (dec 200 °C). It crystallizes in the orthorhombic space group P2{2{2X with a = 6.217 (2) Á, b = 12.557 (4) Á, c = 16.519 (6) Á, and Z = 4. The arrangement of the five bonds around phosphorus is close to that of a regular trigonal bipyramid (displaced 10.4% from the idealized trigonal bipyramid toward the square pyramid). Both BH3 groups are coordinated to apical nitrogen atoms, but the B-N bonds do not lie in the same plane, which implies a slightly helical distortion of the molecule. The apical P-N bonds (1.872 (5), 1.864 (5) Á) are the longest reported for a phosphorane, and it is proposed that each of them is a single apical P(V)-N(III) bond. Among the derivatives of cyclenphosphorane whose structure is known, 2 also has the shortest equatorial P-N bonds (1.645 (5), 1.654

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“…3•5 The harder BF3 is more inclined to coordinate at nitrogen, and N-bonded BF3 adducts have indeed been reported to form with F2PNMe26 and FPN(Me)(CH2)2NMe.7 The recent obtainment of a stable adduct in which two borane groups are coordinated to two nitrogen atoms occupying apical positions on a five-coordinated bipyramidal phosphorus atom must also be mentioned. 8 The bicyclic aminophosphanes 1-39 are attractive because their bicyclic structure forces the P-bonded nitrogen atom to remain pyramidal; 1 is obtained as a mixture of meso and racemic f Université de Nice.…”

Section: Introductionmentioning

confidence: 99%

“…IR v(P)B_H(asym) 2395(vs), cm"1; v(P)B_H(sym) 2330(w) cm"1; V(N)B-H(asym) 2460 (vs) cm"1; "(N)B-H(sym) 2280 (s) cm"1. Mass spectrum (15 eV, 150 °C): = C6H18B2N02P; m/e (relative intensity) 346 (8) [2 M -CH3], 190 (8) [MH], 175 (11) [M -CH3], 160 (100) [C6H12NG2P], 117 (28) The borane adducts are stable for several months in the solid state. They are generally slightly soluble in toluene, more soluble in chloroform, dichloromethane, or acetonitrile; the solubility increases with the number of methyl groups present on the cyclic frame.…”

Section: Introductionmentioning

confidence: 99%