Anisotropy of the 1J(PSe) spin-spin coupling. X-ray and liquid crystal NMR study of trimethylphosphine selenide

Solid-state phosphorus-31 NMR and x-ray crystallographic studies of tertiary phosphines and their derivatives

“…The P-Se bond length of 2.108 (1) A is comparable to that reported for Me3PSe (2.111 (3) A). 29 We found that Cy3PSe crystallizes in the orthorhombic system and that the data could be successfully refined in the centrosymmetric space group Pnma with Z = 4. Without an available, sensitive, and unambiguous test for the absence of a center of inversion, such as second harmonic generation, we have reported the data in the centrosymmetric space group.…”

Multinuclear NMR Study of HFeCo3(CO)9[P(OCH3)3]3 in the Solid State and in Solution

“…Therefore, assuming that the difference between the calculated D IS and experimental | D ‘ IS | values is entirely due to the J coupling anisotropy, we get for sites 1 and 2 (Table ) (i) Δ J (1) = 522 ± 75 Hz, Δ J (2) = 1158 ± 138 Hz if J iso , D ‘ IS > 0 and (ii) Δ J (1) = 6228 ± 75 Hz, Δ J (2) = 5592 ± 138 Hz if J iso , D ‘ IS < 0. There are only a few reliable data on the anisotropy of indirect spin−spin coupling tensors in the literature. − However, it may be remarked that the relative anisotropy |Δ J / J iso | has always been observed to be smaller than ∼1. Hence, considering also the fact that the sign of J iso = 1 J ( 31 P− 59 Co) is expected to be positive from double-resonance solution-state data, we may infer that (i) is the most probable solution, i.e., Δ J (1)/ J iso ≈ 0.6 and Δ J (2)/ J iso ≈ 1.4.…”

“…There are only a few reliable data on the anisotropy of indirect spin-spin coupling tensors in the literature. [50][51][52][53] However, it may be remarked that the relative anisotropy |∆J/ J iso | has always been observed to be smaller than ∼1. Hence, considering also the fact that the sign of J iso ) 1 J( 31 P- 59 Co) is expected to be positive from double-resonance solution-state data, 54 we may infer that (i) is the most probable solution, i.e., ∆J(1)/J iso ≈ 0.6 and ∆J(2)/J iso ≈ 1.4.…”

31P solid state nuclear magnetic resonance principal values of the chemical shift tensors of phosphane oxides, phosphane sulphides and phosphane selenides

“…The Slater atomic orbital exponents are taken from [27] for all the atoms except hydrogen for which a value of 1-2 is used. The molecular geometry comes from microwave (P(CH3) 3 [28]), electron diffraction (O=P(CH3)3, S=P(CH3) 3 [29]) and X-ray diffraction (Se=P(CH~) 3 [42]). For Te=P(CH3)3, as there is no structural data available, the Te-P bond length is taken from [30] with a standard C-P bond length of 1.786 A.…”