Coupling constants in cis‐phosphine platinum complexes containing chalcogen‐nitride anions

Abstract

The 31P NMR spectra of complexes of the type Pt(SeSN2)(PR3)2 and Pt(Se2N2)(PR3)2 display trans 2J(77Se-31P) couplings of ca. 30-80 Hz, with no corresponding cis coupling; in contrast Pt(TeSN2)(PMe2Ph)2 has both trans and cis 2J(125Te-31P) couplings of 146 Hz and 103 H z respectively. The 31P spectra of the complexes Pt(S215N2)(PMe2Ph)2 and [Pt(S215N2)Cl(PMe2Ph)lshow both 2J-and 4J{1sN-31P} couplings, which alter substantially upon protonation of the SZNz2-ligand. The I5N NMR spectra of Pt(S215N2H)Cl(PMe2Ph) and Pt(S315N)Cl(PMe2Ph) show the presence of both 3JP-15N and J95Pt-15N couplings but no significant "N--l5N interactions.

Selective Cleavage by Acids of One Metal–Carbon σ‐Bond of a Bis(ortho‐platinated) Triarylphosphane: A 31P NMR trans‐Influence Series Based on the Unit Pt(κ2‐C6H3‐5‐Me‐2‐PPh2)(PPh2‐4‐tol)

“…[52] The selenocyanato complex cis-[Pt(CNSe)(κ 2 -C 6 H 3 -5-Me-2-PPh 2 )(PPh 2 -4-tol)] (15) could not be isolated in a pure state because of its ready decomposition to the cyanido complex 11, among other unidentified products. The 31 P NMR spectrum of 15 shows a pair of sharp doublets at δ = 19.2 and -68.8 ppm, the latter displaying an additional coupling of 82.2 Hz that is typical of 2 J( 77 Se-31 P); [55,56] this observation is consistent with the presence of SeCN. Thus, for the three complexes containing XCN as ligands, only the N-bound species is present when X = O, only the Xbound species is present when X = Se, and both isomers are formed when X = S. The trend is consistent with expectations based on the hard/soft acid/base theory.…”

The Preparation and Structure of [Pt(S2N2){P(OR)nR′3–n}2] and [Pt(SeSN2)­{P(OMe)nPh3–n}2] (n = 0–3)

“…1070 cm -1 was slightly lower than expected (1059 cm -1 Figure 2 for labelling and Figure 3 for a typical spectrum) with 2 J P,P couplings together with satellites due to 1 J Pt-P couplings. 7-10 also exhibit 2 J P-Se(trans) couplings [26] though 2 J P-Se(cis) couplings were not observed. These couplings en- 2-complexes has been previously reported, [2] with 1 J cation as to the trans-influence [27,28] of the chalcogen-nitrogen fragments.…”

“…No cis-selenium satellites were observed and given the small magnitudes of previously reported 2 J P-Se(cis) values this is understandable . [26] The structures of the [S 2 N 2 ] 2-complexes 1 and 3-6 (Table 3, Figures 6 and 7) exhibit square-planar geometry about platinum. The Pt-P distances (Table 3, Figure 8) lie in the range 2.217(3) Å and 2.256(2) Å.…”

Synthetic Applications of (Me3SiNSN)2E (E = S, Se) in Chalcogen-Nitrogen Chemistry: Formation and Structural Characterization of Cl2TeESN2(E = S, Se) and [PPh4]2[Pd2(μ-Se2N2S)X4] (X = Cl, Br)

“…Since then, however, several examples of systems containing combinations of chalcogens have been reported. In general, all such complexes are based on one fundamental unit, namely, a five-membered metallacycle containing the [S 3 N]or [S 2 N 2 ] 2ligands (or the protonated analogue of the latter, i.e., [ 20 and [TeSN 2 ] 2-21 together with the protonated forms of the latter three are all known (Scheme 1a).…”

“…In general, all such complexes are based on one fundamental unit, namely, a five-membered metallacycle containing the [S 3 N] - or [S 2 N 2 ] 2- ligands (or the protonated analogue of the latter, i.e., [S 2 N 2 H] - ). Complexes of [Se 3 N] - , [Se 2 N 2 ] 2- , [SeSN 2 ] 2- , and [TeSN 2 ] − together with the protonated forms of the latter three are all known (Scheme a).

1

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