A ³¹P nmr spectroscopic study of complexation of tin(II) and lead(II) by some phosphines, phosphine oxides, and related ligands, with the ³¹P nuclear magnetic resonance spectra of two tetratertiary phosphine tetraoxides and the analogous tetra-sulfides and -selenides

Abstract

31P nmr has been used to show that, in MeNO2, M(SbF6)2 (M = Sn or Pb) forms 1:1 complexes with Ph2P(CH2)2PPh2, PhP[(CH2)2PPh2]2, MeC(CH2PPh2)3, [Formula: see text][Formula: see text]P[(CH2)2PPh2]3, and Ph2P[(CH2)2PPh]2(CH2)2PPh2. The phosphonium ligands are formed in situ. Spectra characteristics of slow inter- and intramolecular exchange were obtained in all cases except, perhaps, those involving the last two ligands, which may be involved in rapid intramolecular exchange. For the first five ligands, the maximum denticity is achieved and unambiguous one-bond M(II)—31P (M = 117/119Sn or 207Pb) coupling constants are reported and discussed. In the presence of M(SbF6)2 (M = Sn or Pb). PPh3 is protonated in MeNO2, while in acetone Sn(SbF6)2 forms a 1:1 complex with PPh3 which appears to be solvent-inserted, [Sn—O—CMe2PPh3]2+.Reduced temperature 31P nmr spectroscopy has allowed the detection of 1:2 and 1:3 (M:L) complexes of OPPh3, and 1:1 complexes of Ph2P(O)(CH2)2P(O)Ph2, PhP(O)[(CH2)2P(O)Ph2]2, and (O)P[(CH2)2P(O)Ph2]3, with both tin(II) and lead(II). The 1:1 complexes with polydentate ligands are isolable; nmr shows that the maximum denticity occurs except with the last ligand which behaves in a tridentate manner. Several two-bond M—O—P coupling constants have been obtained. Also, the changes which complexation produces in the P—P couplings are compared with changes produced in the analogous phosphine complexes.The synthesis and characterization of Ph2P(E)[(CH2)2P(E)Ph]2(CH2)2P(E)Ph2 (E = S or Se) and (Se)P[(CH2)2P(Se)Ph2]3 are reported. The 31P nmr spectra of these compounds are compared with those of the parent tetraphosphines and other members of the corresponding tetraoxide–tetrachalcogenide series.

Coordination chemistry of the main group elements with phosphine, arsine and stibine ligands

“…In situ 31 [311,312]. Although the data mostly indicated that three phosphine donors are bound to the tin, the interpretation is not unequivocal with P,N-coordination, but in solution the phosphine donor easily dissociates, with complex temperature dependent equilibria present [313].…”

Lead(ii) nitrate and hexafluorosilicate complexes with neutral diphosphine coordination

“…There is a significant high frequency shift in the 1 H NMR spectrum of this complex confirming that the phosphine is coordinated, while a sharp singlet at δ = 89.3 is observed in the 31 P{ 1 H} NMR spectrum. This is a very large, high frequency shift from 'free' Et 2 P(CH 2 ) 2 PEt 2 (δ = −18) whose magnitude is mirrored in the shifts seen by Dean et al 8 in their in situ NMR studies of phosphine complexes of Pb-(SbF 6 ) 2 . Upon cooling the solution to 223 K, 207 Pb satellites were observed, which sharpened upon further cooling to 193 K ( 1 J PPb = 2532 Hz).…”

“…7 Several 1 : 1 polydentate phosphine complexes of Pb(SbF 6 ) 2 have also been studied by in situ 31 P{ 1 H} and 207 Pb NMR spectroscopy in MeNO 2 , although no complexes were isolated. 8,9 One of the major challenges in synthesising lead(II) complexes with neutral diphosphine ligands is in finding a suitable lead precursor. Main group phosphine coordination chemistry has mostly been performed with metal halides, 5 but the insoluble and intractable nature of the lead dihalides precludes easy synthetic access to this area; instead lead(II) oxosalts such as acetate, nitrate or perchlorate are often used.…”

Self-assembly of [Sn(OPMe3)3(CF3SO3)2]6 metallocyclic Sn(ii) hexamer stacks with CF3-lined channel interiors

“…The 119 Sn NMR resonance for (1) occurs at −793 ppm, similar to the chemical shifts reported for Sn(II) phosphines and phosphine chalcogenides with SbF 6 − anions. 20 The formation of the [Sn(OPMe 3 ) 3 (CF 3 SO 3 ) 2 ] 6 metallocycle identified in this work was very unexpected and the weakly coordinating CF 3 SO 3 − linkers clearly play an important role in its assembly. Very recently Itoh and co-workers described a series of fluorous oligoamide nanorings with diameters ranging from 0.9-1.9 nm, which undergo supramolecular polymerisation in bilayer membranes forming nanochannels with a similar dense F-atom coverage of the interior walls as observed in our hexamer assemblies.…”