Heteroaromatic Substituted Phosphoranes with Enhanced Hemilabile Character

Abstract

New ligands with enhanced hemilabile character compared to iminophosphoranes known in the literature are presented. When diphenyl-2-picolylphosphane was oxidized with elemental sulfur or gray selenium, the new ligands Ph 2 P(S)(CH 2 Py) (1) and Ph 2 P(Se)(CH 2 Py) (2) were obtained. In addition, the calcium complex [(thf) 2 Ca{(PyCH)(Se)PPh 2 } 2 ] (3), based on 2, is presented. This is only the second example of a molecular structure displaying a direct calcium-selenium contact. A structural comparison of the parent ligands and the related motifs in the organometallic complex reveals the bonding to the central phosphorus atom to be mostly strengthened by electrostatic means rather than by any double bonding. The spectroscopic data of 3 show features similar to those of iminophosphoranes, despite small differences in electronegativity. All of the compounds presented are accessible in good yields and high purity. The DTA analysis of 3 points to possible CVD applications to form CaSe from the gas phase.

Chiral alkaline earth metal complexes with M–Se direct bond (M = Mg, Ca, Sr, Ba): syntheses, structures and ε-caprolactone polymerisation

“…6a. P1-Se1 2.1447 15, P1-N1 1.597(5), P1-C9 1.833(5), P1-C15 1.832 6, C1-N1 1.483 7, C1-C2 1.533(9), C1-C3 1.511(8), P2-Se2 2.1514 15, P2-N2 1.607(5), P2-C35 1.823 7, C21-N2 1.486 6, C21-C22 1.535(8), C21-C23 1.515(9), Ba1-Se1 3.3181(6), Ba1-N1 2.693(4), Ba1-O1 2.690(5), Ba1-O2 2.719(5), Ba1-Se2 3.3524(7), Ba1-N2 2.679(5), N1-P1-Se1 109.88 17, C1-N1-P1 120.0(4), C2-C1-N1 111.3(5), C9-P1-C15 103.1(2), N1-Ba1-Se1 60.56(10), O1-Ba1-O2 78.94 (19), N2-Ba1-Se2 60.19(9), N2-P2-Se2 109.23 18, C21-N2-P2 120.6(4), N1-Ba1-N2 103.52 15, Se1-Ba1-Se2 168.708 (19).…”

“…7a. P1-B1 1.915(5), P1-N1 1.638(3), P1-C9 1.817(3), P1-C15 1.818(4), C1-N1 1.466(4), C1-C2 1.531(5), C1-C3 1.530(4), B1-H1A 0.9600, B1-H1B 0.9600, B1-H1C 0.9600, N1-P1-B1 113.73 (19), C9-P1-C15 104.54(14), C9-P1-B1 110.97 (19), C15-P1-B1 112.8(2), C9-P1-N1 109.58 (16), C15-P1-N1 104.62 (16), P1-N1-C1 125.8(3), N1-C1-C2 109.3(3), N1-C1-C3 109.8(3), C2-C1-C3 114.3(3), H1A-B1-H1B 109.5.…”

Synthesis and structural characterization of alkaline–earth complexes containing a triazole-based selenide ligand

“…Nonetheless, an important development in the coordination chemistry of alkaline-earth metals is based on the use of bulky ligands, which provide increased solubility in organic solvents and reduce the tendency for oligomerization of the resulting complexes. During the last decade a small number of alkaline-earth selenium-based complexes have been reported and structurally characterized, among these are [Mg(SeMes ⁄ ) 2 (thf) 2 ] (Mes ⁄ = 2,4,6-t Bu 3 C 6 H 2 ) [4], [M(SeMes ⁄ ) 2 (thf) 4 ] (M = Ca, Sr, Ba) [5][6][7], [Ca{CH(py)(Se)PPh 2 } 2 (thf) 2 ] 2 (py = pyridine) [8], [{Ba (SeTrip) 2 (py) 3 (thf)} 2 ] (Trip = 2,4, 6-iPr 3 C 6 H 2 ) [6], [Ba(18C6)(SeTrip) 2 ] [6] and [Sr{SeSi(SiMe 3 ) 3 } 2 {(CH 2 ) 2 (NMe 2 ) 2 } 2 ] [9].…”

Unprecedented Calcium Metalla‐macrocycle Having Phosphinoselenoic Amide and Diphenylphosphinate in the Coordination Sphere

“…The most interesting feature is that the Ca–Se bond lengths [3.0259(6) Å and 3.0418(6) Å] are similar in range with those of complex 2 [3.0337(9) Å] and [Ca(THF) 2 ‐{Ph 2 P(Se)N(CHPh 2 )} 2 ] [2.989(8) Å] as we reported. Ca–Se bond lengths observed in complexes 2 and 3 also match with the reported Ca–Se values with 2.945(1) Å for [(THF) 2 Ca{(PyCH)(Se)PPh 2 } 2 ]16 and 2.9336(4) Å for [(THF) 4 Ca(SeMes') 2 ]17 in literature. Thus, complexes 2 and 3 are examples of compounds with direct calcium–selenium bond 15–17.…”