Crystal structure of 1,3-bis[seleno(phenyl)-μ5-phospha]-3-selena-4,5-[1,2- dicarba-closo-dodecaborano(12)]-cyclopentane, Se[P(C6H5)Se]2(C2B10H10)

Abstract

Source of materialThe reaction of the 1,2-diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion [1,2-(1,2-C 2B10H10)Se2] 2 as the dilithio derivative with dichlorophenylphosphane in diethylether at 78°C and warming to ambient temperature affords the expected 1,3,2-diselanaphospha-cyclopentane as the major product [1] along with a small amount of another less soluble crystalline material. This was isolated and identified by X-ray structure analysis as the title compound. DiscussionThe first type of 1,3-bis(phenyl-phospha)-1,2-dicarba-closo-dodecaborane(12)-cyclopentane, a sulfur derivative, has been introduced recently [2]. We described here the molecular structure of the analogous selenium species. For the five-membered C1P1Se2P2C2 ring a deviation from plane of 0.105 Å was observed. The sum of the angles (ÐC1P1 Se2 = 100.3°, ÐP1Se2P2 = 98.5°, ÐC2P2Se2 = 101.9°, ÐC1 C2P2 = 117.1°, ÐC2C1P1 = 118.9°) is 536.7°. Both phenyl rings of the phosphorous atoms are twisted with regard to the C1P1Se2P2C2 ring with dihedral angles of 77.7°and 79.6°. A transoid arrangement of the Se1 and Se3 is observed with respect to the phosphorous atoms with P2=Se1 and P1=Se3 distances of 2.082 Å and 2.070 Å, respectively. The phosphorous centers show pseudo tetrahedral coordination environments. The C1C2 distance in the carborane unit (1.669 Å) is found in the expected range.

Exploiting the Ring Strain of Diphosphetanes: A Synthetic and Computational Approach towards 1,2,5‐Selenadiphospholanes

“…Both compounds show an envelope conformation of the C 2 P 2 Se ring and a trigonal‐pyramidal geometry around the phosphorus atoms (Figure ). The C cluster −C cluster bond length as well as the bond angles around the phosphorus atoms in both compounds have similar values to those found in diphospholane diselenide III and are comparable to previously published carborane‐substituted bisphosphanes ,,. The P−Se and P=Se bond lengths as well as the P−Se−P angles observed in both compounds are within the range of published values for diphospholane diselenides Ia , Ib and III , as well as the open‐chain diphosphaselenanes VI .…”

“…The C cluster −C cluster bond length as well as the bond angles around the phosphorus atoms in both compounds have similar values to those found in diphospholane diselenide III and are comparable to previously published carborane‐substituted bisphosphanes ,,. The P−Se and P=Se bond lengths as well as the P−Se−P angles observed in both compounds are within the range of published values for diphospholane diselenides Ia , Ib and III , as well as the open‐chain diphosphaselenanes VI . Furthermore, the envelope geometry of the C 2 P 2 Se rings is stabilised by several intramolecular C−H⋅⋅⋅Se interactions with H⋅⋅⋅Se distances ( 2‐ meso : 2.89–3.01 Å, 4‐ meso : 2.82–2.93 Å, Figure ) being well within the sum of the van der Waals radii (3.00 Å) .…”

“…Especially ring‐opening reactions could open up new synthetic pathways towards functionalised bisphosphanes which could be useful ligands in homogeneous catalysis . However, to the best of our knowledge, such compounds have not been reported in the literature and only a few derivatives are known (Scheme 1, I–III ) – . Ia , b were synthesised by reacting Woollins reagent with dienes, II was obtained by treatment of dppe with a Se II source and III was isolated as a side product in the reaction between ortho ‐carborane‐1,2‐bis(selenoate) and dichlorophenylphosphine .…”

“…However, to the best of our knowledge, such compounds have not been reported in the literature and only a few derivatives are known (Scheme 1, I–III ) – . Ia , b were synthesised by reacting Woollins reagent with dienes, II was obtained by treatment of dppe with a Se II source and III was isolated as a side product in the reaction between ortho ‐carborane‐1,2‐bis(selenoate) and dichlorophenylphosphine . In contrast, the open‐chain analogues of selenadiphospholanes, diphosphaselenanes VI , are readily accessible by treatment of chlorophosphanes IV with sodium selenide or reaction of elemental selenium with diphosphanes V bearing bulky substituents (Scheme ) –.…”