Diphosphaborane and Metalladiphosphaborane: Ligands for Transition‐Metal Chemistry

Phosphorus as Lone Pair Donor and Ligand Acceptor: A Paddlewheel with Ru←P Axis

“…Hence, in the coordination sphere of one TM atom phosphorus becomes tetracoordinate, whereas examples of pentacoordinate phosphorus in a TM coordination sphere are rather scarce, [2] and examples of TM complexes with hexacoordinate phosphorus (which is not incorporated in a boron cluster [3] and bonded to a single TM) are unknown so far. Nonetheless, phosphorus(V) can easily attain hexacoordination {e.g., in [P(1,2-O 2 C 6 H 4 ) 3 ] -, [4a] [P(acac)(CF 3 ) 3 F] - [4b] }, and electron-rich TMs (d 8 , d 10 ) proved capable of forming complexes with Lewis acidic main group metals or metalloids with the TM acting as σ-donor and the main group element as σ-acceptor, a so-called Z-type [1] ligand site (Au→Sb, [5a] Ni→Sb, [5b] Pd→Si, [5c] Pd→Sn, [5d] Ni→Al, [5e] Ru→B;…”

Phosphorus as a heteroatom in metallaborane structures: Cyclopentadienylcobalt diphosphaboranes

“…Thus the phosphorus atom functions as a ''carbon copy'' in this metallaborane system. In addition the diphosphaborane P 2 B 10 H 10 can use one of its phosphorus lone pairs to function as a monohapto Lewis base ligand in the cobalt hydride HCo(g 1 -P 2 B 10 H 10 ) 2 (PEt 3 ) 2 [12]. Deltahedral diphosphaboranes having fewer than 12 vertices do not appear to have been synthesized.…”

The presence of cobaltdibismuth triangular faces in the lowest energy deltahedral cobaltadibismaborane polyhedra: Major differences from their cobaltadiphosphaborane analogues

“…The icosahedral diphosphaborane P 2 B 10 H 10 was first synthesized in relatively low yield by Todd and co-workers in 1989 [11] and much later in better yield by Welch and co-workers [12]. An isomer of the cobalt complex CpCoP 2 B 9 H 9 has been synthesized from P 2 B 10 H 10 and structurally characterized by X-ray crystallography [13]. Nonicosahedral diphosphaboranes or their metal complexes do not appear to have been synthesized.…”

“…This leads, for example, to complexes such as HCo(h 1 -P 2 B 10 H 10 ) 2 (PEt 3 ) 2 [13] in which phosphorus lone pairs in two P 2 B 10 H 10 ligands are coordinated to an exopolyhedral cobalt atom to give an HCoL 4 derivative related to the long-known HCo(CO) 4 . In order to suppress any effects of potentially basic lone pairs in Group 15 polyhedral vertex atoms, we have now studied the cobaltadibismaboranes CpCoBi 2 B ne3 H ne3 corresponding to the previously studied cobaltadiphosphaboranes CpCoP 2 B ne3 H ne3 (n ¼ 10, 11, and 12).…”