Coordination chemistry of P-rich phosphanes and silylphosphanes. XXVI - Formation and structure of [(cyclo-P-4((PBu2)-Bu-t)(4)}{Ni(CO)(2)}(2)]

[{cyclo-P-4((PBu2)-Bu-t)(4)}{Ni(CO)(2)}(2)] is formed by reaction of the cy clotetraphosphane P-4((PBu2)-Bu-t)(4) with [Ni(CO)(4)]. Each Ni(CO)2 unit i s coordinated by two adjacent tBu(2)P groups forming two five-membered P4Ni rings above and below the planar cyclotetraphosphane ring, respectively. T he compound crystallizes in the triclinic space group P (1) over bar (No. 2 ) with a = 893.29(5), b = 1140.75(7), c =1235.52(8) pm, alpha = 109.179(7), beta = 100.066(7), gamma = 97.595(7)degrees and Z = 1.