The syntheses and crystal structure detns. of cis-PtL(NCS)2 (L = 1,2-bis(diisopropylphosphino)ethane) and cis-PtL1(NCS)(SCN) (L1 = 1,2-bis(diethylphosphino)ethane) are reported. cis-Pt(L)(NCS)2 is monoclinic space group Cc, a 12.279(6), b 9.330(8), c 20.102(7) ? b 108.90(9)? R = 0.0419, Rw = 0.0406. cis-Pt(L1)(NCS)(SCN) is monoclinic, space group P21/n, a 7.296(5), b 14.343(4), c 18.042(4) ? b 95.72(8)? R = Rw = 0.0564. The NCS coordination changes from N,S bonded form for L1 to N,N bonded for L. This linkage isomerization is explained in terms of steric effects.

Key words: CRYSTAL STRUCTURE DETERMINATION, MOLECULAR STRUCTURE, CIS-FORM, ORGANO PHOSPHORUS COMPOUNDS, ACETONE, PLATINUM COMPLEX, ACID RADICAL, THIOCYANIC ACID, ISOTHIOCYANIC ACID, BONDED