SYNTHESIS OF NOVEL DONOR-ACCEPTOR MANGANESE(I) COMPLEXES OF FERROCENYLACETYLENE - CRYSTAL-STRUCTURE OF [(C-5H-5)FE(C-5H-4) C-EQUIVALENT-TO-CMN(CO)(3)(PH2PCH(ME)CH2PPH2)] WHICH HAS POTENTIAL FOR 2ND-ORDER NONLINEAR OPTICS - COLBERT, MCB; EDWARDS, AJ; LEWIS, J; LONG, NJ; PAGE, NA; PARKER, DG; RAITHBY, PR (JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1994)