Crystal and molecular structure of tricyclohexylphosphineethylidenenickel tricarbonyl: a reaction product of Ni(CO)4 and (C6H11)3P=(CH)CH3

The structure of tricyclohexylphosphineethylidenenickel tricarbonyl, (C₆H₁₁)₃P(CH)CH₃.Ni(CO)₃, has been determined by direct methods from 5858 automatic diffractometer data, and refined anisotropically to a finalR value of 0·094 (including hydrogen atoms). The crystals are monoclinic, space group P2₁/n, with a=10·670(1), b=13·879(2), c=16·222(2) Å, =91·80(1)° and z=4. The main feature of the structure determination is the confirmation of the predicted arrangement of the ligand with its bonding to nickel via the secondary carbon of ylid-ligand. This carbon and the nickel atoms show approximate tetrahedral geometry. There seems to be no direct interaction between phosphorus and nickel (closest approach distance is 3·30 Å). The nickel-carbon distance (2·10 Å) is longer than any other Ni-C(sp³) distance previously reported.No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of Plenum Publishing Company Limited.National Lending Library Supplementary Publication No. 60056 contains 29 pages of structure factor tables on 1 microfiche.