FRANKFURT (Reuters) – BASF said it has given up efforts to separately list its oil and gas business Wintershall Dea via an initial public offering (IPO) for now due to the joint-venture’s exposure in Russia. “We want to list the company on the stock exchange. Wintershall Dea has interests in production facilities in Russia. This makes an IPO difficult at this time,” Chief Executive Martin Brudermueller said in a speech to shareholders at the chemical group’s annual general meeting. There was no change to the decision in principle to withdraw from the oil and gas business, he added. The speech …